Fish Hatchery Management - fisheries & aquaculture

FishHatcheryManagement

Fifth printing. 1992IStsN 0 9t3235-01 2This publication has been reprinted bg the American Fisheries Societg in cooperatinn@ith thc Flsh andWil.dlife Sen:ice but at rw erperce to the (J .5. Coaernment.Tradc and companv n4ntes nrcntiarcd in this publicatian are for informatiorulpurposes onlg. lt does rutt implg u.s. Goaernment endnrsement of the produa. Alluses of frshery compounds must be registered bg approprbte state andlor Fed.eralagencies. Onlg thase uses described on the lnbel are perrnitted and onlg at th.e ratesl*ted.

FishHatcheryManagementRobert G. PiperIvan B. McElwainLeo E. OrmeJoseph P. McCrarenLaurie G. FowlerJohn R. LeonardSpecial AduisorsArden J. TrandahlVicky AdrianceUnited States Department of the InteriorFish and Wildlife ServiceWashington, D. C.I 982

J. T. Bowen Jack BessThls publlcation is dedicated toJ. T. BowenJack Besswhose initial efforts and dedicationinspired us all to accomplish the task.

ContentsPreface xaAbbreviations Used in the 'Iext xixCommon and Scientific Names of F'ish Species Cited in the Textxxi1: Hatchery RequirementsWater Quality 3Temperature 3Dissolved Gases 4Oxygen 5NitrogenBCarbon Dioxidc 9Toxic Gases 10Dissolved Gas Criteria 10Suspended and Dissolved Solids 1 0Suspended Solids I 0Acidity 1 IAlkalinity and HardnessTotal Dissolved Solids 1 2'foxic Materials 12I IHeavy MetalsSalinity 13Turbidity 14l3

ViFISH HATCHERY MANAGI,MEN'fPesticides 7 5Water Supply and Treatment 16Treatment of Incoming Water 16Temperature Control 1 6Aeration 1 7Sterilization 1 7Treatment of Water for ReuseAmmonia Toxicity 20Biological Removal of Ammonia 21Ion Exchange Removal of Ammonia 22Other Ammonia Removal Techniques 23Estimation of Ammonia 24Treatment of Effluent Water and Sludge 25Hatchery Pollutants 26Sedimentation Basins 27Solid Waste Disposal 30Hatchery Design 32Buildings 33Egg Incubation 39Rearing Facilities 40Circular Rearing Units 40Swedish Pond 43Rectangular Tanks and Raceways 43Rectangular Circulation Rearing Pond 46Earthen Ponds 47Cage Culture 48Pen Rearing 50Selection of Rearing Facilities 50Biological Design Criteria 51Application of Biological Criteria 54Bibliography 551 I2: Hatchery OperationsProduction Methods 60Length-Weight Relationships 60Growth Rate 61Growth at Variable Water Temperatures 62Carrying Capacity 63Flow Index 67Density Index 7lWarmwater Fish Rearing Densities 75Largemouth Bass 75

CONTENTSViiBluegill 76Channel Catfish 76High-Density Catfish Culture 77Striped Bass 77Northern Pike and Walleye 77Inventory Methods 78Intensive Culture 79Extensive Culture 87Fish Grading 83Fish Handling and Harvesting 84Rearing Unit Management BBSanitation 88Water Supply Structures 90Screens 91Pond Management 91Preseason PreparationWild-Fish Control 939lFertilization Procedures 94Organic Fertilizers 97Inorganic Fertilizers 98CombiningFertilizers 101Aquatic Vegetation Control | 02Special Problems in Pond Culture 105Dissolved Oxygen 105Acidity 110Turbidity1l2Hydrogen Sulfide 112Water Loss1 l3Problem Organisms 113Recordkeeping 714Factors to be Considered 7 | 4Production Summary 116Lot History Production Charts 117Definitions 118Instructions1 I BTotals and Averages 122Hatchery Production Summary 122Definitions 122Instructions | 23Totals and Averages 124Warmwater Pond Records 126Bibliography 126

I'ISH HA'|CHERY MANAGEMEN't3: Broodstock, Spawning, and Egg HandlingBroodstockManagement 131Aquisition of Broodstock 132Care and Feeding of Broodfish 132Forage Fish 1 40White Sucker 140Fathead Minnow 141Goldfish 142Golden Shiner 143Tilapia 144Improvement of Broodstocks 144Selective Breeding 144HybridizationandCrossbreeding 148Spawning 149Natural Spawning Method 149Salmonid Fishes 150Warmwater Fishes 150Artificial Spawning Method 156FactorsAffectingFertilization 167Gamete Storage 168Anesthetics 1 69Artificial Control of Spawning Time 170Photoperiod 7 70Hormone Injection 1 71Egg Incubation and Handling 173Egg Development 174Sensitive Stage 1 75Eyed Stage 1 75Enumeration and Sorting of Eggs 175Egg Disinfection 189Incubation PeriodI B9Factors Affecting Egg Development 190Light 190Temperature 191Oxygen 192Transportation of Eggs 1 93Types of Incubators 1 93Hatching Trays 193Clark-Williamson Trough 194Catfish Troughs 195Hatching Baskets 1 95Hatching Jars 195

coNTEN't SlxMontana Hatching Box | 96Vertical-Traylncubators 197Simulated Natural Conditions and Rearine Pond Incubation 199Bibliography 2004: Nutrition and FeedingNutrition 208Factors Influencing Nutritional Requirements 210Water Temperature 210Species, Body Size, and Age 211PhysiologicalChanges 211Other Environmental Factors 2l2Digestion and Absorption of Nutrients 212Oxygen and Water Requirements 2l3ProteinRequirements 214Protein in Salmonid Feeds 215Protein in Catfish Feeds 216Protein in Coolwater Fish Feeds 217Carbohydrate Requirements 21 7Carbohydrates in Salmonid Feeds 218Carbohydrates in Catfish Feeds 21 ILipid Requirements 220Lipid Requirements for Salmonids 227Lipid Requirements for Catfish 224Energy Requirements 224Energy Requirements for Salmonids 225Energy Requirements for Catfish 226Vitamin Requirements 227Mineral Requirements 229Nonnutritive Factors 231Fiber 231Pigment-ProducingFactors 232Antioxidants 232Materials Affecting Fish Quality and Flavor 232Organic Toxicants in Feeds 233Sources of Feeds 233Natural Foods 233Formulated Feeds 234Feed Manufacturing 234Open- and Closed-Formulated Feeds 235Handling and Storing Procedures 236Feed Evaluation 238

XFISH TIA'fCHERY MANACF]MI]N I'Feeding 238Feeding Guides for Salmonids 239Feeding Guides for Coolwater Fishes 248Feeding Guides for Warmwater Fishes 249Catfish 249Largemouth and Smallmouth Bass 252Striped Bass 254Time of Initial Feeding 254Feeding Frequency 255Feed Sizes 257Feeding Methods 259Bibliography 2605: Fish Health ManagementDisease Characteristics 264Disease-Causing Organisms 264Disease Recognition 264Stress and Its Relationship to Disease 265Disease Treatment 266Treatment Methods 268Dip Treatment 270Prolonged Bath 271Indefinite Bath 271Flush Treatment 272Constant-Flow Treatment 272Feeding and Injection 273General Information on Chemicals 274Chemicals and Their Uses 275Salt Baths and Dips 275Formalin 275Copper Sulfate 276PotassiumPermanganate(KMnO1) 277QuaternaryAmmoniumCompounds 278Terramycin* 279Nitrofurans 280Sulfonamides 2BlAcriflavine 28lCalcium Hydroxide 282Iodophores 282Di-n-Butyl Tin Oxide 282Masoten@ 282Equipment Decontamination 283Facility Decontamination 284

CONI'ENI'SElimination of Fish 284Preliminary OPerations 284Decontamination 285Maintenance of the HatcherY 285Defense Mechanisms of Fishes 286Immunization of Fishes 288Vaccination Methods28Bl'ish Disease Policies and RegulationsDiseases of Fish 294Viral Diseases 2942BgInfectious Pancreatic Necrosis (IPN) 294Viral Hemorrhagic Septicemia (VHS) 295Infectious Hematopoietic Necrosis (IHN) 296Channel Catfish Virus Disease (CCV) 298Herpesvirus Disease of Salmonids 298Lymphocystis Disease 299Bacterial Diseases 300Bacterial Gill Disease 300Columnaris Disease 302Peduncle Disease 303Fin Rot 304Furunculosis 304Enteric Redmouth (EnU) 306Motile Aeromonas Septicemia (MAS) 307Vibriosis 310Kidney Disease 312Fungus Diseases 314Protozoan Diseases 31 5External Protozoan Diseases 315Ichtyobodo 31 5IchthyoPhthirius 31 6Chilodonella 319Epistylis 3l ITrichodina 320AmbiphrYa 321TrichoPhrya 323Internal Protozoan Diseases 323Hexamita 323HenneguYa 324Ceratomyxa 326Myxosoma 327Pleistophora 328Trematode Diseases (Monogenetic) 329Gyrodactylus 330

XIIIiISHHA'I'CHI.]IIYMANA(;I]MI]N'I'Dactylogyrus 330Cleidodiscus 330Trematode Diseases (Digenetic) 332Sanguinicola 332Copepod Parasites 333Argulus 334Lernaea 3 3 4Packing and Shipping Specimens 335Shipping Live Specimens 340Shipping Preserved Specimens 341Fish f)isease Leaflets 342Bibliography 3446: Transportation of Live FishesTransportation Equipment 348Vehicles 348Tank Design 350Circulation 352Aeration 353Water Quality 355Oxygen 355Temperature 3 5 6Ammonia 357Carbon Dioxide 357Buffers 358Handling, Loading, and Stocking 358Stress 358Anesthetics 359Carrying Capacity 360Trout and Salmon 361Channel Catfish 362Largemouth Bass, Bluegill, and Other Centrarchids 363Striped Bass 363Northern Pike, Muskellunge, and Walleye 364Stocl

CONTL,NTSXIIIAppendix B: Ammonia Ionization 378Appendix C: Volumes and Capacities of Circular Tanks 383Appendix D: Use of Weirs to Measure Flow 384Appendix E: Hatchery Codes for Designating Fish Lots 387Appendix F: Nutritional Diseases and Diet Formulations 390Appendix G:Chemical Treatments: Calculations and Constant FlowDelivery 401Appendix H: Drug Coatings for Feed Pellets 405Appendix I: Length-Weight Tables 406Glossary 469Index 503

PrefaceThe most recent Fish Cultural Manual published by the United States Fishand Wildlife Service was authored by Lynn H. Hutchens and Robert C.Nord in 1953. It was a mimeographed publication and was so popular thatcopies were jealously sought by fish culturists across the country; it soonwas unavailable.In 1967, the Service's Division of Fish Hatcheries began to develop aManual of Fish Culture, with J. T. Bowen as Editor. Several sections werepublished in ensuing years. Efforts to complete the manual waned until1977 when, due to the efforts of the American Fisheries Society and of theAssociate Director for Fishery Resources, Galen L. Buterbaugh, a taskforce was established to develop and complete this publication.As task-force members, our first business was to identify the audience forthis publication.We decided that we could be most helpful if we produceda practical guide to efficient hatchery management for practicingfish culturists. Research and hatchery biologists, bioengineers, and microbiologistswill not find the in-depth treatment of their fields that theymight expect from a technical publication. For example, we offer a guidethat will help a hatchery manager to avoid serious disease problems or torecognize them if they occur, but not a detailed description of all fishdiseases, their causative agents, treatment, and control. Similarly, we outlinethe feed requirements and proper feeding methods for the productionof healthy and efficiently grown fish, but do not delve deeply into thebiochemistry or physiology of fish nutrition.

FISH HA,I.CH ER.I' MANAL; EM FNTThe format of Fish Hatchery Management is functional: hatchery require,ments and operations; broodstock management and spawning; nutritionand feeding; fish health; fish transportation. We have tried to emphasizethe principles of hatchery culture that are applicable to many species offish, whether they are from warmwater, coolwater, or coldwater areas of thecontinent. Information about individual species is distributed through thetext; with the aid of the Index, a hatchery manager can assemble detailedprofiles of several species of particular interest.In the broad sense, fish culture as presented in Fish Hatchery Managementencompasses not only the classical "hatchery" with troughs and raceways(intensive culture), but also pond culture (extensive culture), and cage andpen culture (which utilizes water areas previously considered inappropriatefor rearing large numbers of fish in a captive environment). ttre coolwaterspecies, such as northern pike, walleye, and the popular tiger muskie, traditionallywere treated as warmwater species and were extensively reared indirt ponds. These species now are being reared intensively with increasingsuccess in facilities traditionally associated with salmonid (coldwater)species.We have no pretense of authoring an original treatise on fish culture.Rather, we have assembled existing information that we feel is pertinent togood fish hatchery management. We have quoted several excellent literaturesources extensively when we found we could not improve on theauthor's presentation. We have avoided literature citations in the text, buta bibliography is appended to each chapter. We have utilized unpublishedmaterial developed by the United States Fish and Wildlife Service; Dale D.Lamberton's use of length-weight tables and feeding rate calculations, andhis procedures for projecting fish growth and keeping hatchery recordshave been especially useful. Thomas L. Wellborn's information on fishhealth management greatly strengthened the chapter on that subject.Many people have helped us prepare this manual. Our special recognitionand appreciation go to Ms. Florence Jerome whose dedication anddiligent efforts in typing several manuscript drafts, and in formating tablesand figures, allowed us to complete the book.Roger L. Herman and the staff of the National Fisheries Research andDevelopment Laboratory, Wellsboro, Pennsylvania, supported the projectand assisted in preparation of the manuscript.We greatly appreciate review comments contributed by federal, state,university, and private people: James W. Avault; Jack D. Bayless; ClaudeE. Boyd; Earnest L. Brannon; Carol M. Brownl Keen Buss; Harold E. Calbert;James T. Davis; Bernard Dennison; Lauren R. Donaldson; RonaldW. Goede; Delano R. Graff; William K. Hershberger; John G. Hnath;Shyrl E. Hood; Donald Horak; Janice S. Hughes; William M. Lewis;David O. Locke; Richard T. Lovell; J. Mayo Martin; Ronald D. Mayo;

Pl{lllf ACllxviiDavid W. McDaniel; Fred P. Meyer; Cliff Millenbach; Edward R. Miller;Wayne Olson; Keith M. Pratt; William H. Rogers; Raymond C. Simon;Charlie E. Smith; R. Oneal Smitherman; Robert R. Stickney; Gregory J.Thomason; Otto W. Tiemeier; Thomas L. Wellborn; Harry Westers. Allthese people improved the manual's accuracy and content. Carl R. Sullivan,Executive Director of the American Fisheries Society, helped tostimulate the creation of our task force, and his continued interest in thisproject has been a source of strength.There was much encouragement and effort by many other people whohave gone unmentioned. To all those who took any part in the developmentand publication of the lalsi Hatchery Management, we express our gratitude.Lastly, I would like to recognize the guidance, perserverance, tact, andfriendship shown to the task force by Robert Kendall, who provided editorialreview through the American Fisheries Society. Without his involvement,the task force would not have accomplished its goal.RosnRr G. PrrER,Editor-in-Chief

Abbreviations Usedin the TextBHA butylhydroxyanisoleBHT butylhydroxytolueneBOD biochemical oxygen demandBTU British thermal unitC condition factor (English units)"C degrees centigrade or CelsiuscalccCFRcmcu ftDDOEPAet al.F'FftFWSggalgpmcaloriescubic centimeterCode of Federal Regulationscentimetercubic footdensity indexdissolved oxygenEnvironmentalProtectionAgencyand othersflow indexdegrees FahrenheitfootFish and Wildlife Servicegram\s/gallon(s)gallon(s) per minute

XXFISH HATCHERY MANAGEMENTGVWHCGIi.m.i.p.IUKkcalLlblbsLHPmmgminmlmmMS-222NNRCO.D.ozPP.C.PCBppbppmpptpsiSETsp.sq ftT.H.TUpgUSUSPVWW.P.WtZngross vehicle weighthuman chorionic gonadotrophinwater inflowintramuscularintraperitonealinternational unitscondition factor (metric units); insulation factorkilocalorielength (totul)poundpoundsLot History Production Chartmeter(s)milligram(s)minutemillilitermillimetertricaine methane sulfonatenitrogenNational Research Counciloutside diameterouncephosphorousPublic Codepolychlorinated biphenolspart(s) per billionpart(s) per millionpart(s) per thousandpound(s) per square inchstandard environmental temperaturesspeciessquare foot (feet)total hardnesstemperature unitsmicrogramUnited StatesUnited States Pharmaceuticalvolume of raceway in cubic feettotal weightwettable powderweightzinc

Common and ScientificNames of Fishes Citedin the TextAmerican eelAmerican shadArctic charAtlantic salmonBlack bullheadBlueback salmonBlue catfishBluegillBrook troutBrown bullheadBrown troutBuffaloChain pickerelChannel catfishChinook salmonChum salmonCoho salmonCommon carpCutthroat troutDog salmonFathead minnowFlathead catfishAnguilla rostrataAlosa sapidissimaSaluelinus alpinusSalmo salarIctalurus melassaa sockeye salmonIctalurus furcatusLepomis macrochirusSaluelinus fontinalisIctalurus nebulosusSalmo truttaIctiobus spp.Esox nigerIctalurus punctatusOncor hy nc hus ts haw I tsc haOncorhynchus ketaOncorhynchus kisutchCyprinus carpioSalmo clarkisea chum salmonPimephales promelasPylodictis oliaaris

IiISH HA I'CItI]I{\' N'I,\NA(;I.]NI I.]N'IGrass carpGolden shinersGoldfishGreen sunfishG,rppyHerringLake troutLargemouth bassMuskellungeNorthern pikePink salmonPumpkinseedRainbow troutRedbreast sunfishRedear sunfishSaugerSea lampreySculpinSmallmouth bassSockeye salmonSteelheadStriped bassTenchThreadfin shadTilapiaWalleyeWhite catfishWhitefishWhite suckerYellow perchC te nop hary ngo do n ide I laN o te migo nus cry so leucasCarassius auratusLepomis cyanellusPoecilia reticulataClupea harengusSaluelinus namalcushMicropterus salmoidesEsox masquinongtEsox luciusOncor hync hus gor busc haLepomis gibbosusSalmo gairdneriLepomis auritusLepomis microlophusS tiTo s te dion cana de ns ePetromylon marinusCottus spp.Micropterus dolomieuiOncorhynchus nerkasss rainbow troutMorone saxatilisTinca tincaDorosoma petenenseTilapia spp.S tizos tedion aitreum aitreumIctalurus catusCoregonus spp.Catostomus commersoniPerca flauescens

FishHatch"ryManagement

1Hatch.ry RequirementsThe efficient operation of a fish hatchery depends on a number of factors.Among these are suitable site selection, soil characteristics, and water quality.Adequate facility design, water supply structures, water source, andhatchery effluent treatment must also be considered. This chapter willidentify the more important hatchery requirements and the conditionsnecessary for an efficient operation.Water QualityWater quality determines to a great extent the success or failure of a fishcultural operation. Physical and chemical characteristics such as suspendedsolids, temperature, dissolved gases, pH, mineral content, and the potentialdanger of toxic metals must be considered in the selection of a suitable watersource.TemperatureNo other single factor affects the development and growth of fish as muchas water temperature. Metabolic rates of fish increase rapidly as temperaturesgo up. Many biological processes such as spawning and egg hatching

FISH HA'fCHERY MANAGE,MENTare geared to annual temperature changes in the natural environment.Each species has a temperature range that it can tolerate, and within thatrange it has optimal temperatures for growth and reproduction. These optimaltemperatures may change as a fish grows. Successful hatchery operationsdepend on a detailed knowledge of such temperature influences.The temperature requirements for a fish production program should bewell defined, because energy must be purchased for either heating or coolingthe hatchery water supply if unsuitable temperatures occur. First considerationshould be to select a water supply with optimal temperatures forthe species to be reared or, conversely, to select a species of fish thatthrives in the water temperatures naturally available to the hatchery.It is important to remember that major temperature differences betweenhatchery water and the streams into which the fish ultimately may bestocked can greatly lower the success of any stocking program to whichhatchery operations may be directed. Within a hatchery, temperatures thatbecome too high or low for fish impart stresses that can dramatically affectproduction and render fish more susceptible to disease. Most chemical substancesdissolve more readily as temperature increases; in contrast, and ofconsiderable importance to hatchery operations, gases such as oxygen andcarbon dioxide become less soluble as temperatures rise.Some suggested temperature limits for commonly cultured species arepresented in Chapter 3, Table 17.Dissolued GasesNitrogen and oxygen are the two most abundant gases dissolved in water.Although the atmosphere contains almost four times more nitrogen thanoxygen in volume, oxygen has twice the solubility of nitrogen in water.Therefore, fresh water usually contains about twice as much nitrogen asoxygen when in equilibrium with the atmosphere. Carbon dioxide also ispresent in water, but it normally occurs at much lower concentrations thaneither nitrogen or oxygen because of its low concentration in the atmosphere.All atmospheric gases dissolve in water, although not in their atmosphericproportions; as mentioned, for example, oxygen is over twice as solubleas nitrogen. Natural waters contain additional dissolved gases that resultfrom erosion of rock and decomposition of organic matter. Several gaseshave implications for hatchery site selection and management. Oxygenmust be above certain minimum concentrations. Other gases must be keptbelow critical lethal concentrations in hatchery or pond water. As for otheraspects of water quality, inappropriate concentrations of dissolved gases insource waters mean added expense for treatment facilities.

HATCHERY RDqUIREMENTS5101520Water temperatures'Cent0xygen mgmpef I ter (PpM)6 / 8 9 l0 llFIGURE l. Rawson's nomagram of oxygen saturation values at different temperaturesand altitudes. Hold ruler or dark-colored thread to join an observed temperatureon the upper scale with the observed dissolved-oxygen value on thelower scale. The values or units desired are read at points where the thread orruler crosses the other scale. The associated table supplies correction values foroxygen saturation at various altitudes. For example, if 6.4 ppm of oxygen isobserved in a sample having an altitude of approximately 500 m (1,640 feet), theamount of oxygen that would be present at sea level under the same circumstancesis found by multiplying 6.4 by the factor 1.06, giving the product6.8; then the percentage saturation is determined by connecting 6.8 on the lowerscale with the observed temperature on top scale and noting point of intersectionon the middle (diagonal) scale.OXYGENOxygen is the second-most abundant gas in water (nitrogen is the first)and by far the most important-fish cannot live without it. Concentrationsof oxygen, like those of other gases, typically are expressed either as partsper million by weight, or as percent of saturation. In the latter case, saturationrefers to the amount of a gas dissolved when the water and a[mosphericphases are in equilibrium. This equilibrium amount (for any gas)

FISH HAfCHERYMANAGEMENTdecreases-that is, less oxygen can be dissolved in water-at higher altitudesand, more importantly,at higher temperatures. For this reason, therelationship between absolute concentrations (parts per million) and relativeconcentrations (percent saturation) of gases is not straightforward.Special conversion formulae are needed; in graphical form these can bedepicted as nomograms. A nomogram for oxygen is shown in Figure 1.Dissolved oxygen concentrations in hatchery waters are depleted inseveral ways, but chiefly by respiration of fish and other organisms and bychemical reactions with organic matter (feces, waste feed, decaying plantand animal remains, et cetera). As temperature increases the metabolic rateof the fish, respiration depletes the oxygen concentration of the water morerapidly, and stress or even death can follow. Fluctuatingwater temperaturesand the resulting change in available oxygen must be considered ingood hatchery management. In ponds, oxygen can be restored during theday by photosynthesis and at any time by wind mixing of the air andwater. In hatchery troughs and raceways, oxygen is supplied by continuouslyflowing fresh water. However, oxygen deficiencies can arise in bothponds and raceways, especially when water is reused or reconditioned.Then, chemical or mechanical aeration techniques must be applied by culturists;these are outlined below for raceways, and on pages 108-110 forponds. Aeration devices are shown in Figures 2 and 3.In general, water flowing into hatcheries should be at or near 100% oxygensaturation. In raceway systems, where large numbers of fish are culturedintensively, oxygen contents of the water should not drop below 80%saturation. [n ponds, where fish densities are lower (extensive culture) thanFtCUnn 2. A simple aeration device made of perforated aluminum can add oxygento the water and restrict fish from jumping into the raceway above. (FWSphoto.)

HATCHERY REQUIREMENTSFIGURE 3. Electric powered aerators midway in a series of raceways can provideup to 2 ppm more oxygen for increased fish production. This type aerator isoperated by a I horsepower motor and sprays approximately I cubic foot persecond of water. Note the bulk storage bins for fish food in the center background.(Courtesy California Department of Fish and Game.)in raceways, lower concentrations can be tolerated for short periods. However,if either raceway or pond fish are subjected to extended oxygen concentrationsbelow 5 parts per million, growth and survival usually will bereduced (Figure 4).The lowest safe level for trout is approximately 5 parts per mlllion.Reduced food consumption by fingerling coho salmon occurs at oxygen

t,.ISH HA'I'CI{ERY M ANAGL,M DN-I'00.31.0SMALL FISH SU RVIVESHORTEXPOSURE)) LETHAL IF EXPOSURE PROLONGED)E.U,Jt-JC'=z.lrlIxooUJJoC)(no2.03.04.05.0FISH SURVIVE, BUT GROWTH SLOWFOR PROLONGED EXPOSURE\ DESIRABLE RANGEFrcuRE 4. Effectsof dissolved oxygen on warm water pond fish.Milligrams/liter : parts per million. (Sourc", Swingle 196{).)concentrations near 4-5 parts per million, and these fish will die if it dropsbelow 3 parts per million. Walleye fry do not survive well in water containing3 parts per million dissolved oxygen or less. Low levels of dissolvedoxygen below 5 parts per million can cause deformities of striped bass duringembryonic development.NII'ROGENMolecular nitrogen (wz) may be fixed by some aquatic bacteria and algae,but it is biologically inert as far as fish are concerned. Dissolved nitrogenmay be ignored in fish culture so long as it remains at 100",' saturation orbelow. However, at supersaturation levels as low as 102')i it can induce gasbubble disease in fish.

HAI'CHERY REqUTREMENTSITheoretically, gas bubble disease can be caused by any supersaturatedgas, but in practice the problem is almost always due to excess nitrogen.when water is supersaturated with gas, fish blood tends to become so aswell. Because oxygen is used for respiration, and carbon dioxide entersinto the physiology of blood and cells, excess amounts of these gases in thewater are taken out of solution in the fish body. However, nitrogen, beinginert, stays supersaturated in the blood. Any reduction in pressure on thegas' or localized increase in body temperature, can bring such nitrogen ourof solution to form bubbles; the process is analogous to "bends" in humandivers. such bubbles (emboli) can lodge in blood vessels and restrictrespiratory circulation, leading to death by asphyxiation. In some cases,fish may develop obvious bubbles in the gills, between fin rays, or underthe skin, and the pressure of nitrogen bubbles may cause eyes to buluefrom their sockets.Gas supersaturation can occur when air is introduced into water underhigh pressure which is subsequently lowered, or when water is heated. waterthat has plunged over waterfalls or dams, water drawn from deep wells,or water heated from snow melt is potentially supersaturated. Air sucked inby a water pump can supersaturate a water system.All fish-coldwater or warmwater, freshwater or marine species-are susceptibleto gas bubble disease. Threshold tolerances to nitrogen supersaturationvary among species, but any saturation over 10091, poses a threat tofish, and any levels over 110% call for remedial action in a hatchery. Nitrogengas concentrations in excess of 1059t cannot be tolerated by troutfingerlings for more than 5 days, whereas goldfish are unaffected by concentrationsof nitrogen as high as 120114 for as long as 48 hours and 105lirfor 5 days. whenever possible, chronically supersaturated water should beavoided as a hatchery source.CARBON DIOXIDEAll waters contain some dissolved carbon dioxide. Generally, waters supportinggood fish populations have less than 5.0 parts per million carbondioxide. Spring and well water, which frequently are deficient in ,xygen,often have a high carbon dioxide content. Both conditions easily can becorrected with efficient aerating devices.carbon dioxide in excess of 20 parts per million may be harmful to fish.If the dissolved oxygen content drops to 3-5 parts per million, lower carbondioxide concentrations may be detrimental. It is doubtful that freshwaterfishes can live throughout the year in an average carbon dioxide contentas high as l2 parts per million.A wide tolerance range of carbon dioxide has been reported for variousspecies and developmental stages of fish. chum salmon eggs are relatively

IOFISII HAI.CHERY MANAGEMENl.resistant to high levels of carbon dioxide but 50(l; mortality can occurwhen carbon dioxide concentrations reach 90 parts per million. However,concentrations of 40 ppm carbon dioxide have little affect upon juvenilecoho salmon.TOXIC GASESHydrogen sulfide (UrS) and hydrogen cyanide (HCN) in very low concentrationscan kill fish. Hydrogen sulfide derives mainly from anaerobicdecomposition of sulfur compounds in sediments; a few parts per billionare lethal. Hydrogen cyanide is a contaminant from several industrialprocesses, and is toxic at concentrations of 0.1 part per million or less.DISSOLVED GAS CRI'fE,RIAAs implied above, various fish species have differing tolerances to dissolvedgases. However, the following general guidelines summarize water qualityfeatures that will support good growth and survival of most or all fishspecres:OxygenNitrogenCarbon dioxideHydrogen sulfideHydrogen cyanide5 parts per million or greater100(ll saturation or less10 parts per million or less0.1 part per billion or lessl0 parts per billion or lessIn general, oxygen concentrations should be near 100(li, saturation in theincoming water supply to a hatchery. A continual concentration of 80'li, ormore of saturation provides a desirable oxygen supply.Suspended and Dissolaed Solids.,Solids"in water Ieave tangible residues when the water is filtered(suspended solids) or evaporated to dryness (dissolved solids). Suspendedsolids make water cloudy or oPaque; they include chemical precipitates,flocculated organic matter, living and dead planktonic organisms, and sedimentstirred up from the bottom on a pond, stream, or raceway. Dissolvedsolids may color the water, but leave it clear and transParent; they includeanything in true solution.SUSP!]NDED SOI,IDS,,Turbidity"is the term associated with the presence of suspended solids.Analytically, turbidity refers to the penetration of light through water (the

HATCHITRYREQUTREME,NTS1llesser the penetration, the greater the turbidity), but the word is used lessformally to imply concentration (weight of solids per weight of water)'Turbiditiesin excess of 100,000 parts per million do not affect fishdirectly and most natural waters have far lower concentrations than this.However, abundant suspended particles can make it more difficult for fishto find food or avoid predation. To the extent they settle out, such solidscan smother fish eggs and the bottom organisms that fish may need forfood. Turbid waters can clog hatchery Pumps, filters, and pipelinesIn general, turbidities less than 2,000 parts per million are acceptable forfish culture.ACIDITYAcidity refers to the ability of dissolved chemicals to "donate" hydrogenions (H+). The standard measure of acidity is pH, the negative logarithmof hydrogen-ion activity. The pH scale ranges from I to l4; the lower thenumber, the greater the acidity. A pH value of 7 is neutral; that is, thereare as many donors of hydrogen ions as acceptors in solution.Ninety percent of natural waters have pH values in the range 6.7-8.2,and fish should not be cultured outside the range of 6.5-9.0. Many fish canlive in waters of more extreme pH, even for extended periods, but at thecost of reduced growth and reproduction. Fish have less tolerance of pHextremes at higher temperatures. Ammonia toxicity becomes an importantconsideration at high pH (Chapter 2).Even within the relatively narrow range of pH 6.5-9.0, fish species varyin their optimum pH for growth. Generally, those species that live naturallyin cold or cool waters of low primary productivity (low algal photosynthesis)do better at pH 6.5-9. Trout are an example; excessive mortalitycan occur at pH above 9.0. The affected fish rapidly spin near the surfaceof the water and attempt to leave the water. Whitening of the eyes andcomplete blindness, as well as fraying of the fins and gills with the frayedportions turning white, also occur. Death usually follows in a few hours.Fish of warmer climates, where intense summer photosynthesis can raisepH to nearly 10 each day, do better at pH 7.5-9. Striped bass and catfishare typical of this group.ALKALINITY AND HARDNESSAlkalinity and hardness imply similar things about water quality, but theyrepresent different types of measurements. Alkalinity refers to an ability toaccept hydrogen ions (or to neutralize acid) and is a direct counterpart ofacidity. The anion (negatively charged) bases involved mainly are carbonate(COrj ) and bicarbonate (HCO, ) ions; alkalinity refers to these

12 r'rsH HAICHERY MANAGEMENTalone (or these plus OH ) and is expressed in terms of equivalent concentrationsof calcium carbonate (CaCO3).Hardness represents the concentration of calcium (Ca' ') and magnesrum(tutg**) cations, also expressed as the CaCO,-equivalent concentration.The same carbonate rocks that ultimately are responsible for most of thealkalinity in water are the main sources of calcium and magnesium as well,so values of alkalinity and hardness often are quite similar when all areexpressed as CaCO.., equivalents.Fish grow well over a wide range of alkalinities and hardness, but valuesof 120-400 parts per million are optimum. At very low alkalinities, waterloses its ability to buffer against changes in acidity, and pH may fluctuatequickly and widely to the detriment of fish. Fish also are more sensitive tosome toxic pollutants at low alkalinity.TO'TAL DISSOI-VI]D SOLIDS"Dissolved solids" and "salinity" sometimes are used interchangeably, butincorrectly. The total dissolved solids in water are represented by theweight of residue left when a water sample has been evaporated to dryness,the sample having already been filtered to remove suspended solids. Thisvalue is not the same as salinity, which is the concentration of only certaincations and anions in water.The actual amount of dissolved solids is not particularly important formost fish within the ranges of 10-1,000 parts per million for freshwaterspecies, l-30 parts per thousand for brackish-water species, and 30-40parts per thousand for marine fish. Several species can live at concentrationswell beyond those of their usual habitats; rainbow trout can tolerate30, and channel catfish at least 11, parts per thousand dissolved solids.However, rapid changes in concentration are stressful to fish. The blood offish is either more dilute (marine) or more concentrated (fresh water) thanthe medium in which they live, and fish must do continual physiologicalwork to maintain their body chemistries in the face of these osmotic differences.Hatchery water supplies should be as consistent in their dissolvedsolid contents as possible..fOXIC MATERIALSVarious substances toxic to fish occur widely in water supplies as a resultof industrial and agricultural pollution. Chief among these are heavy metalsand pesticides.

HAI CHF],RY RFTQIJIRLMEN I Sl3Heauy MetalsThere is a wide range of reported values for the toxicity of heavy metals tofish. Concentrations that will kill 50'li, of various species of fish in 96 hoursrange from 90 to 40,900 parts per billion (ppb) for zinc,46 to 10,000 ppbfor copper, and 470 to 9,000 ppb for cadmium. Generaily, trout and salmonare more susceptible to heavy metals than most other fishes; minuteamounts of zinc leached from galvanized hatchery pipes can cause heavylosses among trout fry, for example. Heauy metals such as copper, lead, {nc,cadmium and mercurl should be aaoided in fish hatcher] water supplies, as shouldgalvanized steel, copper, and brass fittings in water pipe, especially inhatcheries served by poorly buffered water.SalinityAll salts in a solution change the physical and chemical nature of waterand exert osmotic pressure. Some have physiological or toxic effects aswell. In both marine and freshwater fishes, adaptations to salinity arenecessary. Marine fishes tend to lose water to the environment by diffusionout of their bodies. Consequently, they actively drink water and get rid ofthe excess salt by way of special salt-excreting cells. Freshwater fishes takein water and very actively excrete large amounts of water in the form ofurine from the kidneys.Salinity and dissolved solids are made up mainly of carbonates, bicarbonates,chlorides, sulphates, phosphates, and possibly nitrates of calcium,magnesium, sodium, and potassium, with traces of iron, manganese andother substances.Saline seepage lakes and many impounded waters situated in aridregions with low precipitation and high rates of evaporation have dissolvedsolids in the range of 5,000-12,000 parts per million. Fish production insaline waters is limited to a considerable extent by the threshold of toleranceto the naturally occurring salt. Rainbow trout, as an example, generallytolerate up to 7,000 parts per million total dissolved solids. Survival,growth and food efficiency were excellent for rainbow trout reared inbrackish water at an average temperature of 56"F. The trout were convertedfrom fresh water to i30 parts per thousand over a 9-day period andwere reared to market size at this salinity.Mineral deficiencies in the water may cause excessive mortality, particularlyamong newly hatched fry. Chemical enrichment of water with calciumchloride has been used to inhibit white spot disease in fry. Brook trout canabsorb calcium, cobalt, and phosphorous ions directly from the water.

l4FISH HA'lcHERY MANACEMENI'TABLT. L sllc;cEs l LD wA f lrR qUALl.fY cRl l l.RIA F()R oP l lMUNt tlEAt.TH oF sALMONIDIISHI.,S, CONCI,N'I'RA'I'ION*S ARI] IN PAI].'I'S P!]R MII,I-ION iPPM). {SOL]RCEw!tt)uNI uYl,lR l 1)77. iCtII-NIIC'.\IL: PPF,R I,I NI I'f S IOR C]ON'I'I N I]0I'S F,XPoSTI R IArrmonia (NH1)L adrnlutnl)t aomilrnlChlorineCopper'Hydrogen sulfidcl-ca dMcrcury (organicor ln orgit n lclN itrogenNirrite (N()2 )L)zOnt'Polychlorinatcdbiphenyls (PCB's)'[otal suspended andZincsettleable solids0.0l2l ppm (un ionizcd form)0.000.1 ppm (in soft n'ater < 100 ppm alkalinity)0.(X)l| pprr (ln hard water )0.013 ppm0.000 ppm in soft water0.002 ppm0.0i3 ppm100 ppm alkalinitv)0.002 ppm maximum, 0.000011 ppm averageMaximum total gas pressure I l0' , of saturation0.1 ppm in soft water,0.2 ppm in hard u'ater (0.0i.iand 0.0(i ppm nitrite-nitrogen)0.(X)r ppm0.(X)2 ppmtlO ppm or less0.013 ppma l'o protect salmonid eggs and frv. l or non-salmonids, 0.00't ppm is acceptable"'I o prottct salmonid eugs and frv. For non-salmonids, 0.01.| ppni is acceptable.tC.ppe.at 0.005 ppm may supress gill adenosine triphosphatase and compromise srroltilicationin anadromous salmonids.Walleye fry hatched in artesian well water containing high levels of calciumand magnesium salts with a dissolved solid content of 1,563 parts permillion were twice the size of hatchery fry held in relatively soft spring fedwater. This rapid growth was attributed to the absorption of dissolvedsolids.Channel catfish and blue catfish have been found in water with salinitiesup to 11.4 parts per thousand. Determination of salinity tolerance in catfishis of interest because of possible commercial production of these species inbrackish water.TurbiditlClay turbidity in natural waters rarely exceeds 20,000 parts per million.Waters considered "muddy" usually contain less than 2,000 parts per million.Turbidity seldom directly affects fish, but may adversely affect productionby smothering fish eggs and destroying benthic organisms in

HATCHERY REqL. TRL,NIENTSl5TABLE 2. sriccLS lL,D cHFrMrcAL vAr.LrF,s F()R HAi ctu,rRy wA.t t,.R sLrppt-n.rs. coNct,rNTRATION ARE IN pARTS pF-R t\4 Il.t.tuN lppMl ls()URClt: H()!\iAu.t) N. LARsuN. LtNpLrBLISHED.]VARIAI]I,IDissolved oxygenCarbon dioxideTotal alkalinity (as CaCOr)'1,'as phenolphthalein'rLras methyl orange"', as ppm hydroxide1rl,as PPm carbonate1i, as PPm bicarbonatepH'fotal hardness (as CaCOq)Calciu mMagnesiumManganescIron (total.)lerrous ionl'erric ionPhosphorousN itrateZincHydrogen sulfide5 saturation0 l0I0.10002575 l0002575 100(i.5 lt.0l0 .100,1 I(t0Needed for buffer systcm0 0.0I0 0.15(,0.50.01 3.00 lJ.00 0.050\{.\R\1 \\'l t uR5 saturation0 1550 .1(X)0..1060 I (X)00 ,107r 100(i.5 1).050 .100I0 I(t00 0.0I0 0.500 0.ri0.0l 3.00 lJ.0same0ponds. It also restricts light penetration, thereby limiting photosynthesisand the production of desirable plankton in earthen ponds.PesticidesMany pesticides are extremely toxic to fish in the low parts-per-billionrange. Acute toxicity values for many commonly used insecticides rangefrom 5 to 100 microgram/liter. Much lower concentrations may be toxicupon extended exposure. Even if adult fish are not killed outright, longtermdamage to fish populations may occur in environments contaminatedwith pesticides. The abundance of food organisms may decrease, fry andeggs may die, and growth rates of fish may decline. Pesticides sprayed ontofields may drift over considerable areas, and reach ponds and streams. Ifwatersheds receive heavy applications of pesticides, ponds usually are notsuitable for fish production.Suggested water quality criteria for salmonid and warmwater fishes arepresented in Tables I and 2.

l6FTSH HATCnltRy NIANAcENlltNtWater Supply and TreatmentAn adequate supply of high quality water is critical for hatchery operations.Whether fish are to be cultured intensiaej, requiring constant waterflow, or extensiuely, requiring large volumes of pond water, the water supplymust be abundant during all seasons and from year to year. Evenhatcheries designed to reuse water need substantial amounts of "make-up"flow. Among other criteria, hatchery site selection should be based on athorough knowledge of local and regional hydrology, geology, weather, andclimate.Groundwater generally is the best water source for hatcheries, particularlyfor intensive culture. Its flow is reliable, its temperature is stable, andit is relatively free of pollutants and diseases. Springs and artesian wells arethe cheapest means of obtaining groundwater; pumped wells are much lesseconomical.Spring-fed streams with a small watershed can give good water supplies.They carry little silt and are not likely to flood. The springs will ensure afairly steady flow, but there still will be some seasonal changes in watertemperature and discharge; storage and control structures may have to bebuilt. It is important that such streams not have resident fish populations,so that disease problems can be avoided in the hatchery.Larger streams, lakes, and reservoirs can be used for fish culture, butthese vary considerably in water quality and temperature through the year,and may be polluted. They all have resident fish, which could transmitdisease to hatchery stocks.Even though the water supply may be abundant and of high quality,most hatcheries require some type of water treatment. This may be as simpleas adjusting temperatures or as involved as treating sewage. Excludingmanagement of pondwater quality, discussed in Chapter 2, and medicationof diseased fish (Chapter 5), water may have to be treated at three porntsas it passes through a hatchery system: as it enters; when it is reused; andas it leaves.Treatment of Incoming WaterWater reaching a hatchery may be of the wrong temperature for the fishbeing cultured, it may have too little oxygen or too many suspended solids,and it may carry disease pathogens. These problems often are seasonal innature. but sometimes are chronic.TEMPERATURE CONTROLThe control of water temperature is practical when the amount of water tobe heated or cooled is minimal and the cost can be justified. Temperature

HAICHERYREQUTREMENTSl7control generally is considered in recycle systems with supplemental makeupwater or with egg incubation systems where small quantities of waterare required. A number of heat exchange systems are available commerciallyfor heating or chilling water.AERATIONWater from springs and wells may carry noxious gases and be deficient inoxygen; lake and river sources also may have low dissolved oxygen contents.Toxic gases can be voided and oxygen regained if the water ismechanically agitated or run over a series of baffles.STERILIZATIONAny water that has contained wild fish should be sterilized before itreaches hatchery stocks. Pathogens may be killed by chemical oxidants orby a combination of sand filtration (Fieure 5) and ultraviolet radiation.BACKWASH TROUGHSFILTER TANKBAC KWASHOU T FLOWGRAVELLARGE STONESPERFORATED LATERALSFILTER FLOORFtcuRE 5.COLLECTION MAIN FOR CLEAN WATERDISCHARGE ANO BACKWASH INFLOWDiagram of a sand filter. The water supply is clarified as it flowsdown through the sand and gravel bed, and is then collected in the perforatedlateral pipes and discharged from the filter. The filter is backwashed to clean itby pumping water up through the gravel and sand; the collected waste materialis washed out the backwash outflow.

l8 FISH HATCHERY MANAGEMENTFIGURE 6. Micro-screen filters consist of a rotating drum covered with wovenfabric of steel or synthetic material with various size openings. The raw waterenters the center of the drum and passes through the fabric as filtered water. Asthe fabric becomes clogged, the drum rotates and a high-pressure water spray(arro*) removes the filtered material from the screen into a waste trough.Micro-screen fabric is available with openings as small as 5 microns. (FWSphoto.)Filtration followed by ultraviolet radiation is a proven method for sterilizinghatchery water. For example, 125 gallons per minute of river watercontaining large numbers of fish pathogens can be sterilized by passagethrough two 30-inch diameter sand filters, then through an l8-lamp ultravioletradiation unit. The sand filter removes particles as small as 8-.15microns and the ultraviolet radiation kills organisms smaller than l5microns. It is important that pathogens be exposed to an adequate amountof ultraviolet intensity for the required effective contact time. Treatedwater must be clear to permit efficient ultraviolet light penetration.Maintenance of sand filters includes frequent backflushing and ultravioletequipment requires periodic cleaning of the quartz glass shields andlamp replacement. Commercially available microscreen filters can be usedas an alternative to sand filters (Figure 6).Chlorine gas or hypochlorite can be used as sterilants, but they are toxicto fish and must be neutralized. Ozone is a more powerful oxidizing agent

HA'l CHllRY RE(2U IREMIrNl Sthan hypochlorite, and has been used experimentally with some success. Itis unstable and has to be produced on site (from oxygen, with electrical orultraviolet energy). Ozonated water must be reaerated before fish can livein it. Although very effective against microorganisms, ozone is extremelycorrosive and can be a human health hazard-Treatment of Water for ReuseOften it is feasible to reuse water in a hatchery; some operations run thesame water through a series of raceways or ponds as many as ten times.Any of several reasons can make it worthwhile to bear the added cost ofreconditioning the water. The quantity of source water may be low; thecost of pollution control of hatchery effluent may be high. The price of energyto continuously heat large volumes of fresh source water may limitproduction of fish; continuous quality control and sterilization may beexpensive.A hatchery that uses water only once through the facility is called a"single-pass" system. Hatcheries that recycle water for additional passes bypumping and reconditioning it are termed "reuse-reconditioning" systems.In either system, water that passes through two or more rearing units istermed "reused." Most practical water-reconditioning systems recycle90-95'li, of the water, the supplement of make-up water coming from thesource supply. To be practical, the system must operate for long periodswithout problems and carry out several important functions (Flgure 7).As water passes through or within a hatchery, fish remove oxygen, giveoff carbon dioxide, urea, and ammonia, and deposit feces. Uneaten foodaccumulates and water temperatures may change. This decline in waterquality will lower growth and increase mortality of fish if the water rs recycledbut not purified. A water-reconditioning system must restore originaltemperatures and oxygen concentrations, filter out suspended solids, andremove accumulated carbon dioxide and ammonia. [Jrea is not a problemfor fish at the concentrations encountered in hatcheries.Temperatures are controlled, and suspended solids filtered, in ways outlinedabove for incoming water. oxygen is added and excess carbon dioxideremoved by mechanical aeration. The removal of ammonia is moreinvolved, and represents one of the major costs of recycling systems.The advantage of manipulating rearing environments in a recycle systemhas been demonstrated in the rearing of striped bass fry and fingerlings.They have been reared to fingerling size with increased success when thesalinity of the recycled water was raised to 47 parts per thousand duringthe rearing period. channel catfish also have been successfully reared inrecycled-water svstems.

20 FISH IJAl'CIIERY MANAGIJM I]NI'FI LTERHATCH ERYREARINGPON DSRECON DITION EDWATERREMOVE AMMONIAREMOVE CARBON DIOXIDEADD OXYGEN (AERATION)TEMPERATURE CONTROLOH CONTROLWASTE SOLIDS DISPOSALFIGURE 7.Schematic diagram of a fish hatcherywater reuse system. (Modified from Larmoyeuxr972.)AMMONIA TOXICITYWhen ammonia gas dissolves in water, some of it reacts with the water toproduce ammonium ions, the remainder is present as un-ionized ammonia(NFI,'j). Standard analytical methodsrdo not distinguish the two forms, and1Th" bnok, by Claude E. Boyd and rhe American Public Health Association et al.' listed inthe references, give comprehensive procedures for analyzing water quality.

HA'I CHITRY l{llQlllRllNrl.Nl S 21,both are lumped as "total ammonia." l'igure ti shows the reaction thatoccurs when ammonia is excreted into \4'ater by fish.'I'he fraction of totalammonia that is toxic ammonia (NHr) varies with salinity oxygcn conccntrationand temperature, but is determined primarily by the pH of thesolution. For example, an increase of one pH unit from tt.0 to !).0 increascsthe amount of un-ionized ammonia approximately 10-fold. These proportionshave been calculated for a range o[ temperatures and pH and aregiven in Appendix B. Note that the amount of NHl increases as temperatureand pH increase. From Appendix B and a measurement of totalammonia (parts per million: ppm), pH, and temperature, the concentrationof un- ionized ammonia can be determined: ppm un- ionizedammonia: (ppm total ammonia x percent un-ionized ammonia) ': 100.When un-ionized ammonia levels exceed 0.0125 part per million, adecline in trout quality may be evidenced by reduction in growth rate anddamage to gill, kidney, and liver tissues. Reduced growth and gill damageoccur in channel catfish exposed to 0.12 part per million or greater unionizedammonia.Ammonia rapidly limits fish production in a water-recycling system unlessit is removed efficiently. Biological filtration and ion exchange are thebest current means of removing ammonia from large volumes of hatcherywater.BIOLOGICAL REMOVAL OF AMMONIABiological removal of ammonia is accomplished with cultures of nitrifyingbacteria that convert ammonia to harmless nitrate ions (NOi). These bacteria,chiefly species of lfitrosomonas and Nitrobacter can be grown on almostany coarse medium, such as rocks or plastic chips. The best culture mate.rial contains calcium carbonate, which contributes to the chemical reactionsand buffers pH changes; oyster shells often are used for this purpose.By the time water reaches the biological filter, it should be already wellaerated(oxygen is needed for the p.o.e..) and free of particulate matterFISH+NH3 ++ IIU N-IO N IZE DTOXIC FORM"2--NHI-IHIpHDEPEN DENTNH, + 0H-\ IONIZEDNON.TOXIC FORMFIGLIRE t],Reaction of ammonia excreted into water by fish.

,2,2FISHIIAI.CIIERYMANAC;EMEN'l(which could clog the filter). It is important that the water be pathogenfree,because an antibiotic or other drug that has to be used in thehatchery can kill the nitrifying bacteria as well.Settling chambers and clarifiers can extend the life of biofilters and reduceclogging by removing particulate matter. Filter bed material with large voidspaces also can reduce clogging, and foam fractionation will remove dissolvedorganic substances that accumulate. These foaming devices are also called,,protein skimmers," which refers to their ability to remove dissolved organicsubstances from the water. The foam is wasted through the top of the deviceand carries with it the organic material. In a small system, air stones can beused to create the foam. The air produces numerous small bubbles that collectthe organic material onto their surface. Because foam fractionation doesnot readily remove all particulate organic material, it should follow the settlingor clarifying unit in a reconditioning system.Nitrite (ttO;) is an intermediate product of nitrification, and a poorlyoperating biofilter may release dangerous amounts of this toxic ion to thewater. A more rapid growth rate of Nitrosomonas in the biological systemcan lead to accumulation of nitrite, which is highly toxic to freshwaterfishes. Nitrite oxidizes blood hemoglobin to methemoglobin, a form whichis incapable of carrying oxygen to the tissues. Methemoglobin ischocolate-brown in color, and can be easily seen in the fish's gills'Yearling trout are stressed by 0.15 part per million and killed by 0.55part per million nitrite. Channel catfish are more resistant to nitrite, but 29parts per million can kill up to 50'lo of them in 48 hours. Nitrite toxicitydecreases slightly as the hardness and chloride content of water increases.ION T]XCHANGE RI]MOVAI- OF AMMONIAIon exchange for removal of ammonia from hatchery water can be accomplishedby passing the water through a column of natural zeolite. Zeolitesare a class of silicate minerals that have ion exchange capacities (they areused in home water softeners) . Among these, clinoptilolite has a particularlygood affinity for ammonium ions. It is increasingly being used inhatcheries, where it effects 90 !)7'1,, reductions in ammonia (Figure 9).Clinoptilolite does not adsorb nitrate or nitrite, nor does it affect waterhardness appreciably. It can be regenerated by passing a salt solutionthrough the bed. The ammonia is released from the salt solution as a gasand the solution can be reused. Any ion exchange unit can develop into abiofilter if nitrifyingbacteria become established in it. This may lowerexchange efficiencies and cause production of nitrite, so periodic disinfectionmay be necessarY.

HATCHERY REQLIIREN,TINTSWASTE WATERSOLIDSR EM OVALAM MON IAAERATIONI I I IiR ECON DITIONWATERFIcURF; 9. Schematic diagram of ion exchange removal ofammonia from hatcherv waste water.o t'HER AMMONTA REMOVAt. ]'ECHNt(2UESSeveral procedures for removing ammonia from hatchery water have beentried. Many of them work, but are impractical in most circumstances.When the pH of water is raised to 10 or 11 with calcium or sodium hydroxide,most of the ammonia goes to the gaseous form (NH1) and will dissipateto the air if the water is sprayed in small droplets. This ',ammoniastripping" does not work well in cold weather, and the water has to bereacidified to normal pH levels.Chlorine or sodium hypochlorite added to water can oxidize g5-ggli, ofthe ammonia to nitrogen gas (Figure 10). "Breakpoint chlorination" createshydrochloric acid as a byproduct, which must be neutralized with lime orcaustic soda, and residual chlorine must be removed as well. This is anuneconomical process, although future technological advances may rmprove

FISH HATCHL,RY MANAGEMEN'IWASTE SLUDGECHLORINEBREAKPOINTCHLORINATIONNITROGEN GASACT I VAT EDCA R BONADSORPTIONCHLORAMINES,EXCESS CHLORINEAND DISSOLVEDORGAN ICSAE RATI ONIItRECONDITIONEDWATERFtcunn .10. Schematic diagram of breakpoint chlorination removalof ammonia from hatchery waste water.its practicality in hatcheries. An advantage of this system is that all treatedwater is sterilized.Oxidation ponds or lagoons can remove 35-U5'il of the ammonia inwastewater through microbial denitrification in the pond bottom andthrough uptake by algae. This method requires considerable land area andextended retention time of the wastewater in the lagoon. Oxidationlagoons work best in southern climates. Cold weather significantly reducesbiological activity.ESTIMATION O!'AMMONIABecause of the importance of ammonia to fish production total ammonia inhatchery water should be measured directly on a regular basis. However,rough estimates of total ammonia can be made from an empirical formula,if necessary. Although ammonia can be contributed by source water and by

HAT( H[.R\ RF.QI rRt.l\lt..N l5',25microbial breakdown of waste feed, most of it comes from fish metabolism.The amount of metabolism, hence the amount of ammonia excreted, isconditioned by the amount of food fish eat. For each hatchery and feedtype, an ammonia factor can be calculated:ammonia f'actor-ppm total ammonia x gpm water inflowlbs food fed per dayHere, ppm is parts per million concentration, gpm is gallons per minuteflow, and lbs is pounds. To establish the ammonia factor, total ammoniashould be measured in raceways, tanks, and ponds several times over oneday. Once the factor is established, the formula can be turned around togive estimates of total ammonia:Ppmtotal ammonialbsfood/dav x ammonia factorgpm flowThen, by reference to Appendix B with the appropriate temperature andpH, the concentration of un-ionized ammonia can be estimated.Example: Three raceways in a series have a water flow of 200 gallonsper minute. Fish in the first raceway receive 10 pounds of food per day, 5pounds of feed per day go into the second raceway, and 20 pounds of feedper day go into the third. The ammonia factor for these raceways is l'].0. Inthe absence of any water treatment, what is the expected concentration oftotal ammonia nitrogen at the bottom of each raceway?Raceway ' l' +:g: o.l5 ppm200(10* 5) x gRaceway 2:U.ZJ DDm200(ro*s*zo) x 3Raceway 3::0.51i ppm200Treatment of Effluent Water and SludgeThe potential of hatchery effluent for polluting streams is very great. Likeany other source of waste water, hatcheries are subject to federal, state, andlocal regulations regarding pollution. The United States EnvironmentalProtection Agency requires permits of hatcheries that discharge effluentinto navigable streams or their tributaries. Hatchery operators are responsiblefor knowing the regulations that apply to their facilities. Some treatmentof hatchery effluent is required of almost every hatchery. This is trueeven for systems that recycle and treat water internally; their advantage

I ISH HA'ICHIR}'N'lANAC;L,M NNTlies in the greatly reduced volume of effluent to be treated compared withsingle- pass hatcheries.HATCHERY POI,I,U'I'AN'I'SGenerally, three types of pollutants are discharged from hatcheries: (l)pathogenic bacteria and parasites; (2) chemicals and drugs used for diseasecontrol; (3) metabolic products (ammonia, feces) and waste food. Pollutionby the first two categories is sporatic but nonetheless important. If itoccurs, water must be sterilized of pathogens, disinfected of parasites, anddetoxified of chemicals. Effluent water can be sterilized in ways outlinedfor sourcc water (page i7). Drug and chemical detoxification should followmanufacturers' instructions or the advice of qualified chemists and pathologists.Standby detoxification procedures should be in place before the drugor chemical is used.The third category of pollutants-wasteproducts from fish and food-isa constant feature of hatchery operation, and usually requires permanentfacilities to deal with it. Two components-dissolved and suspendedsolids - need consideration.Dissolved pollutants predominantly are ammonia, nitrate, phosphate, andorganic matter. Ammonia in the molecular form is toxic, as already noted.Nitrate, phosphate, and organic matter contribute to eutrophication ofreceiving waters. For the trout and salmon operations that have been studied,each pound of dry pelleted food eaten by fish yields 0.032 pound oftotal ammonia, 0.087 pound of nitrate, and 0.005 pound of phosphate tothe effluent (dissolved organic matter was not determined separately). Thefeed also contributes to Biological Oxygen Demand (BOD), commonlyused as an index of pollution; it is the weight of dissolved oxygen taken upby organic matter in the water.More serious are the suspended solids. These can, as they settle out,completely coat the bottom of receiving streams. Predominantly organic,they also reduce the oxygen contents of receiving waters either throughtheir direct oxidation or through respiration of the large microbial populationsthat use them as culture media. For the trout and salmon hatcheriesmentioned above, each pound of dry feed results in 0.3 pound of settleablesolids-that part of the total suspended solids that settle out of the waterin one hour. Most of these materials have to be removed from the effluentbefore it is finally discharged. Typically, this is accomplished with settlingbasins of some type.It should be noted that except for ammonia, the pollutants listed can beaugmented from other sources such as waste food and organic material inthe incoming water. The fish culturist should not assume that the total pollutantconcentrations in the effluent are derived only from food eaten bythe fish.

HATCHL,RY REQUIREMENTSTABLE 3. pot-t.urANT LEVELS IN'fHE Et'FL(-rEN-T'FRoM EAR.IHUN cAfFIsHREARINGPONDS DURIN(; TISH SI]INING AND DRATNING OI I'HE PONI)- IA['TER BOYI) I1]71).]PONI)I'ISI IP()l.l.t-ltANIdI)R IN IN(;S!,INI\(Settleable solids (ppm)Settleable oxygen demand (ppm)Chemical oxygen demand (ppm)Soluble orthophosphate (ppb as P)Total phosphorus (ppm as P)Total ammonia (ppm as N)Nitrate (ppm as N)0.0u1.3130.2t(i0.1 I0.!)tt0.I('2tJ.52u.I)l1'25{)0..11)'2..110. 1.1aConcentrations (parts per million or per billion) are on a weight basis except for settleablcsolids. which are on a volume basis.The levels of pollutant in a hatchery effluent can be determined with thefollowing general equation:Average ppm Pollutant:pollutant factorr lbs food fedwater flow (gpm)The following pollutant factors should be used in the equation:Total ammonia 2.67Nitrate 7.25Phosphate Q.417Settleable solids 25.0BOD 2U.3Example: A trout hatchery in which fish are fed 450 pounds of food perday and which has a water flow of 1,500 gallons per minute has a totalammonia concentration of 0.8 parts per million in the hatchery effluent.ppm ammont":?Jli# 0.8Studies in warmwater fish culture have shown that there is no consistentrelationship between the weight of fish harvested in earthen Ponds and theamount of settleable solids discharged in the effluent. In general, anincrease in fish weight results in an increase in settleable solids. Pollutantlevels in the discharge from earthen ponds vary with the volume of waterbeing discharged and the pond design. Some pollutant levels that havebeen reported in the effluent of catfish ponds are presented in Table 3.SEDIMENTATION BASINSThe principle of sedimentation basins is to spread flowing hatchery effluentout in area, thus slowing it down, so that suspended solids will settle out of

FISH HA'I'CHERY MANAGEMEN'I'R FORATED1OO FTa o-OaoUJFFUU)1006€ O 50 FT 1OO FTPROFILESOLID SETTLINGFIGURE 11. A characteristic settling profile for settleable waste solids isshown for a lJO ft x 100 ft tank with a 4-ft water depth and a watervelocity (V) of 0.056 ftlsecond. (Sorrtce' Jensen 1972.)their own weight under conditions of reduced water turbulence (Figure 1l).The design of settling basins should take four interrelated factors intoaccount: (1) retention time; (2) density of waste solids; (13) water velocityand flow distribution; (4) water depth.Retention time is the average period that a unit of water stays in thebasin before it is swept out. Depending on the quantity of wastes carriedby the water, retention time can be anywhere from l5 minutes to 2 hours.In general, retention time increases as the area and depth of the basinincrease. If flow currents are not managed correctly, however, some of thewater passes rapidly through even a larger structure while other waterlingers in backwater areas; the aaerage retention time may seem adequate,but much waste will still leave the basin. Therefore, it is important thatflow be directed evenly through the structure, and a system of baffles mayhave to be incorporated in the design. If water is too shallow, it constantlyscours the bottom, suspends wastes, and carries solids out to receivingwaters. Conversely, if water is too deep, solids do not have time to settlefrom top to bottom before water leaves the basin. A water depth of ii feetis a practical compromise in most circumstances.

HATCHERY REqUIREMENTS 29Sedimentation basins can take several forms. One is a modified concreteraceway, called a linear clarifier (Figrrres 12, 13, and l4). Water entering alinear clarifier should do so through a screen-preferablyof two or more screens-atthrough a seriesthe head end of the unit. Such screens, whichshould be more than 50% open area, distribute flow and reduce turbulencemuch better than dam boards, which cause turbulence near them and astronger surface than bottom flow.Perhaps the most common settling basins are outdoor earthen ponds or"lagoons." These can be of varying sizes and configurations. Obviously, thebigger the pond, the more effluent it can accommodate. Because of theamount of land settling ponds occupy, there usually are practical limitationson lagoon size.Several commerciallyproduced settling systems incorporate baffles andsettling tubes. These are quite efficient and require less space and retentiontime than either linear clarifiers or lagoons. However, they can be quiteexpensive.FIGURE 12. Effluent treatment system at the Jordan River National FishHatchery consists of two linear clarifiers (top), 30 ft x 100 ft with a water depthof 4 feet. The system will handle up to 600 gpm divided equally between the twobays. The bays are cleaned by drawing off the top water and moving the sludgewith a garden tractor to collection channels. The sludge is then removed with atruck-mounted vacuum liquid manure spreader (bottom). (FWS photos.)

30 FISH HATCHERY MANAGEMENTFIGURE 13. Three linear clarifiers located at the Jones Hole National FishHatchery, 114 ftx4l ft and 6 ft deep. Each unit has a sludge scraper system forsludge removal. These are long redwood boards attached by chain to move anddeposit sludge into the sumps at the upper ends of the clarifiers. This system isdesigned to pump sludge to drying chambers. (FWS photo.)A warmwaterfish rearing pond acts as its own settling basin. Exceptwhen the water level is so low that any water movement scours the bottom,draining a pond usually does not cause much waste escapement. However,during seining operations when the bottom is disturbed, levels of suspendedsolids in the effluent can increase several hundred times. Special attentionshould be given to discharges at such times. If water flow through thepond cannot be stopped until solids can resettle, the effluent may have tobe filtered or diverted away from receiving streams. Likewise, pollutantloads from other hatchery operations can increase sharply at times. Periodsof raceway cleaning are examples, and there should be means available tohandle the added waste concentrations. Sometimes, raceways and tanks canbe vacuumed before they are disturbed, although this is labor-intensivework (Figure 15).SOLID WASTE DISPOSALOver half of the total nutrients produced by hatchery operations are in theform of settleable solids. They must be removed frequently from lagoonsand clarifiers, because they rapidly decompose and would otherwise pollutethe receiving waters with dissolved nutrients.The "solid" wastes from settling basins and various filtration unitsaround a hatchery, being g0% water, can accumulate into large volumesthat must be disposed of. Hatchery sludge has considerable value as a fertilizer.In warm climates and seasons, it can be spread directly on the

HATCHERY REqUIREMENTS3lground; winter storage at northern hatcheries may be a problem, however.If transportation is available, or on-site mechanical separators and vacuumfilters can be justified, the sludge can be reduced to moist cakes and soldto commercial fertilizer manufacturers; some municipal sewage plantsdispose of sludge this way.Alternatively,if the hatchery is near an urban area, it may be possible todispose of solid waste in the municipal system. Incineration of sludge is theleast desirable means of disposal, as dewatering and drying the material iscostly, and the process merely exchanges air pollution for water pollution.Ftcunp 14. Sludge is collected from the linear clarifiers into storage lagoons atthe Jones Hole National Fish Hatchery, Utah. The lagoons are periodicallydewatered and the sludse dried for removal.

32 FISH HATCHERY MANAGEMENTFIGURE 15.(l) A vacuum liquid manure spreader with a modified hose connectioncan be used to remove settleable waste solids from fish rearing units.(Z) Water flow is controlled with a f -turn ball valve (arto*). The valve is shutoff whenever the cleaning wand is not actually drawing up waste. Note the settlingarea providedsolids are then spread on agriculture(Fws photos.)at the lower end of the raceway. (3) The collected wastelands or lawn areas away from residences.Hatchery DesignIn judging the suitability of a site for a fish hatchery, the primary purposeof the hatchery should be considered. If egg production is an importantfunction, somewhat lower temperatures may be desirable than if thehatchery is to be used primarily for rearing fish to catchable size. Whereno eggs are handled even higher water temperatures may be desirable toafford maximum fish growth.For efficient operation of a hatchery, the site should be below the watersource. This will afford sufficient water head to provide aeration and adequatewater pressure without pumping. Site considerations should also includesoil characteristics and land gradient. An impervious soil will holdwater with little seepage. Land that is sloped provides drainage and allowsthe construction of raceways in a series for reuse of water by gravity flow.Possible pesticide contamination of the soil and the presence of adjacentland use that may cause agricultural or industrial contamination should beinvestigated. Flood protection is also essential.

HAI CHItRY REqUIRLMLNI'SIf earthen ponds are being considered, sandy or gravel soils should beavoided. Soils that compact well should be considered where concretestructures are proposed.Hatchery labor is an expensive item in rearing fish and good hatcherydesign, including use of mechanized equipment, can eliminate a large percentageof the labor.Many items of equipment are available today that can dramaticallyreduce hand labor in the fish hatchery. Consideration should be given forautomatic feeding, loading and unloading fish, transporting fish betweenfish rearing units and access to rearing units with vehicles and motorizedequipment. As an example, raceways can be designed so that vehicles haveaccess to all points in the facility. Raceways built in pairs provide a roadwayon each side so that vehicle-drawn feeding equipment can be utilized.A suitable hatchery site should include sufficient land area for potentialexpansion of the facilities. Hatchery planners often overestimate the productioncapacity of the water supply and underestimate the facilityrequirements.BuildingsThe principal buildings of a fish hatchery include an office area for recordkeeping,a hatchery building, garages to protect equipment and vehicles, ashop building to construct and repair equipment, crew facilities and a laboratoryfor examining fish and conducting water analyses.The hatchery building should include facilities for egg incubation andfry and fingerling rearing and tanks for holding warmwater pond-rearedfish prior to shipment. Storage facilities must also be considered for feed,which may require refrigeration. Separate facilities should also be providedfor chemical storage. A truck driveway through the center or along oneside of building is convenient for loading and unloading fish. Primary considerationshould be given to the design and location of buildings andstorage areas to create a convenient and labor saving operation.Table 4 provides a summary of suggested standards for fish hatchery siteselection and water requirements along with hatchery design criteria.

lJ.1IIISII IIA'I'CI I I]R\' NIANAOF]MI]N'II'ABLI.t.1. sLtcc;t.sfl)) stANt)ARI)s l'()R ilsH tJAICHt.RY I)uVI.].()l'Nil.tNL IIIt,.sl.slANt)AIr.l)s \\'n.t. cilAN(;1.. AS Nt,.\\' c()NSIRt cil()\lllAluRI.\l.s ,\Nt) \1()Ru t.tltlCILNIt)llSl(;\S I'ilrC()\'lll AVAIl.,\Bl.ll. H,\'l CHl.RY S\'\18()1.: I - 1R()LrI ANI) S.\1.\'1()\lc()l.t) WAIlllil;C:(lO()1. \{,\i!.lt;W : Wr\l{Nl W;\llllill,\l( il1..R\S\ I' IIO I, (.RI II.,I{I,\LanclArea rtgutrcd'[ apagraph_tWatcr supplrUuailltl.l'I (mp(ra lurrC(lCllnouqh for facilities, protection of water supplv, and future expansion; trelltment ()felllucnt: Iuturc s'ater rcuse ancl rccirculationsy ste tt s.Sufl'icicnt {'lcvation bettet'r watcr sourcc andprodLrction facilities for aeraliorr ancl qravit)I'kru. l,and should havc qcntlc slopcs ornroderatr reliel'thrrt can be qradcd to pro'viclc adccluate drainaqe. Avoid areas subjcctto floodinq.'I hc uatcr supplr should bc consiclcrcd in thisordcr ol prrlrrcnce:rircr; lakc or rcst'rvoir. Ansprinq; ucll; streanr;!vatcr \ource shoulcl bc invcstiqatc.l.unclcrqrounclLakt' or rcscr\'oit uatcr prt'lerred orel crct'k orstrerrnr suppl\.Warter rt,qLrirernents are di< tatecl brthe sizcIuturt. ol the unit plarrnt'd. I hc supplyshould provide lJ chanets per hour thrruqhcach unit and no less than I change perhourthrouqh the enlire svsten). Wht-rtrvatcrreconditioning is planncd, rcquirc'ments should be adjusted to the rapabilitiesol thc system. Wcirs or watcr nrt.tcrs shouldbe installcd to rneasure total inflor'.Allorvfor fulure expansiorr. Prospective sorrrcesshould undtrqo long-ternr chenrical anallsisand biolosical or live fish tests, rvithemphasis on periods of dt'stratification w ht nreservoir or lakt' supply is contemplated.Studies should inc lude exar)rinatiorr ol'lvatershcd for potential sourccs o1 pollrrtionincluding turbiditr.filter and sterilize \\ atcr.Consitler equipmcnt t()l)tpt nclent upor) acr(-aqe irrrolled and requirements..15 {i5"F for Iish, 15 55'l' for egus. ['lan cqrripntentt() tool Or heat Iarter to temperalurcd csired.(t0 70'F dcsirablc for rvallevc and northcrnpike culture.;{l 8tl I Prolcrrcd drrrirrq ur,,rring sea.,'rr

.\ l c'tIl.tR\ Rl.(ft iRr.\r1..\ I sf',\Br.r 4. coYfINL.l.])IIAI('III.-I].\sYl\i ll( )t. ( lil 1 l..R L\Water supply (.continued)Auailabilit.y7 utLidlt.,Supph lines,\i1tTlt,,Rearing facilitiesTtf,Jr;eT'ffGravitt or artcsian flow preferred.Clear.Clear or onlv slightl; turbid.Adequate to rarrr Ijtimrs quantit\ of taterrcquired. Consider Iuture hirtcherv cxpansion rvfrt-n sizing supplt lrnt's.Main suppll lines adequatc to fill l -acre pondin 2 days ancl all ponds in l-l dars or less.Cast iron, concrete, or stccl, unless size or soilconditions make othrr materials desirablc.'l eflon, nrlon, or other provcn, durablc inertsubstances are acccptablc. Linder no conclitionsshould copper, brass, or zinc galvanizecl pipe be used.Racewars and circular pools.Earthen ponds.Rectangular race\\'a) s: l.l' x u0' x .10' or(i'x (i0'x lli"; Burrou,s recirculation poncls:17 x 7;' ; 11' Swedish t,vpe ponds:lJ(i'x 3(i'l circular ponds: r,ar\inq frorn (i to50 feet diamcter, con(.rete or Iiberulass construction.Earthen ponds: 0.75 to 1.0 acrc preferred; I to.1 acres allouable; 0.1 to 0.5 acrc for specialI;laor slopeIntake tonlrolpurposcs. Minimurn depth of ll lect at shallou'cnd, (j Ii'ct at dccp encl Ior rearin{ponds. [)eeper ponds (10 l2 Icet) ma1 beclesirable in northern areas, and fbr channclcatfish rearing regirrdless of clirrate. A 2:lslope is standard rvith riprap on sidcs andl3:l slope without riprap. Dyke tops shouldbe l2 feet tvidc rvith qravel surlace. C)orcwall rnandatory. Sced banks to grass.0.{i" to 1.0" in l0', cxr.ept botton of rt'circulationponds, which should be level.Headbox u ith concrcte overllou rvall andadjustable metal rvcir platc control lirr indi,vidual racewals, or pipe discharginu abovethe pond tater surface; inlct sliould bc fullwidth of race\\'ay.Cast iron pipc w,ith shutofl r irlvc for take oll'to ponds.It mav be dcsirable t() have trvosupplies: the main supply at the outlet t

3bIISH HA'TCHF],RY MANAG!]MEi\'ITABLE 4. CoNTINUEI)HA'TCH I']RYSY M BOt-C]RI'TI]I{IARearing facilities Go n ti nued)Outlet controLScreen slatsFreeboardll'ater thanges IArrangementElectric linesScreensWalk.sCCCC(-Uprovide fresh water in the catch basin whenpond is harvested; and a supplemental supplyat the opposite end from the outletstructure. l'he supplies should enter thepond above the water surface or not lowerthan the top of the drain structure.Overflow full width of raceway, with standpipeor valve that is tamperproof.Standard plans are available, and may bemodified to include concrete baffle andvalve where pumping is necessary. Structureslocated in the bank should have adequate wing-walls to prevent sloughing ofembankments. Outside catch basins shouldbe used where practicable and servc as manyponds as feasible. Provide steps and walkwayaround the catch basin. A minimum of10"" slope in pipeline from the pond kettlesto the outside catch basin is required. Outsidecatch basins must have a fresh watersupply available. Kettle chimneys shouldhave l" X 3" keyway for safety covers.Doublc slots in walls and floor at drain end,either 2-inch double angle or 2-inch channelof noncorrosive metal.6 l2 inches in raceways, pools.In earthen ponds, I ll inches is sufficient.Ponds should be oriented to limit sweep ofprevailing winds.Minimum of 3 per hour, except one for Bur'rows recirculation ponds.Double in series or in rows. Provide l4 feet orwider driveways between series. Allow sufficientfall between series for aeration; lti-24inches is recommended, up to 1.tr feet isac cep tab le.To be laid at the time of construction either inraceway walls or alongside with outletsspaced to satisfy operational requirements.Consider automatic feeder installations,floodlights, raceway covers, etc.Perforated noncorrosive metal.l4-16-inch concrete walkways, broon finish;aluminum skid-proof grating. For safety allopen flumcs, control structures, etc., shouldbe covered with nonslip grating.

HATCHERY REqUIREMENTS 37Taslr 4. coN'rrNUEDIT'IMHATCH[,RYSYMBOLCRITERIARearing facilities (continued)Type of soilTwAvoid rocky terrain or unstable soil conditionssuch as swamps and bogs. Obtain subsoilinformation during site investigations. Conducttest borings prior to selecting pond site.Avoid rocky soil, gravel, limestone substrata,or old stream beds. Seek solid ground reasonablyimpervious to water for earthenponds.TroughsTtPeTwFiberglass, metal, wood; rectangular,14'x 14" x 8" deep or rectangularScreensArrangementTTCCWwl6'x 16" x 16" double, deep-type.Perforated metal.Double with individual supply and drains. Ifused in series, allow fall between tanks of atleast l2 inches and an aisle between tanks.TanksTlpe and si4TCircular 4-8 feet diameter, slopedbottoms ] inch per foot of radius; rectangu-ScreensWater changesArrangementTTTCCCwwwlar, 3'x.3'x30' double arrangement.Perforated aluminum.Five per hour.For convenience, with sufficient aisle space forEg incubation Twhandling and removing fish.Commercial incubators such as Heath orequivalent recommended. J". culture orhatching boxes may be adaptable in someinstances.Effluent treatmentTWProvide settling basin of size and design thatwill effectively settle out solids from usedwater prior to its release from the hatcheryproper.BuildingsGeneral layutTwArrange buildings to expedite work, to presenta pleasing appearance, and to be compatiblewith topography and approach routes. Con-General construction T C wsideration of local architecture is desirable.Provide adequate spacing between buildingsfor fire control.Design for economical heating; steam or hotwater is preferred for large buildings. Avoidcondensation problems in the tank room byproviding adequate insulation, ventilation,and heating.

3llFlsH llA r( Ht.R\ MANAULMLN ITABI.E 4. c()N.. r'rNLIIf)I1 |\1H A'I'C H [, I{ \sl Nt I|()1.cRI l ltRl?1Hatcherl buildingsA rra ngene n I'I-ank roontInruhatian ureuFeed storage()encra/ staragc0JJitcLa boralorycCCCHatchery room, incubation area, feed storage,material storage, crew's room, toilet facilities,and small office area. Administrative officesand visitor facilities are not recommendedIor inclusion in hatchery building proper.Allow 2.5-foot aisles between tanks and.tr (ileet around cnds. Floor: concretc w,ithbroom finish, slope (1" in 10') for drainage.Walls and ceilings should be cement asbestosor other u aterproof material. Water supplyand drain ststerrs should be designedfor flexibility and alteration. lluricd linesshould be kept to a minimum. A fish transportsystem (pipe) from tank room to outside ponds is desirable. I'ortals in thc wallsare convcnicnt for moving fish out of thehatchery building.Separate room or designated area in the tankroom should be provided for egg incubation.Use of stackcd commercial incubators isrecommended. Permit flexibility in arrangingincubators, small troughs, or tankswithin the room.A separate storage area for dry feed is recommendedbecause of undesirable odors. Itshould be located convenicnt to use area.Consider bulk feed storase and handlingwherc morc than 50 tons of feed is requiredannually. Provide storage for one fourth ofannual dry fced rt'quircments with protection a{aainst moisture irnd vermin. Thereshould be proper ventilation and temperaturccontrol. he delivery arca should have'lturnaround room for large trucks. Includeelevation loading dock or mechanicalunloading equipment. If moist pcllcts areused, cold storage (10"F) for (i0 days supplyshould be provided,Locate convenient t() tank roorn, provideample size for intended purpose, and designfbr maximum utilization of w,all space withshelves and storage lockers.Main offices should bc located in a separateadministration building.Equipped and sized in accordancc with anticipatedneeds.

HA',fCHI..l{y RI.tqUInEN,tI,tN I Si.i9Teer-E 4. coNTrNUEnITEMIIA fCHER\sY \'1tlot,CRII't,RINHatchery buildingsL'reu roomGarage and storageShopbuildingOil and paintstorageFertilizer andchemicalstorage\continued)'t'c'fTtTCCw Room should provide lockcr space for eachemployee, and be adequate to serve as alunch room. Shower facilitics should be provided.Size of building or buildings is dependentupon the number of truck stalls requiredand the amount of material to be stored.Concrete floors should be broom finish witha I" in l0'slope to doors.Minimum of 300 square feet, floor l" in l0'slope to door or ccnter drain. Provide heatingand electrical systems to satisfy requirements,including 220-volt outlets; ovcrheaddoor should be at least l0 feet wide and l)feet high. Build in cabinets for tool storageand adequate work bench area.Provide a separate building, or materials maybe stored in another building if a specialroom rated for a 2-hour fire, with outsideaccess, is provided. The electrical installationshould be explosion, proof. Provideheat if storage of water base paints is contemplated.Explosion proof electrical fittings and positiveventiliation must be provided,Egg IncubationIncubation equipment is being modified constantly and several differenttypes are available commercially. There are basically two concepts for theincubation of fish eggs. One method involves the use of wire baskets orrectangular trays suspended in existing hatchery troughs to support theeggs. The hatched fry drop through the wire mesh bottom of the basket ortray to the bottom of the trough. This method does not require additionalbuilding space because existing facilities are utilized. Other methods of eggincubation are jar culture or vertical tray incubation. Additional space inthe hatchery building is required for this equipment. Control of water temperatureshould be part of any hatchery design involving egg incubationand hatching of fry. Heating or chilling of water for optimum incubation

40 FISHHAIcHIIRYNtANAcL,.N{Er\-Ttemperature is practical with today's equipment, which requires relativelyless water flow than older methods of egg incubation. Various types of eggincubation are described in detail in Chapter 3.Rearing FacilitiesRearing units for intensive fish culture include starting tanks or troughs forswim-up fry, intermediate rearing tanks for fingerlings, and large outdoorrearing ponds or raceways.Rearing units should be constructed so they can be drained separatelyand quickly. They should be adequate not only for the normal operatingflow in the hatchery but also for increased volumes of water needed duringdraining and cleaning of the facilities.Much personal opinion and preference is involved in the selection of arearing unit. Fish can be raised successfully in almost all types of rearingunits, aithough some designs have distinct advantages in certain applications.Adequate water flow with good circulation to provide oxygen andflush metabolic waste products are of paramount importance in the selectionof any facility. Ease of cleaning also must be considered.CIRCLTI,ARE,ARING UNITSLimited water supplies make semiclosed water recycling systems highlydesirable. The most efficient involve circular units and pressurized watersystems. By common acceptance, circular "tanks" refer to portable or semrportableunits up to l2 feet in diameter, while "pools" refer to permanentlyinstalled units up to 40 feet in diameter.There are basic criteria for construction and design of circular tanks andpools that are essential for their satisfactory operation. Double-walled or insulatedtanks reduce external condensation and eliminate dripping water.Adequate reinforcement must be incorporated in the bottom of the tank tosupport the filled units. There is no need for a sloping bottom except todry out the tank. Flat-bottomed tanks will self-clean well if proper watervelocities are established. The walls should be smooth for easy cleaning. Inthe case of portable tanks, the preferred material is fiber glass, but goodtanks can also be constructed of wood or metal. Large circular pools areusually constructed of masonrY.Without proper equipment, removal of fish from larger circular tanks isdifficult. crowding screens facilitate the removal of fish (Figu.es l6 and17). Some types of pools have inside collection wells for the accumulationof waste and removal of fish.

HATCHERY REqUIREMENTS4lFIGURE 16.Crowding screen used in smaller circular tanks.Large circular tanks and pools can be modified with a flat center bottomscreen and an outside stand pipe to control water depth for ease of operation.An emergency screened overflow is advisable in the event the bottomeffluent screen becomes clogged. Horizontal slots in the drain screens allowbetter cleaning action and are not as easily clogged as round holes. Theyalso provide more open screen area. cylindrical center screens used in4-6-foot diameter tanks provide better cleaning action if they are not perforatedin the upper portion, so that all effluent leaves the tank throughthe bottom portion.self-cleaning properties of the pool are dependent on the angle at whichinflowing water enters, The angle of inflow must be adjusted according tothe volume of water being introduced and the water pressure (Figure lg).The carrying capacity (number or weight of fish per volume of container)of circular tanks and pools is superior to those of troughs, rectangulartanks, and raceways if there is sufficient water pressure for reaeration.

42 FISH HATCHERY MANAGEMENTFTGURE 17. A fish crowder for large-diameter circular pools. (1) Screens areinserted into the three-sided frame, after it is placed in the pool. (2) One end ofthe frame is anchored to the pool wall with a retaining rod, and the other end iscarefully guided around the circumference of the pool, herding the fish ahead ofthe crowder. (S) T'he fish can be readily netted from the rectangular enclosureformed by the three sides of the crowder and weighed. Note the hanging dialscale and dip net (see inventory methods in Chapter Z). (l) 1'ne crowder alsocan be used for grading fish when appropriately spaced racks are inserted in theframe. Small fish will swim through the racks, leaving the larger ones entrapped.Aluminum materials should be used to construct the crowder to reduce weight'(FwS photo.)Air, driven into the water by the force of the inflowing water, provides additionaloxygen as the water circulates around the tank or pool. water introducedunder pressure at the head end of rectangular troughs or racewaysdoes not have the same opportunitythrough those units.to reaerate the water flowingAn example of the effect of water pressure on circular tank environmentsis presented in Table 5. At low pressures, the amount of dissolved oxygenlimits the carrying capacity; at high Pressures the buildup of metabolites(ammonia) limits production before oxygen does'There must be a compromise between velocity and the flow pattern bestsuited for feed distribution, self-cleaning action of the tank and the energyrequirement of continuously swimming fish. This environment may not besuitable for such fish as northern pike, which do not swim actively all ofthe time. When properly regulated, the flow Pattern in a circular tank willeffectively keep feed particles in motion and will eventually sweeP uneaten

HATCHERY REqUIREMENTS 43Tent.n 5. AMMONTA AND oxycEN coNcENTRATToNS tN tDENl'rcAL cTRCULARTANKS WITH HIGH ANI) LOW-PRESSURE WATER SYS'fEMS. TANK DIAME'I'L,RS ARE (JI'EE]', 'I'ANK VOLUMES ARE 530 GALLONS, FLOWS ARE IO GALLONS PER MINUTE(GPM), WATER CHANGES ARI] I.I3 PER HOUR, FISH SIzE IS tI.5 INCHES, AND OXYGENCONTI,N1' oF INFLOW WATER I].5 PAR'IS PL,R MILLIONPOUNDS PER SqUARE INCH (PSI).IPPM). WATER PRESSURE,S AREWATI']R PRESSUREHIUII l2r Pslll.u\\ il.i PsliFish weight (pounds)Pounds/cubic footPounds/gpmTotal ammonia (ppm)Dissolved oxygen (ppm)100 200 2501.4 2.U 3.5l0 20 250.21 0.44 0.807.5 6.5 5.23004.3ll00.u95.1100 200 2501..1 2.8 3.5l0 20 250.21 0.4,1 0.7,15.8 4.3 3.2food and excrement toward the center for removal through the outletscreen. velocity should never be great enough to cause fish to drift withthe current. Velocities for small fry may be so low that the tank does notself-clean and it will be necessary to brush accumulations of waste to thecenter screen.Oxygen consumption per pound of fish is higher in circular tanks thanin troughs and raceways. This difference may be due to the increased energydemand created by the higher water velocity in the circular tank.SWEDISH PONDThe Swedish Pond was developed specifically for Atlantic salmon. It issquare with rounded corners and its operation is very similar to that of acircular tank. Water is supplied through a pipe at the surface of the water.Waste water leaves the tank through a perforated plate in the center of theunit and the water level is controlled by a standpipe outside the wall of thetank. This design provides a large ratio of surface area to water volume;some fish culturists feel that Atlantic salmon require more surface area asthey do not stack over each other like other salmonids.RECTANGULAR TANKS AND RACEWAYSOriginally rectangular raceways were elongated earthen ponds. Such pondsrequired considerable maintenance because weeds and plants grew alongthe banks and the pond walls eroded. Irregular widths and depths resultedin poor water flow patterns.Rectangular tanks or troughs generally are used for rearing small fry andfingerlings in the hatchery building (Figu.e lg). These can be made ofaluminum, fiber glass, wood, or concrete. Potentially toxic material such as

44 FISH HATCHERY MANAGEMENTFIGURE 18. Piping and water flow arrangement in (A) 20-ft and (B) S-ft diametercircular tanks. The velocity and direction of water flow can be changed byswinging the horizontal pipe toward or away from the tank wall, and twistingthe pipe clockwise to change the angle of inflow. The velocity is lowest when thewater is directed downward into the tank, as shown in (n). fle bottom screenplate and external head-box (a.ro*) eliminate vertical screens and standpipes inthe center of the tank. Note that only one automatic feeder is required per tank.(fWS ptroto.)

HATCHERY REqUIREMENTS 45galvanized sheet metal should be avoided. Dimensions of raceways vary,but generally a length:width:depth ratio of 30:3:l is popular. Properly constructedraceways have approximately identical water conditions from sideto side, with a gradual decline in dissolved oxygen from the head end tothe lower end. Levels of ammonia and any other metabolic waste productsgradually increase towards the lower end of the unit. Although thisrepresents a deterioration of water quality, some hatchery workers feel thata gradient in water quality might be better for the fish because it attractsthem to the higher quality water at the inflow end of the raceway. In circularponds, there is no opportunity for the fish to select higher oxygen andlower ammonia levels.FIGURE 19. Rectangular aluminum troughs (background) and concrete tanks.Small swim-up fry generally are started on feed in the troughs and thentransferred to the tanks when they are 1-lj-inch fingerlings. (fWS photo.)

FISH HATCHERYMANAGEMENTlllr,la::i; il;:FIGURE 20. Rectangular circulation rearing pond ("Burrows pond"). Water isrecirculated around the pond with the aid of turning vanes (arrow). waste waterflows out through floor drains located in the center wall (not shown). (FWSphoto.)Raceways should not vary in width, since any deviation can cause eddiesand result in accumulation of waste materials. It is desirable to have approximatelyone square foot of screen area at the outflow of the racewayfor each 25 gallons per minute water flow. The percent open area of thescreen material must also be considered.Raceways have some disadvantages. A substantial supply of water isrequired and young fish tend to accumulate at the inflow end of the unit,not utilizing the space efficiently. The raceway is believed by manyhatchery operators to be the best suited for mass-producing salmon fingerlings.Its ease of cleaning, feeding, and fish handling make it desirablewhere ample water supplies are available.RECTANGULAR CIRCULATION REARING PONDThe rectangular circulation rearing pond is commonly known as the"Burrow's Pond" (Figure 20).Its basic design incorporates a center wall partly dividing a rectangularpond into two sections of equal width. Water is introduced into the pondunder pressure and at relatively high velocities, through two inflow pipeslocated at opposite ends of the pond. The flow pattern is controlled with

HA'TCHERY REqUTREMENTS 47vertical turning vanes at each pond corner. The water generally flowsparallel to the outside walls of the unit, gradually moves toward the centerwall, and leaves the pond through the perforated plates in the pond bottomat opposite ends of the center wall.The rectangular pond operates well at a water depth of either 30 or 36inches, depth being controlled by a removable standpipe in the waste line.An advantage of the rectangular circulation pond is that fish are well distributedthrough the pond and the water current carries food to the fish.This reduces concentrations of fish at feeding time. It is relatively selfcleaningdue to the water path created by the turning vanes at inflows of400 gallons per minute or greater. The water flow and turbulence along thecenter wall carry debris and waste material to the outlet.Pond dimensions and water flows are very specific, and any change inthe design criteria of this rearing unit may drastically alter the hydraulicperformance. This can prove a distinct disadvantage when flexibility of fishloads and water flows is desired.F]AR'fHEN PONDSThere is general agreement that concrete raceways are cheaper to maintainand operate than earthen ponds. Many fish culturists contend, however,that fish reared in dirt raceways and ponds are healthier and more colorful,have better appearing fins, and are a better product.Rectangular earth ponds usually are more convenient and efficient, andmay range in size from ] acre to 3 acres or more. Large ponds of irregularshapes are more difficult to clean, and it is harder to feed and harvest fishand to control disease in them.It is doubtful that fish production will become as intensive in largeearthen ponds as in smaller types of rearing units that have more waterchangeovers. Earth ponds do have relatively low water requirements andproduce some natural food. Successful culturing of trout and salmon havebeen accomplished in this type of facility and use of supplemental aerationhas increased catfish production dramatically in recent years.Harvest methods must be considered in the design of an earthen pond.Ponds must be drainable and contain a basin or collection area for harvestingthe fish (Figures 2l and 22), although many of the fish can be seinedfrom the pond before it is drained. The bottom of the pond should slopegradually toward the outlet from all sides. Pond banks should be built withas steep a slope as possible to avoid shallow-water areas along the edge ofthe ponds. Shallow areas collect waste material and allow dense growths ofvegetation to develop.Topography for construction of earthen ponds should be gently slopingand should have only moderate relief that can be economically removed.

FISH HATCHERY MANAGEMENTDRAIN PIPESCREENFIGURE 21. Pond outlet with catch basin. (Source: Davis 1953)The soil type is extremely important; clay soil or subsoil is best. Seepagetests at the pond sites are highly desirable. Seepage loss is not as importantin intensive salmon or trout culture where abundant quantities of waterflow through the pond, but is important in warmwater fish culture wherecirculating water flows are not required.Pond banks must be stable and well drained, because heavy tractors andfeed trucks must have access to the ponds preferably along gravelled roadways.Cement or transite material is best for water supply lines and drainlines.CAGE CULTUREThere is growing interest in cage culture of warmwater species such as catfish.This involves rearing fish in small enclosures built of wire or plasticnetting stretched over a frame. The cages are attached in series to floatingplatforms and anchored in rivers, lakes, and ponds or in protected areasalong coastal shores (Figu.e 23). Water currents and wind action carry

HATCHERY REqUIREMENTS 49FIGURE 22. A pond catch basin should have a supply line (arrow) toprovide fresh water to the fish when they are collected in the basin.This pond outlet also has a valve to open the pond drain.away wastes and provide fresh water. Cage culture is readily adapted toareas that cannot be drained or from which fish cannot be readily harvested.However, good water circulation must be assured, as an oxygendepletion in water around cages can cause catastrophic fish losses. Diseasecontrol is very difficult in cage culture and labor requirements are high.Feeding and treatment for disease must be done by hand.Largemouth bass fingerlings have been experimentally grown in cages.Cylindrical instead of rectangular containers were used to prevent crowdingin corners, which might cause skin damage to active fish such as bass.Moist trout pellets were fed to the fish; a retaining ring kept the food insidethe cage until it could be eaten.Frcunr 23.Cage culture of catfish. (FWS photo.)

FISH HATCHERY MANAGEMEN'IPEN REARINGMarine culture of salmon and trout in cages is called "pen rearing'" Penculture developed in Scandinavia and Japan, and commercial operationsbegan recently in Washington state. Rainbow trout and Atlantic, chinook,and coho salmon have been cultured in sea water. Coho salmon have beenthe most popular in the United States because they are relatively resistantto disease and can be fed formulated feeds. After initial rearing in freshwater, the juvenile fish complete their growth to marketable size in saltwaterpens.The term "sea ranching" is used when hatchery-reared salmon arereleased as smolts and allowed to migrate to the ocean to complete the marineportion of their life cycle.Pen rearing relies on tidal currents to supply oxygen and flush out metabolicwastes. The pens and floating structures cost less than a fish hatcheryon land, but must be protected from storms and high winds, and some typeof breakwater may be necessary. Some freshwater facilities must be availableon land, however, to incubate the salmon eggs and initially rear thefry.Water temperatures should not fluctuate greatly during pen culture;50-57'F are best for salmon. Prolonged higher temperatures lead to diseaseproblems. Although disease has been a serious problem in saltwater farming,recent developments in immunization of fish with vaccines show greatpromise for overcoming this (Chapt"t 5).SELECTION OF REARING FACILITIESNo single pond type will meet all requirements of fish hatcheries under allrearing conditions. Topography of the land, water source, species of fishbeing reared, and availability of funds and material will influence the selectionof the rearing unit. There is a wealth of literature describing thestrong and weak points of various hatchery rearing facilities, much of itconflicting. Personal preference based on experience tends to play a keyroll in making a selection. As pointed out previously, all of the types ofrearing units described successfully raise fish.In any hatchery construction there are several important objectives thatmust be kept in mind: (l) to provide a comPact rearing unit layout thatwill allow future development of the hatchery; (2) to Prouide adequateintake and outlet water supply facilities to meet the special requirements ofpond cleaning, treatment of fish for disease, and collection and handling offish; (3) to allow sufficient slope on pond bottoms for complete drainageand provide for a practical and efficient means of collecting fish forremoval, sorting, or treating; and (4) to provide adequate water and rearingspace to safely accommodate the anticipated production of the hatchery'

HATCHERY REqUIREMENTS 51Table 6 summarizes some of the characteristics of the various rearinsunits that have been described.Bio logica I Design CriteriaEvery species of fish has basic environmental requirements and each hasoptimum conditions under which it thrives and can be efficiently cultured.Biological criteria are essential in the design of any fish culture facility andthese criteria must be recognized before a successful fish rearing programcan be developed. The following comments are abstracted fromNightingale (1976).Information required in designing a facility includes fishery managementneeds, fish physiology, chemical requirements, disease, nutrition, behavior,genetics, and fish handling and transportation.These criteria must be developed for each species to be cultured. Thefishery management criteria include identification of the species to bereared, desired sizes for production, and desired production dates. Managementcriteria are usually listed as the number and length (or weight) of fishthat are required on certain dates. Physiological criteria include oxygenconsumption for various fish sizes and optimum temperatures forbroodstock holding, egg incubation, and rearing. Required rearing space,water flows, and spawning and incubation methods are included in thesecriteria. Chemical criteria include water quality characteristics that affectthe species of fish to be reared, such as tolerable gas saturation, pH, andwater hardness. Disease criteria include methods for disease prevention andtreatment. Nutrition criteria involve the types of feeds, feeding rates, andexpected food conversions at different temperatures and fish sizes.Behavior criteria are needed to identify special problems such as cannibalismand excessive excitability; for example, a decision may be made to useautomatic feeders to avoid a fright response. Genetic criteria involveselection of specific strains and matching of stocks to the environment.Transportation and handling criteria involve the acceptable procedures andlimitations for handling and moving the fish.The application of these criteria to the particular circumstances at eachhatchery can result in a biologically sound culture program. A program canbe developed by combining the management and physiological criteriawith the particular species and water temperatures to be utilized. Rearingspace and water flow requirements can be defined and combined with theother criteria to establish a suitable hatchery design.Good program development for fish hatchery design should include, inaddition to biological criteria, adequate site evaluation, production alternatives,and layout and cost estimates.

52 FrsH HATcIIERy MANAcEMENT'Tast.e 6. suMMARY ()F Rt ARtNc uNlt CHARAC I.uRIsl.tcs toR !tsn ltAt cHI.tRllrs,I'\'P!,\\':\'l l.R SL PPI,\ I ( ) I'( ,ti R \ I'll \Oircular tanLs and pond.;Various sizes available Pump or high-prcssure Lt,r,el or slopec:in a variety of materi-qravity; low flowals. Can be uscd forvolurre.small or laree groupsof fish.Retla ngu lar rtrru ln I io n rear i ng fon d sF'airly rcstricted to one Same as;rbovc. Samc as abovrsize; used extcnsivelywithlarge groups ol'production fish.Sudi.sh pondsVarious sizcs; used for Same as above. Same as abovesmall or large urou psof fish. Larger unitsmade ol concretc.Reclansular lanks and rarcu,a.l'sSmall t.nks made with a High- or kru pressurc Slrpc prelcrrecl 1irrvariety ol materials; sravity i high flou reaeration ol \!.aterused for srnall or large volumc prefcrred. betwccn units.groups of fish. Racewaysgcnerally madcol concrete for largegroups of productionfish.f,arthen fiandsGenerally for large High or krw prcssure l,erel preferred. Lionsiclgroups of production gravity; high or lorv t,rable arca ol lanclfish. flow volu mc. req u ire d.(.t1, rullut, dild fu tt tttttril\Various net matcrials; Lake or pond with somc llrotectccl shorrlint.can be built in various current or protectcdsizes. Cenerally coastal or strearn lirca.smaller units thanraccsays or ponds.

lA',r'cHERY RL,QL]TREMF,Nl S 53l)ist.t.\sL ( ()N I Il( )lSPI](]IAI, I.I.] I T RI.]SOircular lanks und pond.rcan be a problern bt'cuuse of recirculating$ater and lorv flou rates.controlling velocities, self-clcani.gRec la n uu I ar circu Ia tio n rrari n,q po nd.rSarrt'as abovo. Uniform velocity throughout; relativelyelf-clcaning. lixpensive construction.,\u,tdi.rh pandsSirme as abovr'.Self,cleaning; larce surface area to depthrati(). Moderate velocitl control.lltrltrtt!illot lunAt and rdrcua)\Vcrv qood if tank desi{ned properlv Rclatively inexpensive construction,readily adaptable to mechanization(cleaning, feeding, crowding).Earthen pond.tA problenl bccause ol florv patterns andbuildup of lastcs from larue qroups ofprodu

FISH HATCHERY MANAGEMENTTeSLt 7. TyptCAL BIOLOGICAL DATA ORGANIZED INTO A CONCISE FORMAI'T() AIDIN DEVELOPING A REARING PROGRAM AND ULTIMATE,LY DESIGNING A HATCHERY'TSOURCE: KRAMER, CHIN AND MAYO luTrr''TEMPAVERACI] TOI'AL FLOW SPACEDA'I'EEVENTLOCA A'I'URE NUMBDR'I'IC]NTF) IMILLIONS]LI,NGTH WEIGH'T N!]EDED NEEI)!,I)irNCHES) (pouNDS) (t;pvd)54March 15Egg 150June l5 Release take JarsIncubtionMarch 29 HatchAprilI Begin 8ST' 54feedApril 1 Release51May I3 RW' 60June 14 RWr 6645l5J1.3l.l1.00.20.21.02.02.61503005203,7807,0001503U0700I,2U04,7307,000oGallo.. per minute.iStu.t". tunkr.tRace-ays.APPLICATION OF BIOLOGICAL CRITERIAThe following is a brief explanation of the methodology and format usedby Kramer, Chin and Mayo, engineering consultants, in formulating a rearingprogram based on biological criteria. A typical program is used todemonstrate step-by-step planning. Table 7 illustrates how collected biologicaldata can be organizedconcisely.(l) Determine temperature. The first step in preparing a rearing program isto obtain either the ambient or adjusted monthly water temPerature expectedfor use in the hatchery system. Example: 54"F'(2) Determine ilate of eaent and length 0f fish. As a baseline for the programprojection, the date of spawning of the stock that will serve as parents forthe hatchery stocks should be determirred. Example: March 15. Determinethe date of hatching and initial feeding. Because water temperatures in thisexample will be approximately 54'F, calculate Daily Temperature units(Of d) as follows: 54"F - 32'F: 22 D'IIJ per day. (The standard basis forcalculating temperature units is 32'F.) Determine days to hatch, if 300DTU are required to hatch eggs: 300 DTU + 22 DTU : 14 days. Addingl4 days to March l5 makes the expected hatching date March 29' Determinethe day to begin feeding, if 40 DTUare required for hatched fry todevelop to feeding stage: 40 DTU+22 D'lu:2 days. This results in ananticipated feeding date of April 1. In this example, 12,000'000 fiy are tobe released immediately to begin natural feeding in a rearing pond, leaving

HATCHERY REQUIREMENTS 553,000,000 fry in the hatchery. Final release in this example calls for1,000,000,2j-inch fingerlings. Determine the date fish will reach this size.A search of the literature indicates that fry begin feeding at a length of 0.2inch. By a method described in Chapter 2, the growth is projected; the fishwill average 2.6 inches on June 15. (For convenience, all releases have beenassumed to fall on either the first or fifteenth of a month.)(3) Determine weight. Fish lengths can be converted to pounds from thelength/weight tables provided in Appendix l.(4) Determine the number of fish or egs required to attain desired proiluction.For example, to determine requirements on June I for a release of1,000,000 on June 15, use one-half the monthly anticipated mortality (7.5%in our example). Convert this to survival: 100% - 7.50h:92.5010, or 0.925.Divide the required number of fish at the end of the period by this survivalto determine the fish needed on June l: 1,000,000 + 0.925: 1,081,000. Thiscan be rounded to 1.1 million for planning purposes.(5) Determine total weight. Total weight is determined by multiplyingweight per fish (Appendix I) by the number of fish on that date.(6) Determine flow requirements. Adequate biological criteria must bedeveloped for the species of fish being programmed before flow rates canbe calculated. For this example a value of I gallon per minute per 10pounds of fish was used. Because there is a total weight of 3,850 pounds,3,850+10:385 gallons per minute are required. Flow requirements for incubationare based upon I gallon per minute per jar.(7) Determine rearing space. All density determinations follow the samemethod described for Density Index determinations in Chapter 2. Biologicalcriteria must be developed for each species of fish being programmed.BibliographyAmerican Public Health Association, American Water Works Association, and Water PollutionControl Federation, 1971. Standard methods for the examination of water andwastewater, l3th edition. American Public Health Association, Washington, D.C. 874P.ANlnrws, Jlvrs W., LEE H. KNtcHf, and TAKEsHt MuRAL 1972. Temperature requirementsfor high density rearing of channel catfish from fingerlingFish-Culturist 3414) :240 241.to market size. ProgressiveB,rnxs, Jor L., LAURTE G. Fowun, and J

56 FISH HA'I'CHERY MANAGEMENTBovn, ct,ertor, E. 1979. waterquality in warmwater fish ponds. Agricultural ExperimentalStation, Auburn University, Auburn, Alabama. 35{) p.BRt-tt, J. R. 1952. Temperature tolerance in young Pacific salmon, Genus Oncorhlnchus. Journal of the Fisheries Research Board of Canada S)(6):265-323.BuRRows, R(xjER E. ll)611. Water temperature requirements for maximum productivity of salmon.I)ages 29 34 in Proceedings of the Twelfth Pacific Northwest Symposrum onwater Pollution Research, US Department of Health Education and welfare, publicHealth Service, Corvallis, Oregon.-. 1972. Salmonid husbandry techniques. Pages 375 402 in Fish nurrition. AcademicBt:ss, Kll-xPress, Ncw York.and H.,lnny H. Cul:NOwtrH.1970. 'l'he rectangular-circulating rearing pond. progressiveFish Culturist :12(2):67 tl0.and Bogsy D. CclNtgs. 1968. Controlled environments for salmon propagation. progressiveFish-Culturist lJ0(l]):123 llJ(j.and E. R. MILl.FlR. 1971. Considerations for conventional trout hatchery desisnand construction in Pennsylvania. Progressive Fish-Culturist 33(2):86-9,1.CH.lru,rN, G. 1973. Effect of heavy metals on fish. Pages l4l-162in Heavy metals in theenvironment. Water Resources Research Institute Report SEMN WR 016.73.Covus, Bobby D. 1965. Effect of temperature on the development of salmon eggs. progressiveFish-Culturist 27(3) :13,1 1:.i7.cntrxln, Motttus c. 1972. Design problems of water re-use systems. Great Lakes FisheryBiology-EngineeringWorkshop (Abstracts), Traverse City, Michigan.DeVts, H. S. 1953. Culture and diseases of game fish. University of California Press, Berkeley.332 p.DL,coLA, JosrPH N.l1)70. water quality requirements for Atlantic salmon. US Departmentof the Interior, Federal Water Quality Administration,Heights, Massachusetts. 52 p.Northeast Region, NeedhamI)lNNts, BrnN,,LRD A., and M. J. MARCHysHyN. 1973. A device for alleviating supersaturationof gases in hatchery water supplies. Progressive Fish-Culturist l.i5(l):55 58.DWYER, WrllrAu P., and Howeno R. Trssln. 1075. A method for settleable solids removal infish hatcheries. Bozeman Information Leaflet Number 5, US Fish and Wildlife Service,Bozeman, Montana. ti p.EICHER, GlrlRcl J., Jr. ll)'t{i. Lethal alkalinity for trout in water of low salt content. Journalof Wildlife Management l0(2):82 tl5.ELt-rs, JAMES E., Drwr:v L. TACKr'r'r', and Rlrponds. Progressive Fish-Culturist,l0(4):165 166.R. c,qnTr:R. lgTt]. Discharee of solids from fishEvtc, JouN W. 1966. Bluegill sunfish. Pages 375-31)2 in AIex Calhoun, editor. Inlandfisheries management. California Department of Fish and Game, Sacramento,Environmental Protection Agency (US). I !75. Process design manual for nitrogen control. USEnvironmental Protection Agency, Office of Technology Transfer, Washington, D.C.Goorv, Wrr.r-r,rM A., J^cK D. LARMoyEUX, and JosErH J. VauNrrul:. 1976. Evaluation offish hatchery effluent treatment systems. US Fish and Wildlife Service, Washinston,D.C. 59 p. (Mimeo.)HAGIN, wrLr.rAM, Jr. l1)51]. Pacific salmon, hatchery propagation and its role in fishery management.US Fish and Wildlife Service, Circular 24, Washington, D.C.56 p.HERRMANN, R()BLRr B., C. E. WARREN, and P. Douoor.oFF. 1962. Influence of oxygen con_centration on the growth of juvenile coho salmon. Transactions of the AmericanFisheries Society !)l (2):155 l(i7.Hor

HATCHERY REqUIREMENTS 57and J. H. Tucrrn.1973. Thermal requirements for maturation,spawning, and embryo survival of the brook trout, Saluelinus fontinalis. Journal of theFisheries Research Board of Canada 30(7):975-984.HUNtnR, GenRv. 1977. Selection of water treatment techniques for fish hatchery water supplies.Baker Filtration Company, 5352 Research Drive, HuntingtonBeach, California.HutcueNs, LYNN H., and Rosenr C. Nonn. 1953. Fish cultural manual. US Department ofthe Interior, Albequerque, New Mexico. 220 p. (Mimeo.)INrnRuertoNAL ATLANTIC SALMoN FouNoertoN. 197 l. Atlantic salmon workshop. SpecialPublication Series 2(l). Sa p.JnNseN, Revuotto. 1972. Taking care of wastes from the trout farm. American Fishes and USTrout News, l6(5) : 4-6,21.JoNes, DAVID, and D. H. Llwts. 1976. Gas bubble disease in fry of channel catfish lctaluruspunctatus. Progressive Fish-Culturist 38(l) :41.KELLEY, JoHu W. 1968. Effects of incubation temperature on survival of larsemouth basseggs. Progressive Fish-Culturist 30(3) : 159-l 63.KNenr, G. L., and G. F. Anxtru. 1973. Ammonia toxicity levels and nitrate tolerance of channelcatfish. Progressive Fish-Culturist 35(a) :221-224.KonNst, Wer-rrn M., and LI-ovo L. SuIrH, Jr. 1976. Thermal requirements of the early lifehistory stages of walleye, Stizostedion uitreum uitreum, and sauger, Sti

58 FIsH HATCHERY MANAGEMENTand Rox.,tLD D. M,qvo. l1)72. Salmonid hatchery water rc-use systems. 'l echnicalReprint Number 2ll, Kramer, Chin and Ma1o, Consulting Engineers, St'attle, Washington.b P.-, and l{)7.1. Intensified fish culture combining u,ater reconditioning with pollutionabatement.'I'echnical Reprint Number 2'1, Kramer, Chin and Mayo, ConsultinqFingineers, Seattle, Washington. l3 p.M.,rcKlNxOr-, DANIFII- F. l1)(il). Effect of mineral enrichment on the incidence of white,sootdisease. Progressive Fish-Culturist 3l (2):7,1 7ll.MaHxxt.x, CoNn.,lD V. W. ll)71r. Commercial salmon culture in Puqet Sound. CornmercialFich Farmer and Aquat trlture Neui 2'll:i{ ll.MA\'(), RON^l.r) D. l1)7-1. A format for planning a commercial model aquaculture facilitv.Technical Reprint Number ii0, Kramer, Chin and Mayo, Consulting F)nginters, Seattle,Washington. l5 p.McrConllcx, J. Hr.rw,r.nn, KlNutlH E. I. Hor..rNsctN, and []. R. J()NES.l1)72. Flllects oftemperaturc on growth and survival of young brook trout, Salulinus Jbntinalis. Journalofthe Fisheries Research Board ofCanada 2!)(tt):1107 lll2.McKl.r,.J^cK E., and Hlnoln W()r.r. l1)63. Water quality criteria. California State WaterQuality Control Board, Publication Nurnber i:)-A, Sacrarnento. 5.18 p.Mcn-lrl, WILI-r^Nl J., and J.lcrr< E. BAu.t.\'. l1)75. Salmon rancher's manual. National MarineFisherics Service, NorthwcstBay, Alaska, Processed Report. 1)5 p.Fisheries Center, Auke Bay Fisheries Laboratory,, AukeMI'lCHtrNl, D()L GI.AS L. 11)71. Effects of tlie salinity ol natural waters on various species oftrout. Wyoming Game and Fish Cornmission, Cheyenne.NIGH'rlN(;Al-[], J()tlN W. l1)7(i. Development of biological design criteria for intensive cultureof warm and coolu,ater species. Technical Reprint NumberMayo, Consultinq Engineers, Seattle, Washington. 7 p.41, Kranter, Chin andNOVo.ttit, ANIHoNY J., and Cr.rxn'tn V. W. M,qHrur

HA'TCHERY REqUIREMENTS 59Srl:l:ctt, RIctt,rnD E. l1)71|. Trout metabolism characteristics and thc rationaJ design of nitrification facilities for watcr re-use in hatcheries. Transactions of the Arncrican Fisht'riesSociety I0212) :321J 3i1.1.and W. E. LEyEND[.1]KrR. 11)(j1]. F ish tolerance to dissolvecl nitroqen. EnqincerinqExperimental Station Technical Report, Nerv Mexico Statc Universitr','fechnicalReport Number 5{), l,as Cruces.St,ot"rl, Srr,ptttx H. 1970. Fish and invertebrate culture. John Wiley and Sons, Neu York.1,15 p.Srrcnxr,v, R()ts[.Rr R., and B. A. Srltco. l1)71. Salinitl' to]erance of catfish hybrids. l ransactionsof the American Fisheries Society 1(X)(1):7{X) 71)2.Stltn-{;Lr, H. S. l1)57. Relationship of pH of pond u'aters to their suitabilitv of fish r:ulturc.Proceedings of the Pacific Scientific Congress l0:72 75.WEDEIr{Evr-R, G.tnv A. 11)77. Environmental requiremcnts for fish health, Pages '11 55 rzProceedings of the International Symposium on Diseases of Cultured Salmonids,'I'avolek, Inc., Seattle, Washington.Wnorltl-vl.n, G,rRv A., and Jlltr,s W. W()()D. l!)7,1. Stress as a predisposing factor in fishdiseases. US Fish and Wildlife Service, Fish Disease Leaflet llli, \Vashineton, I).C. it p.WESTERS, Hennr', and K[]r'rH M. PRAI I. l!)77. Rational design of hatcheries for intensive salmonidculture, based on metabolic characteristics. Progressive Fish-Culturist39(4):ls7-165.WrLr.oucHB\', H,q.nvnr', How,rno N. l,ensr:u, andJ.'I'.Bo\\'l'lN. ll)72. The pollutional effects offish hatcheries. American Fishes and US I'rout News l7(i.]):ti 7,'20 21.

2Hatch"ryOperationsProduction MethodsThe information presented in this chapter will enable the fish culturist toemploy efficient management practices in operating a fish hatchery. Properfeeding practices, growth projections, and inventory procedures are a fewof the essential practices for successful management. Although particularspecies are used in examples, the concepts and procedures presented in thischapter can be applied to warmwater, coolwater, and coldwater fish culture.L ength- Weight Re la tions hipsIncrease in fish length provides an easily measured index of growth.Length data are needed for several aspects of hatchery work; for example,production commitments are often specified by length. On the other hand,much hatchery work, such as feed projections, is based on fish weight andits changes. It is very useful to be able to convert back and forth betweenlength and weight without having to make measurements each time. Forthis purpose, standardized length-weight conversion tables have been availablefor several years. These are based on the condition factor, which is theratio of fish weight to the length cubed. A well-fed fish will have a higher60

HA'|CHERY OPERATIONS6Iratio than a poorly fed one of the same length; it will be in better condition,hence the term condition factor.Each fish species has a characteristic range of condition factors, and thisrange will be small if fish do not change their bodily proportions as theyg.ow (some species do change, but not the commonly cultured ones). Rei_atively slim fish, such as trout, have smaller typical condition factors thando stouter fish such as sunfish.The value for a condition factor varies according to how length is measuredand, more importantly, according to the units of measurement,English or metric. For purposes of this book, lengths are total lengths,measured from the tip of the snout (or lower jaw, whichever projectsfarther forward) to the tip of the tail when the tail is spread normally.when measurements are made in English units (inches and pounds), thesymbol used is c. For metric measurements (millimeters, g.ams), the symbolis -6. The two types of condition values can be converted by the formulac: 36'13f,. In either case, the values are quite small. For example,for one sample of channel catfish, condition factors were c: 2gltt x l0 7(0.0()029ltl) and ,f : tJ0.76 x l0 ;.once c is known, the tables in Appendix I can be used to find lengthweightconversions. The eight tables are organized by increasing values ofc, and representative species are shown for each. Because not all speciesare listed, and because C will vary with strains of the same species as wellas with diet and feeding levels, it is wise to establish the condition factorindependently for each hatchery stock. weigh a sample of 50-100 fishtogether, obtaining a total aggregate weight. Then anesthetize the fish andmeasure their individual lengths. Finally, calculate the average length andweight for the sample, enter the values in the formula c (or K): wl L3,and consult the appropriate table in Appendix I for future lensth-weiehtconversions.Growth RateGrowth will be considered as it relates to production fish, generally thoseless than two years of age. The growth rate of fish depends o., -urry factorssuch as diet, care, strain, species, and, most importantly, the water tem_perature (constant or fluctuating) at which they are held.Knowing the potential growth rates of the fish will help in determiningrearing space needs, water-flow projections, and production goals. The abilityto project the size of the fish in advance is necessary for determiningfeed orders, egg requirements, and stocking dates. A key principle underlyingsize projections is that well-fed and healthy fish grow at predictablerates determined by water temperature. At a constant temperature, the

62 FISH HATCHERY MANAGEMENTdaily, weekly, or monthly increment of length is nearly constant for somespecies of fish during the first I j years or so of life. Carefully maintainedproduction records will reveal this growth rate for a particular species andhatchery.Example:On November I, a sample of 240 fish weighs 12.0 pounds.The water temperature is a constant 50'F. From past hatchery records, it isknown that the fish have a condition factor C of 4,010 x l0 ; and thattheir average monthly (fO-auy) growth is 0.66 inches. Will it be possible toproduce 8-inch fish by next April l?(l) The average weight of the fish is 12 pounds/24O fish : 0.05 poundsper fish. From the length-weight table for C : 4,000 x l0i (Appendix I),the average fish length on November I is 5.00 inches.(2) The daily growth rate of these fish is 0.66 inch/3O days : 0.022inch/day.(3) From November I through March 31, there are 151 days.(4) The average increase in fish length from November 1 through March31 is l5l days x 0.022 inch/day : 3.32 inches.(5) Average length on April I is 5.00 inches + 3.32 inches : 8.32 inches.Yes, 8-inch fish can be produced by April l.GROWTH AT VARIABI-E WAT'ER TEMPERATURESIn the previous example a growth of 0.660 inch per month at 50'F wasused. If all factors remain constant at the hatchery, growth can be expectedto remain at 0.660 inch per month and growth can readily be projectedfor any given period of time. Not all hatcheries have a water supplythat maintains a constant temperature from one month to the next. Unlesswater temperature can be controlled, a different method for projectinggrowth must be used.Growth can be projected if the average monthly water temperature andincrease in fish length are known for several months. The Monthly TemperatureUnits (MTU) required per inch of growth must first be determined.Monthly Temperature Units are the average water temperature fora one-month period, minus 32'F (the freezing point of water). Thus, ahatchery with a monthly average water temperature of 50'F would have l8MTU (50" - 32'F) available for growth. To determine the number of MTUrequired for one inch of growth, the MTUthe monthly gain in inches (available from past records).for the month are divided byConsider a hatchery with a water temperature that fluctuates from a lowof 4l'F in November to a high of 59"F during June. June would have 27MTU (59'-32'F) but November would have only I MTU (+t'-sz"F).

HATCHERYOI'ERATIONS 63Let us assume from past records that the fish grew 0.33 inch in Novemberand 1.00 inch in June. How many MTUof growth?are required to produce one inch(t) In November, 9 MTU + 0.33-inch gain : 27 MTIJ per inch ofgrowth.(2) InJune, 27 MTIJ - 1.0-inch gain: 27 MTIJ per inch of growth.Once the number of MTUrequired for one inch of growth is determined,the expected growth for any month can be calculated using the equation:MTU for the month + MTU required per inch growth : monthlygrowth in inches.Example: From past hatchery records it is determined that 27 MTU arerequired per inch of growth, and the average water temperature for themonth of October is expected to be 48'F. What length increase can beexpected for the month of October?(t) The MTU available durine the month of October will be 16(48'- 32'F).(2) Since 27 MTIJ are required for one inch of growth, the projected increaselor October is 0.59 inch (tO + ZZ).If fish at this hatchery were 3.41 inches on October 1, the size can be projectedfor the end of October. The fish will be 4 inches long (3.41+0.59).Generally, monthly variation occurs in the number of MTU required perinch of growth, and an average value can be determined from past records.Carrying CapacityCarryingcapacity is the animal load a system can support. In a fishhatchery the carrying capacity depends upon water flow, volume, exchangerate, temperature, oxygen content, pH, size and species of fish beingreared, and the accumulation of metabolic products. The oxygen supplymust be sufficient to maintain normal growth. Oxygen consumption varieswith water temperature and with fish species, size, and activity. Whenswimming speed and water temperature increase, oxygen consumptionincreases. As fish consume oxygen they also excrete metabolic productsinto the water. If the fish are to survive and grow, ammonia and othermetabolic products must be diluted and removed by a sufficient flow ofwater. Because metabolic products increase with increased fish growth andovercrowding, the water flow must be increased.Low oxygen in rearing units may be caused by insufficient water flow,overloading with fish, high temperature which lowers the solubility of

64 FISH HA.I.CHERY MANAGEMENToxygen in water, or low oxygen concentration in the source water. Athatcheries with chronic low oxygen concentrations and comparatively highwater temperatures, production should be held down to levels that safelyutilize the available oxygen, or supplemental aeration will be required. Adepleted oxygen supply can occur at night in ponds that contain largeamounts of aquatic vegetation or phytoplankton, and fish kills may occurafter the evening feeding. Here again, aeration may be necessary toincrease the oxygen supply.The carrying capacity of a rearing unit is usually stated as pounds of fishper cubic foot of water. Reference is also made to the pounds of fish pergallon per minute water inflow. In warmwater fish culture the carryingcapacity as well as production is usually expressed in pounds per acre.Although these criteria are commonly used to express carrlting capacity, they areoften used without regard for each other. This can be misleading. The term FlouIndex refers to the relationship of fish weight and size to water inflow andthe term Density Index refers to the relationship of fish weight and size towater volume. There are clear distinctions in the affects of these two expressions.The Flow Index deals specifically with the amount of oxygenavailable for life support and growth. The Density Index indicates the spacialrelationship of one fish with another. Even though water flows may beadequate to provide oxygen and flush wastes, too much crowding maycause behavioral and physical problems among the fish.VruI.coftrJ 1L r.a0.un-nLV.0.AVERAGE WEIGHT IN GRAMSFIGURE 24.Effect of fish size onsalmon, expressed as pounds of(From Burrows and Combs 1968.)maximumloading density offish per cubic foot of water.

HAl'CHERY OPERATIONS 65=JL=UF=zEz.Ja-U)IIIaz.fo-I5o9t /tb10g. 15g45 /tb 30/ rnFISH SIZEFlcunE 25. Carrying capacity of oxygen-saturated waterat normal activity level of fingerling chinook salmon asaffected by water temperature and fish size. (Source: Burrowsand Combs 1968.)catastrophic fish losses because of overloaded rearing facilities are anever-present danger in fish hatcheries. Many successful managers haveoperated a fish hatchery as an art, making judgements by intuition and experience.However, there are several quantitative approaches for estimatingcarrying capacities in fish hatcheries.Experience has shown that fish density can be increased as fish increasein size. Figure 24 demonstrates the increase in density that is possible withchinook salmon. The carrying capacity of oxygen-saturated water at fivewater temperatures and several sizes of chinook salmon fingerlings ispresented in Figure 25. Oxygen is usually the limiting factor at warmer

FISH HATCHERY MANAGEMENTIaf,Loa ozlo-^Q^v(UFIGURE 26.FISH LENGTH IN INCHESThe weight of different sized fish that would receive thesame quantity of food (5 pounds) at a Hatchery Constant of 10.(Source: Piper 1972.)water temperatures. These two graphs do not depict 0ptimum stocking ratesbut rather what we believe to be the maximum loading or density that mustnot be exceeded if normal growth rates are to be maintained.There is a relationship between the amount of feed that can be metabolizedin a given rearing situation and the pounds of fish that can be carriedin that rearing unit. There is much suPPort for two major premisespresented by David Haskell in 1955:l. The carrying capacity is limited Uy (e) oxygen consumption, and (B)accumulation of metabolic products.2. The amount of oxygen consumed and the quantity of metabolic productsproduced are proportional to the amount of food fed.Haskell postulated that the accumulation of metabolic products and theconsumption of oxygen are the factors that limit the carrying capacities ofrearing units. If this is true, metabolism is the limiting factor because boththe utilization of oxygen and production of metabolic products are

HAI'CHERY OPERATIONS 67regulated by metabolism. If the carrying capacity of a unit is known for aparticular size and species of fish at any water temperature, then the carryingcapacity for another size of the same species held at other water temperatureswill be the weight of fish thaf would consume the same amountof feed.FLOW INDEXThe feeding guide developed by Buterbaugh and Willoughby demonstratesa straight line relationship between the length of fish in inches and percentbody weight to feed (Figu.e 2tj). At a Hatchery Constant of 10, 100 poundsof 2-inch fish will receive the same quantity of food (5 pounds) as 200pounds of 4-inch fish, olt00pounds of 8-inch fish. (The Hatchery Constantis explained on page 245.)Haskell states, "if the carrying capacity of a trough or pond is known forany particular size of fish at a particular temperature, then the safe carryingcapacity for other sizes and temperatures is that quantity of fish whichwill require the same weight of feed daily." By Haskell's premise, if 100pounds of 2-inch fish is the maximum load that can be held in a rearingtank, then 200 pounds of 4-inch fish, 300 pounds of 6-inch, or 400 poundsof 8-inch fish also would be maximum loadsThe followingformula was derived for a Flow Index, where fish size ininches was used instead of weight of food fed to calculate the safe carryingcapacity for various sizes of trout.F : Flow IndexF:I,y+(Lxt)W : Known permissible weight of fishZ : Length of fish in inches1 : Water inflow, gallons per minuteTo determine the Flow Index (,F), establish the permissible weight offish in pounds (W) at a given water inflow (f) for a given size fish (Z).The Flow Index (F) reflects the relationship of pounds of fish per gallonsper minute water flow to fish size.As an example, 900 pounds of 4-inch trout can be safely held in a racewaysupplied with 150 gallons per minute water. What is the Flow Index?F:900+(+xt50)F : 1.5How do you establish the initial permissible or maximum weight of fishwhen calculating the Flow Index? A Flow Index can be estimated by

FISH HATCHERY MANAGEMENTadding fish to a rearing unit with a uniform water flow until the oxygencontent is reduced to the minimum level acceptable for the species at theoutflow of the unit (5 parts per million recommended minimum oxygenlevel for trout). The information required for calculating the Flow Indexcan also be determined with an existing weight of fish in a rearing unit byadjusting the water inflow until the oxygen content is reduced to 5 partsper million at the outflow of the unit.The Flow Index can then be used to determine the permissible weight ofany size fish (l/), by the formula: l,y: F x L x I.Example: In the previous example, a FIow Index of 1.5 was determinedfor a raceway safely holding 900 pounds of 4-inch trout in 150 gallons perminute water flow. (t) Ho* many pounds of 8-inch trout can be safelyheld? (2) How many pounds of 2-inch trout?\t) 14/: l.5x8xl50W :1,800 pounds of eight-inch trout0)w:t.5x2xt5oW :450 pounds of two-inch troutFurthermore, when weight of fish is increased or decreased in a raceway,the water inflow requirement can be calculated by the formula:r:yry+@xL).For example, if 450 additional pounds of 8-inch trout are added to theabove raceway containing 1800 pounds of 8-inch trout, what is the requiredwater inflow?1 : (1800 +450) + (1.5 x 8)1 : 18ti gallons per minute water inflowThe Flow Indexshown in the example should not be considered arecommended level for all hatcheries, however, because other environmentalconditions such as water chemistry and oxygen saturation of the watermay influence the holding capacities at various hatcheries.Table 8, with an optimum Flow Index of 1.5 at 50"F, considers the effectsof water temperature and elevation on the Flow Index. This table isuseful in estimating fish rearing requirements in trout and salmonhatcheries. For example, a trout hatchery is being proposed at a site 4,000feet above sea level, with a 55'F water temperature. Production of 4-inchrainbow trout is planned. How many pounds of 4-inch trout can be safelyreared per gallon per minute water inflow (if the water supply is near 100'[roxygen saturation) ?

HA'TCHERY OPERATIONS 69Tasle 8. FLOw INDEX RELATED To wA'TER TEMPERATURF, AND ELE,VATION- FORTROUT AND SALMON, BASED ON AN OPTIMUM INDEX OF F: I.5 A'f 5O'F AND 5,000FEE,T ELNVATION. OXYGE,N CONCEN'I'RAI'ION IS ASSUMED TO BE, AT OR NEAR IO0'".SATURATION, (SOURCE: BRUCE B. CANNADY, UNPUBLISHED.)WATERTEMPL,RATLIRE(.F)t.l.t.\ A I tuN rt ut_ i lI,000 2,000 3,000 ,r,000 5,000 6,000 7,000 rJ,000 {),000.104l42,{:l442.70 2.6t 2.52 2.4.12.ri I 2.52 2.41 2.:Ja2.52 2.41 2.3.5 2.272.43 2.3r 2.27 2.l:,'2.,14 '2.2('2.ltl 2.ll2.3+ 2.25 2.t6 2.09 2.01 I .9.12.26 2. l8 2.09 2.02 I .9'1 L872.1lt 2.t0 2.0'2 1.95 I .uu l .tJ I2.1| 2.03 1.94 l .tilJ I .til )..7 +2.03 1.95 l.u7 1.81 t.71 l.6lJ454647.{ti492.'25 2. I 8 2. l0 2.0J2.tti 2.09'2.021.942.07 2.00 I .93 l.U6f.9tl 1.9 I l.lJj |.7 o1.89 l.tt3 ]176 r.70l.9ir l.tltit.87 1.801.7!t | .731.72 I .65t.64 l.5ll1.80 t.7 4 I .(ill l (i I1.7.t 1.r,7 l.t;t 1..;-1.6{i l.r;0 I.Jl l.{o1 .51t 1 .5:J l . t7 t.4zl.i l Llri t..l t t. 50515253545556575u591.80 1.74 l.6ti 1.621 .73 |.67 |.62 l.5t)t.67 l.til 1.56 I .50l.6l l.si 1.50 1.151.55 r.50 r.45 L40LiO 1.4; 1.40 1..i51 ..r5 1 .40 l.ll5 L3I1.41 1.36 l.3l 1.27I .ltrl | .32 | .'27 |.2.)1.32 l.2U l.24 l.l9l.56 t.50 |.4+ r.:l{) L3,t 1.291.50 1.1+ I .llti 1 .3,1 t.29 t.,2+| .44 I .39 L33 r .2{) t.').+ I . l9I .39 1.34 r .2!t | .21 I .20 L 15I .iJ'l 1.29 t.24 1.20 I . 16 1 . I I1 .30 1.25 l 20 I . 16 |.l'2 1.07L26 t.2t l.l(i t.t'z 1.08 1.0.1r .22 | .t7 l.l3 1.09 1.05 I .01l .l8 l. 1.1 I .01) 1.05 I .02 0.9r.tt.l5 l.r0 1.0{i 1.02 0.99 0.95606l6263641.29 t.24 1.20 l.l(i| .25 | .'2t | .t7 l. 13l.'22 t.|l{ Ll,t 1.09l.l8 l.l4 l. l l 1.07l.l5 l. 12 l.0l:t | .0 Il.ll 1.07 l.0lll.Ou l.0'1 1.00l .05 l .01 0.971.03 0.99 0.951.00 0.9(i 0.920.91) 0.9(i 0.1)20.!)7 0.{)3 0.900.9'1 0.t) I 0.ti70.92 O.ltfl 0.tt50.1.t9 O.lJ(i 0.u3(t) fne Flow Index (f) is t.gO (tabte 8,4,000 feet elevation,55"F temperature).(Z) We can now estimate the permissible weight of trout that can be heldper gallon per minute, by the formula W: F x L x I, where F: 1.30,Z:4 inches, and 1: I gallon per minute. Approximately 5.2 pounds oftrout can be safely reared per gallon per minute water inflow (t.gO x 4 x 1).The effect of water temperature on the Flow Index can readily be seen inthe table. For instance, a hatchery at a 5,000-foot elevation having a water

FISH HATCHERY MANAGEMENTtemperature drop from 50' to 46'F would have an increase in Flow Indexfrom 1.50 to 1.80, because the metabolic rate of the fish normally woulddrop and the oxygen concentration would increase with a drop in watertemperature. The reverse would be true with a rise in water temperature.Although Tabk I is useful for planning and estimating preliminarl carrying capacityin a trlut or salmon hatchery, it should be considered only as a guide andspectfic Flow Indexes ultimately should be deueloped at each indiaidual hatcherl.The table is based on oxygen levels in the inflowing water at or near100%r saturation. If a rise or drop in oxygen occurs' there is a correspondingrise or drop in the Flow Index, proportional to the oxygen aaailable forgrowth (that oxygen in excess of the minimum concentration acceptable forthe species of fish being reared).Example: There is a seasonal drop in oxygen concentration from 11.0 to8.0 parts per million (ppttt) lt the water supply of a trout hatchery, and theminimum acceptable oxygen concentration for trout is 5.0 ppm. The FlowIndex has been established at 1.5 when the water supply contained 11.0ppm oxygen. What is the Flow Index at the lower oxygen concentration?(t) Wlttr 11 ppm oxygen in the water supply, there is 6 ppm availableoxygen, since the minimum acceptable level for trout is 5 pp- (11 ppm-5pPm).(Z) Wittr 8 pp- oxygen in the water supply, there is 3 pp- available oxygen(8 ppm- 5 ppm).(g) fhe reduction in Flow Index is the available oxygen at 8 ppm dividedby the available oxygen at 11 ppm or a 0.5 reduction (e+6).(4) The Flow Index will be 0.75 at the lower oxygen concentration(r.s x o.s).Table 9 presents dissolved oxygen concentrations in water at various temperaturesand elevations above sea level. The percent saturation can be calculated,once the dissolved oxygen in parts per million is determined forthe water supply.Many hatcheries reuse water through a series of raceways or ponds andthe dissolved oxygen concentration may decrease as the water flowsthrough the series. As a result, if aeration does not restore the used oxygento the original concentration, the carrying capacity will decrease through aseries of raceways somewhat proportional to the oxygen decrease. The carryingcapacity or Flow Index of succeeding raceways in the series can becalculated by determining the Percent decrease in oxygen saturation in thewater flow, but only down to the minimum acceptable 0x!8en concentration for thefish species.Calculations of rearing unit loadings should be based on the finalweights and sizes anticipated when the fish are to be harvested or loadings

HATCHERY OPERATIONS7ITasr-E 9. DlssoLvED oxycEN rN PARTS pER MrLLroN FOR FRESH WATER rN EqurlrBRIUM WITH AIR. {SOURCE: LEITRITZ AND LEWIS 197(i.l1'[,M P!,RAI'I-REi'F)F,I,EVATIoN IN FEEI'1,000 2,000 3,000 4,000 5,000 6,000 7,000 tJ,000 9,000 10,000.1045,+04u49505l52535.155(i065707513.0 t2.5t2.t | | .7I 1.1) l 1.5ll.n ll.3ll.(i tl.211.5 ll.lI 1.3 10.9tt.2 lO.ttI 1.0 lO.tiI 0.{) 10.5l0.u l0.'1l 0. (; 10.310.0 9.(t9.4 1).I9.0 8.7u.(; t|.312.1 I 1.6| | .'2 10.1.iI l.l t0.710.9 10.510.8 I 0..110.6 10.310.5 l0.l10.,1 l 0.010.2 9.910. 1 9.ll10.0 9.69.9 9.lr9.3 U.t)tt.tJ u.4tt..1 u.0u.0 7 .7I 1.2 l0.ul0.ir l0.l10.3 9.9to.2 g.ltI 0.0 !,.79.9 9.59.U 9.49.7 9.39.5 9.29.4 9.19.3 9.09.2 U.9u.6 u.3n.l 7 .87.8 7.47.4 7.l10.,19.79.rt9.,t9.39.2LI9.0rJ.98.7u.(iu.58.07.57.26.tl10.09.39.29.19.08.98.7u.(iu.58..1tJ.3u.27.77.2(i.96.59.6 9.39.0 8.7ti.g ti.ritt.ti ti.lr8.7 8.38.6 U.2u.,1 tt.lu.3 ti.0rJ.2 7.9u.l 7 .8u.0 7.77.9 7.67.,1 7.17.0 6.76.7 tt.46.3 6.19.0u.,1u.38.'2r'1.07.97.u7.77.67.57.36.u(i.4tt. I5.llreduced. In this way, maximum rearing unit and water flow requirementswill be delineated and frequent adjusting of water flows or fish transferscan be avoided.Generally, these methods are limited to intensive culture of fish in situationswhere oxygen availability is regulated by the inflowing water. In extensiveculture systems involving large ponds, oxygen availability dependsto a greater extent on oxygen replacement through the surface area of thewater. Water inflow in such situations is not as significant as pond surfacearea and water volume in determining carrying capacity.Estimates of oxygen consumption under intensive cultural conditionshave been determined for channel catfish. Oxygen consumption rates declineas the available oxygen decreases, and there is a straight-line (semilog)relationship between fish size and oxygen consumption; smaller fishrequire more oxygen per unit size than larger fish (Figure 27).The data in Figure 27 can be used to estimate the carrying capacity forchannel catfish if the available oxygen in a rearing unit is determined. Oxygenconsumption will change proportionately as the water temperature increasesor decreases.DENSITY INDEXCarrying capacity has been discussed in relation to water inflow or, morespecifically, oxygen availability. What affect does density, as pounds of fish

FISH HATCHERY MANAGEMENT3.53.0>- 2.5o- ^^a z.vLar I.5

HATCHERY OPERATIONS7'.]in Figure 28. There is no effect on the rate of length increase or foodconversion of rainbow trout as frsh density increases from less than I to 5.6pounds per cubic foot.A rule of thumb that can be used to avoid undue crowding is to holdtrout at densities in pounds per cubic foot no greater than 0.5 their lengthin inches (i.e.,2-inch fish at one pound per cubic foot,4-inch fish at twopounds per cubic foot, etc.). A density index can be established that is theproportion of the fish length used in determining the pounds of fish to beheld per cubic foot of rearing space. Fish held at densities equal to one-halfatIE.UAL"amJ72.5OU)tUz.LOU;Ur.zzr.l-az.U)Ia,'/.^- .'-l \./,:/'/ ,t.ta'8/v'CONVERSIONt--t\---z^-----BIWEEKLY GROWTH PERIODSFIcunE 28. Relationship of cumulative length increase, foodconversion, and pounds per cubic foot (ftr) of rainbow troutreared in aluminum troughs for l0 months. (Source: pipert972.)

74 FISH HATCHERY MANAGEMENTTABLE IO. RECOMMENDED HATCHERY POND LOADINGS (POUNDS OF FISH PER GAL-LoN PER MINUTE, INFLOW), BASED ON DISEASE CONSIDERATIONS, FOR CHINOOKAND COHO SALMON HELD IN lJO X 2O.FOOT PONDS. THE VALUE,S REPRESENT FINALPOND OR RACEWAY LOADINGS A1' 'TIME OF RELEASE OR HARVEST FOR FISH SIZES OFlOOO }ISTI PER POUND AND LARGL,R, I,OADINGS SHOUI,D NOTEXCEEDTHE'IABLEVALLTE BEFORE TIME O!' REI,EASE, INFORMATION IS NOT AVAILABI,E FOR OTHER.I'EMPERAI'URES. SIZES, OR SPE,CIES O!' FISH. (SOURCE: WEDEMEYER AND WOOD I97'1.]WA I I,]R1'I,M PI'JRAl rrnrs ("F) 1,000 500FISH SIZ!] iNUMBER PI]R POI.'ND]100 33Coho salmonllu,1u5ll63(iuli.5'2.72.25.0'1.03.02.0u.0(;.0,+.53.51.5I 1.010.07.05.02.015.0 20.0 25.01,1.0 16.0 11J.010.0 12.0 15.07.0 9.0 10.03.0 ll.0 ,1.0l'all and spring chinook salmon3lJ,1u5u(ilI3.02.52.0,1.03.02.2t.26.05.0ll.53.08.06.5.1.53.5l 1.0 r2.0 13.09.0 10.0 l l.06.0 7.5 9.0.1.0 5.0 5.5their length have a density index equal to 0.5. A useful formula to avoidovercrowding raceways is:W:DXVXLWhere I,/ :Permissible weight of fishD : Density index (0.5 suggested for trout)I/ : Volume of raceway in cubic feetZ : Fish length in inchesRaceway or pond volume requirements can be calculated with the formula:V:W+(oxL).Volumes of circular tanks can be determined from Table C- I in AppendixC.This concept of space requirement assumes that the Density Indexremains constant as the fish increase in length. In reality, larger fish maybe able to tolerate higher densities in proportion to their length. Thismethod has proved to be a practical hatchery management tool, nonetheless,and can be used with any species of fish for which a Density Indexhas been determined.

HAI'CHERY OPL,RATIONS 7 5Warmwater Fish Rearing DensitiesChannel catfish have been reared at densities of up to eight pounds Per cubicfoot of water. Stocking density and water turnover both had substantialeffects on growth and food conversion. Reduced growth due to the increasein stocking density was largely compensated by increased water exchange,and growth rate data indicated that production of over 20 pounds per cubicfoot of water was possible in a 365-day period. High-density culture ofcatfish in tanks or raceways can be economical if suitable environmentalconditions and temperatures are maintained'Fish weight gain, food utilization, and survival may decrease as fish densityincreases, but faster water exchanges (inflow) will benefit high stockingdensities. The best stocking densities and water exchange rates will takeinto consideration the various growth parameters as they affect theeconomics of culturing channel catfish. Stocking densities between five andl0 fish per cubic foot have been suggested as feasible and production canbe increased to higher densities by increasing the oxygen content withaeration, if low oxygen concentration is the limiting factor.Acceptable stocking densities for warmwater fish are related to the typeof culture employed (intensive or extensive) and the species cultured. Theappropriate density is influenced by such factors as desired growth rate,carrying capacity of the rearing facility, and environmental conditions.Most warmwater fish, other than catfish, normally are cultured extensively.The following paragraphs cover representative species of the major groupsof commonly cultured warmwater and coolwater fishes. Stocking rates forrelated species can be estimated from these examples.LARGEMOUTH BASSProduction methods used for largemouth bass are designed to supply 2-inch fingerlings.Fry are stocked in prepared rearing ponds at rates varying from 50'000to 75,000 per acre. If a fingerling size larger than 2 inches is desired, thenumber of fry should be reduced. Normal production of small bass rangesfrom 30 to 150 pounds per acre depending on the size fish reared' the productivityof the rearing pond, and the extent to which natural food hasbeen consumed and depleted.The length of time required for the transferred fry to grow to a harvestablesize depends mainly upon the prevailing water temPerature and theavailable food supply. Normally, it is 20 30 days in southeastern UnitedStates at a temperature range of 65-75'F.A survival rate of 75 to 90'fl isacceptable. A higher survival suggests that the number of fry stocked wasestimated inaccurately. Less tharr 7 5ol: survival indicates a need for

FISH HATCHERY MANAGEMEN'Timproved enumeration technique, better food production, or control ofdisease, predators, or competitors.Production of 3- to 6-inch bass fingerlings requires careful attention tosize uniformity of the fry stocked. The number of fry stocked is reduced by75 to 90'h below that used for 2-inch bass production. Growth past a sizeof 2 inches must be achieved mainly on a diet of immature insects, mainlymidges. If a size larger than 4 inches is needed, it will be necessary to providea forage fish for the bass. There are no standard procedures for this,but one method is to stock lj-inch bass at a rate of 1,000 per acre into apond in which fathead minnows had been stocked at a rate of 2,000 peracre 3 or 4 weeks previously. The latter pond should have been fertilizedearlier with organic fertilizer and superphosphate so that ample zooplanktonwill have developed to support the minnows. The minnows are allowedto grow and reproduce to provide feed for the bass when they are stocked.If weekly seine checks show that the bass are depleting the supply offorage fish, additional minnows must be added to the pond. Variablegrowth among bass fingerlings is common but if some fingerlings becometoo much larger than others, cannibalism can cause heavy losses. If thisoccurs, the pond must be drained and the fingerlings graded.BLUEGILLNumerically, bluegills and redear sunfish are the most important of the culturedwarmwater fishes. Generally, spawning and rearing occurs in thesame pond, although some fish culturists transfer fry to rearing ponds forone reason or another.In previously prepared ponds, broodstock bluegills I to 3 years old arestocked at a rate of 30 to 40 pairs per acre. Spawning-rearing ponds forbluegills can be stocked in the winter, spring, or early summer. About 60days are required to produce harvestable-size fingerlings under averageconditions.CHANNEL CATFISHChannel catfish reared in ponds are stocked at a rate of 100,000 to 200,000fry per acre. At these rates, survival should be 80%, and 3- to 4-inch fingerlingscan be produced in 80 to 120 days if there is adequate supplementalfeeding. Stocking at a higher rate reduces the growth rate of fingerlings. Astocking rate of 40,000 to 50,000 per acre yields 4- to 6-inch fingerlings in80-120 days if growth is optimum.Although channel catfish can be reared on natural food, production islow compared to that obtained with supplemental feeding. A well-fertilizedpond should produce 300-400 pounds of fingerling fish per acre, with no

HATCHERY OPERATIONSsupplemental feeding. Up to 2,000 pounds or more of fingerling fish peracre can be reared with supplemental feeding.If fish larger than 4 inches are desired, stocking rates must be reduced.Experimental evidence suggests that 1,500,3- to 6-inch fingerlings per acrewill produce l-pound fish in 180 days.HIGH-DENSITY CATFISH CULTURESpecialized catfish culture systems have received much publicity in recentyears, and several high-density methods are currently under investigation.These include the use of cages; earthen, metal, or concrete raceways; varioustank systems; and recirculation systems. High-densityfish culturedemands not only highly skilled and knowledgeable management but alsorequires provision of adequate amounts of oxygen, removal of wastes, and acomplete high-qualitydiet. The methods used for calculating carryingcapacity in salmonid hatcheries can readily be used for intensive culture ofcatfish.STRIPED BASSAt present, most striped bass rearing stations receive fry from outsidesources. Eggs are collected and usually hatched at facilities located nearnatural spawning sites on the Atlantic coast. Fry are transferred to thehatchery at I to 5 days of age. There they are either held in special tanksor stocked in ponds for rearing, depending on the age of the fry andwhether or not they have sufficiently developed mouth parts to allowfeeding.Earthen ponds are fertilized before stocking to produce an abundance ofzooplankton. In these prepared ponds, striped bass fry are stocked at a rateof 75,000 to 125,000 per acre. A stocking density of 100,000 fry per acre,under normal growing conditions, yields 2-inch fingerlings in 30 to 45days. Survival is very erratic with this species, and may vary from 0 to100% among ponds at the same hatchery. As with most pond-cultured fish,the growth rate of striped bass increases as the stocking density decreases.If a 3-inch fingerling is needed, the stocking density should be reduced to60,000 to 70,000 fry per acre.Culture of striped bass larger than 3 inches usually requires feeding formulatedfeeds. Striped bass larger than 2 inches readily adapt to formulatedfeeds, and once this has taken place most of the procedures of trout culturecan be applied.NOR'THERN PIKE AND WAI,LEYEThese coolwater species represent a transition between coldwater andwarmwater cultural methods. A combination of extensive and intensive

78 FISH HATCHERY MANAGEMENTculture is applied. Fry are usually stocked in earthen ponds that have beenprepared to provide an abundance of zooplankton. Fry are stocked at densitiesof 50,000 to 70,000 per acre to produce 2-inch fingerlings in 30 to 40days. Because of the aggressive feeding behavior of these species, especiallynorthern pike, care must be taken not to let the zooplankton decline orcannibalism will occur and survival will be low. At a size of 2 to 3 inchesthese fish change from a diet of zooplankton and insect larvae to onepredominantly of fish. At this stage, the fingerlings usually are harvestedand distributed. If fish larger than 2 to 3 inches are desired, the fingerlingscan be restocked into ponds supplied with a forage fish. Stocking rates donot normally exceed 20,000 per acre' and generally average about 10,000to 15,000. As long as forage fish are present in the pond, northern pike andwalleyes can be reared to any size desired. As the fish become larger, theyconsume more and larger forage fish. Northernpike and walleyes arestocked at lower densities if they are to be raised to larger sizes. Stockingdensities of 10,000 to 20,000 fingerlings per acre are used to rear 4- to 6-inch fingerlings; 5,000 to 10,000 per acre for 6- to 8-inch fish; and usuallyless than 4,000 per acre for fish 8 inches or larger'This method of calculating carrying capacities of ponds or raceways ignoresthe effects of accumulative metabolic wastes. Where water is reusedthrough a series of raceways, the Flou Index wou]rd remain fairly constant,but metabolic products would accumulate.Inaentory MethodsThe efficient operation of a fish hatchery depends on an accurately maintainedinventory for proper management. Whether weight data are applieddirectly to the management of fish in the rearing units or used in an administrativecapacity, they are the criteria upon which most hatchery practicesare based.Hatchery procedures that are based upon fish weight include feed calculations,determination of number per pound and fish length' loadings ofdistribution trucks for stocking, calculations of carrying capacities in rearingunits, and drug applications for disease control.Administrative functions based upon weight of fish include preparationof annual reports, budgeting, estimating production capability of rearing facilities,recording monthly production records, feed contracting, and planningfor distribution (stocking).Some managers inventory every two or three months to keep their productionrecords accurate; others use past record data to project growth forseveral months and obtain a reasonable degree of accuracy. An inventory isessential after production fish have been thinned and graded, and one

HATCHERY OPE,RATIONS 79should be made whenever necessary to assure that records provide accuratedata. In any inventory, it is imperative that fish weights be as accurate aspossible.INl'ENSIVE CLILl'UREFish can be weighed either by the wet or /ry method. The zs'el method involvesweighing the fish in a container of water that has been preweighedon the scale. Care must be exercised that water is not added to thepreweighed container, nor should water be splashed from it during weighingof the fish. This method is generally used with small fish. Dry weighingis a popular method of inventorying larger fish. The dip net is hungfrom a hook at the bottom of a suspended dial scale. The scale should beequipped with an adjusting screw on the bottom, so the weight of the netcan be compensated for. Dry weighing eliminates some fish handling and,with a little practice, its accuracy is equal to that of wet weighing.The most common ways to determine inventory weights are the samplecount,total-weight, and pilot-tank methods.In the sample-counting method, the total number of fish is obtained initiallyby counting and weighing the entire lot. In subsequent inventories, asample of fish is counted and weighed and either the number per pound orweight per thousand is calculated (Figr-,.e 29). To calculate the number perpound, divide the number of fish in the sample by the sample weight' Tocalculate the weight per thousand, divide the sample weight by the numberof fish (expressed in thousands). ttre total weight of fish in the lot then isestimated either by dividing the original total number of fish (adjusted forrecorded mortality) by the number per pound or by multiplying it (nowexpressed in thousands) by the weight per thousand. This method can beinaccurate, but often it is the only practical means of estimating the weightof a group of fish. To assure the best possible accuracy the following stepsshould be lollowed:(t) fn" fish should be crowded and sampled while in motion.(Z) Otrc" a sample of fish is taken in the dip net, the entire sampleshould be weighed. This is particularly true if the fish vary in size. Thepractice of weighing an entire net full of fish will obtain more replesentativedata than that of weighing preset amounts (such as 5 or 15 pounds).Light net loads should be taken to prevent injury to the fish or smotheringthem.(g) Wtren a fish is removed from water it retains a surface film of water.For small fish, the weight of the water film makes up a larger part of theobserved weight than it does for larger fish. The netful of fish should becarefully drained and the net bottom wiped several times before the fishare weished.

80 FISH HATCHERY MANAGEMENTFIGURE 29. Muskellunge fry being sample-counted for inventory. (courtesyWisconsin Department of Natural Resources.)(4) Several samples (at least five) should be taken. If the calculatednumber of fish per pound (or weight per 1,000) varies considerably amongsamples, more samples should be taken until there is some consistency inthe calculation. Then the sample values can be averaged and applied to thetotal lot; all samples should be included in the average. Alternatively, thecounts and weights can be summed over all the samples, and an overallnumber per pound computed. Larger samples are required for large fish.Even with care, the sample-count method can be as high as 15-20% inaccurate.some fishery workers feel it is necessary to weigh as much as lzo/oof a population to gain an accuracy of 5-10%. Hewitt (tgag) developed aquarter-sampler that improved the accuracy of the sample count method(Figure 30).In the total-weight method, as the name implies, all of the fish in a lotare weighed, thus sampling error is avoided. Initial sample counting mustbe conducted during the first weighing to determine the number of fish inthe lot, but this is done when the fish are small and more uniform in size.This method involves more work in handling the fish, but is the most accuratemethod of inventorying fish.

HATCHERY OPERATIONS8IThe pilot-unit method utilizes a tank or raceway of fish maintained tocorrespond to other tanks or raceways of the same type' The pilot unit issupplied with the same water source and flow, and the fish are fed thesame type and amount of food per unit of body weight. All the fish rearedin the pilot unit are weighed and the gain in weight is used to estimate thefish weight in the other rearing units. This method is more accurate thansample counting for fish up to six inches long.EXTENSIVE CULTUREFish grown in ponds are relatively inaccessible and difficult to inventoryaccurately before they finally are harvested. Pond fish still are sampled frequently,as they are in raceway culture, but the value of such sampling isFIGURE 30. A quarter-sampler can be used to.accurately estimate the number offish per pound or weight per thousand fish. (l) A framed net with four removablepociets in the bo-ttom is designed to fit snugly in a large tub of water. (2)several netfuls of fish are put in the tub and when the frame is removed the fishare divided into four uniform samples. (f) Onty one-quarter of the fish are actuallyused in the sampling. The fish are counted and then weighed. (4) A modifiedframe design has onl of the net pockets closed (arrow) and the other threeopen.Astheframeisliftedoutofthetubthefishintheclosedpocketareretained for counting. It is felt that a sample taken in this manner, from severalnetfuls of fish, reduces bias in sampling' (FWS photos')

82 FISH HATCHERY MANAGEMENTFIGURE 31. Pond fish being sampled with a lift net. The fish areattracted to the area with bait.as much to determine the condition and health of the fish, to adjust feedapplications, and to estimate harvest dates, as it is to estimate growth andsurvival. Usually, it is impractical to concentrate all fish in a pond together,so sampling is done on a small fraction of the population. Numericalcalculations based on such small samples may be biased and unreliableexcept as general guidelines.One way to sample pond fish is to attract them with bait and then capturethem, as with a prelaid lift net (Figure 3l). ttre problem with thistechnique is that fish form dominance hierarchies, and the baited areaquickly becomes dominated by the larger and more vigorous individuals.This will bias the sample.Most pond samples are taken with seine nets. Such samples can be extrapolatedto the whole pond if the seine sweeps a known area, if few fishescape the net, and if the population is distributed uniformly throughoutthe pond. The area swept by the net can be calculated with little difficulty;

HATCHERY OPERATTONShowever, fish over ll inches long can outrun the pulled seine, and are likelyto escape, leaving a nonrepresentative sample. This problem can be partiallyovercome by setting the net across, or pulling it into, a corner of thepond instead of pulling it to a straight shore. The uniformity of fish distributionis the most difficult aspect to determine. Many species form aggregationsfor one reason or another. A seine might net such a cluster or therelatively empty space between them. It helps to sample several areas ofthe pond and to average the results, although this is time-consuming, andseines rarely reach the pond center in any case.Fish can be concentrated for sampling if the pond is drawn down. Thiswastes time-it can take two or three days to empty a pond of severalacres-and a lot of water. It also can waste a lot of natural food productionin the pond. Unless fish have to be concentrated for some other purpose,such as for the application of disease-control chemicals, ponds should notbe drawn down for sampling purposes.In summary, pond fish should be sampled regularly, but the resulting informationshould be used for production calculations only with caution.Fish GradingFish grading-sorting by fish length-makes possible the stocking of uniformlysized fish if this is necessary for fishery management programs. Also,it reduces cannibalism in certain species of fish; some, such as striped bassand northern pike, must be graded as often as every three weeks to preventcannibalism. Grading also permits more accurate sample counting and inventoryestimates by eliminating some of the variation in fish size. An additionalreason for grading salmon and steelhead is to separate smaller fishfor special treatment so that more of the fish can be raised to smolt size bya specified time for management purposes (Flgure 32).In trout culture, good feeding procedure that provides access to food byless aggressive fish can minimize the need for grading. However, grading offish to increase hatchery production by allowing the smaller fish to increasetheir growth rate is questionable. Only a few studies have demonstratedthat dominance hierarches suppress growth of some fish; in most cases,segregation of small fish has not induced faster grorvth or better food utilization.In any fish population there are fish that are small because of theirgenetic background and they will remain smaller regardless of opportunitiesgiven them to grow faster.In warmwater culture-and extensive culture generally-fish usuallycannot be graded until they are harvested. Pond-grown fish can vary greatlyin size, and they should be graded into inch-groups before they are distributed.Products of warmwater culture often are sold in small lots to

FISH HAI'CHEI{Y MANAGEMENl'several buyers, who find them more attractive if the fish are of uniform sizewithin each lot.A number of commercial graders are available. Mixed sizes of fish mayrequire grading through more than one size of grader. Floating gradingboxes with panels of metal bars on the sides and bottom are commonlyused in fish hatcheries. Spacing between the bars determines the size offish that are retained; fish small enough to pass between the bars escape.The quantity of fish in the grader at any one time should not exceed fivepounds per cubic foot of grader capacity. Small fish can be driven from thegrader by splashing the water inside the grader with a rocking motion.Recommended grader sizes for such warmwater fish as minnows andchannel catfish are as follows:MinnowsChannel catfishSpacing Length Spacing Lengthbetween of fish between of fishbars held bars heldftnches) Gnches) 6nches) Gnches)II(,1l)l() I:-'i,1llt;1li)l'll.l 2l:rI2()lI,) |29l'2iIl,t!(rl10{i1.18l) Irll;('{ri.lJA5(;78A 1]-inch grader will retain J-l-pound channel catfish. Catfish passmost readily through the bottom of a grader and minnows through thesides.Fish Handling and HaruestingHandling of fish should be kept to a minimum to avoid injury and stressthat can lead to disease or death. Losses from handling can be substantial,but they do not always occur immediately and can go unnoticed after thefish have been stocked in natural waters.An adequate supply of oxygen must be provided in the raceway or pondduring harvest, and during transit in containers. Silt and waste materialsuch as feed and feces in the water should be avoided or kept to aminimum. Overloading nets or containers will abrade the skin of the fish.Extremes in water temperature should be avoided in the hauling containersand between rearing units. Sudden changes in water temperature of 6"F or

HATCHERY OPERATIONS 85FIGURE 32. A mechanical crowder used in concrete rearing ponds \ /ith an adjustableWilco grader mounted on the crowder frame. (Courtesy California Departmentof Fish and Game.)greater have adverse effects on most fishes. The use of l-3% saline solutionfor handling and moving fish has been recommended by some fisheryworkers to reduce handling stress. Containers should be full of water. If thewater cannot slosh, fish will not be thrown against the sides of thecontainer.A dip net and tub can be used to avoid physical damage when smallpoundages of fish are moved. Large-meshed nets should be avoided, particularlywhen scaled fish are involved. Nets used for catfish commonly aretreated with asphaltum or similar substances to prevent damage due tospine entanglement.Many warmwaterfish hatcheries comprise a number of earthen pondsthat normally are harvested through a combination of draining and seining(Figure 33). When large poundages of fish are present, a substantial portionis removed by seining before the pond is lowered. The remainder are theneasily harvested from collection basins (Figure 34). Small fingerlings areharvested by lowering the pond water level as rapidly as possible withoutstranding the fish or catching them on the outlet screen.If the contents of a pond cannot be removed in one day, the pondshould be partially refilled for overnight holding. Holding a partially harvestedpond at a low level for long periods of time should be avoided

86 FISH HATCHERY MANAGDMENTFIGURE 33. Marketable size catfish being graded and harvested from a largeearthen pond (Fish Farming Experimental Station, Stuttgart, Arkansas).because this increases loss to predators and the possibility of disease.crowding and the lack of food also will reduce the ability of small fish towithstand handling stress. A fresh supply of water should be providedwhile the fish are confined to the collection basin'Although harvesting the fish crop by draining the pond has the majoradvantage of removing the entire crop in a relatively short time, trapping isanother popular harvesting technique. The advantages associated with trappinginclude better overall condition of the fish, because they are collectedin silt-free waterl reduced injury, because the fish are handled in smallnumbersl avoidance of pond draining; successful harvesting in vegetatedponds; avoidance of nuisance organisms such as tadpoles and crayfish; andreduced labor, as one person can operate a trap successfully. The majordisadvantage to trapping is it does not supply a reliably large specifiednumber of fish on a given date.The most widely used trap on warmwater fish hatcheries is the V-trap(Figure 35). Successful trapping requires knowledge of the habits of thefish and proper positioning of the device. The trap usually is used in combinationwith pond draining; it is positioned in front of the outlet screensand held away from them, against the water current, by legs or some othermeans. The trap is constructed so it floats with about 10% above the water

HATCHERY OPERATIONS 87surface and 90% below. As the pond is drained the trap simply falls withthe water level. Fish are attracted to the outlet screen for a number of reasons,the two main ones being the water current and the abundance of foodorganisms that are funneled there. Some species of fish are attracted tofresh cool water, and a small stream of this should be introduced near thetrapping area if possible. The fish attracted to the area have to swimagainst the outgoing current to keep from being pulled against the outletscreen. They rest behind a glass plate that shields them from the currentlfollowing this glass they come into the trap, from which they can periodicallybe harvested with a small net.The trap is used in another manner for harvesting small fish. Theadvanced fry and early fingerlings of many species, such as largemouthbass, smallmouth bass, and walleye run the shoreline of ponds in schools ofvarying numbers. To collect them, the trap is fixed far enough out in thepond that the fry swim between it and the shore. A wire screen lead runningfrom the mouth of the trap to the shore, and extending from thewater surface to the pond bottom, intercepts the fish. As they attemPt toget around the lead, the fish follow it toward deep water and into the trap.Four such traps set around a pond have caught up to 80% of the availablelargemouth bass fry.FIGURE 34.Removing fish from a collection basin in an earthen pond'

FISH HATCHERY MANAGEMENTFtcuRE 35. Diagram of a v-trap. Fish follow the wire screen into the V andenter the cage, where it is difficult for them to find a way back out through thenarrow opening in the V.Physical characteristics of earthen ponds play an important part in theefficient harvest of fish. Removal of all stumps, roots, and logs is necessaryfor harvesting with seines. The pond bottom should be relatiiely smooth toprovide adequate and complete drainage. Low areas that will not drain towardsthe collection basin should be avoided.Rearing Unit ManagementSanitationsanitation is an important phase of any animal husbandry. A number ofundesirable situations can arise when waste feed and fecal material collectin rearing units. If fish feed falls into waste material on the pond or racewaybottoms, fish will generally ignore it and it will be wasted. Excessivefeces and waste food harbor disease organisms and can accumulate in themucus of the gills, especially during disease outbreaks. Disease treatment isalso difficult in filthy rearing units because treatment chemicals may reactwith the organic matter, reducing the potency of the chemical. The wastematerial may become stirred up as the chemical is mixed in the water: thiscan be hazardous to the gills of the fish. Tanks, troughs, and racewaysmust be cleaned frequently, whatever species-cold-, cool-, or warmwater-isgrown in them.In large earthen ponds, accumulated waste may reduce the oxygen contentof the water. This can become a severe problem during periods of reducedwater flow in the warm summer months.

HATCHERY OPERATIONSMost fish diseases are water-borne and are readily transferred from onerearing unit to another by equipment such as brushes, seines, and dip nets.All equipment used in handling and moving fish can be easily sanitized bydipping and rinsing it in a disinfectant such as Roccal, Hyamine, or sodiumhypochlorite. Solutions of these chemicals can be placed in containersat various locations around the hatchery. Separate equipment should beprovided for handling small fish in the hatchery building and should notbe used with larger fish in the outside rearing units. Detailed proceduresfor decontaminating hatchery facilities and equipment are presented inChapter 5.Dead and dying fish are a Potential source of disease organisms andshould be removed daily. Empty rearing units should be cleaned andtreated with a strong solution of disinfectant and then flushed before beingrestocked. Direct sunshine and drying also can help sanitize rearing units.If possible, ponds and raceways should be allowed to air-dry in the sun forseveral weeks before they are restocked. To prevent long-term buildup oforganic matter, ponds typically are dried and left fallow for two to fivemonths after each harvest. Manytimes, the pond bottoms are disked,allowing the organic matter to be oxidized more quickly. After the pondsoil has been sun-baked, remaining organic material will not be releasedeasily when the pond is reflooded.Disinfection of warmwater fish ponds is a process by which one or moreundesirable forms of plant and animal life are eliminated from the environment.It may be desirable for several reasons: disease control; eliminationof animal competitors; destruction of aquatic weeds, among others. Disinfectionmay be either partial or complete, according to the degree to whichall llfe is eliminated. It is impractical, if not impossible, to achieve completedisinfection of eathern ponds.Disinfection of ponds with lime is a common practice, especially in Europe.This is particularly useful for killing fish parasites and their intermediatehosts (mainly snails), although it will also destroy insects, other invertebrates,and shallow rooted water plants for a few weeks. Calcium oxideor calcium hydroxide are recommended; the latter is easier to obtainand less caustic. Lime may be applied either to a full or dewatered pond(so long as the bottom is wet) ; in either case, the lime penetrates the pondsoil less than an inch. It is most important that the lime be applied evenlyacross the pond, and mechanized application is better for this than manualdistribution. Except for the smallest ponds, equipment for applying limemust be floated. This means that at least some water must be in the ponds,even though lime is most effective when spread over dewatered soils.Lime makes water alkaline. If the pH is raised above 10, much aquaticlife will be killed; above ll, nearly all of it. Application rates of 1,000 to2,500 pounds of lime per acre will achieve such high pH values. Appropriaterates within this range depend on the water chemistry of particular

FISH HA'I'CHERY MANAGEMENTponds' especially on how well the water is naturally buffered with bicarbonates.Agricultural extension agents and the Soil conservation servicecan provide detailed advice about water chemistry and lime applications.Normally, a limed pond will be safe for stocking within l0 days aftertreatment, or when the pH has declined to 9.5. However, a normal foodsupply will not be present until three to four weeks later.Chlorine has been used by fish culturists as a disinfecting agent. Tenparts per million chlorine applied for 24 hours is sufficient to kill all harmfulbacteria and other organisms. Several forms of chlorine can be obtained.Calcium hypochlorite is the most convenient to apply. It contains 700iichlorine and is readily available. It can be applied to either flooded ordewatered ponds.A 600 parts per million solution of Hyamine 1622, Roccal, or Hyamine3500 may be used for disinfecting ponds. Twice this strength may be usedto disinfect equipment and tools. The strength of the disinfecting solutionis based on the active ingredient as purchased.Water Supply StructuresThe water supply for a fish hatchery should be relatively silt-free and devoidof vegetation that may clog intake structures. For this reason, anearthen ditch is not recommended for conveying water because of algalgrowth and the possibility of aquatic vegetation becoming established. Athatcheries with a silt problem, a filter or settling basin may be necessary.The water intake structure on a stream should include a barred grill to excludelogs and large debris and a revolving screen to remove smaller debrisand stop fish from entering the hatchery.There are a vast number of methods used to adjust and regulate waterflows through fish rearing units. some of these include damboards, headboxeswith adjustable overflows, headgates, headboards with holes boredthrough them, molasses valves, faucet- type valves, and flow regulators.Each type has advantages.Generally, damboards and headboxes will not clog, and they provide asafe means of regulating water flows. They are particularly useful withgravity water supplies, but they are not easily adjusted to specific waterflows. valves and flow regulators are readily adjustable to specific waterflows and are preferred with pressurized water supplies, but are prone [oclogging if any solid material such as algae or leaves is present in thewater.water flows can be measured with a pail or tub of known vorume and astop watch when valves or gates are used to regulate the water flow. Damboards can be modified to serve as a rectangular weir for measuring flows(Appendix D).

HA'|CHERY OPERAI'IONS9IScreensVarious materials have been used to construct pond or raceway screens.Door screening and galvanized hardware cloth can be used, but clog easily.Wire screening fatigues and breaks after much brushing and must be replacedperiodically. Perforated sheet aluminum screens are used commonlyin many fish hatcheries today. They can be mounted on wood or metal angleframes. Redwood frames are easier than metal ones to fit to irregularconcrete slots in raceway walls.Perforated aluminum sheets generally can be obtained from any sheetmetal company. Some suggested sheet thicknesses are l6 gauge for largescreens (ponds, raceways: 30 x 96 inches) and ltl-20 gauge for smallscreens (troughs: 7 X l3 inches). Round holes and oblong slots are availablein a number of sizes (Figure 36). Horizontal oblong slots are preferred bysome fish culturists who feel they are easier to clean and do not clog asreadily as round holes. They can be used with the following fish sizes:Slot sizeFish size--X-- xln.1Ixlfry up to 1,000/lb1,000-200/lb200-30/tb- X'2'30/lb and largerPerforated aluminum center screens can also be used in circular rearingtanks, but only the bottom 2-3 inches of the cylinder should be perforated.These provide some self-cleaning action for the tank and prevent shortcircuitingof water flows by drawing waste water off the bottom of thetank.Pond ManagementPRESI,ASON PREPARATIONProper management of earthen ponds begins before water is introducedinto them. During the winter it is advisable to dry and disk ponds to promoteaerobic breakdown of the nutrient-rich sediments. Although some nutrientsare desirable for fingerling culture, because they promote algalgrowth on which zooplankton graze, an overabundance tends to producemore undesirable blue-green and filamentous algae. Relatively new pondswith little buildup of organic material, or those with sandy, permeable bottomsthat allow nutrients to escape to the groundwater, are less likely thanolder or more impermeable ponds to require drying and disking. They may

92 FISH HATCHERY MANAGEMENTFrcunn 36. Perforated aluminum screens showing (l) round holes, (2) staggeredslots, and (3) nonstaggered slots. (Courtesy California Department of Fish andGame.)actually leak if the bottom is disturbed, and it may be necessary to compacttheir bottom with a sheepsfoot roller, rather than to disk them.If a pond is to remain dry for several months it should be seeded aroundthe edges with rye grass (8-10 pounds per acte). This cover prevents erosionof pond dikes and it can be flooded in the spring to serve as a sourceof organic fertilizer. The grass should be cut and partially dried before thepond is reflooded, or its rapid decay in water may deplete dissolvedoxygen.Application of 1,000 pounds per acre of agricultural lime during the fallowingperiod, followed by disking, may imProve the buffering capacity of

HATCHERY OPERATIONS 93a soft-water pond. Fertilizers are often spread on the pond bottom prior tofilling, and nuisance vegetation may also be sprayed at this time.WILD.FISH CONTROLWild fish must be kept from ponds when they are filled, as they competewith cultured species for feed, complicate sorting during harvest, may introducediseases, or confound hybridization studies. Proper construction ofthe water system and filtration of inlet water can prevent the entrance ofwild fish.A sock filter is made by sewing two pieces of 3-foot-wide material into al2-foot-long cylinder, one end of which is tied closed and the other endclamped to the inlet pipe (Figure 37). lt can handle water flows up to1,000 gallons per minute. This filter should be used only on near-surfacedischarges, to prevent excessive strain on the screening.A box filter consists of screen fastened to the bottom of a wooden boxeight feet long, three feet wide, and two feet deep (Figrr.e 38), and is suitablefor water flows up to 1,000 gallons per minute. The screen bottom issupported by a wooden grid with I x 2 foot openings, which prevents excessivestress and stretching. The filter may be mounted in a fixed positionor equipped with floats. If the inlet water line is not too high above thepond water level, a floating filter is preferred. This allows the screen toremain submerged, whatever the water level, which reduces damage causedby falling water.If the water supply contains too much mud or debris and cannot be effectivelyfiltered, ponds can be filled and then treated with chemicals tokill wild fish. Rotenone is relatively inexpensive and is registered and labeledfor this purpose. It should be applied to give a concentration of 0.5to 2.0 parts per million throughout the pond. Rotenone does not alwayscontrol some fishes, such as bullheads and mosquitofish, and it requires upto two weeks to lose its toxicity in warm water and even longer in cold water.However, 2 to 2.5 parts per million potassium permanganate (f Utror)can be added to detoxify rotenone.AntimycinA is a selective poison that eliminates scaled fishes in thepresence of catfish. It does not kill bullheads, however, which are undesirablein channel catfish ponds. The chemical varies in activity in relation towater chemistry and temperature; the instructions on the label must beclosely followed. Expert advice should be sought in special cases.Chlorine in the form HTH, used at concentrations of 5 parts per millionfor as little as one hour, will kill most wild species of fish that might enterthe pond. Chlorine deteriorates rapidly and usually loses its toxicity afterone day at this concentration. Chlorine can be neutralized if need be withsodium thiosulfate. Chlorine is a nonspecific poison, and will kill most ofthe organisms in the pond, not only fish.

94 FISH HATCHERY MANAGEMENTFERTILIZATION PROCEDURESFertilization promotes fish production by increasing the quantity and qualityof food organisms. Bacteria are important in the release or recycling ofnutrients from fertilizers. Once in solution, nutrients stimulate growth andreproduction of algae which, in turn, support populations of zooplankton.UPPLY LINESOCK FILTEWATER SURFACESARAN SOCK ATTACHED TO THE WATER LINEFIGURE 37. Sock-type filters with saran screen for pondinflows, (Diagra- from Arkansas Game and Fish Commis.sion; photo courtesy of Fish Farming Experimental Station,Stuttgart, Arkansas.)

HATCHERY OPERATIONS 95UPPLY LIN EBOX FILTEWATER SURlllltlSCREEN BOX FILTERFIGURE 38. Box-type filters mounted in fixed positions.(Diagram from Arkansas Game and Fish Commissionlphoto courtesy of Fish Farming Experimental Station,Stuttgart, Arkansas.)Depending on the fish species, either algae or zooplankton (or both) supplyfood to fry and fingerlings.A number of factors effect the use of fertilizers, and responses are notpredictable under all conditions. Physical influences include area anddepth of the pond, amount of shoreline, rate of water exchange, turbidity,

FISH HA'f CHLI{Y MANAGL,MEN'Iand water temperature. Biological influences include type of plant and animallife present and the food habits of the fish crop. Chemical elements alreadypresent in the water supply, composition of the bottom mud, pH,calcium, magnesium, and chemical interactions have significant effects onfertilizer response.Not all ponds should be fertilized; fertilization may be impractical if apond is too large or too small. Turbid or muddy ponds with light penetrationless than six inches should not be fertilized, nor those having a highwater exchange rate. Ponds having low water temperatures may not give agood return for the amount of fertilizer applied. If the species of fish beingreared is not appreciably benefited by the type of food produced, fertilizationshould not be considered. In cold regions where winterkill is commonin shallow productive ponds, fertilization may be undesirable.Ponds should be thoroughly inspected before they are fertilized. Includedin the inspection may be a secchi disc reading to determine the waterturbidity; close examination for the presence of filamentous algae, rootedaquatic vegetation, and undesirable planktonic forms; oxygen determinationson any pond where low oxygen concentrations are suspected, and observationof nesting locations in spawning ponds.Fertilizer to be applied should be weighed or measured on platform orhanging scales, or with precalibrated buckets. It is necessary to calibrate abucket for each type of fertilizer used, because fertilizers vary considerablyin density. Small amounts of fertilizer may be dispensed with a metalscoop, Iarge amounts with a shovel or a mechanical spreader.Distribution of the fertilizer in the pond will vary with wind direction,size of the pond, whether organic or inorganic materials are used, and theparticular reason for fertilizing. On a windy day (which should be avoidedwhen possible), fertilizers should be distributed along the windward side ofthe pond. In general, organic fertilizers (especially heavy forms such asmanure) should be given a more uniform distribution than the more solubleinorganic ones. However, when insufficient phosphorus is thought to beresponsible for plankton die-off, an inorganic phosphate fertilizer should beevenly distributed over most of the pond. Ordinarily, inorganic fertilizerneed not be spread over any greater distance than about half the length ofthe pond on one side. If a pond is being filled or if the water level is beingraised, it may be advantageous to apply fertilizer near the inlet pipe.Avoid wading through the pond while spreading fertilizers, if possible.Wading stirs up the bottom mud and some of the fertilizer nutrients, particularlyphosphates, may be adsorbed on the mud and temporarily removedfrom circulation. A wader may destroy fish nests, eggs, and fry. Fertilizershould not be spread in areas where nesting activity is underway orinto schools of fry. Larger fingerlings can swim quickly away from areas offertilizer concentration.

HATCHERI OPF-RATIO\S 97TABLE I l.col,tposrrroNsNow u.t AL. llxi].lOI SI.]\'I,RAT, ORGANIC FERl'ILIZL,I{NIA'fL,I{IALS. iSOURC]I;(.\l(l|( )I l.t{ l n_tzt.l{\t tR()(;1.\ fH()SPH()RLS P()l^SSIL\1t,R() I l.jN ti\l)Rl I llsAlfalfa hayGrass hayPeanut vine hayCottonsecd rneal 3(i",Cottonseed meal .13",Fish mealPeanut mealMeat scrapSoybean oil mealHorse rnanureCow manurcChicken manureSheep rnanureC ladophera sp.Potamageton sp.Najas Jlexili.tC hara sp.Wood yeast ('I'orula)Green Italian ryegrassGreen ryeGreen oatsGreen vetchGreen, rvhite clover'2.371.12|.62.)_t)+7.t2t0.'22(t.9(iti.2 I7.070.,r1)0..1il1.3 I0.772.1)01.301.900.706.{)'8.(i0.500.420.+20.670.u20.2.t0.210.1lJ0.t13t.122.670.r;.15.lrl0.51)0.260.51)0.+00.390.320. 130.300.270.r12 1.9(;0.0{)0.t00.090.070.09oCalculated by dividing protein content by {i.25.2.01;1.20t.251.2',2l.+J0..10Ll51.900. +u0..1,10.5.10.592.0lJ2. l90.5r10..100.500.4I0.3ul .1. fi10. I lllJ.511,1.(i'2+.5.13.1) l5.u(i3.1) '2.1'11|.5 3 t.il51.0 3.5+1.',2 21).0.135.1 37..1 .13.9li.l 11.52.6 12.1)'2.613.51.'2 u. I5. I (i.(tORGANIC FERTILIZERSOrganic materials such as composted plant residues, manure, stabledrainage, slaughterhouse waste, and municipal sewage are very goodsources of nitrogen. They also contain a large Percentage of organic carbonas well as other minerals in small amounts. Typical analyses are shown inTable 11. Values may vary slightly depending on the conditions underwhich the crops were grown or the Products were processed.Organic fertilizers are recommended for only fingerling fish productionto accelerate the production of zooplankton in rearing ponds, particularlyin new or sterile ponds. Their use is limited by cost and labor requirementsfor application. The advantages of organic fertilizers are their (1.) shortercycle for plankton production than inorganic fertilizers, (2) decompositionto liberate CO2, which is used by plants for growth, (3) aia in clearingsilt-laden waters, and (4) use as a supplemental feed.Their disadvantages are that they (l) are more expensive than inorganic fertilizers,(2) may deplete the oxygen supply, (3) may stimulate filamentousalgae growth, and (4) require more labor to apply than inorganic fertilizers.

I ISH HA'I'CHLRY NTANAGEME,NTINORGANIC FERTILIZERSInorganic fertilizers are relatively inexpensive sources of nitrogen, phosphorus,and potassium, which stimulate algal growth, and calcium, whichhelps to control water hardness and pH.In nitrogen-free water,0.3 to 1.3 parts per million of nitrogen must be addedto stimulate phytoplankton growth, and to sustain this growth aboutone part per million must be applied at weekly intervals. In a normalhatchery pond this comes to about eight pounds of nitrogen per surfaceacre. Because nitrogen can enter the pond system from the atmosphere,watershed, and decomposing organic matter, it is not always necessary toadd more.For the operation of warmwater hatchery ponds, it is recommended thatnitrogen be included in the fertilizer applications during the late springand summer months for all ponds except those which have been weed-freefor at least three years. If development of phytoplankton is delayed longerthan four weeks, nitrogen should be added.Forms of nitrogen available for pond fertilization are listed on Table 12.Phosphorus is an active chemical and cannot exist alone except undervery specialized conditions. It is generally considered to be the most essentialsingle element in pond fertilization and the first nutrient to become alimiting factor for plant growth. Plankton require from 0.01U to 0.09 partper million as a minimum for growth. Several workers have recommendedapplications of about 1.0 part per million phosphorus pentoxide (P2O5)periodically during the production season.T'\BLI.] 12. \.. l t R()ct.tN Il.tR I I t-tzl.){s lf oR p()N D ENRIcII\I IiNT.pFl O IiC H l.NI I Cr\ t,PF]R(]I]N IAqL E( )r,Ss()t R( t.t \{.\ I URIAIF( )Rt\t I ]l..\NI I'ROCI.]Ns()l-t't I()\Ammonium nretaphosphateAmmonium nitrateAmmonium phosphateAmmonium sull'ateAnhydrous ammoniirAqua-ammoniaCalcium cyanamideDiammonium phosphatcU rcaSodiurn nitrate{NH r).rP()rt7"NHlNO.l33.5(Nu.,),,tct,ll,(NH,)rso,'20NH r.H2C)tt2NHr.H2()10 50CaCN22'2(NHr)2HI'o '2t'lH2HC()NH2,l ()NaNO I l(t+.o.1.05.0u.07.27.0"Also contains 7iJ P2O',.1'Also contains -llt ' I'2O t.rAlso contains,tlJ ,12' l'2Oi.

HAl'CHERY OPERAl'IONSTABLE13.s()L.l{CEs()tp2();tN-coNtN,l!.RCIALpH()spHAIEFI,,R'til.tzl.tRss()t'Rc t.t l\,l,\ I I.rRtAIcll r'r1r1 lc,\1. t. ()R\.'rL r..{ P2()1 .\\'1il.'\Ult. II\Ammoniummetaphosphate(NH1) rPo rVariable solubility: hasI 7' nitroqenBasic slag(cat))r.Prt), sit),Poor in cirlciun-richwa tc rsflone meall5Not readilv availableCalciu mca (po3)2(i0 {jjL,qual to superphosphatemetaphosphatein acid and neutral soilDefluorinatcdCa(ect,),-1 1.3Used prirnarilr. in lire'rockstock feeds; insolublein $ atcrD iam rnon iu rl(su,)rHto,53Cornplctcly uatt'r solu-phospha tcble has 2lnitroqenEnrichedCa(H2PO{)2.12About the same as orriisu perphosp hatenar) superllhosphateM onoammon iu rnNHlH2l'O++lJCorrpletelrwaterphosphatesolublc in form o[ammophosphate; hasI I ', nitrogcnOrdinaryca(H,P() r),I 8-20Notcompletcl\' $ atcrsu perp hosp hatesolublePhosphoric acidH JPOl7'2.5Water soluble and acidin reaationPotassiumKPO r;5 5lJEqual to or superior tometaphosphateordinarysuperphosphate;has it5 3itKrORock phosphate(Ca.(POn)2). CaF2'.1'2Least soluble ol calciurrsalts; availabilitv varies fron 0 to I 5'I riplelCa(H2t'O1)2).1-1-1 5 IA rnajor portion iswater-solublcPhosphorus will not exist for long in pondwater solution. Although bothplants and animals remove appreciable amounts of the added phosphate,the majority of applied phosphorus eventually collects in the bottom mud.Here, phosphorus may be bound in insoluble compounds that are permanentlyunavailable to plants. Some 90 95",, of the phosphorus applied tofield crops in fertilizers becomes bound to the soil, and the same may holdtrue in ponds.

100 FISH HATcHERY MANAcIEMEN fA number of phosphate fertilizers are available for use in ponds' Ordinarysuperphosphate is available commercially more than any other formand is satisfactory fbr pond use' More concentrated forms may save laborin applicatio.t, ho*"u"t' Sources of P2On in commercial phosphate fertiliz-ersarelistedinTablel3'Whennitrogenalsoisdesired'ammoniatedphos-phates are recommended as they are completely water-soluble and generallyshould give a more rapid resPonse' An application rate of 8 poundsP,O;persurfaceacreisnormalinpondfertilization'Thisamountsuppliesabout I part Per mrllion in a pond averaging about 3 feet .deepln theUnited States, the usual practice is to supply the needed phosphorusperiodically throughout the growing season' In Europe' however' the sea-sonalphosphorusrequiret"n"t'ut"suppliedinoneortwomassiveapplica-tions either belore ,r. shortly after pond is filled, or at the beginning andmiddle of the fish productio" cycle' A 50-l00"" increase over normalapplications is.lustifled in ponds with unusually hard waters' lareea-o,,,'t, of iron and aluminum, or high rates of water exchange'Potassium generally is referred to as potash' a term synonomous with po-,urrr.,- o*ii" (KrO)' l]tre most common sources are muriate of potash(I(Ct) and potassium nitrate (XNO') ' Potassium sulfate (f.:SOt) also is asource of Potassium'Potassium is less important than nitrogen or phosphorus for planktongrowth, but it functions in plants as a catalyst'Increasedphytoplanktongrowthoccurswithincreasesinpotassiumfrom0 to 2 parts per million; above 2 Parts per million there is no additionalphytoplankton growth' Many waters have an ample supply of potassium forplant growth, but where 'oil' o' the water supply are deficient or whereheavy fertilization with nitrogen and phosphorus is employed' addition ofpotassium is desirable' It ta" b" applied at the beginning of the productioncycle, or periodically during the cycle'. It is quite soluble and unless adsorbedby bottom deposits - tuk"tt up by plants' it can be lost by seepageor leaching'Calciumis essentral for both plant and animal growth' It seldom is defi-cienttothepointthatitexertsadirecteffectongrowth.Manyofitsef-fects are indirect, however, and these secondary influences contribute significantlyto the productivity of a body of water' Waters with hardness ofmore than 50 parts per million CaCO' are most productive' and those ofless than l0 parts ier million rarely produce large crops' Calcium acceleratesdecomposition of organic matter, establishes a strong pH buffersystem, precipitates iron, and serves as a disinfectant or sterilant' In somecases, fish production can be increased 25-10010 by adding lime at the rateof 2 to 3 tons Per acre'Calcium is available in three principal forms' It is 7l'li' of calcium oxide(cuo) o. quicklime, 5,[,],, of .ul.irr- hydroxide, (ca(ou)z-) or hydrated.lime, and up to 40'li, of calcium carbonate (CaCOt) or ground limestone'

HATCHERY OPERATIONS 101The form of calcium to apply depends upon the primary purpose forwhich it is used. Unless bottom mud is below pH 7, lime is not recommendedexcept for sterilization purposes. For general liming, calcium hydroxideor ground limestone are the forms most suitable. Each has certainadvantages and disadvantages which make it desirable in specific situations.Waters softer than l0 parts per million total hardness generally requrreapplications of lime, whereas waters harder than 20 parts per million seldomrespond to liming. The need for lime may be indicated when inorganicfertilization fails to produce a substantial plankton bloom. However,analysis of the water or, preferably, of the bottom mud should be made fortotal hardness and alkalinity before lime is applied. A state agriculturalexperiment station or extension service can assist with these (and other)analyses.Liming can be done with the pond either dry or filled with water. Suitablemechanical equipment is needed to assure uniform dispersion. Aboat-mounted spreader can be used for ponds filled with water. If the pondcontains water, additional amounts of lime may be added to satisfy theneeds of the water as well as of the bottom mud. It may take 3 to 6 monthsbefore the pond responds. In some situations, limed ponds revert to an acidcondition within two years after the initial application.COMBINING FER'f ILIZERSIn making a decision on whether to use organic or inorganic fertilizers, theadvantages and disadvantages should be carefully considered. Comparativetests have been attempted but conclusive answers as to which material isbest often will depend upon the individual situation or production cycle involved.Combining organic and inorganic fertilizers is a common practice. Manyworkers have found that a combination of an organic meal and superphosphate,in a ratio of ll:1, gave higher fish production than the organicmaterial alone. In hatchery rearing ponds where draining is frequent andtime for development of a suitable food supply often is limited, combiningorganic and inorganic fertilizers appears to be advantageous. While thecost of such a procedure is greater than with inorganic fertilization, thehigh value of the fish crop involved normally justifies the added cost,particu- larly in the case of bass and catfish rearing.The ratio of 4 4 1, N2 P2O. KrO, is needed to produce favorableplankton growth for fish production ponds. The fertilizer grade most commonlyused is '20-2Q-5, which gives the 4 4-l ratio with relatively littlefiller.The type of fertilizer program chosen will be determined by such factorsas species of fish reared, time of year, cost, availability of product, and past

IO2FISH HATCHERY MANAGEMENTexperience. If the species to be reared is a predator species such as largemouthbass, striped bass, or walleye, a typical program might be as follows'In spring, while the pond is still dry, disk the pond bottom' Apply limeif needed to bring pH into a favorable range. The fertilizer can be spreadon the dry pond bottom and the pond then filled, or the pond filled andthen the fertilizer spread; the following example assumes it is on the pondbottom.Spread:500 pounds per acre chopped alfalfa hay;200 pounds PeI acremeat scraps;200 pounds per acre ground dehydrated alfalfa hay;50pounds per acre superphosphate; 10 pounds Per acre potash; 1,000 poundsp". u.." chicken manure. Fill the pond and wait 3 to 5 days before stockingfish.This fertilizer program for sandy loam soils and slightly acid waters willproduce an abundance of zooplankton needed for rearing the predator,peci".. Usually this amount is added only one time and will sustain thepond for 30-40 days. If the fish crop is not of harvest size by that time, asecond application of all or part of the components may be needed'If the species to be reared is a forage species such as bluegill, redear sunfish,goldfish, or tilapia, the following program might be used: 100 poundsper acre ammonium nitrate;200 pounds per acre superphosphate;50pounds per acre potash;100 pounds Per acre chopped alfalfa hay;300pounds per acre chicken manure. This fertilizer program will produce morephytoplankton than the one outlined for predators. As with the one above,this program will have to be repeated about every 30-45 days'The type of fertilizer program that works best at any particular stationwill have to be developed at that station. The program that works best atone station will not necessarily work well at another. The examples givenabove are strictly guidelines.AqUATIC VEGEI'ATION CONl'ROLAquatic plants must have sunlight, food, and carbon dioxide in order tothrive. Elimination of any one of these requirements inhibits growth andeventually brings about the death of the plant. The majority of the commonwater weeds start growth on the bottom. Providing adequate depth toponds and thus excluding sunlight essential to plant growth may preventweeds from becoming established. Water plants are most easily controlledin the early stages of development. Control methods applied when stemsand leaves are tender are more effective than those applied after the planthas matured. In most cases, seeds or other reproductive bodies are absentin early development and control at this time minimizes the possibility ofrees tablishme nt.The first step in controlling aquatic vegetation is to identify the plant.After the problem weed has been identified, a method of control can be

HATCHERY OPERATIONS 103selected. Control methods may be mechanical, biological, or chemical,depending upon the situation.Mechanical control consists of removal of weeds by cutting, uprooting, orsimilar means. While specialized machines have been developed for mowingweeds, they are expensive and not very practical except in special circumstances.In small ponds, hand tools can be employed for plant removal.Even in larger bodies of water, mechanical removal of weeds may be feasibleprovided that work is begun when the weeds first appear.Biological weed control is based on natural processes. Exclusion of lightfrom the pond bottom by adequate water depth and turbidity resultingfrom phytoplankton is one method. Production of filamentous aleae thatsmother submerged rooted types of weeds is another.The most inexpensive form of weed control for many ponds is control orprevention through the use of fertilizers. When an 8-tl-2 grade fertilizer isapplied at a rate of 100 pounds per acre, every 2 to 4 weeks during thewarm months of the year, microscopic plants are produced that shade thebottom and prevent the establishment of weeds. Although 8 to l4 applicationsare needed each season, fish production is increased along with theweed control achieved. Generally, most aquatic weeds may be controlledby fertilization in properly constructed ponds. However, such a program offertilization will be effective in controlling rooted weeds only if the secchidisk reading already is l8 inches or less.winter fertilization is a specialized form of biological control effective onsubmerged rooted vegetation if the ponds cannot be drained. An 8-8-2grade fertilizer or equivalent is applied at a rate of 100 pounds per acreevery 2 weeks until a dense growth of filamentous algae covers the submergedweed beds. Once the algae appears, an application of fertilizer ismade at 3- to 4-week intervals until masses of algae and rooted weeds beginto break loose and float. All fertilization is then stopped until theplants have broken free and decomposed. This will start in the late springand generaliy takes from four to six weeks. Phytoplankton normally replacethe filamentous algae and rooted weeds and should be mantained byinorganic fertilization with 100 pounds of U-8,2 per acre applied every 3to 4 weeks.Lowering the water level of the pond in the late fall has been helpful inachieving temporary control of watershield. This practice also aids in thechemical control of alligator weed, water primrose, southern water grass,needlerush, knotgrass, and other resistant weeds that grow partially submergedand have an extensive root system.Plant-eating fish that convert vegetation to protein have been consideredin biological control. Among these are grass carp, Israeli carp (a race ofcommon carp), and tilapia. Experiments have indicated that the numbersof Israeli carp and tilapia required to control plants effectively are so large

IO4FISH HATCHERY MANAGEMENTthat these fish would compete for space and interfere with the productionof other, more desirable species.Extensive development of herbicides in recent years makes chemical controlof weeds quite promising in many instances. When properly applied,herbicides are effective, fast, relatively inexpensive, and require less laborthan some of the other control methods. Chemical control, however. is not asimple matter. Often the difference in toxicity to weeds and to fish in thepond is not great. Some chemicals are poisonous to humans or to livestockand they may have an adverse effect on essential food organisms. Decay oflarge amounts of dead plants can exhaust the oxygen supply in the water,causing death of fish and other aquatic animals. It is essential that discretionregarding treatment be followed if satisfactory results are to be obtained.An important aspect of vegetation control is the rate of dilution of appliedherbicides and the effect of substances present that may neutralizethe toxicity of the chemical used. The rate of water exchange by seepageor outflow and the chemical characteristics of the water and pond bottomalso affect the success of chemical control measures. Often the herbicidemust reach a high percentage of the plant surface before a kill is obtained;the chemical must be applied carefully if good results are to be achieved.The herbicide is applied directly on emergent or floating weeds and tothe water where submerged weeds are growing. The first type of treatmentis called a local treatment, the second is termed a solution treatment appliedeither to a plot or to the entire pond.Conventional sprayers are used to apply the local treatments and insome instances may be suitable for solution treatments. Chemicals for solutiontreatment are sometimes diluted with water and poured into the wakeof an outboard motor, sprinkled over the surface of the pond, or run bygravity into the water containing the weed beds. Crystalline salts may beplaced in a fine woven cotton bag and towed by boat, allowing the herbicideto dissolve and mix with the pond water. Some herbicides areprepared in granular form for scattering or broadcasting over the areas tobe treated. Generally, the more rapidly the chemical loses its toxicity themore uniformly it must be distributed over the area involved for effectiveresults. Also, if the chemical is at all toxic to fish, it must be uniformly distrib'rted.Emergent or floating vegetation receiving local treatments appliedwith spray equipment should be uniformly covered with a drenching sprayapplied as a fine mist.A number of precautions should always be taken when herbicides areused. Follow all instructions on the label and store chemicals only in theoriginal labeled container. Avoid inhalation of herbicides and prevent theirrepeated or prolonged contact with the skin. Wash thoroughly after handlingherbicides, and always remove contaminated clothing as soon as possible.Prevent livestock from drinking the water during the post-treatmentperiod specified on the label. Do not release treated water to locations that

HA'I'CHERY OPERAI'IONS 105may be damaged by activity of the chemical. Avoid overdoses and spillages.Avoid use near sensitive crops and reduce drift hazards as much aspossible; do not apply herbicides on windy days. Clean all applicationequipment in areas where the rinsing solutions will not contaminate otherareas or streams.Fish culturists must also be aware of the current registration status ofherbicides. Continuing changes in the regulation of pesticide and drug usein the United States has created confusion concerning what chemicals maybe used in fisheries work. Table l4 lists those chemicals that presently possessregistered status for use in the presence of food fish only, a food fishbeing defined as one normally consumed by humans.Special Problems in Pond CultureDISSOLVED OXYGENBecause adequate amounts of dissolved oxygen are critical for good fishgrowth and survival, this gas is of major concern to fish culturists (Figure39). On rare occasions, high levels of oxygen supersaturation-caused byintensive algal photosynthesis-may induce emphysema in fish. Virtuallyall oxygen-related problems, however, are caused by gas concentrationsthat are too low.Tolerances of fish to low dissolved oxygen concentrations vary amongspecies. In general, fish do well at concentrations above 4 parts per million.They can survive extended periods (days) at 3 parts per million, but do notgrow well. Most fish can tolerate l-2 parts per million for a few hours, butwill die if concentrations are prolonged at this level or drop even lower.In ponds that have no flowing freshwater supply, oxygen comes fromonly two sources: diffusion from the air; and photosynthesis. Oxygen diffusesacross the water surface into or out of the pond, depending onwhether the water is subsaturated or supersaturated with the gas. Onceoxygen enters the surface film of water, it diffuses only slowly through therest of the water mass. Only if surface water is mechanically mixed withthe rest of the pond-by wind, pumps, or outboard motors-will diffusedoxygen help to aerate the whole pond.During warmer months of the year when fish grow well, photosynthesisis the most important source of pond oxygen. Some photosynthetic oxygencomes from rooted aquatic plants, but most of it typically comes from phytoplankton.Photosynthesis requires light; more occurs on bright days thanon cloudy ones. The water depth at which photosynthesis can occurdepends on water clarity. Excessive clay turbidity or dense blooms of phytoplanktoncan restrict oxygen production to the upper foot or less of water.Generally, photosynthesis will produce adequate amounts of oxygen for

106 FrsH HAT CHF,Ry NIA\AcE1\'rE\'lTABLE 14. IItiRBICTTDES RFrc;rsTF,Rr:D B\' 'r'HI UNr.r'l.D S t.r'r'Est()()t) .\\t) t)Rl-t(;AL. l1)7(i: SNOW lll At.. l1)(i.t.l\t.(;t.1.\ll()\I0\ICII\I0ct( )Nt P() U N I)r'()t{}11 L.\ I l()N",\l IL( il.1),\\llt.\1.5Coppersulfatt-Cr-vstals, I00 'Aluae and subnrcrgeclrootcd plantsModeratc to highDiquat(bromide)Endothall.iquid, il5',Liquid, i35"Enrerqent, terrestrial,su b m ergedSubmerged, rootecll,ot[,o*Si m azinePou der, liOAlgae, subncrgcd,tcrrestrial[,ou2,4,D'Granular, l0salt, ll0'ester, l]7 12'amine,2l'l-.12'granular, 20'I loating, emerqent,terrestria Il,ou or modcraleol'ercentages are percent actual ingredient.'Consult product labels for limitations on use.'Only for use b1' federal, state, and local public agencies.fish to a depth of two to three times the secchi disk visibility. Penetrationof oxygen below this depth depends on mechanical mixing.Two processes use up dissolved oxygen: chemical oxidation and respiration.Both occur throughout the water column and in the top layer of pondsediments. The first involves chiefly inorganic compounds and elements,and rarely is of major significance in ponds. Respiration is the main causeof oxygen depletion. All aquatic organisms respire - not only fish, butplants, phytoplankton (even during photosynthesis), zooplankton, bottomanimals (such as crayfish), and perhaps most importantly, the bacteria thatlive off nitrogenous and organic material'Over the whole year, but especially during the growing season, the oxygenconcentration in a pond is determined primarily by the balance of photosynthesisand respiration. For pond fish culture to succeed, photosynthesismust stay ahead of respiration. Pond management techniques involvemanipulation of both comPonents.Of all the physical variables that affect dissolved oxygen concentrations,temperature is by far the most important. It has direct influences on theoxygen balance: photosynthesis, respiration, and chemical oxidation allproceed faster at higher temperatures. It has a direct influence on a pond's

HA I CHlll{Y ()PliRAl'l()N..S 107At)\llNISlR:\ll()N F()l{ t's1.. wllH f()()l) FIsH. ll.Bl{t AR\'. l1)7ti. S()LlR('1.: l\ll.\'l.lt l. I\I'PI-IC1'I I()\I{A I I.]S0.1 ir.O pprn2.i pounds/acre0.5 2.0 ppmI :] ppnr0..)'2.() ppmll0 10 pounds/(n..c)13 I ir pounds/acre\1()t)u()FACt',l t()NNonsystemicNonsy ste micI'robabllnons,VstemicSl stemicS) stem icc()NlNlt.tN1 S1'I-imit is onc part per nillion lorcopper complexes, butCuSO*'5H20 and basic coppercarbonate are exempted fromthe limitInterim Iimit rn potubl,'sater is0.0I part per nillionInterim limit in potablt rrater i.0.2 part per millionUpper limits are l2 parts pcr mil'lion in raw fish and 0.01 partper million in potable $'ater.Upper limit in raw fish and shelllishis I part per million.oxygen capacity: less oxygen dissolves in water at higher temperatures' Ithas an indirect effect on oxygen circulation: as temperature rises, water becomesmore difficult to mix. If temperatures rise high enough, and the wateris deep enough, the pond may stratify into an upPer' warmer, windmixedlayer and a lower, cooler, poorly circulated layer. In such cases, littlewater moves across the thermocline separating the two layers. Theupper layer receives, and keeps, most of the new oxygen (chiefly from photosynthesisby phytoplankton); the lower layer receives little new oxygen,and loses it-sometimes completely-to respiration (chiefly by bacteria).Several pond management techniques attempt to ovelcome the effects suchtemperature-induced stratification has on the oxygen suPply.It is easy to see why pond-oxygen problems are more acute in summerthan in autumn, winter, and spring. when the water is cool, it can dissolvemore oxygen, and it is more easily mixed by wind action to the pond bottom.Photosynthesis is less, but so is respiration, and photosynthetic oxygenis kept in the pond.In contrast, water circulation is constrained in summer' In the upperlayers, especially in stratified ponds, photosynthesis may be so intense thatthe water becomes suPersaturated with oxygen so that much of the gas is

108 FISH HATCHERY MANAGEMDNTFIGURE 39' An essential instrument in any fish rearing operationis an oxygen meter' Catastrophic fish losses can beavoided if oxygen concentrations are checked periodically andthe optimum carrying caPacity of the hatchery can be determined.severalbrandsofmetersareavailablecommercially.(FwS photo.)lost to the air. The water has a lower capacity for oxygen, and little of it^"y,"'.t,thepondbottom.Planktonicanimalshaveshortlifespans;as*or" .r" produced during warm weather, more also die and sink to thebottom,wherebacteriadecomposethem_utilizingoxygenintheprocess.Respiration levels are high, meaning that more metabolism is occurringand more wastes produced. These also are stimulants to bacterial production.So is any uneaten food that may be provided by the culturist' Bothoxygen production and consumPtion are very rapid' and the balance is

HAl'CHERY OPERATIONS 109vulnerable to many outside influences: a cloudy day that slows photosynthesis;a hot still day that causes stratification; a miscalculated food rationthat is too large for fish to consume before it decomposes.Typically the summer oxygen content in a pond iollows a 24-hour cycle:highest in the late afternoon after a day of photosynthesis; lowest at dawnafter a night of respiration. It is the nightiime oxygen depletion that ismost critical to pond culturists.Pond managers can take several precautions to prevent, or reduce theseverity of, dissolved oxygen problems.(l) Most ponds are fertilized to stimulate plankton production for naturalfish food. Suitable plankton densities allow secchi disk readings of 12-24inches. Fertilization should be stopped if readings drop to 10 inches or less.Special care should be taken if the pond is receiving supplemental fishfood, as this can stimulate sudden plankton blooms and subsequent dieoffs.(2) Because the frequency of dissolved oxygen probrems increases withthe supplemental feeding rate, fish should not be given more than 30pounds of food per acre per day.(3) tr atglciaes are used to control plankton densities, they should be appliedbefore, rather than during, a bloom. otherwise, the accelerated dieoffof the bloom will worsen the rate of oxygen depletion.(4J During critical periods of the summer, the oxygen concentrationshould be monitored. This is most easily accomplished at dusk and two orthree hours later. These two values can be plotted against time on a graph,and the straight line extended to predict the dissolved oxygen at dawn.This will allow emergency aeration to be prepared in advance.Dissolved oxygen problems may arise in spite of precautions. correctivemeasures for specific problems are suggested below.(1) If there has been an excessive kill of pond weeds or plankton thatare decaying, add 20% superphosphate by midmorning at a rate of 50-100pounds per acre. Stir the pond with an outboard motor or otherwise mix orcirculate water to rapidly distribute phosphate and add atmospheric oxygen;I to 2 hours of stirring a r-acre pond should suffice. Dilute theoxygen-deficient water with fresh water of about the same temperature.Dis.tribute, as evenly as possible, 100-200 pounds of hydrated lime,ca(oH)r, per acre in the late afternoon if co2 levels are l0 parts per millionor higher. Then stir for another one to two hours.\2) Low dissolved oxygen may be caused by excessive rooted vegetationand a lack of phytoplankton photosynthesis. If the pond is unstratified, addPto; and stir or circulate as in (l) above. Add fresh water if available. Ifthe pond is stratified, which is the usual case in warm months, aerate thesurface waters by agitation, draw off the cool oxygen-deficient bottom water,or add colder fresh water.

ll0FISH HATCHERY MANAGEMENT(3) If the problem is caused by too much supplemental feed, drasticallyreduce or eliminate feeding until the anaerobic condition is corrected.Drain off foul bottom water. Refill the pond with fresh water and add P20.;to induce phytoplankton growth.(4) Summer stratification of ponds often is inevitable. During its earlystage of development, when cool anaerobic water is less than 20-25"[ of thetotal pond volume and upper waters have a moderate growth of greenplants, top and bottom water can be thoroughly mixed. Aerate the pondwith special equipment or an air compressor, or vigorously stir it with anoutboard-powered boat or with a pump. If the layer of anaerobic water ismore than ] the total pond volume, drain off the anaerobic water, refillwith fresh water, and fertilize to re-establish the phytoplankton bloom.(5) Low dissolved oxygen may result from excessive application oforganic fertilizers, which overstimulates plankton production. Treat thisproblem as in example (l), above. Two to six parts per million potassiumpermanganate (KMnOr) may be added to oxidize decaying organic matter,freeing the available oxygen for the pond fish.Quite often, oxygen depletion is caused by two or more of the above factorsacting simultaneously. In such cases, a combination of treatments maybe needed. If a substantial amount of foul bottom water exists, the pondshould never be mixed, because the oxygen deficit in the lower water layermay exceed the amount of oxygen available in the surface layer. Drain offthe anaerobic water and replace it with fresh water from a stream, well, oradjacent pond. An effective technique is to pump water from just belowthe surface of the pond and spray it back onto the water surface with force.Small spray-type surface aerators are in common use. These aerators aremost effective in small ponds or when several are operated in a large pond.More powerful aerators such as the Crisafulli pump and sprayer and thepaddlewheel aerator supply considerably more oxygen to ponds than thespray-type surface aerators. However, Crisafulli Pumps and paddlewheelaerators are expensive and must be operated from the power take-off of afarm tractor. The relative efficiency of several types of emergency aerationappears in Table 15.ACIDI'TYFish do not grow well in waters that are too acid or too alkaline, and thepH of pond waters should be maintained within the range of 6.5 to 9. ThepH of water is due to the activity of positively charged hydrogen ions(H'), and pH is controlled through manipulation of hydrogen ion concentrations:if the pH is too low (acid water), H'concentrations must be decreased.The treatments for low pH (liming) were discussed on pages 108-109.The principle involved is to add negatively charged ions, such as carbonate

HATCHERYOPERATIONSIllTABLE 15. AMOUNTS oF oxYGEN ADDED TO POND WATERS BY DIFFERENT TECHNIqUES OF EMERGENCY AI.RATTON (SOURCE: BOYD 1979.)TYPE OF EMERGENCY AREATIONPaddlewheel aeratorCrisafulli pump with sprayerCrisafulli pump to discharge oxygenatedwater from adjacentpondOtterbine aerabr (3.7 kilowatts)Crisfulli pump to circulate pondwaterOtterbine aerator (2.2 kilowatts)Rainmaster pump to circulatepond waterRainmaster pump to dischargeoxygenated water from adjacentpondAir-o-later aerator (0.25 kilowatt)OXYGENADDED{LBlACRE)48.931.219.0| 5.2l 1.8I 1.3t0.76.03.9RELATIVEEFFI C I ENCYf)10064393l242322t28(COr:1 or hydroxyl (OH ;, that react with H1 and reduce the latter's concentration.Excessively high pH values can occur in ponds during summer, whenphytoplankton are abundant and photosynthesis is intense. As carbon dioxideis added to ponds, either by diffusion from the atmosphere or fromrespiration, it reacts with water to form a weak carbonic acid. The basicreaction involved is:CO2+HrO r- H2CO3.= H+ +HCO' e 2H+ +COt.As more CO2 is added, the reaction moves farther to the right, generatingfirst bicarbonate and then carbonate ions; H+ is released at each step,increasing the acidity and lowering the pH. Photosynthesizing plantsreverse the reaction. They take CO2 from the water, and the HCO;CO3: ions bind hydrogen; acidity is reduced and pH rises-oftenandto levelsabove ten.Two types of treatment for high pH can be applied. One involves additionof chemicals that form weak acids by reacting with water to releaseH+; they function much like CO, in this regard. Examples are sulfur, ferroussulfate, and aluminum sulfate, materials also used to acidify soils. Theaction of sulfur is enhanced if it is added together witn organic matter,such as manure.A second treatment for high pH is the addition of positively chargedions that bind preferentially with COt;they keep the carbonate from

112 FISH HATCHERY MANAGIJMEN'frecombining with hydrogen and prevent the above reaction from moving tothe left, even though plants may be removing CO2 from the water. Themost important ion used for this purpose is calcium (Cu''), which usuallyis added in the form of gypsum (calcium sulfate, CaSOa).The two types of treatments may be combined. For example, sulfur,manure, and gypsum together may be effective in reducing pond alkalinity.TURBIDI'I'YExcessive turbidity in ponds obstructs light penetration; it can reduce photosynthesisand make it more difficult for fish to find food. Much turbidityis caused by colloids-clay particles that remain suspended in waterbecause of their small size and negative electric charges. If the charges oncolloidal particles can be neutralized, they will stick together -flocculate-andprecipitate to the bottom. Any positively charged materialcan help flocculate such colloids. Organic matter works, although it candeplete a pond's oxygen supply as it decomposes, and is not recommendedduring summer months. Weak acids or metallic ions such as calcium alsocan neutralize colloidal charges, and many culturists add (depending onpH) limestone, calcium hydroxide, or gypsum to ponds for this purpose.HYDROGE,N SULFIDEHydrogensulfide, H25, is a soluble, highly poisonous gas having thecharacteristic odor of rotten eggs. It is an anaerobic degradation product ofboth organic sulfur compounds and inorganic sulfates. Decomposition ofalgae, aquatic weeds, waste fish feed, and other naturally deposited organicmaterial is the major source of H25 in fish ponds.The toxicity of H2S depends on temperature, pH, and dissolved oxygen.At pH values of five or below, most of the H2S is in its undissociated toxicform. As pH rises the H2S dissociates into S: and H'ions, which arenontoxic. At pH [] most of the H2S has dissociated to a nontoxic form. Itstoxicity increases at higher temperatures, but oxygen will convert it tonontoxic sulfate.HrS is toxic to fish at levels above 2.0 parts per billion and toxic to eggsat 12 parts per billion. It is a known cause of low fish survival in organicallyrich ponds. If the water is well oxygenated, H25 will not escape fromthe sediments unless the latter are disturbed, as they are during seiningoperations. Hydrogen sulfide mainly is a problem during warm months,when organic decomposition is rapid and bottom waters are low in dissolvedoxygen.Hydrogen sulfide problems can be corrected in several ways: (1) removeexcess organic matter from the pond; (2) raise the pH of the water (seeabove); (3) oxygenate the water; (4) add an oxidizing agent such as potassiumpermanganate.

HATCHERY OPERATIONSWA'fER I,OSSWater loss by seepage is a problem at many hatcheries. A permanent solutionis to add a layer of good quality clay about a foot thick, wetted, rolled,and compacted into an impervious lining. (In small ponds, the same effectcan be achieved with polyethylene sheets protected with three to fourinches of soil.) Bentonite can be used effectively to correct extreme waterloss when applied as follows:(t) list< the bottom soil to a depth of six inches, lapping cuts by 50'/ir'(2) Harro* the soil with a spike-tooth harrow, overlapping by 50'/o'(g) Oivide treated area into 10-foot by 10-foot squares.(4) U.rlfo.*ly spread 50 pounds of bentonite over each square (ZO,OOOpounds per acre).(S) pist soil to a depth of three inches.(6) Compact soil thoroughly with a sheepsfoot roller.This procedure has reduced seepage over 90'/o in some cases.Evaporation is a problem in farm and hatchery ponds of the southwest.work in Australia indicates that a substantial reduction in evaporation(259i) cu., be reduced by a film of cetyl alcohol (hexadecanol), applied at arate of about eight pounds per acre per year. The treatment is only effectivein ponds of two acres or less.PROBLEM ORGANISMSMost plants, animals, and bacteria in a pond community are important infish culture because of their roles as fish food and in photosynthesis,decomposition, and chemical cycling. However, some organisms are undesirable,and sometimes have to be controlled.Some crustaceans-members of the Eubranchiopoda group such as theclam shrimp (Clzicus sp.), the tadpole shrimp (lpus sp.) and the fairyshrimp (Streptocephalar sp.)-compete with the fish fry for food, cause excessiveturbidity that interfers with phytosynthesis, clog outlet screens, andinterfere with fish sorting at harvest. They usually offer no value as fishfood, because of their hard external shell and because of their fast growthto sizes too large to eat.These shrimp need alternating periods of flooding and desiccation toperpetuate their life cycles, and they can be controlled naturally if pondsare not dried out between fish harvests. However, they usually are controlledwith chemicals. Formalin, malathion, rotenone, methyl parathion,and others have been used with varying degrees of success; many of theseare very toxic to fish. The best chemicals today are dylox and masoten,which contain the active ingredient trichlorfon and which have been registeredfor use as a pesticide with nonfood fish. Treatments of 0.25 partper million dylox will kill all crustaceans in 24 hours, without harming

t4 FISH HATCHERY MANAGEMENTfish. Most of the desirable crustacean species will repopulate the pond intwo or three days.Most members of the aquatic insect groups Coleoptera (beetles) andHemiptera (b"gs) prey on other insects and small fish. In some cases,members of the order Odonata (dragonflies) cause similar problems. Mostof these insects breath air, and can be controlled by applying a mixture ofone quart motor oil and two to four gallons diesel fuel per surface acreover the pond. As insects surface, their breathing apertures become cloggedwith oil and they may get caught in the surface film. The treatment isharmless to fish but supplemental feeding should be discontinued until thefilm has dissipated. Nonsurfacing insects can be killed by 0.25 part per millionmasoten.Large numbers of crayfish in rearing ponds may consume feed intendedfor the fish, inhibit feeding activity, cause increased turbidity, and interferewith seining, harvesting, and sorting of fish. Baytex is an effective control;0.1-0.25 part per million Baytex will kill most crayfish species in 48 hoursor less without harming the fish.Vertebrates that prey on fish may cause serious problems for the pondfishculturist. Birds, otters, alligators, and turtles, to name a few, are implicatedannually. Some can be shot, although killing of furbearing mammalsgenerally requires a special license or permit issued by the states. Fencescan keep out some potential predators, but nonlethal bird control (severalforms of scaring them a*ay) do not produce long-lasting results.Adult and immature frogs have long plagued the warmwater culturist.The adults are predaceous and may transmit fish diseases; the immaturefrogs consume feed intended for fish and must be removed by hand fromfish lots awaiting transport. Adults usually are controlled with firearms,whereas attempts to control the young are limited to physical removal ofegg masses from ponds or by treating individual masses with copper sulfateor pon's green. Although some laboratory success has been achieved withformalin, there still is no good chemical control available for frog tadpoles.RecordkeepingFactors to be ConsideredRecordkeeping, in any business or organization, is an integral part of thesystem. It is the means by which we measure and balance the input andoutput, evaluate efficiency, and plan future operations.Listed below are factors that should be considered in efficient recordkeeping.These factors are particularly applicable to trout and salmonhatcheries, but many of them pertain to warmwater hatcheries as well.

HATCHERYOPERATIONS 115Water(l) Volume in cubic feet for each rearing unit and for the entirehatchery.(2) Gallons per minute and cubic feet per hour flow into each unit andfor the entire hatchery.(3) Rate of change for each unit and for the total hatchery.(4) Temperature.(5,) Water quality.Mortalit!(l) Fish or eggs actually collected and counted (daily pick-off).(2) Unaccountable losses (predation, cannibalism) determined by comparisonof periodic inventories.Food and Diet(1) Composition.(Z) Cort per pound of feed and cost per pound of fish gained.(3) Amount of food fed as percentage of fish body weight.(4) Pounds of food fed per pound of fish produced (conversion).Fish(t) W"igtrt and number of fish and eggs on hand at the beginning andend of accounting period.(Z) fi.n and eggs shipped or received.(3) Gain in weight in pounds and percentage.(+) Out" eggs were taken, number per ounce, and source.(S) Oate of first feeding of fry.(6) Number per pound of all lots of fish.(7) Data on broodstock.Disease(l) Occurrence, kind, and possible contributing factors.(2) Type of control and results.Cosls (other than fish food) :(l) Maintenance and operation.(2) Interest and depreciation on investment.(3) Analysis of all cost and production records.

1 16 FrsH HA t cHERy MANAGL,MENTProduction SummarySome additional records that should be considered for extensive (pond)culture follow.Water(l) Area in acres of each pond.(2) Volrr*e in acre-feet.(3) Average depth.(4) Inflow required to maintain pond level.(5) Temperatures.(6) Source and quality.(Z) Weed control (dut"r, kind, amount, cost, results).(8) Fertilization (dates, kind, amount, cost, results).(g) etgae and zooplankton blooms (dates and secci visibility in inches;kinds of plankton).Fish(l) Broodstock(a) Species, numbers.(b) Stocked for spawning (species, numbers, dates).(c) Replacements (species, numbers, weights).(d) Feeding and care (kind, cost, and amounts of food, includingdata on forage fish production).(e) Diseases and parasites (treatments, dates, results).(f) Fry produced per acre and per female.(2) Fingerlings(a) Species (numbers stocked, size, weight, date)(b) Number removed, date, total weight, weight per thousand,number per pound.(c) Supplemental feeding (kind, amount, cost).(d) Dlsease and predation (including insect control, etc.).(3) Production per acre by species (numbers and pounds).(4) Oays in production.(S) W"igfrt gain per acre per day.(6) Cost per pound of fish produced at hatchery.(7) C"rt per pound including distribution costs.A variety of management forms are in use at state, federal, and commercialhatcheries today. The following examples have been used in the NationalFish Hatchery system of the Fish and Wildlife Service. These forms, orvariations of them, can be helpful to the fish culturist who is designing arecordkeeping system.

HATCHERY OPERATIONSt17Lot History Production ChartsProduction lots of fish originating from National Fish Hatcheries are identifiedby a one-digit numeral that designates the year the lot starts on feedand a two-letter abbreviation that identifies the National Fish Hatcherywhere the lot originated. When production lots are received from sourcesoutside the National Fish Hatchery system the following designations apply:(1) the capital letter "U" designates lots originating from a statehatchery followed by the two-letter abreviation of the state; (2) the capitalletter "Y" and the appropriate state abbreviation designates lots originatingfrom commercial sources; (3) the letter "F" followed by the name of thecountry identifies lots originating outside the United States. For example:Lot 7-En designates the 1977 year class originating at theEnnis National Fish Hatchery.Lot 7-UCA designates the 1977 year class originating at aCalifornia state fish hatchery.Lot 7-YWA designates the 1977 year class originating from acommercial hatchery in the state of Washington.Lot 7-F-Canada designates the 1977 year class originating inCanada.Lots from fall spawning broodstock that begin to feed after November30th are designated as having started on January lst of the following year.The practice of maintaining sublots is discouraged but widely separatedshipments of eggs result in different sizes of fish and complicated recordkeeping. When sublots are necessary, they are identified by letters (a, b, c,etc.) following the hatchery abbreviation. Lot 7-En-a and 7-En-b designatetwo sublots received in the same year from the Ennis National FishHatchery.Identification of fish species should be made on all management records.The abbreviations for National Fish Hatcheries and the states are presentedin Appendix E.Lot History Production charts should be prepared at the end of eachmonth for all production lots of fish reared in the hatchery. This chart providesvaluable accumulated data on individual lots and is useful in evaluatingthe efficiency and the capability of a hatchery. Information recorded onthe chart will be used in completing a quarterly distribution summary anda monthly cumulative summary. These forms were developed for salmonand trout hatcheries. Parts of them are readily adaptable to intensive cultureof coolwater and warmwater fishes. Presently, information needed toestimate the size of fry at initial feeding (which allows projections ofgrowth and feed requirements from this earliest stage) is lacking for speciesother than salmonids. For the time being, cool- and warmwater fish culturistsshould ignore that part of the production chart, and pick up growth

ll8FISH HA'TCHERY MANAGEMENTand feed projections from the time fry become large enough to be handledand measured without damage.The following definitions and instructions relate to the Lot History Productionform used in National Fish Hatcheries (Figure 40).DEFINITIONSDate of initial feeding: This is the day the majority of fry accept feed or, inthe case of fish transferred in, the day the lot is put on feed.Number at initial feeding: If lots are inventoried at initial feeding, thisnumber will be used. If lots are not inventoried, the number of eggs receivedor put down for hatching, minus the number of egg or fish deathsrecorded prior to initial feeding, will determine the number on hand at initialfeeding.Weight at initial feeding: The weight on hand at initial feeding should berecorded by inventory when possible. Otherwise, multiply the number atinitial feeding, in thousands, by the weight per thousand: (thousands onhand) x (weight/1,000 fish) : weight on hand.Length at initial feeding: The length of fish at initial feeding, in inches,can be found from the appropriate length-weight table in Appendix I correspondingto the size (weight per 1,000 fish).ii

HATCHERY OPERATIONS 119LOT HISTORY PRODUCTIONINITIAL FEEDINGWEiGHT PTR IOOO FISHoNTUN T FIEDIO DATEPERI000PERCENTSURVIVALUNTILTRANSFERRED,RTLilSED0RDISTRBUTEO: SACFRY_% FEEDTNGFRy_% F|SH_%REMARKS]FIcunn 40. Production form for recording lot history data. Temperature unitsare monthly temperature units, which equal l'F above 32'F for the averagemonthlv water temDerature.

120 FISH HATCHERY MANAGEMENTTABLE I6. THE SIZE OF SALMoNID FRY AT INITIAL FEEDING, BASED oN'fHE SIZE oFTHE EYED EGG LISTED AND THE CORRESPONDING WEIGHT PER l.OOO FRY,INI'TIAL f!]EDINGINI'I'IAL !'I,I,DINCEYED f]GCWEICH'T PEREYED ECCWEIGHT PER(NUMBERPER OUNCE]1,000 FRY(POUNDS)t-I]NG'IH(r N- c rr us)(N.UM tsI]RPER OUNCE]I,(}(X) FRYIPOLINDS]LEN(]THltNcrHESl200210220230240250260270280290300310:t203303403503603703U039040041042043i)4404500.530.500.,1u0.460.4+0.420.400.390.3ri0.360.350.3,10.330.320.310.300.290.2r10.2u0.270.260.260.250.240.240.23l.l0l.0u1.061.051.03l.o21.000.990.9t]0.960.960.950.940.930.920.910.900.890.tr80.u80.870.u60.u50.u40.840.u3.1604704U04905005105205305405505605705tJ05906006106206306,t06506606706806907000.230.220.220.210.210.210.200.200.190. l90.190. l80.1lt0.1lJ0.1tt0.t70. l70.t70. 1(;0. 1(i0. l60. l60. l50. 150.150.1]30.820.u 10.u l0.u00.750.790.790.7r.t0.7ti0.750.770.770.760.760.750.7 +0.t- 10.740.7 +0.730.730.730.720.72Column 5: Record the total number of fish shipped from the lot for thecurrent month.Column 6: Record the total weight of the fish shipped during the currentmonth.Column 7: Record the total number of fish added to the lot in thecurrent month.Column 8: Record the total weieht of the fish added to the lot in thecurrent month.Column 9: Record the gain in weight for the current month. This is equalto Column 2 (this month) - Column 2 (last month) * Column 6 - Column8.Column /0: Record total weight gain to date. This is equal to Column l0(last month) * Column 9 (this month).

HATCHERY OPERATIONS 121Column //: Record the total food fed for the current month from dailyrecords.Column /2: Record the total food fed to date. This is equal to Columnl2 (last month) *Column ll (this month).Column /3: Record the cumulative cost of fish food fed to date. This isequal to Column 13 (last month) *cost for this month. Report to thenearest dollar.Column /4: Record feed conversions for this month. This is equal toColumn l1 - Column 9. Record conversion to two decimal places.10.Column /5: Record the conversion to date. This is Column 12 - ColumnColumn /6: Record to the nearest cent, the unit feed cost per pound offish reared. This is Column l3 - Column 10.Column / 7: Record, to the nearest cent, the unit feed cost to date per1,000 fish. This is (Colr.-n 3-the weight per 1,000 fish reported at initialfeeding) x Column 16.Column /8: Identify the type of diet fed for the current month includingthe cost per pound.Column /9: Record, to two decimal places, the length of the fish on handthe last day of the current month. This comes from the length-weight tableappropriate for Column 3.Column 20: Record the increase in fish length for this month. For newlots, this is Column l9 the length at initial feeding. For pre-existing lots,this is Column 19 (this month) -Column l9 (last month).Column 2/: Record the number of days since the date of initial feeding.Column 22: Record, to two decimal places, the average daily increase infish length. For new lots, this is Column 20 - the number of days the lotwas on feed. For pre-existing lots, this is Column 20 + the number of daysin the month.Column 23: Record, to two decimal places, the average daily length increaseto date. This is Column 19-length at initial feeding-Column 21.Column 24: Record, to two decimal places, the length increase during a30-day unit period. This is Column 22x30.Column 25: Record the monthly mean water temperature in degreesFahrenheit. Monthly Temperature Units (MTU) available per month arethe mean water temperature minus 32'F. If a lot of fish was started partway through the month, the MTUreported for this column must reflectthe actual days the lot was on feed. For example, if fish were on feed fromJune l6th throughJune 30th, the MTU available to the lot must reflect 15days. A detailed explanation of Monthly Temperature Units is given onpage 62.Column 26: Record, to one decimal place, the temperature units availableto date. This is Column 26 (last month) * Column 25 (this month).

22FISH HATCHERY MANAGEMENTColumn 27: Record the Monthly Temperature Units per inch of gain forthe current month. For new lots, this is Column 25 - Column 20. For preexistinglots, this is Column 25 + Column 24.Column 28: Record the Monthly Temperature Units required per inch ofgain to date. This is Column 26+ (Column l9-length at initial feeding).TOTALS AND AVERAGESTotals in Columns 4, 5, 6, 7, and 8 are the sums of entries in their respectivecolumns.The last entry for Columns 10, 12, 13, 15, and 16 is used as the total forthe respective column.For Column 17, the aggregate feed cost per 1,000 fish is Column13 + Column 5.Totals or averages for Columns 18 through 28 have been omitted for thisform.Hatchery Production SummaryThe Hatchery Production Summary is prepared at the end of each month(Figure 4l). Entries on this form are taken from the Lot History Production(LHP) chart. Hatchery Production Summaries provide cumulativemonthly information for all production lots reared at the hatchery on anannual basis. Once a lot has been entered on this form, the lot should becarried for the entire year. When a lot is closed out during the year, entriesin Columns 2,3,4, 13, and 14 will be omitted for the month the lot wasclosed out and for the remainins months in that fiscal year.DEFINITIONSDensity index is the relationship of the weight of fish per cubic foot of waterto the length of the fish.Flow index is the relationship of the weight of fish per gallon per minuteflow to the length of fish.Weight of fish is the total weight on hand from Column 3.Length of fish is the average length of fish on hand from Column 4.Cu ft water is the total cubic feet of water in which each lot is held thelast day of the month.GPM flow is the total hatchery flow used for production lots the last dayof the month. Water being reused though a series of raceways is not considered;however, reconditioned water (e.g., through a biological filter) isincluded in the total flow.

HATCHERY OPERATIONS 123FIGURE 41. The hatchery production summary is used to record the monthlytotal and average production data. T.U. denotes temperature units; F.Y. is fiscalyeaf.INSTRUCTIONSCompute the following indexes.Density Index :Flow Index :weieht of fish(average length of fish) (cu. ft. water)weisht of fish(are.ag" length of fish) (GPU lo*)Column /: List the species of fish and the lot number.Column 2: Record the number of fish on hand at the end offor the individual lots from Column I of the LHP Chart.Column 3: Record the weight of fish on hand at the end of the month forfor the individual lots from Column l9 of the LHP chart.Column 5: Record the total number of fish shipped from the individuallots during the year, from Column 5 of the LHP chart.Column 6: Record the gain in weight to date for the individualthe year, from Column l0 of the LHP chart.the monththe individual lots from Column 2 of the LHP chart.Column 4: Record the size of the fish on hand at the end of the monthlot during

124 FISH HAlcHERy MANAGEMENTColumn 7: Record the total food fed to date for the individual lot for thefiscal year only, from Column 12 of the LHP chart.Column 8: Record the total cost of food fed to date for the individual lotduring the year, from Column 13 of the LHP chart.Column 9: Record the feed conversion to date. This is Column 7 (thlsform) + Column 6 (this form).Column /0: Record the unit feed cost per pound of fish to date. This isColumn 8 (this form) - Column 6 (this form] .Column //: Record the unit feed cost per 1,000 fish for the individual lotduring the year, from Column 17 of the LHP chart. If a lot is carried overfor two years, subtract the size (weight/1,000) recorded at the end of theyear in Column 3 of the LHP chart from the size (weight/1.000) recordedthe last day of the current month and multiply the difference by the unitfeed cost per pound recorded in Column 10 of the Hatchery ProductionSummary form.Column /2: Record the current month entry from Column 28 of the LHPc hart.Column /3: Record the current month entry from Column 26 of the LHPc hart.Column /4: Record the current month entry from Column 24 of the LHPchart.TO'I'ALS AND AVERAGF]SColumn 2: Record the total number of fish on hand at the end of thecurrent month.Column .7: Record the total weisht of fish on hand at the end of thecurrent month.Column 4: Record the weighted average length of fish on hand at the endof the current month. Multlply each entry in Column 2 by the correspondingentry in Column 4. Add the respective products and divide this sum bythe total number on hand from Column 2.Column 5: Record the total number of fish shipped this fiscal year.Column 6: Record the total gain in weight for the hatchery for this fiscalyear.Column 7: Record the total pounds of fish food fed for this fiscal year.Column 8: Record the total cost of fish food fed for this fiscal year.Column 9: Record the food conversion to date. This is Column7 - Column 6.Column /0: Record the cost per pound gain to date. This is Column8 + Column 6.Column //:Record the average unit feed cost per 1,000 fish reared todate. This is Column 8 + (Column 2 * Column 5).

HATCHERy opERA noNs 125POND RECORDYEAR -COST PER POUND F SH PRODUCEDFert zer --Herbic de _.-TRANSFERRED TO OTHIR UN TS FOR FURTHERREAR NG & NOT CHARGED TO FISH SHIPPEDAMOUNT & K NDS OF fuIATER ALS USED FORWEED & PEST CONTROTPONDRECORDFOR BROOD POND RECORDN.lrb"o' 't j \dtue.paN .nbp'o' 'r7 l.a ,e.tao pp,erd" _REIV]ARKS:ISEASE CONTROT DAIAFIGURE 42.Pond record form usedments, and disease control data.to record fish production, chemical treat-

126 FISH HATCHERY MANAGEMENTColumn 12: The sum of the entries in this column divided by the numberof entries gives the average Temperature Units (TU's) required per oneinch of growth to date.Column 13: The sum of the entries in this column divided by the numberof entries gives the average Temperature Units (TU's) to date.Column 14:.The sum of the entries in this column divided by the numberof entries is the average length increase to date.Warmwater Pond RecordsImportantrecordkeeping information for warmwater fish pond managementis shown in Figure 42. Accurate historical data concerning fertilizationand pond weed control can be useful in evaluating the year'sproduction.BibliographyALL|N, KENNETH o. 1974. Effects of stocking density and water exchange rate on grou,th andsurvival of channel catfish futalurus punclatus (Rafinesque) in circular tanks. Aquaculture,l:2S)-ll[).ANonrws, JAMES W., LEE H. KN-rcHr, Jrlrr,rv W. pece, yosHrexr M,lr.suo,r, and [,\,ANBRclwN. 1971. Interactions of stocking density and water turnover on growth and foodconversion of channel catfish reared in intensively stocked tanks. Progressive Fish-Culturist 33 (a) : 197- 203.-. and Yclsurext MATSUDA. 1975. The influence of various culture conditions on the oxygen consumption of channel catfish. Transactions of the American Fisheries Societyt01(2) 322-327 .and Jrrvtltv W. Pecr:. 1975. The effects of frequency of feeding on culture of catfish.Transactions of the American Fisheries Society 104(2):317 321.BARDAcH, Joun E., JoHN H. R\'1 HF,R, and WIllteu O. Mcl-rnsry. 1972. Aquaculture, thefarming and husbandry of fresh water and marine organisms. Wiley Interscience, Divisionof John Wiley and Sons, New York. tltitl p.BONN, EDWARD W., Wrr-r-r.r.u M. BArLEy, Jecx D. BAyr,F.ss, KtM E. ERTcTKSON and R()BERT E.SrsvtNs.l1)76. Guidelines for striped bass culture. Striped Bass Committee, SouthernDivision, American Fisheries Society. l0i3 p.and BIllv J. Foll,ts. 1967. Effects of hydrogen sulfide on channel catfrsh, IctalurusPumlatus. Transactions of the American Fisheries Society lll;ll ):iJ I 3l;.BoYD, CLAUDE E. 1979. Water quality in warmwater fish ponds. Agricultural ExperimentalStation, Auburn University, Auburn, Alabama. 351) p.E. E. PRAI'HFrR, and Roxat.n W. Penrs. l{)75. Sudden mortality of a massive phytoplanktonbloom. Weed Science 23:61 67.BRoussARD, MrnvlC., Jr., and B. A. SIMCo. 1976. High-density culture of channel catfish inrecirculating system. Progressive Fish-Culturist 3t{(ll) :l:tll l -t l.BROwN, MARGARET E. 1957. The physiology of fishes, volume l, metabolism.Press, New York. ,147 p.Academic

HATCHERY OPERATIONS 127BRr,,rN, R6sERt D., and K. (). Al.t-LN. 11)61). Pond culture of channel catfish fingerlings. ProgressiveFish.Culturist .tl'l)::ltt {3.BLrt-1.()crK, G. L. 1972. Studies on selected myxobacteria pathogenic for fishes and on bacterialgill disease in hatchery-reared salmonids. US l'ish and Wildlife Service'I'echnical Paper60.Bunnon,s, RocER E. l1)(i,1. llffects of accumulated excretory products on hatchery-reared salmonids.US Fish and Wildlife Service Research Report 6(i.and Bgssy D. Ctlrtus. llXiU. Controlled environments for salmon propagation. Progressive l'ish-Culturist ll0(:]):I23- Ill6BL fl.RBAticH, G^t.EN L., and H,qnvl:r'WILI-oucHB\'.and rainbow trout. Progressive Fish Culturist'2)\+):210 215.llXi7 A feeding guide for brook' brownC,,^,ntl:p, R.qv R., and K. O. ALl.l'lN. lt)76. Effects of flou'rate and aeration on survival andgrowth of channel catfish in circular tanks. Progressive Fish-Culturist :lX(4):201206.C()r-T, .JoHN, Clonc;r. TctI()BANocl.()Lrs, and BRIA\ Woxc. l1)75. 'l he requirements andmaintenance of environmental quality in the intensive culture of channel catfish.Department of Civil Engineering, University of California, Davis. I l{) p.Dl:t:rr-, CHanr.lrs R., l)^\'tD C. H,\sKELl., D. R. BROCKw.LY, and O. R KINCsBt'R\'. 1952N.-eu' York State fish hatcher,v feeding chart, 3rd edition Neu' York ConservationDepartment, Albany, New YorkDliXTF,R. RAI-pH W.. and D. B. McC.q.nn.tHtn. l9(i7. Clam shrimps as pests in fish rearingponds. Progressirc Fish-Culturisr 2!t/2):l0l l{)7.D6lvxrxr;, K. M., and J. C. Ml.nxr:r'is. ll)55.'I'he influence of dissolved oxygen concentrationon the toxicity of unionizecl ammonia to rainbow trout (Sa/u0 gairdneri Richardson).Annals of Applied Biology 4i3:211| 2'{(iEl-r-rof r, J. M. l1)75. Wcight of food and time required to satiate bros'n trout, Salmo trutta.Freshu'ater Biologl 5:51 (i'1.Eusnsor-, Kr,NN[.r'il, RoSt-MARIl. C. RL]SSo, Rlcttrno E. LUND, and Rotllnr V.'l'ttUns'ros.l{)75. Aqueous ammonia equilibrium calculations: effect of pH and temperature. Journalof the Fisheries Research Board of Canada 3'2112) t'2:179'2383.Er,r:nH.lnr. W. H-{RR\, At-tRl:lt D. EIPPI'lR, and WIt.t.l.q.lt I)YoL'NGS. 11)75. Principles offishery science. Comstock Publishing Associates, lthaca, New York. 2lll3 p.FLrcK, Wrr-r-rANt. l9(;ll. f)ispersal of aerated water as related to prevention of winterkill. ProgressiveFish-Culturist 30(l) :lll lu.Fnt.l.rt..rr', R. I., D. C. H:\sKr.rr.r., D. L. l,()N(;ACRt:, and E. W. SIll-r:s. l{)67. Calculations ofamounts to fecd in trout hatcheries. Progressive Fish Culturisl 2:)(l) :l l)+ 2t'l'.Gn.A.rt, Dtt.^No R. l{)(;tt. The successful feeding of a dry diet to esocids. Progressive Fish-Culturist ll0(i.]) : I 52.and Lnntlt SontxsoN. l!)70. 'I'he successful feeding of a dry diet to esocids. ProgressiveFi.h-Cultruirt :i2(l ;.tl .Jl.Gnr.l.ll.,r:lo, Dox.,rt-o C., and R. L. Glt-l-. 197'1. A diversion screen for grading pond-raisedchannel catfish. Progressive Fish-Culturist lJtr(2):7t|-71).H.\cKN[,], P. A. l1)7.1. On the theory of fish densitl. Progressive Fish-Culturist 36(2] :(t(i 71.H,rsxl:t.t-, D.cVlD C. ll)55. Weight of fish per cubic foot of b'ater in hatchery troughs andponds. Proqressive Fish-Culturisr l71l':l l7 I lu....................._. l9ir1). 'I'rout grorvth in hatcheries. New York Fish and Game.Journal t,('z):205 237.HE\\,I'r'r', G. S., and BunR

128 FISH HA.l.cHERy MANAGEMENTIssr.l:r,:, T'ul-ot,rrrr.t.s D. ll)77. Starting smallmouth bass Iry and fingerlings on prepared diets.Projccr completion report (pU +lttZ),'fexas.Fish Cultural Dcvelopment Center, San Marcos,7 p.KENNr'r)1, M,rni M. a)T2 rnexpensive aerator saves fish. r'arm pond Harvest (i(3):6.KR'{}rr'r^, crrx and MA\() 11)7(i. washington sarmon Study. Kramer, chin and Mayo, con.srrltinr Engineers, Seattle, Washington.- l!)7(j Staten'ide fish hatchery program, Illinois. CDB Project Number 102 010 00(j.Kramer, Chin and May,o, Inc., Consultins Engineers, Seattle, Washington.L,\(il.r.R' K.*rr. F. lr)5(i. r'resh water fisher'biologf,2nd edition. wiiliam c. Brown, Dubuque,Iowa. .tr21 pLA\tlr'R r ()N' D'\l'[r' l r)77. Fecds and feeding. Spearfish In-service Training Schoor, US Fishand Wildlife Service, Spearfish, South Dakota. (Mimeo.)l1)TT Hatcherl management charts. Spearfish In-service Training Schoor, US Fishand Wildlife Service, Spcarfish, South Dakota. (Mimeo.)LAR\r()\r'r'x, J.lcr< D., and Rosnn'r G. prprn. l!)73. Effects of water re-use on rainbow troutin hattcheries. progressive Fish_Culturist 3,5(l):t_S.Ltr', Brt'l A' l1)Tl Applications for potassium permanganate in fish culture. Transactions olthe American Fisheries Society 100(4) :gl3_|il(j.LLIIRIrz' Fl.rnr., and l{oBrn'r'c. Lr.:urs. r1)7(j. Trout and salmon culture (hatcherv methods).Calilirrnia l)epartmcnt of Fish and Game, Fish Bulletin l(j,!. 11)7 o.LI,{(), P.\t'r. 11)7 tr. Ammonia production rate and its apprication to fish curture systern plan_nins and dcsign. T'cchnical Reprint Number 35, Kramer. Chin and Mayo, 1n.., Cnn_sulting Engineers, Seattle, Washinqton. 7 n.Lt'0r'D, R., and D. w. M. Hr':Rsl:rir'. l1x;0. The inflr"r."of carbon dioxide on the toxicity or.un ionized amrn()nia to rainborv trout (,Salnn gairtlneri Richardson). Annals ol AppliedBiologl 18 (2) :llt)1) .10 Land L'rrr,r D. orn. l{)(il).'r'he diuretic response bl rainbow trout to subrethal con_centrations of ammonia. Watcr lLe,search il(5):335 3{,1.L()*\1AN, lRr]r) G lrxi5 A control fbr crayfish. progrcssive Fish-curturist 27(4),Ig+.M tzL:n"rsrcs, J.HH J. r)71. Basic fish husbandry. Spearfish In-service 'rraining School, uSFish and Wildlife Service, Spearlish, South Dakota. 6l p. (Mimeo.)Mc Cn,rnl::,t, .J. P. lg7-1. Hatchery production of advanced larqemouth bass lingerlings.Proceedings of the 5'1th Annual Conference, western Association of Game and l.ishCommissioners:'260 2.70.and R. M. JoNlrs. l!)7,r. Restoration of sock filters used to prevent entry of wildfishinto ponds. l)rogressive Fish_Culturist 3tj(4) :22,2.J L' Mrr-r-'rn,, and A. M. wr,r.r'r.s. lr)77. Masoten (Dy.t) as a contror 'br clamshrimp in hatchery production ponds. proceedingsof the Annual conferenceSoutheastern Association of the Fish and wildlife Agencies ill:ll2!) ir3l.and'1 . R. purr.r.u,s. ll)77. Effects of Masoten (D).lox) on plankton in earthen ponds.I'rrccedin{s rf the Annuar con'erence Southeastcrn Association of the l..ish andWildlifc Arencies ij l:.1 1l tr-111.and Rr)sr':r{L G. prprR. undated. The use of length-weigfrt tables with c}rannel catfish.US Fish and Wildlifc Servicc, San Marcos, Texas, typld report. 6 p.M( Nr'rr', wr.r.rANr J , and Jacr E. BArLEy. l1)75. Sarmon rancher's manuar. National Marinelisherit.s Service, Northuest Fisheries center, Auke Bav Fisheries Laboratory., AukeBav, Alaska, Processed Report. 1)5 p.Ml:nx"r, .f.'rl*:s w. lr)(i5. Aeration of winterkilr lakes. progrcssiveFish-curturist27\1):t!)tt 202.Mr.rr'n, Fnl' P, R. A ScHxrcx, K. B. Curn^rrsc, and B. L. BrRcrR. lg7(i. Regrsrratronstatus of fishery chemicals. progressive Fish Culturist 3g(l):3 7.

HATCHERY OPERATIONS 129-, K!.Ri\'1tr E. SN[.F.]), and P^t l. [. EscHltl,r t:n, editors. l1)71]. Sccond report to the f ishfarrmers. LIS l ish and Wildlife Service Resourcc Publication I I ii.M()R.t.()N, K. E. l{)53. A neu', rnechanicall,v adjustable three-rvat gradtr.Culturist Iri(:|):1)1) l0l].Proqrcssire Fish--. l1)5(j. A new mechanicallv ad.justable multi-size fish qradcr. Proqrcssire Fislt-Culturist I tt(2):(j2 (i().Pr:t:9n, Crt,rnt.Fts H. l1)7u. Intensire crrlture of tiger muskellunqe in Michiqan clurinq l1)7ljand l1)77. American Fisheries Society Special Publication ll:2()2 201).PH1.r.n,s, AR llrr.R M., .f r. 1l)70. Trout lteds and Iecding. Mirnual of Fish culture, Part IJ.b.i,Bureau of Sport Fisheries and Wildlife, Washinqton, D.C. 11) p.I'tpt..R, R()tlt.tRl G. l1)70. Knou'the propcr carrying capacities of vour farm. American I'islrcsand US Trout Nervs l5(1):-t (;, :]0l1)72. Managing hatcherics bl tbe nunrbers. Arrerican Fishes and US Trorrt Nerrsl7(3):10,25 2(;.J,rNICr. [,. BLt'lrtttL:n(;, and J.rlttlsoN F]. HoL\\'A\. ll)75. Length-rveight rt'lationshipsin somc sarlmonid fishes. I'rogressivc Fish'Culturist ll7('t) :lUl lft'1.Pyr.r, EA11. A. llxi'l. The cflect of gradinu on the total uciqht gained bl brorvn trottt. ProgressiveFish-Culturist 2(j(2) :70 75.Gt.l:x H,'rurtl:tt, and A. M. I'lllt.l.ll':j, Jr. l1){il l he effect ol qrading on the totalwcight gaincd by brook trout. I)rogressivc Fish'Culturist 2l]('1):l(j2 l(ilJR,rr', JeH:lNr, and Vr.nt. S I l.\ I'lNS. l!)70. Using Ba) tex to control crayfish in ponds. I)rogressivc Fish-Culturist ll2(l) :58 (j0.R11trtNl,r'rn, H. R-qNp,.r.t.l.. 11)7(i. Effect of selected sublethal levcls of amrnonia on thc qroIthof chirnnel cajfislt (,lctalurus punttalus). Progressive l'ish-Culturist :i8(l):2(i 21).S-qlcHr:r.r., DoN,\l.D P., S. D. Cnrulotttr, and W. M. LI;\\'ls. l1)Trl Status of sedimcnt fronrcatfish production ponds as a Icrtilizer and soil conditioner. Prttgrcssive Fish-(lrrlturistll7(4):11)l l1)l|.ScrrUr.r'2, Ror,rt.n l'., and C. D.\\ll) V,\RNIcllK. l1)75. Agc and grorvth ol largemouth bass inCalifornia farm ponds. Farm l'ond Harvcst 1)(2) :27 21).SlttrH, Ctr,,rnt.tF. l-,. l\172. llffects of metabolic products on the quality of rainborv trotrt. Amcrican !ishes and US Trout Nervs l7(:i) :7 tt,21., and R0Rl.tt r G. Plt,In. l1)7r1. l,esions associated with chronit cxposure to ammonra.Pages .11)7 'l51.1 ln William l,. Ribelin and George Migaki, editors. hc patholog\ olfishes. The Linivcrsity of Wisconsin Prcss, Madison'ancl -. l1)75. Efli'cts of rrctabolic products on thc qualit) of rainhorv trout.B.zemalInformation l,eaflet Numbcr -1, Fish Cultural l)evelopment Ccnter, 13ozeman,Montana. l0 P.Sx6n,.J. R. 11)5(i. Algae control in $,armwater hatchery ponds. Proceeclings of lhc AnnrralConferenct'Southeastern Association ol Game and Iish Commissioners l0:ll0 u5R. (). l()Nl.s. and W. A. R()(;r.tRs. l1)(i,1. Training nranual firr warmwater fish cultrrre,3rd revision. [JS Department of Interior, WaIms'ater In'Service Training School,Marion, Alabama. 2'l'1 P.56nr.Ns6x, Lr.n6r', K. Byss, and A. D. Iln..rnlrttit). l!)(j(j. The artificial proPasatiorr of csocidfishes in I'ennsylvania. Progressive F ish-Culturist 2tt(3) : ll|:j 1'tl'Si.rcK\r.t\', R. R., and R. 'f. L()\'[]t.l-. l1)77. Nutrition and licdine of channel catfish. SorrthertrCooperative Series, Bulletin 2lll, Auburn Llniversity, Auburn, Alabama (i7 p'I'AcKt.tr.f, Dl:rvl:r L. l l)7-1. Yield of channel catfish and composition of efflrrcnts fronrshallow-water races'ays Progressive Fish Culturist 3(ill):l(i '1u'THyltsroN, R. V., R. C. R('SS(), and K. Eltl:nsl)\. l1)71. Atlutous ammonia cquilihritrm calculations. Technical Report 7-1 1, Fisherics Bioassa,v Laboratorl, Montana stateUniversity, Bozeman, Montana

I30FISH HATcHERY MANAGEMENTTRL Ssll.L, R. P. l1)72. The percent un-ionized ammonia in aqueous ammonia solutions at differentpH levels and temperatures. Journal of the Fisheries Research Board of Canada2{)(10):150s 1s07.Tt'crKER, Cn,uc S., and CLettor: E. Bovo. 1{)77. Relationships between potassium permanganatetreatment and water quality.'l'ransactions106(5):4ul .1tt8.of the American Fisheries SocietyTuxtst.rx, A. V. l{).15. Trout feeds and feeding. Cortland Experimental Hatchery, Cortland,TwoNco,Neu'York. (Mime".)TrNlorHY K., and H. R. MACCRINTN{oN. 1976. Significance of the timing of initialfeeding in hatchery rainbow trout, Sa/mo gairdneri. Journal of the Fisheries ResearchBoard of ('anada 3:t(!):llll-l ll)21.US Bureau of Sport Fisheries and Wildlife. ll)70. Report to the fish farmers. US l'ish andWildlife Service Resource Publication U3.WuDlNlr:\'uR, G.,rnv A., and J,lrrrr.:s W. Woon.11)7'tr. Stress as a predisposing factor in fishdiseases. Fish Disease Leaflet l]ll, US Department of Interior, Fish and Wildlife Service,Washincton, D.C. tt p.Wrs lrns, HARR\. l1)70. Carrying capacity of salmonid hatcheries. Progressive Fish-CulturistWtt-l.otcHuY,ll2(1):.1iJ +(i.and Kr,t rH l'RA I t . I {)77. Rational design of hatcheries for intensive salmonid culture,based on metabolic characteristics. Progressive l'ish-Culturist 3tl(-1):lir7 16.1.H.tnvr,r'. l1)6f1. A method for calculating carrying capacities of hatchery troughsand ponds. Progressive Fish-Culturist 3(r(il):17.1174.Hon rnn N. LARSEN, and J. T. Bolt'r:n. 1972. The pollutional effect of fishhatcheries. Amcrican Fishes and US Trout News l7(i1);tr 7,20 21 .Wtxru, J,rltl:s W. llxitt. Diseases of Pacific salmon, their prevention and treatment. State ofWashington, f)epartment of Fisheries, Ol,vmpia, Washington 76 p.

Broodstock, Spawning,and Egg HandlingBroodstock ManagementPortions of this chapter have been quoted extensively from Bonn et al.(tszo), Kincaid (tgzz), Lannan (tszs), Leitritz and Lewis (tgzo), McNeiland Bailey (1975), and Snow et al. (1968). These and other sources arelisted in the references.The efficient operation of a fish rearing facility requires a sufficientquantity of parent or broodfish of good quality. The quantity of broodfishneeded is determined by the number of eggs needed to produce the fry required,with normal losses taken into account. Quality is a relative termthat is best defined by considering the use of the product. Persons producingfish for a restaurant or supermarket use different measurements of qualitythan a hatchery manager rearing fish for use in research or stocking.Most work defining fish quality has focused on performance in thehatchery, broodfish reproduction, and progeny growth and survival underhatchery conditions. In the future more emphasis will be placed on theability of hatchery fish to survive after release and their contribution to aparticular fishery program.131

t32FISH HATCHERY MANAGEMENTA cq uisition of BroodstockStock for a hatchery's egg supply may be wild stock, hatchery stock, a hybridof two wild stocks, a hybrid of two hatchery stocks, a hybrid of wildand hatchery stock, or purchased from a commercial source. Currently,broodstocks of most trout and warmwater species are raised and maintainedat the hatchery, whereas Pacific and Atlantic salmon, steelhead, andstriped bass broodfish are captured as they ascend streams to spawn. Captureand handling of wild fish populations should utilize methods that minimizestress. The installation of fishways or traps has proved successful in::::".t"tmature salmon and steelhead as they complete their migratoryBroodfish of coolwater species, such as northern pike, muskellunge, andwalleye, usually are wild stock captured for egg-taking purposes. Wildmuskellunge broodstock have been captured in trap nets set in shallowbays. As the nets are checked, the fish are removed and tested for ripeness.Some hatcheries sort the fish and take the eggs at the net site, whileothers transport the fish to the hatchery and hold the fish in tanks or racewaysuntil they are ripe.Walleye and sauger broodfish are collected in the wild with Fyke nets,gill nets with 1.5 or 2.0-inch bar mesh, and electrical shockers. Most successfulcollections are made at dusk or at night when the water temperatureis about 36"F. Gill nets fished at night should be checked every two orthree hours to prevent fish loss and undue stress before spawning. Maturesauger and walleye females can be identified by their distended abdomensand swollen reddish vents which change to purple as they ripen. In transportingbroodfish to the hatchery, at least 2 gallons of water should be providedper fish.Wild northern pike broodstocks can be caught in trap nets, pound netsor Fyke nets (Figure 43). When pike are trapped, they become unusuallyactive and are highly prone to injury. The use of knotless nylon nets willreduce abrasion and loss of scales.Catfish, largemouth and smallmouth bass, and sunfish broodstock maybe captured in the wild by netting, electroshocking, or trapping. However,spawning of wild broodstock is often unreliable during the first year. Consequently,most warmwater species are reared and held as broodstock in amanner similar to that used for salmonids.Spawning information and temperature requirements for various speciesof fish are presented in Table 17.Care and Feeding of BroodfishProper care of domestic broodstock is very important for assuring goodproduction of eggs, fry, and fingerlings. Methods differ with species, but

BROODSTOCK, SPAWNING, AND EGG HANDLING 133FIGURE 43.Wild northern pike broodstock are trapped for egg-taking purposesthe culturist must provide conditions as optimum as possible for suchthings as pond management, disease control, water quality, and food supply.The salmonid fishes generally reduce their feeding activity prior tospawning, and Pacific salmon discontinue feeding entirely during thespawning run. Trout broodfish usually are fed formulated trout feeds inquantities of 0.7-1.0% of body weight per day at water temperaturesaveraging 48-53"F, and then fed ad libitum as spawning season approaches.Food intake can drop as low as 0.3-0.4% of body weight per day dwing adlibitun feeding, when the fish are fed high-protein diets containing 4B-4g%protein and 1,560-1,600 kilocalories per pound of feed.In some cases, coolwater species are held at the hatchery and a domesticatedbroodstock developed. coolwater fishes all are predators and must beprovided with suitable forage organisms. There has been some recent successin developing formulated diets that cool- and warmwater predatorswill accept, and in developing new strains or hybrids of these species thatwill accept formulated feeds.For predator species such as largemouth 6asq providing a suitable food organismfor growth and maintenance in the amount needed is very important.The rapid growth and development of largemouth bass makes raising

13.1 FISH HA'fC]HLRY NIANAGEMENl.TABt-F, 17. sp-\wNlNc I\FORNT;\'fr()\ AND TEMPL,RAI'LlRL, R.EqulRL\{ENls toRIS I,XPI{I]SSI.,I) IN'F,EGGS PERSPA$ N.' l NCTEMPERA'I't] RIPOTINDsPl.rc t l..sI- REQLTtNC)R,4.NGE OP] IMUM SPA\\'NINGOI' FISHChinook salmonC)nce perlife span'33-77'50-57'45 55'350Coho salmonOnce perlife span:l:l-7 7 ".18-58'45-55'.100Sockeye salmonOnce perlife span33 70'50-59'15 54"500Atlantic salmonAnnual-Biennial33 75"50-62",t'2-50'u00Rainbou troutAnnual33 78"50-60' 50 55' l,000Brook troutAnnual3:l-7'2'+.) JJ'15 55"I,200Brohn troutAnnual33 7tt'.18-(;0',18 ir5'l,000Lake troutA n nual3 3-70''12 58",18-52 "800Northern pikeAnnual33 tt0',r0 65".10-,1U'I,1 00M uskellungeAnnual33 r.iO'+5 b5''15 55'7,000Wallel eAnnual33-80".15 60'.18-55"25,000Striped bassAnnual35 90'55 75"55- 7 l'l 00,000Channel catfishAnnual33 9ir'70-u5'7'2 82'3,750FlatheadcatfishAnnual33-95'65 r]O'70-u0'2,000

BROODSTOCK, SPAWNING, AND EGG HANDLINCI35VARIOUS SPECIES OF FISH AS REPOR'IED IN THE LIl'ERATURE. TEMPERATIjREREMAR KSUpstrcam miqration and maturation, 15 ()0', eggs that had developed to thc l2U ccll stagc in.12.5' uater cgrrlcl toleratc water .tt li5'' for the rernaincler ol' the incubirtion periocl. lhe l2llcellstagc was attained in I l1 hours ol incubation.Eggs reached the 128-cell stage in 72 hours at 4',2.5' but required an additional 24 hours ofdevelopment at that temperature before they could withstand l]5'water'Temperatures in excess of 54' affect maturation of eggs and sperm in adults; normal growthand development of eggs does not proceed at temPelatures above'1!)'; at least 50" mortalityat 54" can be expected.Broodfish should not be held in water temperatures exceeding 56", and preferabh not above54. for at least six months before spawning. Rainbow trout eggs will not develop normally inthe broodfish if constant watel temPeratures above 56" are encountered prior to spawning'fhe eggs cannot be incubated in water below'12'withorrt excessive lossBroodfish can tolerate temperatures greater than 66" but the average water temperature shouldbe .tU .50" for optimal spawning activity and embryo survival. Eggs will develop normally atthe lower temperatures, but mortalities are likely to be high.Eggs do exceptionally well in hard water at 50"Water temperatures should not drop during the spauning season. Temperatules neal anoptimum of 5,tr'are recommended in northern pikc management'The optimum temperature ranges for fertilization, incubation, and fry survival are 4ll 5'l',4U-59",59 70", respectively. If unusually cold weather occurs after the fry hatch, Iry survivalmay be affected. Feeding of fry may also be reduced when temperatures are lou'.Temperature shock between tj5" and higher temperatures may have a more deleterious aflecton freshly fertilized eggs than if the eggs are incubated for l(i to.1,l-hours at 65'beforetransfer to the higher water temperatures

I36FISH HATCHERY MANAGEMEN.ITeBr-n 17. coNTTNUEDSPAWN I NC;I'!-MPERA I'URIll(;(is PI]i.POT NI)l REquFrNc\OP'|I}IT]M SI'A\\'NI\(; OI }ISIILargemouth bassAnnual33 95'5 5-lr0'(i0 (irl'I 3,0(X)Smallmouth bassAnnual33 90"50 70"r;ti (i2"1J,000BluegillIntermittentil3-95 "55 lJO'(i5 80'50,(x)0Golden shinerIntermittent3 3-90"50 r]O'(i5-l.t0'7 5,(X)0GoldfishIntermittent3lJ-t)5'.15 ll0'55 80"50,0(x)American shadAnnual33 l.iO'.15 70'50 (i:r'7 0,000Common carpIntcrmittentSemi-annuallyllii 95'5.5-n0'rl5 1.i0'{i0,(xx)broodfish of this species relatively simple. Eggs can be obtained from oneyear-oldfish that have reached a size of0.7-1.0 pounds. Brood bass can beexpected to spawn satisfactorily for three to four seasons and should bebetween 3 and 4 pounds at the end of this time. It is suggested that onethirdof the broodstock be replaced each year. The food organism can bereared on the station or purchased from outside sources. As a minimumstandard, enough food should be provided to produce a weight gain in thebroodstock of 5091, per year. For largemouth bass, as an example, 5 poundsof forage food produce about I pound of fish gain, in addition to the 3Pounds of forage per pound of bass required for body maintenance. Thus, al-pound bass being held for spawning should be provided a minimum of5.5 pounds of forage fish.Fish typically lose 10-20,q0 of their body weight during the spawningseason. Much of this is due to the release of eggs and sperm, and is mostpronounced in females. Feeding may be interrupted during courtship orduring periods when the nest and fry are protected against predators. Notall species protect their young, but male largemouth bass, bluegill, and othersunfishes do. This weight loss must be regained before subsequent eggsand sperm are developed. Feeding schedules should reflect the nutritionalstatus of the fish and be tailored to their respective life histories.Close attention should be given to the quality and availability of theforage fish provided. The forage should be acceptable to the cultured fish

BROODS'fOCK, SPAWNING, AND EGG HANDLINGt37RI.]MARKSEggs can be successfully incubated at constant temperatures between 55" and 75". Hatchingsuccess may be lower at 50' and 80'. The eggs may be especially sensitive to sharp changes intemperature during early developmen t.and small enough to be easily captured and consumed. The pond shouldbe free of filamentous algae or rooted vegetation that might Provide coverand escape for the forage fish. Pond edges with a minimum depth of 2 feetpermit the predator fish to range over the entire pond and readily capturethe food provided.The holding pond should be inspected at 2- to 3-week intervals, andseine samples of forage fish should be taken throughout the summer' fall,and spring months. When samples taken with a 1S-foot seine contain fewerthan 15-25 forage fish of an appropriate size, the forage should be replenished.Tadpoles, crayfish, bluegills, and miscellaneous other fishes thatmay accidentally develop in the pond cannot be depended uPon to satisfactorilyfeed the hatchery broodstock. Instead, a suitable forage speciesshould be propagated in adequate quantities to assure both maintenanceand growth of the cultured species.Maintenance of broodstock represents the first phase of activity thatmust be accomplished in channel catfish c:ulture. Broodfish in most situationsare domesticated strains that have been hatchery-reared. Dependablespawning cannot be obtained until female fish are at least 3 years old,although 2-year-old fish that are well-fed may produce eggs. Femalesweighing l-4 pounds produce about 4,000 eggs per pound of body weight.Larger fish usually yield about 3,000 eggs per pound of body weight. Fish inpoor condition can be expected to produce fewer eggs and lower quality sPawn.

138 FISH HATCHERY MANAGEMENTChannel catfish broodstock usually are maintained in a holding pondand fed a good quality formulated diet. The density of broodfish shouldnot exceed 600-800 pounds per acre. The amount of food provideddepends on water temperature; above 70'F feed 3-4% of body weight perday; from 50'-70'F, 2o/o per day; below 50",2ok twice per week. Spawningsuccess and the quality of eggs and fry are improved, in many cases, if thefish are provided a diet including natural food. For this reason, many culturistssupplement a formulated diet with cultured forage fish. Anotherpractice is to supplement a diet once or twice a week with liver fed at arate of 4% of fish weight.Differentation between male and female channel catfish also can be aproblem. The secondary sex characters are the external genitalia. The femalehas three ventral openings-theanus, the genital pore, and the urinarypore-whereasthe male has only an anus and urogenital pore. In themale, the urogenital pore is on a papilla, while in the female the genitaland urinary openings are in a slit, without a papilla. Experienced breederscan discern the sex of large broodfish and detect the papilla by rubbing ina posterior to anterior direction or by probing the urogenital opening withan instrument such as a pencil tip.Tertiary sex characteristics develop with approaching sexual maturation.In the male, they include a broad muscular head wider than the body, adarkening of the body color, and a pronounced grayish color under thejaws. Females have smaller heads, are lighter in color, and have distendedabdomens at spawning time.Brood bluegil/s generally are obtained by grading or selecting largerfingerlings from the previous year's crop. These replacements may either bemixed with adults stocked in spawning-rearing ponds or stocked alone inproductionponds. The preferred procedure is to keep year classes ofbroodfish separate so that systematic replacement can be carried out afterthe broodfish have been used for three spawning seasons. Distinctive sexualcharacteristics differentiate rnale bluegills from females (Figure 44).Special holding ponds normally are established for keeping broodfish. Ifthe stocking density is below 200 pounds per acre, the broodstock can besustained by natural food organisms, provided the pond has had a good fertilizationprogram. If more than 200 pounds per acre are held, a supplementalformulated diet usually is fed. The feeding rate is 39'o of bodyweight at water temperatures above 70"F, and 2.5'lo of body weight at temperaturesfrom 70-50'F. Below 50'F, feeding can be suspended entirely.Redear sunfish do not adapt to formulated feed as readily as bluegills becausethey are more predatory. Diets can be fed at 0.5-20i0 of body weight,depending on temperature, but suitably sized organisms also should be provided.Redear sunfish eat shelled animals and a holding pond should supporta good crop of mollusks.

BROODSTOCK. SPAWNING, AND EGG HANDLING 139FIGURE 44. Sexual dimorphism develops in mature broodfish. The male bluegillbecomes much darker than the female and changes body shape (upperpanel). Male salmon also show changes in color and the jaw becomes hooked,forming a kype (lower panel).

140 FISH HATCHERY MANAGEMENTForage FishForage species cultured as feed for predatory broodfish vary depending onthe species of broodfish being maintained. Several factors must be consideredwhen a forage organism is selected. The forage must not be toolarge for the predator to consume nor too small to provide adequate nourishment,and should be able to reproduce in adequate numbers at the timewhen it is needed. Forage species should have the right shape andbehavior to attract the predator, be easily captured by the broodfish, andrequire little pond space to rear. If the forage can be obtained commerciallyat a reasonable cost, production space and time will be saved at thehatchery.Species of forage fish propagated as food include suckers, fathead minnows,goldfish, golden shiners and Tilapia. Shad, herring, bluegills, andtrout are used to a lesser degree as forage fish. Suckers, fathead minnows,and goldfish usually are used with coolwater broodfish. These species areearly spawners, making them available as forage when needed by thebroodfish. Northern pike, walleye, and muskellunge prefer a long slenderfish with good body weight, such as the sucker.Culture of forage fish varies with the species; some notes about the mostfrequently utilized species follow.WHITE SUCKERWhite suckers occur east of the Great Plains from northern Canada to thesouthern Appalachian and Ozark mountains. They prefer clearwater lakesand streams. In early spring, they run upstream to sPawn in swift waterand gravel bottoms, although they also will spawn to some extent in lakesif there are no outlets and inlets. White suckers have diversified feedinghabits, but prefer planktonic crustaceans and insect larvae.Broodfish usually are taken from streams during the natural spawningrun.These fish are hand-stripped and the eggs are hatched in jars. Afterhatching, the fry are stocked in ponds prepared for the production of zooplankton.Stocking rates vary with the size of the desired forage:40,000-60,000 per acre for l-2-inch fish; 20,000-40,000 for 2-4-inch fish;5.000-20.000 for 4-6-inch fish.Ponds of moderate fertility usually produce the most suckers. Sterileponds do not produce enough food for white suckers and excessively fertileponds often produce too much aquatic vegetation. Ponds with large populationsof chironomid fly larvae (bloodwor-.) i.t the bottom muds willproduce good sucker crops year after year. Loam and sandy-loam soils producethe best chironomid populations; peat and peat-loam ponds are adequatefor this purpose, but silt and clay-loam ponds are poor. Ponds with

BROODSTOCK, SPAWNING, AND EGG HANDI,IN(;heavy, mosslike growths of filamentous algae over the bottom do not prolengthof l-2 inches, an organic fertilizer suchduce good crops of suckers.After the suckers attain aas manure can be added to increase the production of natural food. Suckfeedsas a supplemental ers will adapt to formulateddiet.FATHEAD MINNOWThe fathead minnow occurs throughout southern Canada and in theUnited States from Lake Champlain west to the Dakotas and south toKentucky and the Rio Grande River. It feeds mainly on zooplankton andinsects. The spawning season extends from May until the latter part ofAugust. The eggs are deposited on the underside of objects in a pond, andhatch in 4.5 to 6 days. Mature fathead minnows range in length from ljto 4 inches, the male being consistently larger than the female. The lifespan of hatchery-reared fathead minnows is 12 to 15 months, depending onthe size of the fish at maturity.During the early spawning season a largemajority of the males usually die within 30 days after the onset of spawningactivities, and a large percentage of the gravid females will die within60 days. One- to two-inch immature fatheads, even though only a year old,die shortly after they become gravid at an age of about 15 months. Thus,the older fish in a pond should be used as forage after they have spawned.Ponds for fathead minnows should have flowing, cool water from aspring or well. The ponds should not be larger than one acre or smallerthan 0.25 acre. The water depth should average about 3 feet and rangefrom 2 feet at the shallow end to 6 feet at the drain. The pond should beequipped with a controllable water inlet and drain. Ponds to be used forreproduction should be lined along two banks with rocks ranging in sizefrom 6 to 12 inches in diameter, or with tile, extending from six inchesabove the planned water level to two feet below it. This material providesspawning surfaces for the minnows.The brood ponds should be stocked in early April with about 60'lt adultminnows and 40'll immature fish. Both adults and juveniles are used asbreeders because of the species' short life span. In this way, one can besure of a continuous, uninterruptedsupply of newly hatched fry. Thebrood ponds should be stocked at the rate of 15,000 to 25,000 fish per acre.Fathead minnows normally start spawning activities during the latterpart of April or at a time when the pondwater temperature reaches 65'F.They spawn intermittentlythroughout the summer, provided the watertemperature does not rise above 85'F. When this temperature is reached,spawning ceases, and is not resumed until the pond is cooled by a weatherchange or by an increased flow of spring water. Withina few days ofspawning activity, small fry will be seen swimming near the surface, a few

142 FISH HATCHERY MANAGEMENTfeet out from shore. As soon as fry become numerous, they can be capturedwith a small fry seine and transferred to rearing ponds at the rate of300,000 to 600,000 fry per acre. From this stocking rate, a harvest of about150,000 fathead minnows can be expected.During the first few weeks of life following transfer to the rearing pond,fry grow very rapidly. Within 4 to 8 weeks, many of these fish will matureand begin to spawn. When this occurs, the pond may become overstockedand the fish become stunted. The excess fry should be transferred toanother pond or destroyed.A productive pond should have a good plankton density; a Secchi diskreading of about l2 inches should be maintained. Fathead minnows readilyaccept a formulated diet, usually in the form of meal. The amount recommendedis 2'li of body weight per day, not to exceed 25 pounds per dayper acre. In 6 to 10 weeks this procedure will produce 2-inch forage organisms.GOLDF'ISHGoldfish are good forage fish. This is a hardy species that prospers duringhot weather. Goldfish feed largely on plankton, but will take insects andvery small fish. They reproduce in large numbers and grow rapidly.Goldfish normally start spawning when the water reaches 60"F and continueto spawn throughout the summer if the temperature remains above60'F and the fish are not overcrowded. The favorite spawning time is rightafter sunrise on sunny days. The females lay their eggs on grass, roots,leaves, or similar objects. A female goldfish may lay 2,000 to 4,000 eggs atone time and may spawn several times during the season. The eggs areadhesive and stick to any object they touch. The live eggs are clear andturn brown as they develop; dead eggs are cloudy and opaque. The eggshatch in 6 to 7 days at a water temperature of 60'F.Goldfish averaging 0.25 to 0.75 pound reproduce well and should beused for broodstock. Broodstock overwintered in crowded ponds will notspawn in the ponds. Maximum egg production is obtained by keeping thebroodfish in the overwintering pond until after the last spring frost. Thenthe fish are stocked in the production ponds at the rate of 100-200 adultsper acre without danger of frost damaging the eggs or fry. Goldfish will acceptformulated feeds and feeding rates should be set to produce 2-3-inchfish in the shortest time.Broodstock ponds should be fertilized to insure that phytoplankton productionis sustained all summer. Secchi disk readings should be l8 inchesor less.Ponds should contain suitable natural vegetation or artificial spawningmaterial. The water level is commonly dropped in early spring to encouragethe growth of grass along the shoreline. When the ponds are filled,

BROODSTOCK, SPAWNING, AND EGC HANDLINCt43this grass provides spawning sites. Aquatic plants are also utilized asspawning sites. If natural vegetation is absent or scarce, hay, straw, or matsof spanish moss may be anchored in shallow areas for spawning purposes.If the eggs are allowed to hatch in the ponds where they are laid, theadults will stop spawning when the pond becomes crowded with youngfish. If the eggs are removed and transferred to clean ponds to hatch, theuncrowded adults will continue to spawn all summer. In general, pondscontaining both young and adults should produce up to 100,000 fingerlingsper acre. In intensive situations, where a heavily stocked brood pond providesfry for eight or ten rearing ponds, production will reach 200,000 to300,000 goldfish per acre.GOLDEN SHINERGolden shiners are widely distributed from eastern Canada to Florida, andwestward to the Dakotas and Texas. They prefer lakes and slack-waterareas of rivers. Young golden shiners eat algae and cladocerans. Adults willconsume a variety of organisms, from algae and zooplankton to mollusksand small fish. Eggs are adhesive and are scattered over filamentous algaeand rooted aquatic plants.Golden shiner breeders should be at least I year old, and 3 8 incheslong. About 5070 of the broodstock should be shorter than 5 inches inlength; otherwise the stock might be predominantly females, as the malesare consistently smaller than females. The stocking rate in large ponds,where the fry will remain with the adults, should range from 2,000 to 3,000fish per acre. In ponds where egg or fry removal is planned, the stockingrate should be 4,000-8,000 adults per acre.Golden shiners start spawning activity when the water temperature risesabove 65'F, but if the temperature exceeds 80'F, spawning ceases. Duringthis period, at least four or five distinct spawning cycles occur, separatedby periods of about 4 or 5 days. Spawning usually starts early in the morningand terminates before noon. The females deposit their eggs on any typeof submerged plants or debris. At temperatures of 75-tt0"F, fertilized eggshatch within four days.Shortly thereafter, fry congregate in schools near the surface along theshoreline, where they can be collected with a fine-mesh net and transferredto growing ponds. Because adults often cannibalize the young if the twoage groups are left together, the fry should be transferred to other ponds atthe rate of 200,000-300,000 fry per acre. Successful production will yield75,000-150,000 2-3-inch fish per acre. In ponds where the fry remain withthe adults, 60,000 shiners per acre is considered good production.Golden shiners, like most other forage species, can be fed a supplementalformulated diet to increase srowth rate.

44FISH HAI'CHERY MANAGEMENl'When golden shiners are seined from a pond, the seine should be of cottonor very soft material because the scales are very loose on this species.Harvesting at water temperatures below 75'F will reduce stress.TILAPIAFish of the genus Tllapta are native to Africa, the Near East, and theIndo-Pacific, but are presently widely distributed through the world. Tilapiaare cichlids, and most species are mouth brooders; females incubateeggs and newly hatched fry in their mouth for 10 14 days. When the fryare free-swimming they begin feeding on algae and plankton.Tilapia tolerate temperatures in excess of 100'F, but do not survivebelow 50 55'F. Consequently, their culture as forage fish is restricted tothe southern UnitedStates. Even there, broodfish usually need to beoverwintered in water warmer than 55"F. Most tilapia are very durable andtolerant, able to survive low oxygen and high ammonia concentrations.Tilapia are excellent forage species in areas where culture is possible:easy to propagate; prolific; rapid growing; disease-resistant; and hardy fortransferring in hot weather. Rearing ponds should be prepared and fertilizedto produce an abundance of phytoplankton. If 200 250 adults arestocked in a pond after the water temperature is 75'F or above, they willproduce 100,000 juveniles of I 3 inches in 2-3 months. The adults willspawn and rear a new brood every 10-14 days throughout the summer.Tilapia accept dry food, and supplemental feeding will increase the growthrate.Improaement of BroodstocksFish stocks may be improved by several methods, some of which are: selectivebreeding, the choosing of individuals of a single strain and species; hybridization,the crossing of different species; and crossbreeding, the matingof unrelated strains of the same species to avoid inbreedine.SELECTIVI] BREEDINGSelective breeding is artificial selection, as opposed to natural selection. Itinvolves selected mating of fish with a resulting reduction in genetic variabilityin the population.Criteria that often influence broodfish selection for selective breedinginclude size, color, shape, growth, feed conversion, time of spawning, age atmaturity, reproductive capacity, and past survival rates. These may varywith conditions at different hatcheries. No matter what type of selection

BROODSTOCK, SPAWNING, AND EGG HANDLINGt45program is chosen, an elaborate recordkeeping system is necessary in orderto evaluate progress of the program.Inbreeding occurs whenever mates selected from a population ofhatchery broodfish are more closely related than they would be if they hadbeen chosen at random from the population. The extent to which a particularfish has been inbred is determined by the proportion of genes that itsparents had in common. Inbreeding leads to an increased incidence ofphenotypes (visible characteristics) that are recessive and that seldom occurin wild stocks. An albino fish is an example of a fish with a recessivephenotype. such fish typically are less fit to survive in nature. Animalswith recessive phenotypes occur less frequently in populations where matingis random.Problems that can arise after only one generation of brother-sister matinginclude reduced growth rate, lower survival, poor feed conversion, andincreased numbers of deformed fry. Broodstock managers must be aware ofthe problems that can result from inbreeding and employ techniques thatwill minimize potential breeding problems. To avoid inbreeding, managersshould select their broodstocks from large, randomly mated populations.Significant differences have been found in rainbow trout between femalesof different ages in egg volume, egg size, and egg numbers per female.Three-year-old females provide a higher percentage of eyed eggs andlarger, more rapidly growing fingerlings than two-year-old females. Growthof the fingerlings is influenced by the age of the female broodfish and isdirectly related to the size of the egg. The egg size is dependent on the ageand size of the female broodfish. Generally, the egg size increases in femalesuntil the fifth or sixth year of life and then subsequently decreases.If inbreeding is avoided, selective breeding is an effective way to improvea strain of fish. A selective breeding program for rainbow trout atthe Manchester, Iowa National Fish Hatchery resulted in fish 22o/,t heavierthan fish hatched from unselected individuals. Selective breeding in trouthas increased growth rate, altered the age of maturation, and changed thespawning date.A system has been developed for maintaining trout broodstocks for longperiods with lower levels of inbreeding than might be experienced in randommating. It requires the maintenance of three or more distinct breedinglines in a rotational line-crossing system. The lines can be formed by, (u)an existing broodstock arbitrarily subdivided into three groups; (b)"gg.taken on three different spawning dates and the fry reared separately toadulthood; o. (c) three different strains or strain hybrids. Rotational linecrossingdoes nothing to reduce the level of inbreeding in the basebroodstock, but serves only to reduce the rate at which further inbreedingoccurs. consequently, it is essential that a relatively high level of geneticdiversity be present in the starting broodstock. The use of three different

146 FISH HAI'CHERY MANAGEMENTLIN EBz.=z.LrJFIGURE 45. Rotational line-crossing system based on threelines. Each box represents a pool of fish belonging to aspecific line. Solid lines show the source of females used toproduce the next generation. The dotted lines represent themales used in the mating system. Generations of offspringfrom the original lines are presented on the left of thecolumns. (Sou.ce' Kincaid 1977.)strains or the subdivision of a first generation strain hybrid is the preferredmethod for line formation, because either of these tends to maximize theinitial genetic diversity within the base population. After the three lineshave been formed, the rotational line-crossing system can be implemented.At maturity, matings are made between lines. Females of line A are matedto males of line C to advance line A. Females of line B are mated to malesof line A to advance line B, and females of line C are mated to males ofline B to advance line C. Each succeeding generation is advanced by repeatingthis procedure (Figure 45).The rotational line-crossing system is flexible enough to fit into mostbroodstock operations. At least 300 fish (50 males and 50 females fromeach of the three lines) are needed for maintenance of the population, butthis number could be set at any level necessary to meet the egg Productionneeds of a particular hatchery operation.

BROODS'fOCK, SPAWNIN(I, AND L,C;G HANDLING 147One potential problem with the system is the amount of separate holdingfacilities required for maintaining up to 15 groups if each line and yearclass are held separately. This problem sometimes can be overcome by usingmarks such as fin clips, brands, or tags to identify the three lines andthen combining all broodfish of each year class in a single rearing unit.The total number of broodfish to be retained in each year class would bedetermined by the production goals of the particular station, but equalnumbers of fish should come from each line. This method will not onlyslow down inbreeding, but will also make a selection program more effectlve.Studies have been conducted on the growth and survival of progenyfrom mating of hatchery and wild steelheads to determine if hatchery fishdiffer from wild fish in traits that affect the survival of wild populations.They indicated that wild fish x wild fish had the highest survival, and wildfish x hatchery fish had the highest growth rates. In the hatchery, however,fish from a hatchery x hatchery cross had the highest survival andgrowth rates.With salmon, where the adult returns to the hatchery exceed the numberof fish required to maintain the run, it has been possible to select that portionof the population having the most desirable characteristics. Throughselective breeding, it has been possible to develop stocks of salmon that arebetter adapted to the needs of both fisheries management and commercialaquaculture. Changes in timing of spawning runs through selection haveresulted in delayed or advanced fish spawning when water in the spawningstreams has cooled or warmed to more desirable temperatures. In some instances,fish that are much larger than most have been selectively bred toproduce many more eggs than the ancestoral stock. Greater temperaturetolerance and disease resistance of selectively bred fish can also increasesurvival. Rapid growth of selectively bred fish shortens the rearing periodso that facilities may be used more efficiently, and earlier maturity decreasesthe rearing period for broodfish.Information on selective breeding of cool- and warmwater fish is limited.Some work has been done toward improving the commercial value of thesefish, increasing their resistance to low dissolved oxygen concentrations, improvingfeed conversion, and developing hybrid strains.Selective breeding of catfishes is relatively new. Some goals to beachieved by selective breeding include resistance to low dissolved oxygenlevels, more efficient food conversion, and development of fish with smallerheads in proportion to body size. Albino channel catfish have been reportedto possess the smaller head characteristic. However, albino channel catfishfry have a significantly lower survival rate than normal fish.The following guidelines should be followed when catfish are managedand selected:

148 FISH HATCHERY MANAGEMEN'I(1) Avoid inbreeding, which includes father-daughter, mother-son andbrother-sister mating. Current practice is to keep the same broodstock 4 tol0 years, with replacement broodstock coming from progeny produced onthe farm. Furthermore, a beginning producer may have unknowinglystarted a broodstock with full brothers and sisters having a narrow geneticbase. Catfish should be marked in some manner to identify broodstock forpen mating to avoid inbreeding. The stocks can be clearly identified byheat branding, applied when water temperature is 72"F or above, so thathealing proceeds rapidly.(2) Enrich bloodlines through the addition of unrelated stock. This canbe effective in correcting deterioration in quality of broodstock common toinbreeding. The need to enrich bloodlines might be suspected if a highpercentage of deformed progeny, low hatchability of eggs, low survival offry, or poor growth becomes evident.(3) Crossbreed unrelated stocks. Stocks orginating from different riversystems and commercial sources are usually quite diverse, and may combinewith resulting hybrid vigor, especially in growth and disease resistance.(,t) Select broodstock carefully; as males grow faster than females inchannel catfish, blue catfish, and white catfish, rigorous selection by gradingin ponds probably will result in practically all males. More properly, arandom sample should be taken at the first selection at 6 months of age,with selection for growth and broodstock occurring at 18-24 months ofage. Select equal numbers of males and females.HYBRIDIZA'IION AN D CROSSBRF]T]DINGHybridization between species of fish and crossbreeding between strains ofthe same species have resulted in growth increases as great as 100%, improvedfood conversions, increased disease resistance, and tolerance to environmentalstresses. These improvements are the result of hybrid vigortheability of hybrids or strain crosses to exceed the parents in performance.Most interspecific hybrids are sterile. Those that are fertile often producehighly variable offspring and are not useful as broodstock themselves. Hybridscan be released from the hatchery if they cause no ecological problemsin the wild.Several species of trout have been successfully crossed, the more notablebeing the splake, a cross between brook and lake trout.Hybridization of the chain pickerel and northern pike in a study in Ohiodid not produce hybrid vigor and the resulting offspring grew at an intermediaterate to the parents. A cross between northern pike males andmuskellunge females has yielded the very successful tiger muskie.

BROODSTOCK, SPAWNIN.G, AND EGG HANDLINC 149A hybrid striped bass was developed by fertilizing striped bass eggs withsperm from white bass. The hybrids had faster growth and better survivalthan striped bass. The chief advantage of the reciprocal hybrid, from whitebass eggs and striped bass sperm, is that female white bass are usuallymore available than striped bass females and are easier to spawn. Underartificial propagation, the reciprocal mature hybrids can be produced in 2years, while 4-5 years are required to produce hybrids when female stripedbass are used. White bass and most male striped bass mature in 2 years,but female striped bass require 4-5 years to mature.Both hybridization and crossbreeding of various species of catfish havebeen successfully accomplished at the Fish Farming Experimental Station,Stuttgart, Arkansas. Hybrid catfishes have been tested in the laboratory forimproved growth rate and food conversion. Two hybrids, the white catfishx channel catfish and the channel catfish x blue catfish, performed well.The channel catfish x blue catfish hybrid had a 22"1, greater growth ratethan the parent channel catfish and 5701, greater growth rate than theparent blue catfish. When the hybrids were mated among themselves,spawning usually was incomplete and spawn production was relativelysmall. Growth of the second generation channel catfish x blue catfish hybridwas inferior to that of the parent hybrid.Various hybrids of sunfish species also have been successful and someare becoming important sport fish in several states. The most commonlyproduced hybrid sunfish are crosses of male bluegill x female green sunfishand male redear sunfish x female green sunfish. They are popular for farmpondstocking because they do not reproduce as readily as the purebredparental stocks and grow much larger than their parents.It is advisable for any hatchery manager to consult a qualified geneticistbefore starting either a selective breeding or hybridization program.SpawningObtaining eggs from fish and fertilizing them is known as spawning. eggtaking, or stripping. The two basic procedures utilized for spawning fishcommonly are referred to as the natural ar^d artificial methods. Naturalspawning includes any method that does not entail manually extractingsexual Droducts from the fish.Natural Spaw ning M ethodFish are placed in prepared ponds or allowed to enter channels resemblingtheir natural habitat to carry out their reproductive activities naturally.

I rl0 I:lSH llA lCHl.lRY NIANi\(;U\{l.tN- If'he fish are allowed to prepare nests or spawning sites as they might inthe wild.SALN{ONII) I'ISHI.]SIn salmonid culture, spawning channels have been used in conjunctionwith natural spawning. In a spawning channel, mature fish are allowed tospawn naturally. The channel has a carefully constructed bottom type anda controllable water flow. Typically, the channel has a carefully gradedbottom of proper gravel types, approximately I foot thick. Over this, therewill be a minimum water level of 1.5 to 2.5 feet. The size of gravel used forthe spawning or incubation areas should pass a 4-inch screen but not a0.75-inch screen. Siltation can kill large numbers of eggs and fry so Propersilt entrapment devices must be provided. The gravel bottom must beloosened and flushed periodically in order to maintain proper water velocitiesand percolation through the gravel. Invert controls or sills placed atintervals across the bottom of the channel also are important. Theseprevent the gravel from shifting downstream and also help to maintainproper percolation of water through the gravel.The density of eggs in a spawning channel is controlled by the spawningbehavior of each species. For example, spawning pink salmon use 10square feet of bottom per pair of fish; sockeye or chum salmon use 20square feet per pair. Densities of spawners that are too high will lead towastage of eggs through superimposition of redds (nests). The final numberof newly fertilized eggs deposited in a spawning channel will not exceed200 eggs per square foot of surface area and may be considerably less thanthis number, even with an optimum density o[ spawners.A typical spawning channel requires at least I cubic foot per second waterflow per foot of channel width during incubation of eggs and fry. Thevolume of flow should be approximately doubled during the spawningperiod to provide adult fish with adequate water for excavation of redds.Spawning channels are not suited for small streams or locations with littlerelatively level land that can be easily shaped with heavy machinery.In general, channels have been most successful with pink, chum, andsockeye salmon. Chinook and coho salmon do not fare as well. Improvedresults with chinook salmon have been reported when emerging fry areretained in the channel and fed artificial diets prior to their release. Experimentswith Arctic char suggest that this species also might adapt to spawningchannels.WA I{MW A'I' I.]R. I.'ISH I,SNatural spawning methods are used extensively with warmwater species offish such as bass, sunfish, and catfish. Pond-water depth is i']-5 feet in the

BROOI]S'I'OCK. SPAWNING. AND EGG HANDLING 151middle and I foot or less around the perimeter. In the case of bass andsunfish, the males either prepare nesting sites at random in the pond or usegravel nests or beds provided by the fish culturist. Following spawning, themales guard the nests until the eggs hatch and the fry swim up. Fry are leftin the pond and reared in the presence of the adults. Less labor is involvedin this method but its use usually is restricted to nonpredatory species suchas bluegills, because predation by adult fish can be extensive. Other disadvantagesinclude the possible transfer of disease organisms from broodfishto fry and lack of control over rearing densities.A more popular method involves the transfer of eggs or fry to preparedrearing ponds. This method commonly is used in the culture of bait,forage, tropical, and ornamental fishes, as well as with several predatorysPecies.The production of largemouth bass fry for transfer to rearing pondsshould begin with the selection of ponds. A desirable pond is of moderatedepth, protected from wind action, and 0.75 to 1.5 acres in size, and doesnot ordinarily develop weeds or dense phytoplankton blooms. If possible,the pond should be thoroughly dried before it is flooded and stocked.Growth of terrestrial vegetation or a green manure crop will provide foodfor the fry and inhibit undesirable aquatic plants. Careful attention mustbe given to oxygen levels if such crops are used, however. It is desirable toflood the pond about 2 weeks before bass fry are expected to begin feedingunless a residual supply of food from a previous cycle is present, as itwould be if the pond had been drained and immediately refilled. The 2weeks provide enough time for natural food organisms to develop for thesmall bass. Preparation of ponds for production of food organisms is discussedin Chapter 2.Most bass culturists prefer to leave the spawning pond unfertilized toavoid a phytoplankton bloom that will hinder observation of the fish. Ifthere is not ample residual fertilityto allow a natural food chain todevelop, the pond may be fertilized lightly to produce a zooplanktonbloom.The spawning pond can be stocked any time after the last killing frost,and preferably near the average date of spawning activity in previous years.At this time, the broodfish should be examined and the ripe fish stocked inthe pond. Ripe females have an obviously distended, soft, pendulous abdominalregion and a swollen, red, protruding vent. Unripe fish can be returnedto the holding pond for one to two weeks before being examinedand stocked.It is preferable to keep various age groups separate when spawningponds are stocked, although this often cannot be done at small hatcheries.Generally the older, larger fish ripen and spawn first.The number of bass broodfish to stock depends upon the number of frydesired, the size and condition of the spawners, and the productivity of the

52F'ISH HATCHERY MANAGF:,MENTpond. Federal warmwater hatcheries usually stock 40 to 85 adults per acre.This stocking rate is recommended if the fry are to be transferred to a rearingpond. If the fry are to be left in the spawning pond, lower stockingrates of 20 to 30 bass per acre are used.When ripe fish are stocked into clean ponds containing water approximately65'F, spawning usually begins within 72 hours, and often within 24hours. Fry will generally hatch within 72-96 hours after spawning, dependingon water temperature. They leave the nest after 8 to l0 days and thencan be transferred.For handling ease and accuracy in estimating numbers stocked, fryshould not be handled until they reach 0.6 to 0.8 inch total length. Thismay be offset by the greater difficulty of collecting entire schools of smallbass, because fry may scatter by the time they are 0.8 inch in length. Thissize is reached in 3 to 4 weeks after spawning during the first half of thespawning period, and in as little as 10 days during the later portion,depending on water temperatures.If fry are moved while very small, the water must be clear. Phytoplankton,rooted vegetation, filamentous algae, and turbidity can limit visibilityand reduce capturing success. Larger fry can be harvested quite readily inspite of these adverse conditions, because they migrate to the edge of theponds, move parallel to the shoreline near the surface, and can be seined ortrapped.Smallmouth bass spawning operations are unique in that special equipmentand techniques often are used for the purpose of collecting fry. Thefry do not school well, and scatter in the spawning ponds following swimuP.Smallmouth bass spawning ponds may be equipped with gravelled nestingsites or elaborate structures containing gravel in a box enclosed by oneto three walls for protection of the nesting fish. Each nesting site is markedby a stake that extends out of the water. The sites should be located 20 to25 feet apart in the shallow two-thirds of the pond so males will not fight.The spawning pond can be filled as water temperature rises above 60'Fand broodfish are stocked at a rate of 40 to 120 adults per surface acre.Smallmouth bass usually spawn about l0 days to two weeks earlier thanlargemouth, when water temperature reaches 62 to 63"F. They are moreprone to desert their nests during cold weather than largemouth bass. If fryare to be transferred, the spawning pond should not be fertilized, becauseobservation of the nesting sites is necessary. When spawning activity is noted,nests must be inspected daily with an underwater viewing glass. Thisconsists of a metal tube 3-4 inches in diameter, fitted with a glass in oneend. When eggs are noted on a nest, the stake is tagged or marked in someway to indicate when the fry will hatch. After hatching, a retainer screen isplaced around the nest before the fry swim up. They will be confined and

BROODSTOCK, SPAWNING. AND EGG HANDLING 153FIGURE 46. Spawning and rearing of smallmouth bass in ponds. (l) Male smallmouthbass guarding eggs (a.ro*) on the gravel nest. (Z) Nests are inspecteddaily with an underwater viewing glass, and (3) a retaining screen is placedaround the nest after the eggs hatch. (+) fne fry are transferred to a rearingpond after they swim up. (fWS photos.)can be readily captured for transfer to rearing ponds (Figure 46). A periodof 14 to 2l days normally can be expected between the time eggs are depositedand the time fry rise from the nest. Most fish culturists transfer smallmouthbass fry to rearing ponds, although good results have been obtainedwhen they were reared in the spawning pond.An alternative approach to smallmouth bass spawning involves the use ofportable nests within a pond. These nests are constructed from I x 4-inchlumber, 24 inches square with a window screen bottom. A nest of l-3-inchdiameter rocks, held in a 16 x 16 x 2-inch hardware cloth basket, is placedon the screen frame bottom. Fry are harvested by lowering the pond level,and gently moving the baskets up and down in the water, washing the frythrough the rocks and onto the screen bottomed frame. The fry are thenrinsed into a container for transfer to a rearing pond. This technique also

t54 FISH HATCHERY MANAGEMENTFIGURE 47. Spawning receptacles for channel catfish are placed in the pondbefore it is filled with water.requires close inspection of nests with an underwater viewer. The methodallows the fish culturist to collect eggs, if so desired, for subsequent hatchingunder controlled conditions. It has the added advantage of allowing theculturist to respawn broodfish during the height of the season.Culture of bluegills and other sunfishes is relatively simple. Thespawning-rearing pond method almost always is used for culturing thesespecies, although a few hatcheries transfer fry to rearing ponds. Bestspawning success with bluegills is obtained by using mature broodfishweighing 0.3 to 0.6 pound. However, good production has been obtainedwith l-year-old fish averaging 0.10-0.15 pound at spawning time. Whenbroodstock of this latter size is used, an increased number of fish per acreis needed to adequately stock the pond. Use of yearling broodstock generallyresults in less uniform spawning, which tends to cause greater sizevariation in the fingerlings produced. Bluegills spawn when water temperaturesapproach 80'F and several spawns can be anticipated during the summer.Catfish generally are spawned by either the open-pond or pen method.In the open-pond method, spawning containers such as milk cans, nailkegs, or earthenware crocks, are placed in the pond with the open end towardthe center of the pond (Figure 47). It is not necessary to provide aspawning receptacle for each pair of fish, because not all fish will spawn atthe same time. Most culturists provide two or three receptacles for eachfour pairs of fish. Fish will spawn in containers placed in water as shallowas 6 inches and as deep as 5 feet. The receptacles are checked most easilyif they are in water no deeper than arm's length.Frequency of examination of spawning containers depends on the

BROODSTOCK, SPAWNING, AND EGG HANDLING 155number of broodfish in the pond and the rate at which spawning is progressing.In checking a container, the culturist gently raises it to the surface.If this is done quietly and carefully, the male usually is not disturbed. Cautionshould be used, because an attacking male can bite severely. If the wateris not clear, the container can be slowly tilted and partly emptied.Catfish eggs may be handled in different ways. The eggs may be removed,or left in the spawning pond to hatch and the fry reared in theponds. Removal of the eggs has several advantages. It minimizes thespread of diseases and parasites from adults to youngr and provides for eggdisinfection. The eggs are protected from predation and the fry can bestocked in the rearing ponds at known rates.The pen method of spawning catfish utilizes pens about 10 feet long and5 feet wide located in a row in the spawning ponds (Figure 48). They areconstructed of wood, wire fencing, or concrete blocks. They should be enclosedon all four sides but the bank of the pond may be used as one side.The sides should be embedded in the pond bottom and extend at least 12inches above the water surface to Prevent fish from escaping. Water shouldbe 2-3 feet deep.Location of the spawning container in the pen is not critical, but generallyit faces away from the pond bank. Broodfish are sexed and paired inthe pens. Usually the best results occur when the male is equal in size to,or slightly larger than, the female. This discourages the female from eatingthe eggs that are being guarded by the male. After spawning, eggs andparent fish may be removed and another pair placed in the pen. Sometimes,the female is removed as soon as an egg mass is found, and the maleis then allowed to hatch the eggs. Usually, containers are checked dailyand the eggs removed to a hatching trough. A male may be used to spawnseveral females.Frcunn 4&. Channel catfish spawning pens. Note spawning receptacle (arrow).(Fws photo.)

156 FISH HA'I'CHERY MANAGEMENlThe pen method has several advantages. It provides close control overthe time of spawning, allows the pairing of selected individuals, facilitatesremoval of spawned fish from the pond, protects the spawning pair fromintruding fish, and allows the injection of hormones into the broodfish.The aquarium method of spawning catfish is a modification of the penmethod. A pair of broodfish is placed in a 30- to 50-gallon aquarium withrunning water. The broodfish are induced to spawn by the injection of hormones.Tar-paper mats are placed on the bottom of the aquarium. As theeggs are deposited and fertilized, they form a large gelatinous mass, andadhere to the mat. The eggs readily can be removed with the mat. It is anintensive type of culture; many pairs of fish can be spawned successfully ina single aquarium during the breeding season. Each spawn is removed immediatelyto a hatching trough for incubation.In methods involving the use of hormones, only females ready to spawnshould be used. Males need not be injected with hormones, but should beabout the same size or larger than the females with which they are paired.If the male attacks the female, he should be removed until after the femalehas been given one to three additional hormone injections. He then may beplaced with the female again. Males may be left to attend the eggs in theaquarium or, preferably, the eggs are removed to a hatching trough.Striped bass have been spawned in circular tanks. This method generallyrequires a water flow of 3 to 10 gallons per minute per tank. Six-foot diametertanks are most desirable. Broodfish are injected with hormones and atleast two males are put in a tank containing one female. After spawning,the broodfish are removed. Striped bass eggs are free-floating, and if themales have participated in spawning, the water will appear milky. The eggscan be left circulating in the tank until they hatch or removed with asiphon to aquaria for hatching. Some egg loss can be expected due tomechanical damage if they are transferred from tank to aquaria. When fertilizedeggs are allowed to hatch in the tank, the fry will become concentratedaround the edge of the tank after 4 or 5 days and they can then bedipped out and transferred to rearing facilities.Artificia I Spawning M ethodThe artificial method of spawning consists of manually stripping the sexproducts from the fish, mixing them in a container, and placing the fertilizedeggs in an incubator. The following description of egg stripping andfertilization is widely applicable to many species of fish, including coolwaterand warmwater species (Figure 49).Any spawn-taking operation should be designed to reduce handling ofthe fish. Anesthetics should be used when possible to reduce stress. Inhand-stripping the eggs from a female, the fish is grasped near the headwith the right hand, and the left hand grasps the body just above the tail.

BROODSTOCK. SPAWNING. AND EGG HANDLINGt57*L*-t'4B **--X*I..4FIGURE 49. Equipment used for spawning wild coolwater fishes (trap net shownin backgrouna). fne males and females are held separately in holding tanks containingan anesthetic (e, S). e bench with a spawning pan (C) is provided forthe spawn taker. (FWS photo.)The fish is then held with the belly downward over a pan, and the eggs areforced out gently by a massaging movement beginning forward of the ventand working back toward it. Care should be taken to avoid putting pressuretoo far forward on the body as there is danger of damaging the heartor other organs (Figure 50). After the eggs have been extruded, a smallamount of milt (spe.-) is added from a male fish. Milt is expressed from aripe male in much the same manner as the eggs are taken from a female(Figure 51). If either eggs or milt do not flow freely, the fish is not sufficientlyripe and should not be used. The fish should be examined frequently,as often as twice a week, to determine ripeness. Fish rarely spawn oftheir own accord under hatchery conditions, and, if they are not examinedfor ripeness frequently, overripe eggs will result. Muskellunge, however,will often spawn on their own accord.The two generally accepted procedures for handling eggs during fertilizationare often referred to as the wet and dry methods. In the dry methodof fertilization,water is not introduced before the eggs are exPressed intothe pan, and all equipment is kept as dry as possible. Sperm and eggs arethoroughlymixed and usually left undisturbed for 5 to 15 minutes before

I58 FISH HATCHERY MANAGEMENTFIcunn 50.Eggs being spawned from a northern pike female. (nWS photo.)FIGURE 51.Sperm being expressed from a northern pike male. (FWS photo.)

BROODSTOCK, SPAWNING, AND EGG IIANDLINGr59water is added to wash the eggs for incubation. In the wet method, a pan rspartially filled with water before the eggs are expressed from the femalefish. The milt from a male is then added. Because the sperm will live lessthan 2 minutes in water after being activated, considerable speed is necessaryby the spawn takers. The dry method generally is accepted as the bestprocedure.Eggs are washed or rinsed thoroughly after they have been fertilized andbefore they are placed in the incubator. In some species, the eggs are allowedto water-harden before being placed in an incubator. Water-hardening is theprocess by which water is absorbed by the eggs and fills the perivitellinespace between the shell and yoke, causing the egg to become turgid. Precautionsshould be taken to protect eggs from exposure to direct rays of brightlight, because both sunlight and artificial light are detrimental.Some species, such as walleye and northern pike, have eggs that are extremelyadhesive. Often during the water-hardening process of adhesiveeggs, an inert substance is added to prevent the eggs from sticking together.Starch, black muck, clay, bentonite clay, and tannin have been used asseparating agents. Starch, because it is finely ground, does not have to bespecially prepared, but muck and regular clay must be dried and siftedthrough a fine screen to remove all coarse particles and then sterilized beforethey can be used. Starch or clay first must be mixed with water to theconsistency of thick cream. One or two tablespoons of this mixture is addedto each pan of eggs after fertilization is completed. When the separatingagent has been mixed thoroughly with the eggs, the pan is allowed tostand for a minute. Water is then added, the separating agent is washedfrom the eggs, and the eggs placed in a tub of water to harden. Constantstirring during water hardening helps prevent clumping. The water shouldbe changed at least once an hour until the eggs are placed in the hatchery.Striped bass also may be hand-stripped as an alternative to tank slrawning.Both males and females of this species usually are injected with hormones,as described in a later section of this chapter. An egg sampleshould be taken and examined between 20 and 28 hours after a hormoneinjection. Egg examination and staging requires microscopic examination.The catheter used for extraction of the egg sample is made of glass tubing,3 millimeter O.D., with fire-polished ends. The catheter is inserted approximately2 inches into the vent and removed with a finger covering theend of the tube to create a vacuum that holds any eggs in place in thetube. Extreme care is needed while the catheter is inserted into the ovary.The catheter should be instantly removed if the fish suddenly thrashes;such thrashing usually is immediately preceded by a flexing of the gill covers.Careful manipulation will permit the catheter to be inserted into thevent with a minimum of force, preventing damage to the sphincter muscles.If these muscles are torn, eggs at the posterior end of the ovary will waterharden.The plug thus formed will prevent the flow of eggs.

160 I'ISH HATCHERY MANAGEMENIThe egg sample is placed on a clean glass slide with a small amount ofwater. Magnification of 20x provides a sufficiently wide field for examinationof several eggs with enough magnification for detailed viewing of individualeggs.Egg samples should be taken between 20 and 28 hours after hormone injection.Approximately l6 hours are required for the effects of the hormoneto be detected in egg development. Early in the spawning season, it isadvisable to wait 28 hours before sampling because it usually requiresabout 40 hours for ovulation, and eggs taken more than 15 hours beforeovulation cannot be accurately staged. Near the peak of the natural spawningseason, ovulation may occur within 20 hours following injection and itis prudent to sample earlier.It is impractical to predict ovulation in striped bass that are more than15 hours from spawning as the eggs are very oPaque and no difference canbe detected between 30-hour and l7-hour eggs. If opaque eggs are found,the ovary should be resampled l2 hours later.At about 15 hours before ovulation, the ova assume a grainy aPPearanceand minute oil globules appear as light areas in individual ova. This is thefirst visible indication of ripening.At l4 hours, the globules in some of the ova have become somewhat enlargedwhile very small globules are evident in others. No distinct progresscan be detected in a few eggs. This mixed development may be confusing,but in order to avoid over-ripeness, a prediction of spawning time shouldbe based primarily on the most advanced eggs. Ijneven maturation persiststo some degree until approximately the l0-hour stage, after which developmentprogresses more uniformlY.At l3 hours, the majority of ova will have enlarged globules and clearedareas occupy over one-half of the surface of most eggs.At l2 hours, the first evidence of polarization of what eventually will becomethe oil globule is apparent. The small globules begin fusion to form asingle globule.At l0 hours, polarization of the oil globule is complete. The entire egg ismore translucent than in earlier stages.At t hours, eggs begin to show more transparency in the yolk, althoughthe majority of the yolk remains translucent'It is difficult to describe differences between eggs that are 6, 7, or 8hours from spawning. There is a continued clearing of the nucleus, andwith experience, the worker will be able to pinpoint the exact stage. However,to avoid over-ripeness, it is best to classify eggs in any of these stagesas the 6-hour stage and attempt to hand-strip the eggs.From 5 hours until ovulation, the ova continue to clear; at I hour, noopaque areas can be detected. For more detailed information describingthis p.ocess consult the publication by Bayless 1972 (Figu.". 52-55).

BROODSTOCK. SPAWNINC. AND EGG HANDLING 161Immature Eggs 15 hrs. before Ovulation14 hrs. before Omlation12 hrs. before belore Orulation Ol'ulation 1l hrs. before OvulationFrcunn 52. Development of striped bass eggs from immaturity to I I hoursbefore ovulation. (Courtesy Jack D. Bayless, South Carolina Wildlife and MarineResources Department.)

t62 FISH HATCHERY MANAGEMENTl0 hrs. before OvulationPolarization Completet hn. before OvulationNucleus ClearingB hrs. before Ovulation7 hrs. before Ovulation6 hrs. before Ovulation 5 hrs. before OvulationFIcunn 53. Development of striped bass eggs from 10 to 5 hours before ovulation.(Courtesy Jack D. Bayless, South Carolina Wildlife and Marine ResourcesDepartment.)

BROODSTOCK, SPAWNING, AND EGG HANDLING 1634 hrs. before Ovulation3 hrs. before Ovulation2 hrs. before OvulationI hr. before OvulationRip. Eggs at OvulationRipe Eggs at Ovulation (50X)FIcune 54. Development of striped bass eggs from 4 hours before ovulation toripeness. (Courtesy Jack D. Bayless, South Carolina Wildlife and MarineResources Department.)

164 FISH HATCHERY MANAGEMENTOvenipe Eggs t hr. (50X)Note Breakdown at InnerSurface of ChorionOverripe Eggs lX hrs. (50X)Breakdown at InnerSurface of Chorion PersistsOu*ip. Eggs 2 hrs. (50X)Note Deterioration Con$nedto One-Half of EggOu*ip. Egg 16 hrs. (20X)(Dark Areas Appear WhiteUnder Microscope)FIcunn 55, Development of striped bass eggs that become overripe before ovulation.(Courtesy Jack D, Bayless, South Carolina Wildlife and Marine ResourcesDepartment.)As ovulation occurs, eggs of striped bass become detached from theovarian tissue. They are deprived of parental oxygen supply, and anoxiacan result in a short period of time if the eggs remain in the body. (Thisalso is true for grass carp.) If eggs flow from the vent when pressure is appliedto the abdomen, at least partial ovulation has occurred. The maximumperiod between ovulation and overripeness is approximately 60minutes. The optimum period for egg removal is between 15 and 30minutes following the first indication of ovulation. Eggs obtained 30minutes after initial ovulation are less likely to hatch.Prior to manual stripping, female striped bass should be anesthetizedwith quinaldine sprayed onto the gills at a concentration of 1.0 part per

BROODSTOCK, SPAWNINC, AND EGG HANDLING 165thousand. The vent must be covered to prevent egg loss. Fish will becomesufficiently relaxed for removal of eggs withinI to 2 minutes. Workersshould wear gloves to prevent injury from opercular and fin spines. Strippingfollows the procedure previously described in this chapter.Because the broodfish of anadromous species of Pacific salmon die afterspawning, no advantage is obtained by stripping the female. Females arekilled and bled. Bleeding can be accomplished by either making an incisionin the caudal peduncle or by cutting just below the isthmus andbetween the opercula to sever the large artery leading from the heart to thegills. The females are allowed to bleed for several minutes before beingspawned. A mechanical device is in common use that effectively kills andbleeds the fish by making a deep cut through the body behind the head.Bleeding reduces the chance of blood mixing with the eggs and reducingfertilization. The point of the spawning knife is placed in the vent toprevent the loss of eggs and the fish is lifted by the gill cavity and heldvertically over a bucket, such that the vent is j-l inch above the lip of thebucket. The fish can be held securely in this position by bracing the backof the fish between the spawner's knees. An incision is made from the ventto a point just below the ventral fin, around the ventral fin, back to thecenter line, and upward to a point just beneath the gill cavity. If the fish isripe, most of the eggs will flow freely into the bucket (Figure 56). Theremaining ripe eggs can be dislodged by gently shaking the viscera. If thefish is not ripe, gentle shaking will not dislodge the eggs and such femalesshould be discarded. Eggr that can only be dislodged by greater force willbe underdeveloped and infertile.The spawning knife needs a sharp blade, but should have a blunt tip toavoid damage to the eggs during the incision. Linoleum knives have beenused for this purpose, but personal preference usually determines thechoice of the knife.Male salmon also are killed prior to spawning. Milt is hand strippeddirectly onto the eggs in the bucket. The eggs and milt are gently mixedby hand.In the case of Atlantic salmon or steelhead, which may return to spawnmore than once, females should not be killed to obtain eggs. A female fishcan be spawned mechanically by placing her into a double walled, rubbersack with the tail and vent of the fish protruding. The sack can be adjustedto fit each fish. Water entering between the walls of the sack causes apressure against the entire fish, and will express the eggs if they are ripe.Female fish handled in this way seem to recover more rapidly than fromother methods of stripping. Milt is collected from the males and stored intest tubes. A male fish is held upside down and the milt is gently pressedout and drawn into a glass tube with suction.Reduction of damage to broodstock and increased efficiency are factorsof prime importance in any spawning operation. The use of air pressure

t66 FISH HATCHERY MANAGEMENTsystems, as introduced by Australian workers and used on some troutspecies in this country, have made spawning fast, easy, and efficient (Figure57). Two to four pounds of air pressure injected into the body cavityby means of a hollow needle will expel the eggs. The needle is inserted inthe area between the pectoral and ventral fins midway between the midventralline and the lateral line. The possibility of damage to the kidney byneedle puncture is reduced if the posterior section of this area is used. Theneedle should be sterilized in alcohol for each operation to reduce the possibilityof infection. It is imperative that a female be ripe if the eggs are toflow freely. When a fish is held in the normal spawning position, a feweggs should flow from the fish without pressure on the abdomen.It is important that the fish be relaxed before the air pressure method isattempted. An anesthetic should be used. The fish should be rinsed andwiped fairly dry to prevent anesthetic dripping into the egg-spawning pan.Air should be removed from the body cavity before the fish is returnedto the water. This is best done by installing a two-way valve and a suctionline to the needle. A supplemental line may be used to draw off the air bymouth, or the air may be forced out by hand when a check is made forremaining eggs, although these methods are generally not as effective.FIcunr 56. Spawning Pacific salmon. Left, female is opened with a spawningknife (cutting edge indicated by arrow). Right, milt is hand-stripped from a maledirectly onto the eggs.

BROODSTOCK. SPAWNING. AND EGG HANDLINGt67Ftcunn 57.Spawning of salmonids with air pressure.Urine-free sperm can be collected through a pipette inserted about 0.5inch into the sperm duct. If the male trout is gently stripped by hand, suctionon the pipette will draw clean sperm out of the fish. Sperm and eggsare then mixed together.Factors Afficting FertilizationSeveral factors may have an adverse affect on fertilization during thespawning process at a hatchery, The contamination of either eggs or spermcan result in low levels of fertility. In the case of most salmonids, prolongedexposure of either sperm or eggs to water will reduce fertility.Sperm mixed with water are highly active for up to 15 seconds; after that,motility declines and usually no activity is recorded after 2 minutes. Eggsrapidly begin absorption of water shortly after contact with it and may becomenonviable if they have not been fertilized.

168 FISH HA'I'CHERY MANAGEMENTThe activation of sperm, however, does require exPosure to either wateror female ovarian fluid. The sperm are active for a longer period when dilutedwith an isotonic salt solution or ovarian fluid than they are in water.sperm activated in ovarian fluid without the addition of water will fertilizethe egg readily and have the additional benefit of prolonged viability. Thisis of particular importance when large volumes of eggs must be fertilizedwith small quantities of sperm.Contaminants associated with the spawning operation also may have asignificant effect on egg fertility. Although skin mucus itself has not beenshown to reduce fertility, there is a good possibility that it can carry a contaminantsuch as the anesthetic used. Therefore, mucus should be kept outof the spawning pan. Occasionally, blood will be ejected into the spawningpan from an injured female; fish blood clots quickly and may plug the micropyleof the eggs, through which the sperm must enter. Occasionally,broken eggs will result from the handling of females either prior to or duringspawning. Protein from broken eggs will coagulate and particles ofcoagulated protein may plug the micropyle, thus reducing fertilization. Iflarge numbers of ruptured eggs occur, fertility sometimes may be increasedby placing the eggs in a 0.6%r salt solution. This will cause the protein togo back into solution.Fertilization can be estimated by microscopically examining a sample ofeggs during the first day or two after fertilization. The early cell divisionsform large cells (blastome.es) that readily can be distinguished from thegerminal disk of unfertilized eggs at l0xmagnification. To improve theexamination of embryos, a sample of eggs can be soaked in a 10'/o aceticacid solution for several minutes. Unfertilized germinal disks and the embryosof fertilized eggs will turn an opaque white and become visiblethrough the translucent chorion. A common procedure is to examine theeggs when the four-cell stage is reached. The rate of embryonic developmentwill vary with temperature and the species of fish. This method maynot be suitable on eggs of some warmwater species.Gamete StorageSperm of rainbow trout and northern pike have been stored and transportedsuccessfully. The sperm, with penicillin added, is placed in dry, sterilebottles and then sealed. The temperature is maintained at approximately32'F in a thermos containing finely crushed ice. Undiluted brook troutsperm has been stored with some success for as long as 5 days. The spermshould be taken under sterile conditions, kept free from all contaminants,chilled immediately to 35'F, and refrigerated until needed. This procedurealso has been used to store rainbow trout sperm for a 7-day period' Someworkers, however, prefer to store brook trout milt for not more than 24

BROODSTOCK, SPAWNING. AND EGG HANDLING 169hours at 34"F and to warm the stored milt to the ambient water temperaturebefore fertilization.Cryopreservation (freezing) of sperm from several warm- and coldwaterspecies has been successful for varying length of times and rates of fertility.These procedures generally require liquid nitrogen and extending agents,and are reviewed by Horton and Ott (1976).At 46' to 48"F, sockeye salmon eggs with no water added maintainedtheir fertility for l2 hours after being stripped, and a few were still fertileafter 175 hours. Sockeye milt maintained its fertility for I t hours and fertilizeda few eggs after l0l hours. Pink salmon eggs have maintained theirfertility for 8 hours, and some were still fertile at 129 hours. Milt of pinksalmon maintained its fertility for 33 hours after being stripped from themale, and fertilized 65'l| of the eggs after 57 hours; none were fertilizedafter U1 hours. Some fish culturists have obtained 90fi fertilization withpink salmon eggs and sperm stored for periods up to 20 hours at 43"F.Storage of chum salmon eggs for 108 hours at temperatures of 36' to 42'Fmaintained an 80'lu fertility when fertilized with fresh sperm. Chum salmonsperm stored under similar conditions for 36 hours maintained a 90% fertilitywhen applied to fresh eggs.Experiments with fall chinook salmon eggs and sperm have shown thatthe eggs are more sensitive to storage time and temperature than sperm.After 4tl hours storage at 33'F, egg mortality was approximately 470/0. Mortalitywas 100(li, after 48 hours storage at 56'F. Forty-eight-hour storage ofsperm at 56"F resulted in about a 129ir mortality. The stored eggs were fertilizedwith freshly collected sperm and the stored sperm was used to fertilizefreshly spawned eggs.AnestheticsAnesthetics relax fish and allow increased speed and handling ease duringthe spawning operation. In general, the concentration of the anestheticused must be determined on a trial and error basis with the particularspecies of fish being spawned, because such factors as temperature andchemical composition of the water are involved. Fish may react differentlyto the same anesthetic when exposed to it in a different water supply. Beforeany anesthetic is used, it is advisable to test it with several fish.At least 15 anesthetic agents have been used by fish culturists. Of theanesthetics reported, quinaldine (2-methylquinoline), tricaine methane sulfonate(MS-222), and, benzocaine are the most popular fish anestheticscurrently in use. Only MS-222 has been properly registered for such use.There are various stages of anesthesia in fish (See Chapter 6, Table 39).When placed in the anesthetic solution, the fish often swim about forseveral seconds, attempting to remain in an upright position. As they lose

t70FISH HATCHERY MANAGEMENTequilibrium they become inactive. opercular movement decreases. whenthe fish can no longer make swimming movements, the respiration becomesquite rapid, and opercular movements are difficult to detect. At this point,the fish may be removed from the water and spawned. If gasping and muscularspasms develop while a fish is being spawned, it should be returnedto fresh water immediately. If the fish has been overexposed to the drug,respiratory movements will cease. Rainbow trout placed in a 2(j4 parts permillion solution of M5-222 require 30 to 45 seconds to become relaxed.concentrations of 0.23 gram of benzocaine per gallon of water or 0.45gram of MS-222 per gallon of water are commonly used to anesthetizedfingerling Pacific salmon.Use of MS-222 as an anesthetic for spawning operations is widespread.However, concentrations as low as ltl.9 parts per million have reducedsperm motility. Therefore, the anesthetizing solution should not come rncontact with the reproductive products. Adult Pacific salmon have beenanesthesized with a mixture of 40 parts per million MS 222 and l0 partsper million quinaldine. carbon dioxide at concentrations of 200 400 partsper million, is used in some instances for calming adult pacific salmon. Itcan be dispersed into the tank from a pressurized cylinder through a carborundumstone.Both ether and urethane have been used in the past, but both should bediscontinued due to the high flammability of ether and the possible carcinogenicproperties of urethane.Artificial Control of Spawning TimeManagement requirements and availability of hatchery facilities often makeit desirable to spawn fish at times different from the natural spawning date.Several methods have been used with success.PHOTOPERIODcontrolledlight periods have been used with several species of fish tomanipulate spawning time. The Fish and wildlife Service's Salmon culturalLaboratory, Entiat, washington, conducted a 13-year study to determinethe effect of light control on sockeye salmon spawning. The study showedthat salmon exposed to shortened periods of light spawn appreciably earlier.Egg mortalities can be significantly higher, however. Light, not temperature,is apparently the prime factor in accelerating or retarding sexualmaturation in this species; although temperatures varied from year to year,salmon receiving no light control spawned at essentially the same timeeach year.

BROODSTOCK, SPAWNING, AND EGG HANDLING 171Artificial light has been used successfully to induce early spawning inbrook, brown, and rainbow trout. The rearing facilities are enclosed andlightproof, and all light is provided by overhead flood lamps. Broodstockshould have had at least one previous spawning season before being usedin a light-controlled spawning program. Eggs produced generally are smallerand fewer eggs are produced per female. The following light schedule isused to induce early spawning in trout. An additional hour of light is providedeach week until the fish are exposed to nine hours of artificial lightin excess of the normal light period. The light is maintained at thisschedule for a period of four weeks and then decreased one hour per weekuntil the fish are receiving four hours less light than is normal for thatperiod. By this schedule, the spawning period can be advanced severalmonths. Use of broodfish a second consecutive year under light-controlledconditions does not always prove satisfactory, and a controlled-lightschedule must be started at least six months Prior to the anticipatedspawning date.Most attempts at modifying the spawning date of fish have been toaccelerate rather than retard the maturation process. However, spawningactivity of eastern brook trout and sockeye salmon have been delayed byextending artificial light periods longer than normal ones. Temperatureand light control are factors in manipulating spawning time of channel catfish.Reducing the light cycle to 8 hours per day and lowering the watertemperature by 14'F will delay spawning for approximately 60-150 days'The spawning period of largemouth bass has been greatly extended bythe manipulation of water temperature. For example, moving fish from 67'to 61'F water will result in a delayed spawning time.HORMONE INJECTIONSpawning of warmwater and coolwater species can be induced by hormoneinjection. This method has not proven to be as successful with coldwaterspecies. Fish must be fairly close to spawning to have any effect, as thehormones generally bring about the early release of mature sex productsrather than the promotion of their development. Both pituitary material extractedfrom fish and human chorionic gonadotropin have been used successfully.Use of hormones may produce disappointing results if broodfish are notof high quality. Under such conditions, a partial spawn, or no spawn at all,may result. It also appears that some strains of fish do not respond to hormonetreatment in a predictable way, even when they are in good spawningcondition.Injection of salmon pituitary extract into adult salmon hastens the developmentof spawning coloration and other secondary sex characteristics,

172 FISH HATCHERY MANAGEMENTripens males as early as three days after injection, and advances slightly thespawning period for females, but may lower the fertility of the eggs. Injectionof mammalian gonadotropin into adult salmon fails to hasten thedevelopment of spawning characteristics, and there is no change in thetime of maturation.Acetone-dried fish pituitaries from common carp, buffalo, flathead catfish,and channel catfish have been tested and all will induce spawningwhen injected into channel catfish (Figrr.e 58). Carp pituitary material alsoinduces ovulation in walleye. The pituitary material is finely ground,suspended in clean water or saline solution, and injected intraperitoneallyat a rate of two milligrams of pituitary per pound of broodfish (Figure 59).One treatment is given each day until the fish spawns or shows resistanceto the hormone. Generally the treatment should be successful by the thirdor fourth day.Goldfish have been injected with human chorionic gonadotropin (HCG)in doses ranging from l0 to 1,600 International Units (IU) l"tonly thosefemales receiving 100 IU or more have ovulated. One hundred IU of HCGis comparable to 0.5 milligram of acetone-dried fish pituitary. In some instancesgoldfish will respond to two injections of HCG as low as 25 IU,when given 6 days apart. White crappies injected with 1,000, 1,500, andFrcunt 58. Collection of pituitary gland (arrow) from a common carp head. Thetop of the head has been removed to expose the brain. (Fish Farming ExperimentalStation, Stuttgart, Arkansas.)

BROODSTOCK, SPAWNING, AND EGG HANDLING 173FtCUnn 59. Injection of hormone intraperitoneally into female channel catfish.(Fish Farming Experimental Station, Stuttgart, Arkansas.)2,000 IU spawned three days after they were injected. Female crappies injectedwith 1,000 IU spawned 2 days later at a water temperature of 62'F.Channel catfish, striped bass, common carP, white crappies, and largemouthbass, injected with 1,000 to 2,000 IU of HCG, also have been inducedto spawn.Hormone injection of striped bass has proven to be effective for spawningthis species in rearing tariks. Females given single intramuscular injectionsat the posterior base of the dorsal fin with 125 to 150 IU of HCG perpound of broodfish show the best results. Multiple injections invariablyresult in premature expulsion of the eggs. Injection of males is recommendedfor obtaining maximum milt production. Fifty to 75 IU per pound ofbroodfish should be injected approximately 24 hours prior to the anticipatedspawning of the female.Channel catfish also can be successfully induced to spawn by intraperitonealinjections of HCG. One 800-IU injection of HCG per pound ofbroodfish normally is sufficient. Two 70-IU injections of HCG per poundof broodfish, spaced 72 hours apart, will induce ovulation in walleyes'Egg Incubation and HandlingEggs of commonly cultured species of fish are remarkably uniform in theirphysiology and development' A basic understanding of the morphologyand physiological processes of a developing fish embryo can be of value to

174 FISH HATCHERY MANAGEMENTthe fish culturist in providing an optimum environment for egg development.Eg DeuelopmentDuring oogenesis, when an egg is being formed in the ovary, the egg's futureenergy sources are protein and fat in the yolk material. At this earlystage, the egg is soft and low in water content, and may be quite adhesive.The ovum, or germ cell, is enclosed in a soft shell secreted by the ovariantissue. This shell, or chorion, encloses a fluid-filled area called theperivitelline space. An opening (the micropyle) provides an entryway forthe sperm. Inside the perivitelline space is a vitelline membrane; the yolkis retained within this membrane (Figure 60). Trout eggs are adhesivewhen first spawned because of water passing through the porous shell. Thisprocess is called water-hardening, and when it is complete, the egg nolonger is sticky. The egg becomes turgid with water, and the shell isseparated from the yolk membrane by the perivitelline space filled withfluid. This allows the yolk and germinal disc to rotate freely inside the egg,with the disc always being in an upright position.The micropyle is open to permit entry of the sperm when the egg is firstspawned. As the egg water-hardens, the micropyle closes and there is noM ICROPYLEGERMINAL DISCVITELLINEM EM BRAN ESH ELLPERIVITELLINESPACEYO LKOIL DROPLETFIcURE 60.Diagrammatic section of a fertilized trout egg. (Sorrrce' Davis 1g53.)

BROODSTOCK, SPAWNING, AND EGG HANDLINGt75further chance for fertilization. In salmonids, water-hardening generallytakes from 30 to 90 minutes, depending on water temperature.The sperm consists of a head, midpiece, and tail, and is inactive when itfirst leaves the fish; on contact with water or ovarian fluid, it becomes veryactive. Several changes take place when the sperm penetrates the egg. Nuclearmaterial of the egg and sperm unite to form the zygote. This zygote,within a few hours, divides repeatedly and differentiates to form the embryo.Schematic drawings of trout and salmon egg development (Figure 61)can be applied in general to other species as well.SENSITIVE STAGETrout and salmon eggs become progressively more fragile during a periodextending roughly from 48 hours after water-hardening until they are eyed.An extremely critical period for salmonid eggs exists until the blastoporestage is completed. The eggs must not be moved until this critical periodhas passed. The eggs remain tender until the eyes are sufficiently pigmentedto be visible.EYED STA(;EAs the term implies, this is the stage between the time the eyes becomevisible and hatching occurs. During the eyed stage, eggs usually areshocked, cleaned, measured and counted, and shipped.At hatching, the weight of the sac fry increases rapidly. Water content ofthe fry increases until approximately l0 weeks after hatching, when it isapproximately 80'li, of the body weight. Water content remains fairly uniformin a fish from this point on.As the embryo develops, there is a gradual decrease in the protein contentof the egg. The fat content remains fairly uniform, but there is a gradualdecrease in relative weight of these materials as water contentincreases. There is no significant difference in the chemistry of large andsmall eggs. However, several studies have shown that larger eggs generallyproduce larger fry and this size advantage continues throughout the growthand development of the fish.Enumeration and Sorting of EggsA number of systems for counting eggs are in general use. Enumerationmethods should be accurate, practical, and should not stress the eggs.

176 FISH HATCHERY MANAGEMENTERMINAL DISCA. ONE DAY AFTER FERTILIZATION, 559'F AVERAGE TEMPERATURE(23.9 T.U ).LASTODISCB. TWO DAYS AFTER FERTILIZATION, 53.9"F AVERAGE TEMPERATURE(43.9 T. U.)DGE OF BLASTODISCMBRYOC. FIVE DAYS AFTER FERTILIZATION 5i.7'F AVERAGE TEMPERATURE(98.4 T. U.)FIGURE 61. Schematic development of trout and salmon eggs. One temperatureunit (TU) equals 1'F above 32'F for a 24-hour period. See Glossary: Daily Tem-Derature Unit. (Source: Leitritz and Lewis 1976.)When small numbers of eggs are involved, counting can be done byhand or by the use of a counting board that will hold a known number ofeggs. A paddle-type egg counter is constructed of plexiglass by drilling andcountersinking a desired number of holes spaced in rows. The diameter ofthe hole will depend on the size of eggs being counted. The paddle is

BROODSTOCK. SPAWNING. AND EGG HANDLING 177HICKENED EDGE OF BLASTODERMMBRYOD. SIX DAYS AFTER FERTILIZATION, 51.5'F AVERAGE TEMPERATU RE(1170 T U )DGE OF BLASTODERMMBRYOE, SEVEN DAYS AFTER FERTILIZATION, 51.2'FAVERAGE TEMPERATURE(134.4 T.U )n/1$ttllt,.,Y**-.IP OF BLASTOPOREF. EIGHT DAYS AFTER FERTILIZATION, 51.7'F AVERAGE TEMPERATURE(157.5 T.U ).Frcunr 61.Continued

178 FISH HATCHERY MANAGEMENTSO M ITEG. NINE DAYS AFTER FERTILIZATION. 51.4"F AVERAGE TEMPERATURE(174.5 T.U.).UTU R E OPTICLOB EIN D BRAINH. TEN DAYSAFTERFERTILIZATION, 51.5'F AVERAGE TEMPERATURE(195.4 T.ULFACTORY CAPSULEUTURE OPTIC LOBEIND BRAINI. ELEVEN DAYS AFTER FERTILIZATION,5l.T'F AVERAGE TEMPERATU RE(216.6 T.U.).FIcunn 61. Continued.

BROODSTOCK. SPAWNING. AND EGG HANDLING 179PTIC LOBEIC CAPSULEUTURE PECTORAL FINJ. THIRTEEN DAYS AFTER FERTILIZATION,51.7"F AVERAGE TEMPERATURE(225.8I.U.tYOM ER EOTOCHORDENTK. FOURTEEN DAYS AFTER FERTILIZATION. 51.5'F AVERAGE TEM PERATU RE(273.2r .U.).FUTURE CAUDAL FINANAL FIN FOLDORSAL FIN FOLDYOM EREFUTURE ANAL FINVENTL.SIXTEEN DAYS AFTERFERTILIZATION,51.7"F AVERAGE TEMPERATURE(315.9 T.U.).Frcunr 61.Continued.

180 FISH HATCHERY MANAGEMENTHI RD VENTR I CL ETrcLOBEENS OF EYEHEAD-VENTRAL VIEWDGE OF MANDIBLEIND BRAINIIC CAPSULELL BAR:.::-FUTURE PECToRAL FtNM SIXTEEN DAYS AFTERFERTILIZATION, 51.7'FAVERAGE TEMPERATURE(315.9 T.U.).CEREBRAL H EM ISPH EREOPTIC LO BN. EIGHTEEN DAYS AFTERFERTILIZATION, 51.8'FAVERAGE TEMPERATURE(357.4 T.U.).HIND BRAIFUTU REFOURTH VENTRICLFUTURE CEREBELLUFIN FOLDVENTVENTRAL FINNAL FINNAL FIN FOLDTWENTY.SIX DAYS AFTERFERTILIZATION,51.2'FAVERAGE TEMPERATURE(500.4 T.U.)FtcunE 61.Continued.dipped into the egg mass and eggs fill the holes as the paddle is liftedthrough them.Three commonly used procedures for counting trout and salmon eggs arethe Von Bayer, weight, and water-displacement methods.The Von Bayr method employs a l2-inch, V-shaped trough (Figure 62).

BROODS'I'OCK. SPAWNING. AND EGG HANDLINGl8lUMBER OFEGGSPER OUNCENUM BER OF EGG12 INCHTROUGHFtcunl 62. Diagrammatic plan view of a Von Bayer V-trough for estimatingnumbers and volumes of eggs.

I82FISH HATCHERY MANAGEMENTA sample of eggs is placed in a single row in the trough until they fill itslength. The number of eggs per 12 inches is referred to Table 18, whichconverts this to number of eggs per liquid ounce or quart. All eggs thenare placed in a water-filled, 32-ounce (quart) graduated cylinder, the submergedeggs being leveled to the 32-ounce mark. The total number of eggsis the number per quart (or ounce) X the number of quarts (or ounces).The weight method is based on the average weight of eggs in a lot.Several 100-egg samples are drained and weighed to the nearest 0.1 gram.The average egg weight then is calculated. The entire lot of eggs is drainedin preweighed baskets and weighed on a balance sensitive to I gram. Divisionof the total weight of the eggs by the average weight of one egg determinesthe number of eggs in a lot. There are two sources of error in theweight method; variation in the amount of water retained on the eggs inthe total lot and variation in sample weights due to water retention. Differencesin surface tension prevent consistent removal of water from the eggs.Blotting pads of folded cloth or paper toweling should be used to removethe excess water from the eggs.In the displacement method, water displaced by the eggs is used to measurethe egg volume. This provides an easily read water level rather than anuneven egg level when volume is determined. Small quantities of eggs canbe measured in a standard 32-ounce graduated cylinder. For larger quantities,a container with a sight gauge for reading water levels is most convenient.A standard 25-milliliter burette calibrated in tenths of millilitersmakes an excellent sight gauge. A table, converting gauge readings to fluidounces, is prepared by adding known volumes of water to the containerand recording the gauge readings. The eggs are drained at least 30seconds in a frame net, and the underside of the net is wiped gently with asponge or cloth to remove excess water. The total volume of eggs then ismeasured by changes in gauge readings (converted to volume) when eggsare added to the container. The amount of water initially placed in thecontainer should be sufficient to provide a clearly defined water levelabove the eggs. The volume of water displaced by a known number of eggsis then determined by sample-counting; the more numerous and representativethe samples, the more accurate the total egg count will be. One ormore random samples should be prepared for each volume measurementand a minimumof five samples for the total lot of eggs. For sampling,count out 50 eggs into a burette containing exactly 25 milliliters of water.Determine the exact number of milliliters of water displaced. The numberof eggs per fluid ounce can then be determined from Table 19.The accuracy of these three methods has been compared, and only theVon Bayer technique showed a significant difference from actual eggcounts, with the displacement method being the most accurate. However,the weight technique is so much faster and efficient that it is considered

BROODSTOCK. SPAWNING. AND EGG HANDLING 183TasLr 18. MoDIFIED voN tsAyL,R TABT.E FoR THF, E,srIMA'I'toN oF tItL NUMBnRS oFFrsH EGGS rN A LTQUTD qUARl .NO. OI'EGGSPUR l2 l ROtrC;HI)tANll.) UR ()F []CC;S(rNclrrslN(). oF EGGS PERr.rQtrrn Qti,,\R'rN(). Ot' [.(.;(;S PURI_tQt.rtI) ()UNCE353fi37:J tJ39404l42.131+4546474u.+9505l5253545556575tt59606l6263646566676u69707l727',,]747576777tl790.3,130.3330.3240.ll I (t0.30t10.3000.'2920.2tt60.27!)0.2730.2670.2{t I0.2550.2500.2+50.2400.2350.2310.2260.2220.21u0.2140.21 I0.2070.20:J0.2000.1970.1940.1910.1ttu0.1ti50.1820.1790.1770.17 {0.1710.1690.1670.1640.1620.1600. l5tt0.1560.1540.1521,67l,8331,9902,t452,31(i2,6062,6902,tt933,1 l63,3263,5563,tt064,0u 14,33 I4,6034,8955,2t 45,4905,8626,I f]56,53 I6,9057,2047,630lt,0898,459u,u5I9,2689,71210,1u410,63utt,225I 1,79912,20312,34ul 3,533| 4,020| 4,52915,34115,9 I (i16,621t7 ,l 57t7,825I 8,52819,270525762677278tt,l.909710,1lll119l2u135t44l5ll163t72IU51932042t622523ti2532612772903043lu334351lJ59lltt I401423,t3u+54{79497516536557579602

184 FISH HAI'CHERY MANAGEMENTTABLE 19. MILLILITERS o!'wATER DrspLAcL,D By 50 EGGS coNVERtED'to NUMBEROF EGGS PER I,LUID OI.JNCE,MILI,INL]MI}T,RMII-I-INI]MBERMILLI.NUMBERLIt URSPEII,I,I I ERSPERI-ITERSPERD tsPl.Ac].])oT]NCEt)ISPLACEI)OUNCEDISPI-ACEDOUNCE3.0lJ. I3.2lJ.ll3.5lJ. (i3.73.It3.94.0.1. I4.34.54.ri,1. tJ.1.95.05.15.25.35.45.55.(;5.75.r.i5.96.06.16.2n.3().46.56.66.7(;.u6.1)7.0.192.tttJ477.00.1(i2.104,1U. 10.r3,1.904',22.45410.75399.653lt9. l0379. I 5369.653n0.65352.0s3,13.8533(i.0532u.60l]2 I ..15314.60308.05301 .75'295.75289.952u4.lJ5279.00273.1102(i8.852n'1.05259..10254.95250.60246.45242.4023u.502:1,1.70231 .05227.5022+.05'220.70217.45214.1|02t | .257.17.27.37.57.67.77.ti7.!)8.0tJ. I8.2IJ. IJu.'1t].5tr. (t8.78.tt8.99.01). I9.29.39.49.59.69.79.89.910.010. I10.210.310.410.510.610.7l0.r']10.1)I 1.0ll.l208.25205.35202.5ir199.80197.15l 94.55192.05I tl9.5ir187.15l it,1.u3l u2.55l80.30l7tt.15176.05173.95l7 1.95169.95168.05166.1516.1.30I 62.50I 60.70159.00l 57.30155.6s15.1.05| 52.+5150.90149.35147 .851,16.40144.951,13.55| 12.t 5140.u0l 39.50138.20136.90135.65134.40133.20I 1.2ll.3I 1.4I1.5I 1.6tt.7I 1.8I 1.9t2.0t2.l12.'212.312.4t2.512.6t2.712.812.913.0llJ.lt3.213.313.413.513.6t3.7l3.tl13.914.01.1.1t4.214.3| 4.414.514.6| 4.7l4.tJ1,1.915.0132.00I 30.89t29.7 0128.60127.45126.'10125.30t24.25123.20t'22.20t'21.20l 20.20l 19.25l 18.30117.35l 16.45I 15.50l 14.60I 13.75l 12.85l12.00I I 1.20I10.35109.55108.70107.95107. I 5l 06.40l 05.60l04.8ir104.15103.40t02.70102.00l0l .30100.6099.9099.2598.60

BROODSTOCK, SPAWNING, AND EGG HANDLINGI{J5the best of the methods evaluated. The displacement method takes twicethe time required by either of the other methods. The weight method isrecommended when large lots of eggs must be enumerated, while the displacementmethod is more desirable with small lots of eggs.Another method of egg inventory, which differs from other volumetricmethods basically in egg measuring technique, sometimes is used by fishculturists. Eggs are measured in a container, such as a cup or strainer filledto the top, and an equal number of containerfuls of eggs are put in eachegg incubator tray or jar. Sample counting consists of counting all the eggsheld in one measuring container. To get accurate egg inventories, the samemeasuring unit must be used for the sample counts as for measuring theeggs into the incubator. Measurement by filling the container to the topeliminates errors in judgment. This method gives a good estimate of the:"",:1":"-O"rof eggs, but does not estimate the number of eggs per fluidSeveral methods have been used for the estimating number of stripedbass eggs. Estimates can be made by weighing the eggs from each femaleand calculating the number of eggs on the basis of 25,000 per ounce. Theeggs can also be estimated volumetrically on the basis of Von Bayer's table.Largemouth bass and catfish eggs are measured by weight or volumetricdisplacement.Various mechanical egg counting devices have been developed that usephotoelectric counters (Figure 63). The eggs are counted as they pass alight source. Velocities producing count rates of up to 1,400 eggs perminute have proven to be accurate. Air bubbles, dirt, and other matter willinterfere with accurate counting and must be avoided.Salmonid eggs should be physically shocked before egg picking (removalof dead eggs) commences, after the eggs have developed to the eyed stage.Undeveloped or infertile eggs remain tender and they will rupture whenshocked. Water enters the egg and coagulates the yolk, turning the eggwhite; these eggs then are readily picked out. Shocking may be done bystriking the trays sharply, siphoning the eggs from one container toanother, or by pouring the eggs from the incubator trays into a tub ofwater from a height of 2 or 3 feet. Care should be taken to make sure thatthe eggs are not shocked too severely or normally developing eggs also maybe damaged. (Figure 6+).Numerous methods for removing dead eggs have been in use in fish culturefor many years. Before the introduction of satisfactory chemical fungicides,it was necessary to frequently remove (pick) att dead eggs to avoidthe spread of fungus. In some instances where exposure to chemical treatmentsis undesirable, it still is necessary to pick the dead eggs.One of the earliest and most common methods of egg picking was with alarge pair of tweezers made either of metal or wood. If only small numbersof eggs are picked, forceps or tweezers work very well. Another device in

186 FISH HATCHERY MANAGEMENTFrcunr 63.photo.)A mechanical egg counter used with salmon"ggs.(FWSFIGURE 64.Salmon eggs being shocked. (FWS photo.)

BROODSTOCK. SPAWNING, AND EGG HANDLING 187use is a rubber bulb fitted to a short length of glass tubing. The diameterof the tubing is large enough to allow single eggs to pass through it anddead eggs are removed by sucking them up into the tube. A more elaborateegg picker can be constructed of glass and rubber tubing and deadeggs are siphoned off into an attached glass jar (Figure 65).A flotation method of separating dead from live eggs still is used inmany hatcheries, and particularly in salmon hatcheries. Eggs are placed ina container of salt or sugar solution of the proper specific gravity, so thatlive eggs will sink and dead eggs will float because of their lower density.A sugar solution is more efficient than salt because the flotation period islonger. The container is filled with water, and common table salt or sugaris added until the dead eggs float and live eggs slowly sink to the bottom.The optimum concentration of the solution may vary with the size anddevelopmental stages of the eggs. Floating dead eggs are then skimmed offwith a net. Best results are obtained if the eggs are well eyed because themore developed the embryo, the more readily the eggs will settle.Several electronic egg sorters are commercially available that seParatethe opaque or dead eggs from the live ones. Manufacturers of thesemachines claim a sorting rate of 100,000 eggs per hour. Another commercialsorter works on the principle that live eggs have a greater resiliencyand will bounce (whereas dead eggs will not) and drop into a collectingtray. This sorter has no electrical or moving parts.Enumeration and transfer of fry are important facets of warmwater fishculture, because the eggs cannot be counted in many instances. The fry ofmany species, such as largemouth bass, smallmouth bass, and catfish, arespawned naturally in ponds, and then transferred to a rearing pond. To assurethe proper stocking density, fry must be counted or their numbers estimatedaccurately. Many methods are used, and vary in comPlexity andstyle.The simplest, but least accurate, is the comparisoz method. A sample offry are counted into a pan or other similar container. The remaining fry arethen distributed into identical containers until they apPear to have thesame density of fry as the sample container. The sample count is then usedto estimate the total number of fry in all the containers. Other methods involvethe determination of weight or volume of counted samples and thenestimating the number of fry from the total weight or volume of the group.The most accurate methods require greater handling of the fry but, whenthey are small, handling should be kept to a minimum to reduce mortality.In catfish culture, a combination of methods is used. The number ofeggs can be estimated by weight or from records on the Parent fish. Thegelatinous matrix in which catfish eggs are spawned makes the volumetricmethod of egg counting impractical. There are approximately 3,000 to5,000 catfish eggs per pound of matrix, and the number of eggs can beestimated from the weight of the mass of eggs. After the eggs hatch, fry are

188 FISH HATCHERY MANAGEMENTl/4" coPPERTU1/4" CoPPERUBEOLDER,RU BBER/r GASKET iz.FlriE.SCREEN SOLDEREDOVER OUTLETUBE-z.oFu(D(D:cf)U)=:

BROODSTOCK. SPAWNING. AND EGG HANDLINGr89enumerated volumetrically if they are to be moved immediately to rearingponds. If they are held in rearing tanks or troughs until they accePt formu-Iated feed, their numbers are estimated from weighed and counted samples.Eg DisinfectionEggs received from other hatcheries should be disinfected to prevent thespread of disease. Disinfection should be carried out in separate facilities inorder to prevent contamination of the hatchery by eggs, water, trays, andpacking material from the shipping crate.The iodophor Betadine, can be used to disinfect most fish eggs. Eggs aretreated at 100 parts per million active ingredient (iodine) for l() minutes. A100 parts per million iodine concentration is obtained by adding 2.6 fluidounces of 0.5'li, Betadine per gallon of water. Betadine also is available in al'lo iodine solution. In soft water below 35 parts per million alkalinity, pHreduction can occur, causing high egg mortality. Sodium bicarbonate maybe added as a buffer at 3.7 grams per gallon if soft water is encountered.Should a precipitate be formed from the sodium bicarbonate it will notharm the eggs. The eggs should be well rinsed after treatment. An activeiodine solution is dark brown in color. A change to a lighter color indicatesan inactive solution and a new solution should be used. Do not treat eggswithin 5 days of hatching as premature hatching may result, with increasedmortality. Tests should be conducted on a feu eggs before Betadine is consideredsafe for general use as an eg disinfectant.Largemouth bass eggs can be treated with acriflavine at 500 to 700 partsper million or Betadine at 100 to 150 Parts per million for 15 minutes.Roccal and formalin are not effective disinfectants at concentrations thatare not injurious to fish eggs.Incubation PeriodSeveral methods have been devised for determining the incubation periodof eggs. One method utilizes temperature units. One Daily TemperatureUnit (DTU) equals l" Fahrenheit above freezing (32'F) for a 24-hourperiod. For example, if the water temperature for the first day of incubationis 56"F, it would contribute 24 DTU (56'-32"). Temperature unitsrequired for a given species of fish are not fixed. They will vary with differentwater temperatures and are affected by fluctuating temPeratures.However, DTU can be used as a guide to estimate the hatching date of a

190 FISH HATCHERY MANAGEMENTTAtsLE 20. NUMBER oF DAYS AND DAILY TEMPERA,TURL, UNITS REqUIRED FoRTROUT EGGS TO HATCH 4, (SOURCE: LL,II'RITZ ANIJ LEWIS I976.)WATER I'EMPT]RATURE,'FRainbow troutNumber of days to hatchDaily temperature unitslJ06404u6243l55tt21 19552 532Brown troutNumber of days to hatchDaily temperature units1564(ttl10080064832738Brook troutNumber of days to hatchDaily temperature unitst4+43210382468utt44479935u05Lake troutNumber of days to hatchDaily temperature units1624u(t1088647293649u82dspaces without figures indicate incomplete data rather than a proven inability of eggs tohatch at those temDeratures.group of eggs at a specific temperature. The required temperature units tohatch several species of fish are presented in Tables 20 through 23.Factors Afficting Egg DeuelopmentThree major factors that affect the development of the embryos are light,temperature, and oxygen.LIGHTDirect light may have an adverse effect on developing fish eggs. The mostdetrimental rays are those in the visible violet-blue range produced by coolwhite fluorescent tubes. Pink fluorescent tubes, which emit light in the yellowto red range, are best suited for hatchery use. The best practice is tokeep eggs covered and away from direct light.In general, embryos of fishes subjected to bright artificial light beforethe formation of eye pigments will suffer high mortality at all stages ofgrowth. Affected eggs exhibit retarded development and accelerated hatchand, if they do hatch, the fingerlings often have reduced growth and severeliver damage. Eggs exposed to artificial light after formation of eye pigmentsare less susceptible to light rays but still exhibit increased mortalityand reduced growth, or both.

tsR(X)DS]'OCK, SPAWNING, AND E,GG HANDLINGr91Tlgll21. DArLy 'I'EMILRAt tjRt rJNrl REqtJrRL,D roR EGC DEVEr.opMnNT oFPectrtc sALMoN.DAI I,\"f I,N'II'[,RA'I'I.IRI] T]N I SSPT,CIT,S'| () ltYI,'I() TIA'I'CII'l () EMt-R(;lChinook salmonCoho salmonChum salmonI'ink salrronSockeye salmon.150'1507507509(X)750750I,100900I,200l,600I,750I,,1501,,150l,u00l l.\l l'1.IL,\'l t' Itl.Chinook salmon cggs have been incubated at temperatures as high as (il"Fwithout significirnt loss. Whcn incubated at.tr0'F and below, they have amuch higher mortality than those incubirted at temperatures of 57 to 60'F.Hou'ever, if chinook salmon cggs are allowed to develop to the l2U-cellstage in ,12'1" water, they can tolcrate l]5"F water for the remainder of theincubation pcriod. Lowcr temperatures have been experienced by sockeyeand chir-rook in natural spawning environments with fluctuating temperaturcswithout adverse affects. 'l'he lower threshold temperature for normaldevelopment of sockcyc salmon is between .10 and 42"F, with an upperthreshold temperature between 55 and 57'F. Watcr temperature appears tobe a primary factor in causing yolk-sac constriction in landlocked Atlantics:rlrnon fry. It apparently is triggcrcd by both constant temperature or anexcessively warm temperature. Fry raiscd in cold water with fluctuatingtempcraturc do not develop the constriction unless they are moved into awarrTler constant tenlDeret tllre.l',rnt.l: 22. RIreutREI) DAII.\' fuMptiRr\TURE UNrrs !'oR rNl.rrAr. DEVELopMENT oFVARI0L]S COOI,, ANI) WARMWAI'F]R SPF,CIES-SPECI I]SllGCl;\KIlI'O HAI'C]H,rllll{r_r_cl\_s_119.IIA I'C]II -I'OAC'I IVI.] SWIllINIINC;A( t l\',lll () s'l AR I ol,SWIiU NIIN(;I.EI]I)INGChannel catfishLargernouth bassSmallmouth bassHybrid sunfishBluegillRedear sunfishNorthern pikeM uskellungeWalleyeStriped bass3501.10I ll07575100Iu02:15300100509010090100100502(;02090100u0tt0r00100100100100201305003103102(i52753003ll059534t)320

t92FISH HA'I'CHERY MANAGEMENTTeslr 23. TTME,IEMPERATURE RELATIONSHIP AND DArLy TEMPERATURE UNIISREqUIRED FOR HATCHING MUSKELLUNGL, EGGS.l UMP!tRAl LrRI-r'lDAYS'fO HAl(]HDAII-Y I'I.,MPERA.'TTIRL U N I'f S.r'() HA r cri (fl45,195l535557596l63ol)672l20l9Iul61,1t2l0d7h27330032334233632230027026124tl'231210Eggs and fry of walleye tolerate rapid temperature fluctuations. Approximatelyl')90 daily temperature units are required for eggs to hatch in fluctuatingwater temperatures, while only 230 daily temperature units generallyare required at more constant temperatures (see Table 22).Low water temperatures during spawning and incubation of largemouthbass eggs can cause high egg losses. Chilling of the eggs does not appear tobe the direct cause of egg loss. Rather, it causes the male fish, which normallyguards and fans the eggs, to desert the nest. As a result, the eggs areleft without aeration and die from suffocation. This is a common cause ofegg losses in areas that are marginal for largemouth bass production.Data gathered at the Weldon Striped Bass Hatchery, Weldon, NorthCarolina, indicate that the optimumspawning temperature range forstriped bass is between 62 and (j7"F. The minimum recorded temperatureat which spawning will occur is 55'F and the maximum temperature is7 l"F.OXYGE,NSac fry from eggs incubated at low oxygen concentrations are smaller andweaker than those from eggs incubated at higher concentrations. The bestconditions for the optimal development of embryos and fry are at or near100'll oxygen saturation. As the development of an egg progresses, oxygenavailability becomes increasingly important. Circulation of water is vital fortransporting oxygen to the surface of the chorion and for removing metabolitesfrom the vicinity of the developing egg. Eggs provided with insufficientoxygen will develop abnormalities and their hatching may be eitherdelayed or premature, depending on the species.

BROODSTOCK, SPAWNING, AND EGG HANDLTNC t 9:lTransportation of EgsEggs can be shipped at four developmental stages: as immature eggs in theliving female; as mature unfertilized eggs; as recently fertilized and waterhardenedeggs; and as eyed eggs.Live females may be shipped, but this method requires more extensivetransportation facilities than is required to ship eggs. Transportation of livefish is covered in Chapter 6.The shipping of mature unfertilized eggs requires some precautions.Sperm should be shipped separately in sealed plastic bags with an air spacein the sperm container of at least 10 parts air to I part sperm. No air requirementsare necessary for eggs. Both eggs and sperm should be kept refrigerated.With these techniques, the fertility of Pacific salmon sperm andeggs is not affected by storage for 4 hours at temperatures of 47 52'F beforethey are mixed. Eggs that are fertilized and then shipped under thesame conditions can suffer high losses. When newly spawned and fertilizedeggs are shipped the eggs must not be shaken in transit. Therefore, no airspace should be allowed in the container.Eggs should not be shipped during the tender stage. They may beshipped over long distances after the eyed stage is reached, if they are keptcool and shipped in properly insulated boxes (Figure 66).Types of IncubatorsMany systems have been developed forof them provide a fresh water supplyproducts, and protect the developingwhich may be detrimental.incubating fish eggs. Basically, allwith oxygen, dissipate metabolicembryo from external influcncesHA'I'CHIN(]'I'RAYSHatching trays are perhaps the simplest type of incubation unit uscd.They have been used successfully for many species of fish. The screenedhatching tray is sized to fit inside a rearing trough. 'Ihe screening has rectangularopenings that will retain round eggs but permit newly hatched fryto fall through. The wire mesh may be obtaincd in a variety of sizes and iscalled triple warp mesh cloth. -fhe triple warp cloth should have nine meshesper inch for eggs that are'100 to 700 per ounce; seven meshes per inch foreggs 240 to 390 per ounce; six meshes per inch for eggs 120 to l-itl0 perounce; and five meshes per inch cloth for eggs that are (i0 to 1)0 per ounce.Eggs are placed on the tray no more than two layers deep, and the tray isinclined and wedged at an angle of approximately l|0 degrees, slanting towardthe incoming water in the trough. When all the eggs have hatched

t94 FISH HATCHERY MANAGEMDNTillFIGURE 66. Commercially available shipping boxes can be used to transport fisheggs. The boxes should be constructed to keep the eggs moist and cool withoutactually carrying them in water. (l) A wet cloth is placed in the shipping trayand the eggs are carefully poured into the tray. (2) The tray should not be filledto the point where the next succeeding tray will compress the eggs and put pressureon them. The cloth is then carefully folded over the eggs and the next trayput in place. (S) fh" top tray is filled with coarsely crushed ice or ice cubes toprovide cooling during shipping. The melting ice also will provide water to keepthe eggs moist. Ice should never be used directly from the freezer and should beallowed to warm until it starts to melt before it is placed with the (A) Th""ggs.insulated lid is put in place, and the box is sealed and properly labeled forshipping. (FWS photos.)and the fry have fallen through the mesh cloth, the trays are removed withthe dead eggs that remain on them. These units are relatively cheap andeasy to maintain, and egg picking is relatively simple. The disadvantagesare that rearing troughs must be available, there must be some means ofexcluding light from the troughs while the eggs are being incubated, andthere is always a danger of improper water flow through the trays.CLARK-WILLIAMSON TROUGHThe Clark-Williamson trough is a tray-hatching system for incubatinglarge numbers of eggs. The eggs are held on screen trays and are stackedvertically rather than being placed horizontally in the trough. Dam boards

BROODSI'OCK, SPAWNING, AND ECG HANDLING 195are placed in slots in the trough to force the waterflow up through eachstack.Many eggs can be handled in this type of unit, but it is difficult to observeegg development during incubation, and all trays in a stack must beremoved in order to examine the eggs on any individual tray. Possible airlocks within the stack can cause poor water circulation through the eggs.CA'fFISH TROUGHSChannel catfish eggs, which are deposited in a cohesive mass, require specialdevices when they are moved to a hatching trough for artificial incubation.The large egg masses usually are broken up into smaller pieces toenhance aeration and then placed in suspended baskets similar to the traysdescribed in the previous section.When catfish eggs are hatched in troughs, they must be agitated by paddlessupported over the trough and driven by an electric motor or a waterwheel (Figure 67). The agitation must be sufficient to gently move thewhole egg mass. Paddles are constructed of galvanized tin or aluminumand attached to a rotating shaft. The paddles are commonly 4 inches wideand long enough to dip well below the bottom of the baskets as they turn.The pitch of the paddles is adjusted as required to insure movement ofspawns in the baskets. The preferred speed is about l']0 revolutions perminute.HA'I'CHING BASKFJ,TSHatching baskets are quite similar to hatching trays, except that they areapproximately 6 to l2 inches deep and suspended in the trough to permita horizontal water flow. In many cases, deflector plates are installed aheadof each basket in such a way as to force the flowing water up through thebaskets for better circulation. In the case of Pacific salmon, as rnany as50,000 eggs may be placed in a single basket.I"IATCHING JARSHatching jars usually are placed in rows on racks with a manifold watersupply trough providing inlets to each jar and a waste trough to catchoverflow water (Figure 68). A simple unit can be fabricated from 2-inchsupply pipe with taps and an ordinary roof gutter as the waste trough. Anopen tee usually is installed between the supply line and the pipe to thebottom of the jar to aid in the elimination of gas bubbles during incubationof salmonid eggs, which must not be distrubed. The open tee may alsobe used to introduce chemicals for treating eggs. The diameter of the tee

196 FISH HATCHERY MANAGEMENTFtcunn 67. Channel catfish trough for egg incubation. Paddles (arrow) gentlycirculate the water in the trough. (FWS photo.)should be larger than the pipe entering the jar to prevent venturi actionfrom sucking air bubbles into the jar.Hatching jars are designed to provide an upward flow of water introducedat the bottom of the jar. When rolling of the eggs is desired, as inthe case of some coolwater species, the bottom of the jar is concave, withthe water introduced at the center. when used for incubating trout or salmoneggs, the jar is modified with a screen-supPorted gravel bottom, andthe water is introduced underneath the gravel. This provides a uniform,upward water flow, and the eggs are stationary. These systems also havebeen used for striped bass and channel catfish egg incubation'Some fry will swim out of the jar and into the waste trough if a coverscreen is not provided. Coolwater species are allowed to swim from the jarsand are collected in holding tanks.MONTANA HATCHING BOXThe Montana Hatching Box operates essentially like a hatching jar. Thebox is constructed of waterproof plywood or fiberglass and is approximatelyI foot square by 2 feet high. A vertical water flow is provided by a

BROODSTOCK, SPAWNING, AND EGG HANDLINGt97manifold of pipes beneath a perforated aluminum plate in the bottom ofthe box. A screened lip on the upper edge of the box provides an overflowand retains the eggs or fry. The box commonly is used in bulk handling ofeggs to the eyed stage for shipping, but it can also be used to rear fry tothe feeding stage (Figure 69).A problem with the hatching box is the tendency for gas bubbles tobuild up below the perforated plate, shutting off the water flow to portionsof the box. As with other systems, it is good practice to aerate any watersupply used for this type of incubation.VERTICAL-TRAY INCUBATORSThe vertical-tray incubator is widely used for developing salmonid eggs(Figure 70). The eggs are allowed to hatch in the trays and fry remainthere until ready to feed. Water is introduced at one end of the rop trayand flows under the egg basket and up through the screen bottom, circulatingthrough the eggs. Water, upwelling through the bottom screen helpsprevent smothering of hatched fry. The water then spills over into the traybelow. and is aerated as it falls.*rS$. ;FIGURE 68. Jar incubation of muskellunge eggs. (Courtesy Wisconsin Departmentof NaturalResources.)

198 FISH HATCHERY MANAGEMENTFIGURE 69.Trout eggs being poured into a Montana hatching box.These incubators can be set up as either 8- or 16-tray units. Drainingand cleaning of each tray is possible without removing it from the incubator.Individualtrays can be pulled out for examination without disturbingother trays in the stack. Screen sizes can be varied to accommodate thespecies of eggs being incubated. Accumulations of air bubbles can causeproblems in water circulation, and care should be taken to de-aerate supersaturatedwater prior to use in this unit. Vertical incubators have severaladvantages over troughs. They require small amounts of water to operate'and use relatively little floor space. Fungus can be controlled easily withchemicals due to the excellent flow pattern through the eggs. The smallquantities of water required for these incubators make it feasible to heat orcool the water as required.

BROODSTOCK, SPAWNING, AND EGG HANDLING 199SIMULATED NATURAL CONDITIONS AND REARING POND INCUBATIONSalmon and steelhead eggs have been incubated successfully between layersof gravel, simulating natural spawning conditions. An incubation box thathas proved successful is made of f-inch marine plywood, 8 feet long, 2 feetwide, and 15 inches deep. Water, which is first filtered through crushedrock, is supplied to the box by four f-inch diameter aluminum conduitpipes placed full length in the bottom of the box. Use of such a device foranadromous fish permits the incubation of eggs in the stream system inwhich the fish are to be released.A similar type of system involves incubation channels. Incubation channelsdiffer from previously discussed spawning channels in that eyed eggsare placed in prepared trenches. Fish reared under these conditions aregenerally hardier than those reared in the hatchery.Plastic substrates can be added to incubation units (such as verticalincubators) to simulate the environment provided by gravel. Plastic substratefabricated from artificial grass also has been used successfully in salmonidincubation systems to provide a more natural environment for newlyhatched fry and has resulted in larger and more hardy fish.The state of Washington has developed a method for incubating salmoneggs utilizing specially designed trays placed in raceways. These units areFtcunn 70. Salmon eggs being measured into a vertical-tray incubator. A screenlid is placed on top of the tray to prevent loss of eggs and hatched fry.

200 F'rsH HA'rcHERy MANAcEMENTsimilar to hatchery trays but are much larger. The raceways are filled withwater, eggs are placed in the trays, and the hatched fry are allowed to exitinto rearing ponds at their own volition.BibliographyAl.DF.Rr)rcE, D. I'., W. P. Wtcxlrr', and J. R. BR[.lt. l1)5U. Some effects of tcmporar,v exposureto low dissolved oxygen levels on Pacific salrron eugs. Journal of the FisheriesResearr h Board of Crnada l5(2);22! 2 l$.Ar.t.B.\t'cH, Clvnr- A., and Jtnnv V. M.,lxz. l1)(i.1. Prelininary study of thc effects of temperature fluctuations on developing walleye cggs and frv. Progressive Fish-Culturist26('r):175- ltlO.At.t-lsol,t, Ltox.q.nl N. l1)51. Delay of spau,ninq in eastern brook trout bl rncans of artiliciallyprolonged light intervals. Progressive Fish-Culturist l.i(3):l I I I lr,.l1)61. 'l'he effect of tricaine mcthanesulfonate (MS 222) on the motilitt of brook troutsperm. Prou,ressivt' Fi'h-Culttrrrsr 2 l/l\:lt'AMEND, Drtl,t.,u-D F. 1974. Comparative toxicit] of trvo iodophors to rainbos trout eggs.1l{.Transactions of the Amcrican Fisheries Societv l{r.J(ll:7r 7x.ANt)LRSON, Rtctt,rno O. M(i.1. A sugar-flotation method of picking trout eggs. ProgressiveAnonymous.Fish-Culturist 2(i(3):12,1 l2(j.l1).rr I . Plastic hatching box for stocking trout and salmon.Culturist I l] (41 :22u.Progressive Fislr-. l!)5.1. Char spau'ning in observation tank in Swedish laborirtorl. I'rogressive Fish-Culturist 1(i(2) :51).. ll)511. Bentonite and largemouth bass eges. I'rogressive Fish-Culturist l7(l):11).l1)67. Temperatures lbr hatching walleye eggs. Proqressive Fish-Culturist 21)(l);20ARNTBRLTsTER, [)e.Ntr:t.. llXi(i. Hybridizationof thc chain pickerel and northern pikc. I)rogrcssiveFish-L'ulturist 2i{(2):7{' 78.BAIt.E\', JAcrK E. l1)(i.1. Russian theories on the inferior quality of hatchery reared churr salmonfr;. Progrersive Iish Culturirt 2{"t:l:1{1.and Wtlll.q.lt R. Hlenu. l1)73. An irnproved incubator for salmonids and results ofpreliminary tests of its use. National Occanic and Atmospheric AdministrationI cchnicalMemorandum,Number l. 7 p.National Marine l'isheries Service, Auke Bay l'isherl Laboratory,JER()N{E J. P[.1.1.A, and SInxt.:t G. Tslt.ott. l!)76. ]']roduction of fry and adults of thel1)72 brood of pink salmon, Oncarhlnchus gorbuvha, from gravel incubators and naturalsparvning at Auke Creek, Alaska.7,1(,1):lXil 1)71.National Marinc Fisheries Service Fishery'Bulletinand StDNI:t G. TAYt-()R. l!)7.1. Plastic turf substitute for gravel in salnon incubators.National Marine Fisheries Service Marine l'isheries Rer ieu tl;(l{)) : tiBexrs, Jot: L. 197r. Methods ol handling and transporting green fall chinook eggs. I'roceedingsof the 2(ith Annual Northwest Fish Culture Conlerence, I)t'cembcr l3 i. l7{i p.BARnur'r', L I{)51. Fertility of salmonid eggs and spcrm after storage. .fournal of the FishericsResearch Boirrd of tanada t{(.t):l2i l:\3.Bett.rss, J.rcx D. l1)72. Artificial propacation and hybridization of striped bass, liorrzs sa.ralr1is.South Carolina WildlifeCarolina. 135 p.Bl:rr l:n, .JoHx A., KER\II'r' E. Sxlrn,and Marine Resources l)eparturcnt, Columbia, Southand H,\RR\ K. I)t lnr.:r:. llXj(i. I hc dilfcrcncc iD qrowthof male and female channel catfish in hatcherv ponds.2u (l ) :17 ir0.lx.Proqressive Fish Culturist

BROODSIOCK, SPAWN*lNG, AND EGG HANDLING 201BrsH()p, R. D. 1975. The use of circular tanks for spawning striped bass (Morane saxati!is).Proceedings of the AnnualCommissioners 2u:1.)5 -1.1.Confercnce Southeastern Association of Game and FishBI-t.rsz, JoHx. l1)52. Propagation of largcmouth black bass and bluegill sunfish in federalhatcherics of thc southeast. Progressive Fish Culturist l{(2):t,l (;l'.B()NN, Flr)\\'ARI) W., WILr-r.\Nt M. BArLE\, J.lct< D. Brt't.l:ss, KIN{ E. ERICKSoI, and RoBl.Rl'E. Srrvrxs. l1)7(i. Guidclines for striped bass culture. Striped Bass Committee, SouthernDivision, American Fisheries Socicty, Bethesda, Maryland. 103 p.BTtANN()N, E. L. 11Xj5. l'he influence oI physical factors on the devclopment and rveiqht ofsockeye salmon embryos and alevins. International I'acific Salmon Iisheries CommissionProgress Report I2, New Westminster, British Colurnbia, Canada.25 p.BR^scHLHR, U. W. 11)7ir. Development of pond culture tcchniques for striped bass (,lloroncsaxatilis) (Walbaum). Proceedinqs of thc Annual Conference Southeastern Associalionof Game Fish Cornmissioners 2ll: 1,1 ,!u.Bn.,rurm, .f,rrlES L. 11)71. l'all spawnin{ of channel catfis}r. Proqrcssivc Fish'Culturist3:](3):150 152.-. 1972. A suggested method for sexing bluegills. Progrcssive Fish-Culturist l|-1(l):17.BR\^N, R()tsERt I)., and Kt:xNt.:ttt C). At.t.t,;x. l1)(i1). Pond culture of channel catfish finqerlirrqs. l'roqressive Fislr-('ulturist :i I'l\:.tit l.l.BLJRR()['s, RoctRL. l1)-11). Recommended methods for fertilization, transportation, and careof salmon esgs. Progrcssirc Fish-Culturist l l(.1):l7l l7U.1!)5I . A method for enumeration ol salmon and trou t eggs by displacerrcnt. l)rogressiveFish.( ulturisr I.l(l);2,l .ltr.-. 1951. An cvaluation of methods of egg enurreration. Progressive fish Culturist1:|(2):71) us.l1)(i0. Holding ponds for adult salmon. US Fish and Wildife Servicc Special ScientificRt-port-Fisheries 1357. llj p.and D-rt'rt.r D. PALNu,n. 11)55. A vcrtical egg and fry incubator. I)rogrcssive Fish-Culturist l7 (4) :1.17 l5r.and H. Wtt.t.r,qNr Nl,rrr'NrAN. 1952. Effects of injected pituitar) material uponthe spauning of blueback salmon. Progressive Fish-C'ulturist I l(il):l l3 I lr'.Bt ss, Kt.:l:x. l1)51). Jar culture of trout eggs. Progressive Fish Culturist 2l(l):21; 2!1.and Kt:ttxt.:tlt G. C()R1.. llXj(i. The viability of trout germ cells immersed in watcr.Progressive Fi.h-Culturist 2ltlJ):lJ2 Ii3.and HOn.rnD Fox. l1)(;1. Modilications for the jar culture of trout eggs. ProgrcssiveFish-Culturist 23(:l): 1,12 14,1.and l)rxON W'\rit,.l{Xil. Research units lbr egg incubation and fingerling rearing infish hatcheries and laboratories. Progressive Fish Culturist 2ll(21;tlll 13(i.and J,lrvrr,:s E. WRrcH t. l1)57. Appearance and fertility of trout hybrids. Transa( tir)nsof the American Fisheries Societv fi7: 172 I U l .C,qxrrllo,-, and-. l1)5(i. Results of species hybridization within the family Salmonidae. I'rogressireFish Crrlturist lt'{11':l lll 1.i8.H. L. l1),17. Artilicial propagation of those channel cats. I'rogressivt'Fish Culturist1)(l):27 30.Cenr.s11r, AxlHoxv lL. l1)73. Induced spawning of largcnrouth bass (Micropterus salnoide.r).Transactions of the American Fisheries Society 102 (2):1'12 -1'11CAR.r.ER, Rar R., and Ar.r.l:N Fl. 'l'lt()NlAS. l1)77. Spawning of channcl catfish in tanks. ProgrcssiveFish-('ulturisr't!(l): lll.cH_lsr,rrr-, G. A., and J. R. SN()$'. ll)(i(i. Nylon mats as spawning sites for largemouth bass,Micropterus salmoides. Proceedinqs of the Annual Conference Southeastern Associationof Game and Fish Commissioners l1):'105 'l0tJ.

202 FrsH HAlcHERy MANAGEMENTCl,lnx, MrNon. 1950. Bass production in a Kentucky fish hatchery pond. Progressive Fish-Culturist I 2( l) :l|3-i14.Clr,vurrs,C

BROODSTOCK, SPAWNING, AND EGG HANDLING 203-. l!)7 5. Genetics of reproduction in domesticated rainbow trout. Journalof Animal Science40(l):l{)-29.GETBEL, G. E., and P. J. Munn,rv.Fish-Culturist 2:i(3) :!)l) 105.ll)Ol. Channel catfish culture in California. ProgressiveHecl.N, Wtt.t.t.r.rvr, Jr. l!)53. Pacific salmon; hatchery Propagation and its role in fishery management.US Fish and Wildlife Service Circular 2'tr. 5(i p.HAN{ANO, StrtcEnt:. l1)(jl. On the spermatozoa agglutinating agents of the dog salmon andthe rainbow trout eggs. Bulletin of the Japanese Society of Scientilic Fisheries27 \3):22525r.HASKELL, D. C. 1952. !)gg inventory; enumeration with the egg counter. Progressive Fish-Culturist l.t(2):ul fl2.HENDERSoN, HARNIoN. ll)tiir. Observation on the propagation of flathead catfish in the SanMarcos State l'ish Hatchery, Texas. Proceedings of the Annual ConferenceSoutheastern Association of Game and Fish Comrnissioners 17:l7ll 177.HENDERSON, NANcv E., and JotrN E. DE\\'AR, l1)5{). ShorrtermProgressire lish-Culturist 2l'-l\;llil) l7l.storage of brook trout milt.HrxLrl.:nsox, W. H., and S. Wrlcxt.ln. l1)(iU. A rvinning combination. Texas Parks andWildlife 2(;(10):27 2tt.Htxt:n, LlunlNCu. llxil. Propagation of northern pike. lransactions o{ the AmericanFisheries Society I)0(3) :21)u- 302.H()RroN, Holv,rno F., and ALvtx G. 0t t. 11)7(i. Cryopreservation of fish spermatozoa andova. Journal of the Fisheries Research Board of Canada I i('1,2)!tll5 l{xl(}.IrrsslN, Pelln.HolrRSl()N, W. R., and D. M,\crKINN()N. l{)5(i. LIse of an artificial spawnine channel by salmon.Transactions of the American Fisheries Society, ll(i:220 21j0.l!)76. Selective breeding and hybridization in fisheries management. Journal of'the Fisheries Research Board of Canada 33(2): tl(ill2l.INSLII, TH!.()PHIt.AS D. l1)7];. Increarsed production ol smallmouth bass fry. Pages l3:i7 lj(il inH. CIepper, editor. Black bass bioloqy irnd managcrnent. Sport Fishing Institute,Washington, D.C.Isr.A)r, Ml). ANftNt r-, Yt:t

204 FISH HATCHERY MANAGEMENT-. 1977. Rotational line crossing; an approach to the reduction of inbreeding accumulationin trout broodstocks. Progressive Fish'Culturist 3l)(4):l7U l8l.Kt,ox'tz, Glxtn

BROODS'I'OCK, SPAWNING, AND EGG HANDLING 205OlsoN, P. A., and R. F. FosrER. 1955. Temperature tolerance of eggs and young of ColumbiaRiver chinook salmon. Transactions of the American Fisheries Society tl5:201]-207.OsEID, DoNAV()N M., and LLoYD L. Svt't'u, Jr. 1971. Survival and hatching of walleye eggsat various dissolved oxygen levels. Progressive Fish-Culturist 33(2)Ul u5PAl.r'rER, DAVrr) D., RocER E. BuRROws, O. H. Rosr:nrs()N, and H. Wtlll,qvNllvr'l,r.u.l1)54. Further studies on the reactions of adult blueback salmon to injected salmon andmammalian gonadotrophins. Progressive Fish-Culturist I l;(.1) :!!l 107PARKHI.RST, Z. E., and M. A. SMIfH. l!)57. Various drugs as aids in spawning rainbow troutProgressire Fish-Culturist lllll\:.t:1.Pr,c6n, Cu,tnr-us H. 197U. Intensive culture of tiger muskellunge in Michigan during 1976and l!l77. American Fisheries Society Special Publication ll:2(12 209.PERLMLITIER, At,lnl:o, and Etrwrno WHIlr. lt)62. Lethal effect of fluorescent light on theeggs of the brook trout. Progressive Fish-Culturist 24(l):2fi 30.PHrr-r-rps, A. M. 1957. Cortland in-service training school manual. US Fish and Wildlife Service,Cortland, New York. 271 p.PHrLLrps, ARTHUR M., Jr., and Rtctt,,lno f'. DL'N'tAs. l!)5{). 'fhe chemistry of developing browntrout eyed eggs and sac fry. Progressive Fish-Culturist 2l(4):ll'lPHrLLrps, RAYMoNt) A. 1966. Walleye propagation. US Fish and Wildlife Scrvice, Washington,D.C. lli pp.I'IsARENKOvA, A. S. 195U. Storage and transportation of sperm of rainbow trout and pike.(Khranenie I Transportirovka Spermy Raduzhnoi Foreli I Shchuki.) Rybnaya Promyshlennost'Dal'nego Vostoka 34:47 -50Pl-()srLA, D,qNtl;t- S., and Wet.rln T. KELI.ER. 197,1. Effects of quantity of stored sperm andwater on fertilization of brook trout eggs. Progressive Fish-Culturist 3tt(l):42 15.Il,+.and Thomas.J. McCartney. l!)72. Effects of sperm storage and dilution on fertilizationof brook trout eggs. Progressive Fish-Culturist 3'l(ll):17{l lttlP1lgl, Dnnr,r C., and A. Ktl'lNl,r's JotlNsoN. l{)70. The effect of delayed fertilization ontransported salmon eggs. Progressive Fish-Culturist 12(2):81 x+.PREScofl, DAvlr) M. l!)ir5. Effect of activation on the water permeability of salmon eggs.Journal of Cellular and Comparative Physiology -t:1( | ): I - I 2.RANTAswAMI, L. S., and B. I. SuNoln,tn,q. 19513. Action of enzymes on the gonadotrophic activityof pituitary extracts of the Indian catfish, Heleropneustes. Aclv Endocrinologica'27\2):2s32s6.RErsENBtcHLr-tR, R. R., and J. D. McIN'r'vnt.. l!177. Genetic differences in growth and survivalofjuvenile hatchery and wild steelhead trort, (Salmo gairdneri). Journal of the FisheriesReseach Board of(anada tI(l):l2J 128.RrcKER, W. E. 1970. Hereditary and environmental factors affecting certain salmonid populations.,fn RaymondPacific salmon. H. R. MacMillanVancouver.C. Simon and Peter A. Larkin, editors. The stock concePt inlectures in fisheries. University of British Columbia,Rrcnl;r"r', JoHN D. 1976. Growth and reproduction of largemouth bass and black bullheadscultured together. Progressive Fish-Culturist lltJ(2) :82 tt5.Ron!:nrsolr, O. H., and A. P. RINfR[r.1957. Maturation of the infantile testes in rainbowtrout (Salmo gairdneri) produced by salmon Pituitary gonadotrophins administered incholesterol pellets. Endocrinology {r0/4';5jU-5ri2.Rucr

206 FISH HATCHERy MANAGEMENT'SAI-tLR, Fnl:ttt.:ntt:x H. 1975. A new incubator for salmonicls designed bl Alaska Iaboratory.National Marine Fisheries Servicc Marint'Fisheries Revierv ll7(7).Srxti, H.,rnnv C.,.fecx H. PAllu.., and JoHN Cr.Ayl()\. l1)713. Washington pond trays as amethod for incubating salmon t.ggs and fry. Progressive F ish'L'ultrrrist ,1.'{3l lil2 137.Stt,txt'lON, Euc;t,:t'lt.: H., and Wtt.t,t,c.Nt B. S\II I H. Preliminary observations of the effct t of,11)(itt.temperaturc on striped bass eges ancl sac fry. Proceedings ol tht. Annual Conferenct'Southcastern Assocation of Game Commissioners. 2l:257 2(Jl).SItEL'tr)N, JACK M. l1)55.'f he hatching of chinook salmon eggs under sirnulatecl stream conditrons. l)roqrt'ssivt'l-i'h ( rrltrrri:t l;'l':21) tl, and R. D. P

BROODS'fOCK, SPAWNING, AND EGG HANDI-ING 207-. 1975. llffect of esg devcl()pment at plantins on chinook salmon survival. ProgressiveFish-Culturist il7(4) :2i.] I 2ill].-, and.J. M. Sul:t-'tol,t. ll)(itl. ()peration of Abernathy channel for incubation of salmoncggs. LIS Bureau of Sport l'isheries and Wildlife,'I'echnical Paper 23. l1) p.'fno;N,rrr,J()nN R. l{)77. Eqq hatchability and tolerance of brook tr()ut (Sululinus fontinalis)fry at low pH..Journal of thc Fisheries llescarch Board of Canada :),f(,')):571 57!).US Irish and Wildlifc Scrvice. l1)70. Rcport to the fish farrners. Rcsource Publication 1.lll, LISBureau of Sport Fishcries and Wildlilc, Washington, D.C. 12,1 p.Vtul:nt, Rtctt.,rnD. l1)5IJ. Effect of solar radiation and of gravel cover on devclopnent, growth,irnd loss by prcdation in salmon and trout. Iransactions of the American Fisheries Societvtt:.]; l1).1 20 lVoH B.,rvr:tt., II. l1)0U. A rnethod of measuring Iish eggs. Ilulletin of the US Bureau of'l isheries 28 (2): l ()01) 101.1.!V,lltt., DIxoN, and Kr:r:N Br:ss. llxill. A water filtcr for egg incubating units. ProgressiveFish-Culturist 25('2) :|07.W^l.Frs,.J. H. l1),11. l)evelopment ol steelhead trout eggs. California Fish and Game27(,+):zs(t 260.W,rl.tt:1fi.t'l:n, D,tVttr L. ll)7(j. 'l'iinnin as an agent to eliminate adhesivcncss of walleye cges'fransactionsduring artilicial propauation.of the American l'isheries Society105((i):731 73(i.Wt,:t tttlt,qN, A. S Il:r,utN, and Rrc H,q,nD O. ANr)r.tRS()N. ll)77. Evaluation of flotation soruuonsIor sorting trout eg{s. Proqressive Fish-Culturist 31)(2):7(; 78.Wll.\R'l ()N, J C F. I I)57. A preliminary rcport on nerv techniqucs for the artificial fertilizationof trout ova. Fisheries and Game Department, Fisheries Contribution (i, Victoria, AustraI ia.WItut-l:n, [. C., and R. M. HurrlHRu\s. l1)(i7. I)uration ol fertility of ova and sperm of sockeye(Oncorhlnthus nerka) and pink (O. gorbuscha) salmon. Journal oI thc l'isheries Rescarch Board of Canada 2,1(7):1573 1578.Wtltrtr, E. M. l1)11t. Farct and fiction in spawntakinu. I'rogressive Fish-Culturist l0\'2)1;7 7'2.Wnlt;ttl, L. D., and J. R. Srorv. 1!)75. The cffect of six chemicirls for disinfection of largemouth bass eggs. I'rogressive Fish-Culturist 37l+):21:\ '217.Zlltltl-tt, P.,rut. D. l9(;,1. A salmon and stcclhead egg incubation box. Progressive FishCulturist 2(t(3):li.]1) 1,t2.ZIRC;t.s, Mr\1.('()t.\r H., and L\1.!t D.spawned and fertilized 2,1 hours after dcath of female.il4(.1):ltX).CuRtrs. l1)72. Viability of fall chinook sarrnon egqsProgressive Fish-CulturistZ()l IN, A. I. l1)58. I'he mechanism of hardening of the salmonid esq rnembrane after fertilizationor spontirneous activation. Journal of Embryology and Experime'ntal Morphology(i(.1):5.r(i s(t8.

Nutrition and FeedingNutritionNutrition encomPasses the ingestion, digestion' and absorption of food'The rearing of large numbers of animals in relatively restricted areas,whether they be terrestrial or aquatic, requires a detailed knowledge oftheir nutritional requirements in order that they can be provided a feedadequate for their growth and health. There has not been the emphasis on,"u.i.rg cultured fish as a major human food source that there has been forother livestock. Also, the quantity of fish feed required by hatcheries andcommercial fish farms has not been sufficient to justify feed companies orothers to spend more than a minimal amount of money for fish nutritionresearch. As a result, an understanding of fish nutrition has advanced veryslowly.Biologists first approached the problem of feeding cultured fish by investigatingnatural foods. Several species still must be supplied with naturalfoods because they will not eat prepared feeds. However, as large numbersof fish were propagated and more and more fish culture stations established.it became uneconomical or impractical to use natural feeds. Becauseof the limited supply and uncertain nature of artificially cultured naturalfood organisms, fish culturists turned to more readily available and reliablefood supplies. Glandular parts of slaughtered animals were among the firstingredients used to supplement or replace natural feeds.208

N U'I'R I1'l ON AN l) I L,EDI N..GHatchery operators also started feeding vegetable feedstuffs separately orcombined with meat products to provide greater quantities of finished feed.One of the major problems was how to bind the mixtures so they wouldhold together when placed in the water. In the early days of fish culture, alarge portion of artificial feed was leached into the water and lost. Thisresulted in poor growth, increased mortality, water pollution, and increasedlabor in cleaning ponds and raceways. The use of dry meals in the diet toreduce feed costs compounded the problem of binding feeds to preventloss. The use of certain meat products such as spleen and liver mixed withsalt resulted in rubber-like mixtures, called meat-meal feeds, that weresuitable for trough and pond feeding. These were mixed in a cement orbread mixer and extruded through a meat grinder. This type of feed producedmore efficient food utilization, better growth, and a reduction in theloss of feeds.However, considerable labor was involved in the preparation of themeat-meal feeds. In addition, the use of fresh meat in the diet required eitherfrequent shipments or cold storage. The ideal hatchery feed was onethat would combine the advantages of the meat-meal feed, but would eliminatethe labor involved in preparation and reduce the expense of coldstorage facilities.In 1959, the Oregon State Game and Fish Commission began to use apelleted meat-meal fish feed called Oregon moist pellet (OMP), no*.o--mercially manufactured. These pellets were developed because salmonwould not take dry feed. Use of this feed in production was preceded bysix years of research. The formula is composed of wet fish products anddry ingredients; it has a moist, soft consistency and must be stored frozenuntil shortly before feeding.Many hatcheries use the Oregon moist pellet as a standard productionfeed because it provides satisfactory feed conversion, and good growth andsurvival, at a competitive price. The disadvantage of the Oregon moist pelletis that it must be transported, stored, and handled while frozen. Whenthawed, it deteriorates within 12 hours.By the mid 1950's, development and refinement of vitamin fortificationshad made possible the "complete" dry pelleted feeds as we know them toduy.Fish feeds manufactured in the form of dry pellets solved many of theproblems of hatchery operations in terms of feed preparation, storage, andfeeding. There are several additional advantages to pellet feeding. Pelletsrequire no preparation at the hatchery before they are fed. They can bestored for 90-100 days in a cool, dry place without refrigeration. When afish swallows a pellet, it receives the ingredients in proportions that wereformulated in the diet. There is evidence that fish fed dry pellets are moresimilar in size than those fed meat-meal. The physical characteristics of the

2t0FISH HA'I'CIIERY MANAGEME,NTpellets provide for more complete consumption of the feed. Feeding rates of0.5 to l09t of fish weight per day reduce the chance for feed wastage. Lessfeed wastage results in far less pollution of the water during feeding and acomparable reduction in cleaning of ponds and raceways. Pelleted feeds areadaptable for use in automatic feeders.Many combinations of feedstuffs were tested as pelleted feeds; somefailed because the pellets were too hard or too soft; others did not providethe nutrient requirements of the fish.Along with the testing and development of dry feeds, fish nutritionresearchers, relying largely on information concerning nutrition of other animalssuch as chicken and mink, began utilizing and combining more andmore feedstuffs.Commercial fish feeds were pelleted and marketed in advance of openformulafeeds. A few commercial feeds failed to produce good, economicalgrowth and to maintain the health of the fish but, by and large, most werevery satisfactory.Several items must be considered in developing an adequate feeding programfor fish. These include the nutrient requirements for different fishsizes, species, environmental conditions, stress factors, types of feed, andproduction objectives. General feeding methods are important and will bediscussed extensively in the last part of this section.It would be difficult to determine which factor has the greatest effect ona hatchery feeding program. In all probability, no one factor is more importantthan another, and it is a combination of many that results in an efficientfeeding program. Application of the available knowledge of fish nutritionand feeding will result in healthy, fast-growing fish and low productioncosts. A fish culturist must be able to recognize the factors affectingfeed utilization and adapt a feeding program accordingly.Factors Influencing Nutritional RequirementsThe physiological functions of a fish (maintenance, growth, activity, reproduction,etc.) govern its metabolism and, in turn, determine its nutritionalrequirements. Metabolism is the chemical processes in living cells by whichenergy is provided for vital processes and activities.WATER TI]MPT]RATUREApart from the feed, water temperature is probably the single most importantfactor affecting fish growth. Because fish are cold-blooded animals,their body temperatures fluctuate with environmental water temperatures.Negligible growth occurs in trout when the temperature decreases to 38'F.The lower limit for catfish is about 50"F. As the temperature rises, growth

N U'fRI'fI()N AND }EEDING 211rate, measured as gain in wet body weight or gain in length, increases to amaximumand then decreases as temperatures approach the upper lethallimit. The best temperature for rapid, efficient growth is that at which appetiteis high and maintenance requirements (or the energy cost of living)are low.For every ltJ"F increase in water temperature, there is a doubling of themetabolic rate and, as a result, an increase in oxygen demand. At the sametime that oxygen demand is increasing at higher temperatures, the oxygencarrying capacity of the water decreases. The metabolic rate of the fish increasesuntil the critical oxygen level is approached. Just below this point,the metabolic rate decreases.Temperature is a very important factor in establishing the nutrient requirementsof fish. To deal with this problem, the National ResearchCouncil (NRC) reports Standard Environmental Temperatures (SET) forvarious species of fish. Suggested Standard Environmental Temperaturesare 50'F for salmon, 59'F for trout, and 85'F for channel catfish. At thesetemperatures the metabolic rate for these fish is 100'11,. Caloric needsincrease with rising water temperatures, resulting in an increase in thefishes' appetite. The fish culturist must, therefore, adjust the feeding rate orcaloric content of the feed to provide proper energy levels for the variouswater temperatures. Failure to make the adjustment will result in less thanoptimal growth and feed wastage.SPECIES, BODY SIZE, AND AGT]Within the ranges of their optimal water temperatures, the energy requirementsof warmwater fish are greater than those of equally active coldwaterfish of the same size. At the same water temperature, coldwater fish consumemore oxygen than warmwater fish, indicating a higher metabolic rateand greater energy need. Carnivorous fish have a higher metabolic ratethan herbivorous fish because of the greater proportion of protein andminerals in their diet. Even though fish efficiently eliminate nitrogenouswastes through the gills directly into the water, more energy is required forthe elimination of wastes from protein utilization than from fats and carbohydrates.Species that are less active have lower metabolic rates andenergy requirements for activities than more active ones. In general, theenergy requirements per unit weight are greater for smaller than for largerfish. Fish never stop growing, but the growth rate slows as the fish becomesolder. The proportional increase in size is greatest in young fish.PHYSIOLOGICAL CHANGESSpawning, seasonal, and physiological changes affect the rate of metabolism.Growth rate becomes complicated with the onset of sexual maturity.

IISH }IA]'CHERY MANA(;EMEN'TAt this point, energy, instead of being funneled into the building of bodytissues, is channeled into the formation of eggs and sperm. When sex productsare released a weight loss as much as 10-1596 occurs. Fish also havehigh metabolic rates during the spawning season, associated with thespawning activities. Conversely, during winter, resting fish have very lowmetabolic rates. Fish suffering from starvation have 20ill lower metabolicrates than actively feeding fish. Excitement and increased activity elevatethe metabolic rates. All these affect the amount of energy which must besupplied by the feed.OTHER I]NVIRONMEN'I'AI, FACTORSFactors such as water flow rates, water chemistry, and pollution can putadded stresses on fish, and result in increased metabolic rates in relation tothe severity of the stress. Water chemistry, oxygen content, and amount ofother gases, toxins, and minerals in the water all affect the metabolic rate.For many species, darkness decreases activity and energy requirements.These fish grow better if they have "rest periods" of darkness than they doin constant light.Crowding, disease, and cultural practices also can have an affect on themetabolism and well beins of fish.Digestion and Absorption of NutrientsFeed in the stomach and intestine is not in the body proper because thelining of these organs is merely an extension of the outer skin. Feed components,such as simple sugars, can be absorbed as eaten. The more complexcomponents such as fats, proteins, and complex carbohydrates, mustbe reduced to simpler components before they can be absorbed. Thisbreaking-down process is termed digestion. Feeds cannot be utilized by theanimal until they are absorbed into the body proper and made available tothe cells.Absorption of nutrients from the digestive system and movement of thenutrients within the body is a complicated process and not fully understood.For nutrients to be available for biochemical reactions in the cell,they must be absorbed from the digestive system into the blood for transportto the cells. At the cellular level, they must move from the blood intothe cell.Fish also are able to obtain some required elements directly from the water,this being especially true for minerals.A brief anatomical review of a fish's digestive tract will illustrate thesites of feed digestion and absorption.The mouth is used to capture and take in feeds. Most fish do not chew

NU f RIIIUN AND FI,EIJINC2I3their food, but gulp it down intact. Pharyngeal teeth are used by somespecies to grind feed.The giryard serves as a grinding mechanism in some species of fish.The stomach is for feed storage and preliminary digestion of protein. Verylittle absorption occurs in the stomach.The finger-like pyloric ceca at the junction of the stomach and small intestinesare a primary source of digestive juices.The small intestine is the major site of digestion and receives the digestivejuices secreted by the liver, pancreas, pyloric ceca, and intestinal walls.The absorption of the nutrients occurs in this area.Some water absorption occurs in the large intestine, but its primary functionis to serve as a reservoir of undigested materials before expulsion as feces.Oxl,gen and Water RequirementsOxygen and water normally are not considered as nutrients, but they arethe most important components in the life-supporting processes.All vital processes require energy, which is obtained from the oxidationof various chemicals in the body. The utilization of oxygen and resultingproduction of carbon dioxide by the tissues is the principal mechanism forthe liberation of energy. Oxygen consumption by a fish is altered by size,feed, stress, water temperature, and activity. The oxygen requirement perunit of weight decreases as fish size increases. High-nutrient feeds, density,stress, elevated water temperatures, and increased activity all increase oxygenrequirements of fish. As a consequence, adequate oxygen must be suppliedto assure efficient utilization of the feed and optimal growth.Water is involved in many reactions in animal systems either as a reactantor end product. Seventy-five percent of the gain in weight during fishgrowth is water. Water that is not provided in the feed itself must be takenfrom the environment. Because water always diffuses from the area ofweakest ionic concentration to the strongest, water readily diffuses throughthe gills and digestive tract into freshwater fish. In saltwater fish, the bloodion concentration is weaker than that of marine water, so that the fish loseswater to the environment. This forces the fish to drink the water and excretethe minerals in order to fulfill their requirements.A nutritionally balanced feed must contain the required nutrients in theproper proportion. If a single essential nutrient is deficient, it will affectthe efficient utilization of the other nutrients. In severe cases, nutrient deficienciescan develop, affecting different physiological systems and producinga variety of deficiency signs (Appendix F). Because all essential nutrientsare required to maintain the health of fish, there is no logic to rankingthem in terms of importance. However, deficiencies of certain nutrientshave more severe effects than of others. This is exemplified bv a low level

214 FISH HATCHERY MANAGT]MENTof protein in the feed resulting onlv in reduced growth, whereas the lack ofany one of several vitamins produces well described deficiency signs. Nutrientssuch as protein and vitamins should be present in feeds at levels tomeet minimum requirements, but not in an excess which might be wastedor cause other health problems.The nutrients to be discussed in this chapter include (1) protein, (2) ca.-bohydrates, (3) fats, (4) vitamins, and (5) minerals.Protein RequirementsThe primary objective of fish husbandry is to produce fish flesh that isover 50% protein on a dry weight basis. Fish digest the protein in most naturaland commercial feeds into amino acids, which are then absorbed intothe blood and carried to the cells.Amino acids are used first to meet the requirements for formation of thefunctional body proteins (hormones, enzymes, and products of respiration).They are used next for tissue repair and growth. Those in excess of thebody requirements are metabolized for energy or converted to fat.Fish can synthesize some amino acids but usually not in sufficient quantityto satisfy their total requirements. The amino acids synthesized areformed from materials released during digestion and destruction of proteinsin the feed. Certain amino acids must be supplied in the feed due to theinability of fish to synthesize them. Fish require the same ten essential a-minoacids as higher animals: arginine; histidine; isoleucine; leucine;lysine; methionine; phenylalaninel threonine; tryptophan; valine. Fish fedfeeds lacking dietary essential amino acids soon become inactive and loseboth appetite and weight. When the missing essential amino acids arereplaced in the diet, recovery of appetite and growth soon occurs.In fish feeds, fats and carbohydrates are the primary sources of energy,but some protein is also utilized for energy. Fish are relatively efficient inusing protein for energy, deriving 3.9 of the 4.65 gross kilocalories pergram from protein, for an 84'/o efficiency. Fish are able to use more proteinin their diet than is required for maximum growth because of their efficiencyin eliminating nitrogenous wastes through the gill tissues directlyinto the water. Nutritionists must balance the protein and energy componentsof the feed with the requirements of the fish. Protein is the mostexpensive nutrient and only the optimal amount should be included formaximum growth and economy; less expensive digestible fats and carbohydratescan supply energy and spare the protein for growth.Several factors determine the requirement for protein in fish feeds.These include temperature, fish size, species, feeding rate, and energy contentof the diet. Older fish have a lower protein requirement for maximum

NUTRIl'ION AND FEEDING 215growth than young fish do. Species vary considerably in their requirementslfor example, young catfish need less gross protein than salmonids.The protein requirements of fish also increase with a rise in temperature.For optimal growth and feed efficiency, there should be a balance betweenthe protein and energy content of the feed. The feeding rate determines thedaily amount of a feed received by the fish. When levels above normal arefed, the protein level can be reduced, and when they are below normal itshould be increased to assure that fish receive the proper daily amount ofprotein. Fish culturists can reduce feed costs if they know the exact proteinrequirements of their fish.The quality, or amino acid content, is the most important factor in optimizingutilization of dietary proteins. If a feed is grossly deficient in anyof the ten essential amino acids, poor growth and increased feed conversionswill result, despite a high total protein level in the feed. The dietaryprotein that most closely approximates the amino acid requirements of thefish has the highest protein quality value. Animal protein sources are generallyof higher quality than plant sources, but animal proteins cost more.Vegetable proteins do not contain an adequate level of certain amino acidsto meet fish requirements. Synthetic free amino acids can be added to feed,but there is still some question as to how well fish utilize them. Thus, aminoacid balance at reasonable cost is best achieved by using a combinationof animal proteins, particularly fish meal, and vegetable proteins.Fish meal seems to be the one absolutely essential feed item. Most of theingredients of standard catfish feed formulas can be substituted for, butwhenever fish meal has been left out poorer growth and food conversionhave resulted.Fish cannot utilize nonprotein nitrogen sources. Such nonprotein nitrogensources as urea and di-ammoniumcitrate, which even many nonruminantanimals can utilize to a limited extent, have no value as a feedsource for fish. They can be toxic if present in significant levels.The chemical composition of fish tissue can be altered significantly bythe levels and components of ingredients in feeds. Within limits, there is ageneral increase in the percentage of protein in the carcass in relation tothe amount in the feed. Furthermore, there is a direct relation between thepercentage of protein and that of water in the fish body. A reduction ofbody protein content in fish is correlated with increased body fat; fish fedlower-protein feeds have more fat and less protein.PROTEIN IN SALMONID FEEDSThe protein and amino acid requirements for salmon and trout are similar.The total protein requirements are highest in initially feeding fry and decreaseas fish size increases. To erow at the maximum rate, fry must have a

2t6FISH HATCHERY MANAGEMENTfeed that contains at least 5070 protein; at 6-8 weeks the requirement decreasesto 40% of the feed and to about 35% of the feed for yearling salmonids.Recommended protein levels in trout feeds as percent of the diet are:Starter feed (fry)Grower feed (fingerlings)Production feed (older fish)The level of protein required in feed varies with the quality and proportionsof natural proteins that make up the feed. Between 0.5 and 0.7 poundof dietary protein is required to produce a pound of trout fed a balancedhatchery feed. The requirement for protein is also temperature-dependent.The optimal protein level in the feed for chinook salmon is 40% at 47"Fand 55'li at 58'F.PROTEIN IN CATFISH FEEDSThe natural foods of catfish are rich in protein. Catfish may metabolizesome dietary protein for energy. Protein utilization is affected by the proteinsource and water temperature. Channel catfish convert the best animalprotein source, fish meal, two times better than they do the best plantsource, soybean meal. It is noteworthy that a combination of proteinsources yields better conversion rates than any single source. In catfishfeeds, at least 50'li of the dietary Protein requirement should be animalprotein.Better efficiency is obtained for all proteins when they are fed at temperaturesbetween 75'F and 88'F than at 65'F or below. However, a mixtureof animal protein is utilized almost equally at both extremes. The particlesize of the protein sources in the feeds has no measurable effect onprotein utilization at any temPerature.The protein requirements for catfish are also size-related. The recommendedtotal protein levels in percent of the feed for different-sized catfishat a 75'F water temperature are:Fry to fingerlingsFingerlings to subadultsAdults and broodfish45-55Y035-5'fo30-40'/oWhen catfish are fed as much as they will eat, and the feed is balancedin amino acids and energy, lower protein levels are adequate' When thefeeding rate is restricted, as in pond culture, higher protein levels haveproved beneficial. Fish on higher protein rations require less energy perpound of gain.35-40'/o25 35',i028 32ui,tThe role of carbohydrates and fats in protein-sparing has not been adequatelystudied, but indications are that these nutrients in catfish diets are

NU'I'RITION AND F[L,DINGbeneficial in this regard. The amino acid requirements for catfish have notbeen established, but appear to be similar to those for salmonids'Catfish feeds-or any feeds fed in extensive culture-are classified aseither complete or supplemental diets. Complete feeds are formulated tocontain all the vitamins, minerals, protein, and energy needed by the fish.Usually these complete feeds contain 30 to 40% total crude protein, ofwhich fish meal may make up l0 to 25(x, of the feed. Complete feeds aremore expensive than supplemental feeds. Complete feeds are fed to fry,and also to larger fish raised intensively in raceways, cages, or otherenvironments where the intake of natural feeds is restricted.Supplemental feeds are formulated to provide additional protein, energy,and other nutrients to fish utilizing natural food. Generally, the fish areexpected to eat natural food organisms to supply the essential growth factorsabsent in the feed. Usually supplemental feeds contain a lower level ofcrude protein than complete feeds, and soybean meal is the principal proteinsource.Low stocking rates and low standing crops of fish result in more naturalfood (and protein) being available to each fish. The above factors and others,such as season, fish size, feeding rate, water temPerature, oxygen levels,and disease influence the dietary protein levels required for maximumefficiency in growth. Consequently, no one protein level in feeds will meetall conditions and it remains for the fish culturist to choose the feed with aprotein level that will satisfy production needs.PROTEIN IN COOLWATER FISH FEEDSFeeding trials with northern pike, chain pickerel, muskellunge, walleye,and the hybrid tiger muskellunge showed that the hybrid and, to a lesserdegree, northern pike will accept a dry pelleted, formulated feed. A 50'l1rprotein experimental feed (Appendix F) formulated specifically for coolwaterfish provided the highest survival and growth with fingerlings. Troutfeeds and experimental feeds that contain less protein were inadequate'Therefore, it appears that the protein requirement for the fingerlings ofthese species is about 50'X, of the feed. It is also noteworthy that 60-809[ ofthe dietary protein was supplied by animal protein sources in feeds thatproved satisfactory. Only limited testing has been conducted on feedingadvanced fingerlings of coolwater species, but indications are that the proteinlevel of the feed can be reduced. This follows the similar pattern fortrout and catfish.C ar bo hy dra te R eq uirementsCarbohydrates are a major source of energy to man and domestic animals,but not to salmonids or catfish. Only limited information is available on

2lu! ISH HAl CHERY MANA(IEMliN lthe digestibility and metabolism of carbohydrates by fish. All of the necessaryenzymes for digestion and utilization of carbohydrates have beenfound in fish, yet the role of dietary carbohydrates and the contribution ofglucose to the total energy requirement of fishes remain unclear.There is little carbohydrate (usually less than 1.0'li of the wet weight) inthe fish body. After being absorbed, carbohydrates are either burned forenergy, stored temporarily as glycogen, or formed into fat. Production ofenergy is the only use of carbohydrates in the fish system. No carbohydraterequirements have been established for fish because carbohydrates do notsupply any essential nutrients that cannot be obtained from other nutrientsin the feed.The energy requirement of a fish may be satisfied by fat or protein, aswell as by carbohydrate. If sufficient energy nutrients are not available inthe feed the body will burn protein for energy at the expense of growthand tissue repair. The use of carbohydrate for energy to save protein forother purposes is known as the "protein-sparing effect" of carbohydrate.Carbohydrate energy in excess of the immediate energy need is convertedinto fat and deposited in various tissues as reserve energy for use duringperiods of less abundant feed. Quantities in excess of needed levels lead toan elevated deposition of glycogen in the liver, and eventually will causedeath in salmonids.Fat-infiltrated livers and kidneys in salmonids are a result of fat depositionwithin the organ, resulting in reduced efficiency and organ destruction.This condition results primarily from excess levels of carbohydrates inthe feed.Carbohydrates also may serve as Precursors for the various metabolic intermediates,such as nonessential amino acids, necessary for growth. Thus,in the absence of adequate dietary carbohydrates or fats, fish may makeinefficient use of dietary protein to meet their energy and other metabolicneeds. In addition to serving as an inexpensive source of energy, starchesimprove the pelleting quality of fish feeds.Dietary fiber is not utilized by fish. Levels over 10')t in salmonid feedsand over 20'li, in catfish feeds reduce nutrient intake and impair the digestibilityof practical feeds.CARBOHYDRATES IN SALMONID FEEDSCarbohydrates are an inexpensive food source, and there is a temptation tofeed them at high levels. However, trout are incapable of handling highdietary levels of carbohydrates. The evidence for this is the accumulationof liver glycogen after relatively low levels of digestible carbohydrate arefed. Trout apparently cannot excrete excessive dietary carbohydrate. Inhigher animals, excessive carbohydrate is excreted in the urine' Such excretiondoes not occur in trout even though the blood sugar is greatly in-

NUTRITION AND FEEDINC2t9creased. In trout, the accumulation of blood glucose follows the same patternas that in diabetic humans.No absolute carbohydrate requirements have been established for fish.Trout nutritionists have placed maximum digestible carbohydrate valuesfor feeds at 12-20%. Digestible carbohydrate values are determined bymultiplying the total amount of carbohydrate in the feed by the digestibilityof the carbohydrates. Digestibility values of various carbohydrates are:simple sugars, 100%; complex sugars, 90%; cooked starch, 60%; raw starch,30%: fiber. 0%.Digestible carbohydrate levels over 20% in trout feeds will cause an accumulationof glycogen in liver, a fatty infiltrated liver, fatty infiltratedkidneys, and excess fat deposition, all of which are detrimental to thehealth of the fish.Levels of carbohydrates up to 20(/o can be tolerated in trout feeds in55 65"F water. These same feeds fed in water below 50'F will cause excessivestorage of glycogen in the liver and can result in death. Carbohydratesshould, therefore, be limited in trout feeds. However, there are definitebeneficial effects from the carbohydrate portion of the feed. It can supplyup to 20()t of the available calories in a feed, thus sparing the protein. Theenergy from carbohydrates available to mammals is 4 kilocalories per gram,whereas the value for trout is only 1.6 kcal/g, a 40%r relative efficiency.Most trout feeds do not contain excessive amounts of digestible carbohydrate.A balance between plant and animal components in the feeds generallywill assure a satisfactory level of digestible carbohydrate. The majorsources of carbohydrate in trout feeds are plant foodstuffs, including soybeanoil meal, cereal grains, flour by-products, and cottonseed meal. Mostanimal concentrates such as meat meals, fish meals, tankage, and bloodmeals, are low in carbohydrate (less than 1.0%). The high percentages ofmilk sugar in dried skim milk, dried buttermilk, and dried whey may causean increase in blood sugar and an accumulation of glycogen in the liver iffed at levels greater than l0% of the feed.Pacific salmon have been reported to tolerate total dietary carbohydratelevels as high as 48%, with no losses or liver pathology. The digestible carbohydratevalue would be lower, depending on the forms of the carbohydrate.CARBOHYDRATES IN CATFISH I'E[,DSDietary carbohydrates are utilized by catfish, but only limited informationis available on their digestibility and metabolism. Channel catfish utilizestarches for growth more readily than sugars. In feeds containing adequateprotein, fish weight increases with the level of starch, but remains essentiallythe same regardless of the amounts of sugar in the feed. Liver abnormalities,poor growth, and high mortality observed in salmonids due to highlevels of dietary carbohydrates have not been found in catfish.

FISH HA'I'CHERY MANAGE,MENTNo carbohydrate requirements have been established for catfish; however,carbohydrates can spare protein in catfish feeds. In the absence ofadequate dietary carbohydrates or fats, catfish make inefficient use ofdietary protein to meet their energy and other metabolic needs. In channelcatfish, lipids and carbohydrates appear to spare protein in lower-energyfeeds but not in higher-energy feeds.Fiber is an indigestible dietary material derived from plant cell walls.Fiber is not a necessary component for optimum rate of growth or nutrientdigestibility in channel catfish production rations. Fiber levels as high as2l% reduce nutrient intake and impair digestibility in feeds for channelcatfish. Fiber in concentrations of less than [J')t may add structural integrityto pelleted feeds, but larger amounts often impair pellet quality. Most ofthe fiber in the feed ultimately becomes a pollutant in the water.Lipid RequirementsLipids comprise a group of organic substances of a fatty nature that includesfats, oils, waxes, and related compounds. Lipids are the most concentratedenergy source of the food groups, having at least 2.25 times moreenergy per unit weight than either protein or carbohydrates. In addition tosupplying energy, lipids serve several other functions such as reserve energystorage, insulation for the body, cushion for vital organs, lubrication,transport of fat-soluble vitamins, and maintenance of neutral bouyancy.They provide essential lipids and hormones for certain body processes andmetabolism, and are a major part of reproductive products.Although each fish tends to deposit a fat peculiar to its species, the dietof the fish will alter its type. The fat deposited tends to be similar to thefat ingested. The body fat of fish consuming natural foods contains a highdegree of polyunsaturated (soft) fats similar to those in the food. Becausenatural fats are soft fats that are mobilized and utilized by the fish more efficientlythan hard (saturated) fats, soft fats are beneficial for efficient productionand fish health. Preliminary studies have indicated that some hardfats can be used by warmwater fish.The effect of water temperature on the composition of the body fat offish is difficult to define clearly due to its influence on the digestibility ofhard and soft fats. Soft fats are digested easily in both warm and cold water,but hard fats are digested efficiently only in warm water. Fish living incold water have body fats that are highly unsaturated with a low meltingpoint. These fish are able to more readily adapt to a low environmentaltemperature.Factors to be considered in evaluating dietary lipids for fish feeds includedigestibility, optimal level in the feed, content of fatty acids essential

N U'I'RITION AND FEEDING22rfor the fish, presence of toxic substances, and the quality of the lipid. Fishand vegetable oils that are polyunsaturated are more easily digested by fishthan saturated fats such as beef tallow, especially at colder temperatures.The optimal level of dietary lipid for fish feeds has not been established.Protein content of the feed, and type of fat need to be considered in determiningthe amount to be used in the feed for a given fish species. Lipidsare a primary source of energy for fish and have a protein-sparing effect.Therefore high levels in the feed would be beneficial. However, high fatlevels in the feed can hamper the pelleting of feeds and cause rapidspoilage of feed during storage.Rancidity of lipids, especially of polyunsaturated oils, due to oxidationcan be a problem in fish feeds. Rancid lipids have a disagreeable odor andflavor and can be toxic to fish. The toxic effects may be due to products ofthe oxidation of the lipid itself or to secondary factors such as destructionof vitamins or mold growth. Oxidation of lipids in the feed often results inthe destruction of vitamins, especially vitamin E. The oxidation processalso produces conditions that favor mold growth and breakdown of othernutrients. Because rancid lipids in the feed are detrimental to fish, every effortshould be made to use only fresh oils protected with antioxidants.Feeds should be stored in a cool, drv area to minimize oxidation of thelipids in the feeds.Contamination of fish feeds, especially those for fry and broodstock, withpesticides and other compounds such as polychlorinated biphenols (PCB)cause many health problems and may be lethal in fish. Fish oil is a commonsource of contaminants in fish feeds. Because most contaminants arefat-soluble they accumulate in the fatty tissues of fish. When fish oil is extractedfrom fish meal, these compounds are concentrated in the oil. Fishused in the production of fish meal and oil pick up these compounds fromtheir natural foods in a contaminated environment. Feed manufacturersshould select only those fish oils that contain low levels or none of thesecompounds. Vegetable oils, which are naturally free of these compounds,also can be used.LIPID REqUIRHMEN'I'S FOR SAT,MONIDSWhen there is little or no fat in the feed, a trout forms its own fat from carbohydratesand proteins. The natural fat of a trout is unsaturated with alow melting point. Practical-feed formulators use fish oil and vegetable oilin trout feeds as the primary energy source. These oils are readily digestedby the trout and produce the desired soft body fat. Hard fats such as beeftallow are not as readily digested because they are not emulsified easily,especially in cold temperatures. Hard fats can coat other foods and reducetheir digestibility, thus lowering the performance of the feed. Very hardfats may plug the intestines of small trout.

FISH HATCHf,RY MANAGEMEN']Body fat of a hatchery trout fed production feeds is harder (more saturated)than that of a wild trout, but after stocking the body fat graduallychanges to a softer (unsaturated) typ". This can be attributed to both thechange in environment and feed.Linolenic fatty acids (omega-3 type) are essential for trout and salmon,and should be incorporated at a level of at least l% of the feed for maximumgrowth response. This may be supplied by the addition of 3-570 fishoil or 10%r soybean oil.The level of dietary lipid required for salmon or trout depends on suchfactors as the age of the fish, protein level in the feed, and the nature ofthe supplemental lipid. The influences of age of the fish and protein levelof the diet are interrelated; young trout require higher levels of both fatand protein than older trout. For best performance, the recommended percentageof fat and protein for different ages of trout and salmon should beas follows:Starter feeds (fry)Grower feeds (fingerlings)Production feeds (older fish)% protein % fat50 1540 t2359Hatchery personnel can check the protein and fat content of trout feeds eitheron the feed tag for brand feeds or in the feed formulationdata foropen-formula feeds to determine if these recommended nutrient levels arebeing supplied by the feed they are using.High levels of dietary fat and, to a lesser degree, excess protein or carbohydratescan cause fatty infiltration of the liver. Fatty infiltrated liversare swollen, pale yellow in color, and have a greasy texture. The level offat in affected livers may be increased to several times greater than normal.This condition usually is accompanied by fatty infiltration of the kidneyand can lead to edema and death by reducing the elimination of wastesthrough the urinary system.Fatty infiltrated livers should not be confused with fatty degeneration ofthe liver or viral liver degeneration. Fatty degeneration of the liver iscaused by toxins from rancid feeds, chemical contaminates, certain algae,or natural toxins. This condition is typified by acute cellular degenerativechanges in the liver and kidney. The liver is swollen, pale yellow in colorwith oil droplets in the tissue, but does not feel greasy (Figure 7l). Rancidfats in feeds stored for long periods (more than six months) or under warm,humid conditions are the primary cause of this disorder in hatchery-rearedtrout. Rainbow trout are most severely affected and brook trout to a lesserdegree, but brown trout are rarely affected by rancid oils in the feed. Viralliver degeneration differs from the others by the presence of small hemorrhagicspots in the liver and swelling of the kidney. Anemia is characteristicof advanced staees of all three liver disorders.

N U]'RITION AND T'EI]I)INC 223FIGURE 71. Rainbow trout with liver lipoid degeneration (ceroidosis) ofincreasing severity from toplivers of middle and bottomto bottom. Note yellowish-brown coloration offish. (Courtesy Dr. P. Ghittino, Fish DiseaseLaboratory, Tonino, Italy.)FIGURE 72. Folic acid-deficient (top) and control (botto-) coho salmon.Note the extremely pale gill, demonstrating anemia, and exophthalmia infolic acid-deficient fish. (Courtesy Charlie E. Smith, FWS, Bozeman,Montana.)

224 FISH HA t CHITRY MANAGEMIlNTLIPID RN,qUIRN,ME,NTS FOR CATFISHLipid level and content of essential fatty acids have received little considerationin diets for channel catfish, because little is known about the effectsof, and requirements for, these nutrients in catfish. In practice, thedietary requirements have been met reasonably well by lipids in the fishmeal and oil-rich plant proteins normally used in catfish feeds and those innatural food organisms available in ponds.Weight gain and protein deposition increase as the level of fish oil iselevated to 15')6 of the dry feed. At the 20([r level, the gain decreases. Catfishfed corn oil did not gain as well as those fed fish oil in the feed, showingthat fish oil is a better source of dietary lipid.Beef tallow, safflower oil, and fish oil were evaluated at temperaturesfrom 68 to 93'F. Maximum growth was obtained at 86"F by catfish fedeach lipid supplement. Highest gains and lowest food conversion rates wereobtained with fish oil, followed by beef tallow and safflower oil. As withsalmonids, catfish have little or no requirement for linoleic (omega-6) fattyacids in the feed. No requirements for essential fatty acids in catfish feedshave been determined.Commercial catfish feeds contain less than 8(!l dietary lipids. Test feedswith 10% lipid provided the best growth, whereas 16')l in the feed did notimprove growth or enhance protein deposition.Lipids have the most effect on taste and storage quality of fish products.Tests with animal and vegetable fats showed that fish oil has a significantadverse effect on the flavor of fresh and frozen fish. Beef tallow also influencedthe flavor, but did not induce the "fishy" flavor produced by thefish oil. Fish reared on safflower oil or corn oil have a better flavor thanthose fed beef tallow or fish oil. Catfish producers may be able to use animalfats and oils in fingerling feeds to obtain rapid growth and efficientdeposition of protein, then change to a finishing diet made with vegetableoils to improve the flavor as the fish approach market size.Energt RequirementsEnergy is defined as the capacity to do work. The work can be mechanical(muscular activity), chemical (tissue repair and formation), or osmotic(maintenance of biological salt balance). Fish require energy for growth, activity,reproduction, and osmotic balance. Energy requirements of speciesdiffer, as do their growth rates and activities. Other factors that alter theenergy requirements are water temperature, size, age, physiological activity,composition of the diet, light exposure, and environmental stresses.Food energy is usually expressed as kilogram calories (kcal or Cal). It isreleased in two forms, heat energy and free energy, in animal systems. Heatenergy has the biological purpose of maintaining body temperature in

Nt'f RIl l()N AN-l) IEl]l)lN.-(;'225warm-blooded animals, but this is of less importance to fish because a fish'sbody temperature corresponds to environmental water temperatures. Usually,the body temperature of a resting fish will be at or near the environmentalwater temperature. Free energy is available for biological activityand growth and is used for immediate energy and for formation of body tissueor is stored as glycogen or fat.Fish adjust their feed intake according to their energy needs. An excessivelyhigh energy level in a feed may restrict protein consumption andsubsequent growth. Except for the extremes, fish fed low-energy feeds areable to gain weight at a rate comparable to those fed high-energy feeds byincreasing their feed intake. If a feed does not contain sufficient nonproteinenergy sources to meet the fish's energy requirements then the protein normallyused for growth will have to be used for energy. 'Iherefore, it is difficultto determine a specific energy or protein requirement without consideringthe relative level of one to the other. Absolute figures on optimumenergy requirements are difficult to state in fish nutrition because fish canbe maintained with little growth on a low-energy intake or be forced toproduce more weight by feeding them in excess. To maintain optimumgrowth and the efficiency of a feeding program, the feeding level should beadjusted if energy levels of the feeds vary significantly. The feeding levelshould be increased for low-energy feeds and decreased for high-energyfeeds. Energy needs for maintenance increase with rising water temperaturesand decrease when temperatures are reduced, thus requiring changesin the feeding rates. However, more energy is required to produce weightgains of fish at lower temperatures than at high temperatures.Fish normally use about 70'lo of the dietary energy for maintenance oftheir biological systems and activity, leaving about l.J0"i, available forgrowth. Energy requirements for vital functions must be met before energyis available for growth. A maintenance-type feeding program is designed tosupply the minimum energy and other essential nutrients for the vital functionsand activity, with no allowance for growth. Dietary efficiency or feedconversion are terms used to designate the practical conversion of food tofish flesh. In this concept of estimating gross energy requirements, theamount of food ("rr".gy) required to produce a unit of weight gain is determined.In general, if the conversion of food to fish flesh is two or less, energyrequirements are being met. This is because energy for biologicalmaintenance of fish must be supplied before energy is available for growth.taN[,RGY RI.]qUtRl.tMr.N |S tOR SALMONIDSBrook, brown, rainbow, and lake trout have similar energy requirements.Between 1,700 and l,ll00 available dietary kilocalories are required to producea pound of trout, depending upon the feed being fed and conditionsunder which the fish are reared. The amount of available calories from fishfeeds depends upon the digestibility of nutrients by the fish.

FISH HATCHERY MANAGEMENTNutrientGrosskca I(Per gram)Protein 5.6Fat 9.4Carbohydrate 4.1The values above show that salmonids make more efficient use of energyfrom fats than from proteins, and least efficient use of carbohydrates. Thereis evidence that trout must use some protein for energy. In trout feeds,between 55 and 65(l/ of the total available dietary calories are from the protein.The available calories in 100 grams of a salmon or trout production feedcan be calculated as follows:NutrientProteinFatMoistureAshCarbohydratesXXXXDigestibility(percent)AuailablekcalQer gram)70 3.9u5tt.O40 1.6Total : 295.5 kcal/100 grams or l,il4l kcal/poundAn estimated conversion can be calculated for salmonids by using theenergy requirement to produce a pound of fish and the available calories inthe feed.Percentof feed45"1,tl0'l;10')i)l0'/i,2S',\t,Auailablekca I'to8.0001.6Energltcontent175.5 kcal80.0 kcal0.0 kcal0.0 kcal40.0 kcalkcal to rear a pound of trout (l'700JAvailable kcal per pound of feed (l'341): 1.27 feed conversionENERGY REqUIREMENTS FOR CAT}'ISHAvailable kilocalories required to produce a pound of catfish vary from 8lilto 1,075, depending on the feed and size of fish. Growth and feed conversionsdemonstrate that larger catfish require lower levels of protein andhigher levels of energy than smaller catfish. Nutrient digestibility and energyvalues for catfish are:NutrientGrttsskcalQer gram)Protein 5.6Fat 9.4Carbohydrate 4.1Digestibility(percent)AaailablekcalQer gram)80 4.590 8.570 2.9

N UTRITION. AN D }.EEDING 227The available calories in catfish feeds and estimated feed conversions canbe calculated by the same procedures as for salmonid feeds, with appropriatevalues for catfish beins substituted.Vitamin RequirementsVitamins are not nutrients, but are dietary essentials required in smallquantities by all forms of plant and animal life. They are catalytic tn natureand function as part of an enzyme system.For convenience, vitamins are broadly classified as fat-soluble vitaminsor water-soluble vitamins. The fat-soluble vitamins usually are found associatedwith the lipids of natural foods and include vitamins A, D, E, andK. The water soluble vitamins include vitamin C and those of the B complex:thiami"e (Br), riboflavin (Br), biotitr, folic acid, cyanocobalamin (Brz)and inositol.Vitamins are distributed widely in ingredients used in fish feeds. Some,such as yeast, contain high levels of several vitamins. The level of vitaminssupplied by the ingredients in the feed usually is not adequate to meet thefishes' requirements. These requirements are presented in Table 24. MostTABLL 24. vt'fAMrnw REqutRF]ML,N rs ExPRESSED AS MILLIGRAMS oR lN l lil{NA-I'ION*AL UNI'IS (IU) PER POUND OF DRY IEI,D FOR SAI,MONIDS AND WARMWA'f!]RFISHI'S. {SCIURCI. NA'I'IONAI, RF]SL,ARCTI COUNCIL I973, I1)77,)WARMWAl !,R I'ISHI]SSUPPI,I,]NII.]N'TALcoNIl'l-lll'lVII AMINSAI,MONII)Sl'EEl)F EEI)A (IU)Dr(ru)E (IU]K'I'hiamincRiboflavinPyridoxinePantothenic acidBiotinCholineVitamin Bt2N iacinAscorbic acidFolic acidI nositol90tJla\I ll. (t3(i.39.1,1.5I u.20..15 "I 3(t20.001){;tt+5.,42.3IU2IX)IJ1005'2.:l0.1) li.2ll3.2 52000.0009-0.0017.7 t2.70-.15.,1U0'2,497.15-1.'2',2.7,t.ll1).19.19.1'22.70.0,t2ir00.00915.,113.(t-,1.5..12.:l,15..1dRequired lcvel is not cstablished."Brown trout require ts'ice the level presented

228 F'ISH HATCHERY MANAGL,MEN'Ivitamins can be manufactured synthetically; these are both chemically andbiologically the same as naturally occurring substances. Synthetic vitaminscan be added to feeds with great precision as a mixture (referred to as apremix) to complement the natural vitamins and balance the vitamin contentof the finished feed.Calculations of the vitamin levels to be placed in feeds should providefor an excess, for several reasons: (1) the efficiency with which fish use thevitamins in ingredients is unknown; (2) vitamins in fish feeds are destroyedby heat and moisture primarilyduring manufacturing but also duringstorage; (3) breakdown of other substances in the feed (such as oxidationof oils) may destroy some vitamins; and (4) vitamins react with other compoundsand become inactive.Several vitamins show moderate to severe losses when incorporated intofeeds and stored at different temperatures and relative humidities. Amongthem are vitamins A, D, K, C, E, thiamine, and folic acid. Vitamin C (ascorbicacid) has received considerable attention. Typical losses of vitaminC in feeds are:StorageTemperature Duration LossCatfish feeds (dry)Oregon moist pellet70"F-14"F40 46'F70'F3 months 50'/o3 months None3 days 85%I I hours 8l'/oAssays performed on Oregonand then thawed for 14 hourslows:moist pellet that had been stored 5 monthsshowed reductions of vitamin levels as fol-VitaminCEKFolic acidPantothenic acidChange inconft nlralion hg/kg dict)tt93 to 10503 to 43218.6 to 2.07.1 to 5.3106 to 99Vitamin E is reduced continually from the time the feed is manufactureduntil it is fed, due to oxidative rancidity of oils in the feed; vitamin Eserves as an antioxidant. For these reasons. all feeds should be used within

NU'IRITION AND I'E,EDING 229a 3-month period if at all possible. It is important to store fish feed in acool dry place and to avoid prolonged storage if fish are to be providedwith levels of vitamins originally formulated into the feed. Steps can betaken to help preserve the vitamins in the feed. Some synthetic vitaminscan be protected by a coating of gelatin, fat, or starch. The addition of antioxidantsreduces the oxidation of oils and its destructive effect on vitamins.Maintaining cool, dry storage conditions to eliminate spoilage andmold growth preserves the feed quality and vitamins.Because the metabolic processes and functions of biological systems offish are similar to those of other animals, it is safe to assume that all vitaminsare required by all species. However, the recommended amounts ofthe vitamins for different fishes vary. The required levels of vitamins mustbe added to the ration routinely in order to prevent deficiencies from occurring(Figures 72 and 73). Deficiencies of most known vitamins havebeen described (Appendix F).The total amount of vitamins required by a fish increases as the fishgrows. Conversely, food intake decreases as a percent of body weight as thefish increases in size, which can cause a vitamin deficiency if the feed containsonly the minimum level of vitamins. Therefore, feeds for older fishalso need to be fortified with vitamins.As temperature decreases, so does food intake. However, the vitamin requirementsof fish do not decrease proportionally. A vitamin deficiency canoccur with low intake of diets containing marginal levels of vitamins.Complete catfish feeds are formulated to contain all of the essential vitaminsin amounts required by the fish and are designed to provide normalgrowth for fish that do not have access to natural feeds. Supplemental feedscontain the vitamins supplied by the feed ingredients plus limited supplementation,as the fish are expected to obtain vitamins from natural foodsin the pond.Mineral RequirementsAs nutrients in fish feeds, minerals are difficult to study. Absorption andexcretion of inorganic elements across the gills and skin have an osmoregulatoryas well as a nutritional function. Absorption of inorganic elementsthrough the digestive system also affects osmoregulation.The specific qualitative and quantitative dietary needs will, therefore,depend upon the environment in which the fish is reared and on the typeof ration being fed. Dietary requirements for most minerals have not beenestablished for fish, but fish probably require the same minerals as other

F'ISH HATCHERY MANAGEMEN'fr,. r; "'t)Y-'', 'rl..'j': ':'tii :FrcuRE 73. Gill lamellae from (1) a normal and (2) a pantothenic acid-deficientrainbow trout. Hyperplasia of the epithelium has resulted in fusion of mostlamellae (a..o*) on two filaments of the pantothenic acid-deficient trout. (CourtesyCharlie E. Smith, FWS, Bozeman, Montana.)animals for growth and various metabolic processes. As mentioned, fishalso use mineral salts and ions to maintain osmotic balance between fluidsin their body and the water.Many minerals are essential for life, but not all are needed in the sameamount. Seven major minerals are required in large amounts and constitute60 to 80'X) of all the inorganic materials in the body. The seven are calcium,phosphorus, sulfur, sodium, chlorine, potassium, and magnesium.

NU'I'RITION AND FEEDING 231Trace minerals are just as essential as major minerals, but are neededonly in small amounts. The nine essential trace minerals are iron, copper,iodine, manganese, cobalt, zinc, molybdenum, selenium, and fluorine.Mineral elements, both major and trace, are interrelated and balanceeach other in their nutritional and physiological effects. The minerals thatform the hard and supporting structures of a fish's body (bone and teeth)are principally calcium and phosphorus. Very small amounts of fluorineand magnesium also are essential for the formation of bones and teeth. Fornormal respiration iron, copper, and cobalt are required in the red cell anddeficiencies of any of these trace elements may cause anemia. Sodium,chlorine, and potassium play an important role in regulating bodyprocesses and osmotic pressure. Minerals also are required for reproduction.They are removed from the female system during egg production andmust be replenished by adequate amounts in the feed.Most researchers agree that fish require all of the major and trace elements.Under normal conditions, chloride ions are exchanged very rapidlyfrom both food and water. Calcium and cobalt are absorbed efficientlyfrom the water but are utilized poorly from feeds. The level of calcium inthe water influences the uptake of the calcium from the food. and viceversa.Feeds are a major source of phosphorus and sulfur. Inorganic phosphorusis absorbed efficiently from the stomach and intestine of trout. The skin(including the scales) in trout is a significant storehouse for calcium andphosphorus.Onlyone mineral deficiency is recognized definitely in trout; as inhigher animals, a deficiency of iodine causes goiter. The study of themineral requirements of fish is incomplete, but it is apparent that both dissolvedand dietary minerals are important to the health and vigor of fish.Nonnutritiue FactorsAlthoughnonnutritive factors do not contribute directly to the maintenance,growth, or reproduction of fish, they should be considered in theformulation of rations as they can affect feed efficiency and the quality ofthe final marketable product. Three nonnutritive factors-fiber, pigmentproducingfactors, and antioxidants-warrant discussion concerning fishnutrition.FIBERDue the simple structure of the gastrointestinal tract of fish, the digestibilityof fiber in fish is extremely low, less than 1096. Very little microbial

232 FISH HATCHERY MANAGEMEN'Ibreakdown of fiber has been noted. Herbivorous fish can tolerate higheramounts of fiber than carnivores. It is recommended that crude fiber notexceed l0% in fish feeds and preferably not more than 5 or 6'/n. Some fiberis useful, however, because it supplies bulk and facilitates the passage offood through the fish.PIGMENT-PRODUCING FACTORSoften, producers wish to add color to fish in order to make their productmore attractive to the consumer. This can be achieved through food additives.Paprika fed at 2tlo of the feed will improve the coloration of brooktrout. Xanthophylls from corn gluten meal, dried egg products, and alfalfameal will increase yellow pigmentation of brown trout skin. Shrimp orprawn wastes, which contain carotinoids, produce a reddish colorationwhen fed to trout. Where regulations allow, canthaxanthin can be incorporatedinto trout feeds to impart a red color to the flesh and eggs. Speciesdifferences have been observed, and it is possible to develop color in onespecies of fish, but not another.AN'IIOXIDANTSFish feeds contain high levels of unsaturated oils which are easily oxidized,resulting in breakdown of oils and other nutrients. This can be controlledby the addition of antioxidants such as butylhydroxytoluene (gHf). Uutylhydroxyanisole(BHA), ethoxyquin, and vitamin E. The levels of BHT,BHA, and ethoxyquin allowed in feeds by regulations often are not adequateto control oxidation of the high levels of unsaturated oils in fishfeeds. Therefore, feed formulators should add antioxidants to the levelspermitted by the regulations to protect the oils in fish feeds and supplementwith vitamin E if additional antioxidation is needed. Ethoxyquin andvitamin E are biological antioxidants that function in the fish's physiologicalsystem as well as in feed preservation. The level of vitamin E in fishfeeds must be adequate to prevent oxidation of oils and still meet the nutritionalrequirement of the fish.Materials Afficting Fish QtaliQ and FlaaorFish fed wet feeds containing meat or fish products tend to deposit higherlevels of body fat and have soft textured flesh, whereas those fed dry feedshave a more desirable flavor and firmer flesh. Fresh fish in feeds can impartan off-flavor to the flesh of the fish eating it.

NUTRI'I'ION AND FIEDING 233Other substances such as algal blooms, muskgrass, chemicals, and organiccompounds can produce undesirable flavors in fish. When the water temperatureis high, as it is in late summer, there is a greater chance that off-flavorswill occur in fish flesh.Organic Toxicants in FeedsNumerous naturally occurring and synthetic organic compounds producetoxic responses in fish. Tannic acid, aflatoxin, and cyclopropenoid fatty acidsall induce liver cancer in fish. Gossypol, a toxin present in untreated cottonseedmeal, causes anorexia and ceroid accumulation in the liver. Phyticacid, which ties up zinc in the feed, and growth inhibitors found in soybeanmeal can be destroyed by proper heating during processing. Chlorinatedhydrocarbons occur as contaminants of fish meal and can cause mortalitywhen present in fry feeds. Broodfish transfer these compounds from the feed totheir eggs, resulting in low hatchability and high mortality of swim-up fry.Toxaphene affects the utilization of vitamin C in catfish and can cause the"broken back syndrome." The environment and feed should be free of toxicantsto maintain the health and efficient production of fish. Symptoms ofsome organic toxicants are given in Appendix F.Sources of FeedsNATURAL FOODSAs the name implies, natural foods are obtained from the immediate environment.Small fish feed upon algae and zooplankton. As the carnivorousfish grow, they devour progressively larger animals-insects, worms, mollusks,crustaceans, small fish, tadpoles, and frogs. Many fish remain herbivorousthroughout their lives.Pondfish culturists take advantage of the natural feeds present in stillwaters. The composition of insects, worms, and forage fish used as fish foodis mostly water (75-U0'li,). the remaining components are protein (tZ-tS'lr),fat (3-7%), ash (1-4'X,), and a little carbohydrate (less than 1%). Duringwarm weather when insects hatch and bottom organisms are abundant, apond can provide a considerable amount of feed for fish. This productioncan be increased by pond fertilization. Because the environment tends tobe highly variable in its production of biomass, natural methods of providingfood are inefficient unless the producer is utilizing large bodies of water.Natural food organisms are relied upon to provide nutrients lacking inthe supplemental feeds used in pond culture.

234 FISH HATCHERY MANAGEMFNTFORMULATED FEEDSFormulated feeds are a mixtureof ingredients processed into pellets,granules, or meals and may be either supplemental or complete rations.Supplemental feeds are formulated to contain adequate protein and energy,but may be deficient in vitamins and minerals which the fish are expectedto obtain from natural foods. Such feeds are fed to catfish and otherfish reared at low densities in ponds.Complete feeds are formulated to provide all essential vitamins and nutrientsrequired by fish and are designed to provide optimal growth. If highdensities of fish are being reared, a complete feed must be provided, as naturalfeeds will be limited or absent. Such feeds must be of a physical consistencythat will allow them to be fed in the water without breaking down,but still be easily ingested and digested by the fish. Properly sized feedsare required for different sizes of fish because fish normally do not chewtheir food. The feed must be palatable to the fish so that it will be readilyconsumed and not left to dissipate into the water. Dust and fine particlesthat may occur in the large-sized feeds will create problems because theyare not efficiently consumed and, if present in excess, cause water pollutionand gill disease.Feed ManufacturingFormulated feeds are manufactured in the forms of meals, granules,compressed pellets (sinking), expanded pellets (floating), and semimoistpellets. The use of dry pelleted feeds provides several advantages over otherfeeding programs. Such feeds are available at all times of the year in anyquantity. Fish producers can select the size of feed satisfactory for feedingfish through the rearing cycle. Pelleted feeds give lower feed conversionsand lower feed cost per unit of weight gain than natural or wet feeds andcause less waste and contamination of the rearing water. No hatchery laboris required to prepare the feed. Pelleted feeds purchased in bulk provideadditional efficiency in lower costs of handling and storage. The convenienceof using automatic feeding equipment is also possible with bulkfeeds.Compressed or sinking pellets are made by adding steam to the feed as itgoes into the pellet mill. The steam increases the moisture content by 5 to6%, and raises the temperature to 150-180"F during processing. The mixtureis forced through a die to extrude a compressed, dense pellet. The pelletsare air-dried and cooled immediately after pelleting. The moisture contentof pellets must be sufficiently low (less than l0o,') to prevent moldgrowth during storage.

N T'TRIl-I()N AND FEEDING 235The manufacture of expanded or floating pellets requires higher temperaturesand pressures. Under these conditions, raw starch is quickly gelatinized.Bonds are formed within the gelatinized starch to give a durable,water-stable pellet. The sudden release of pressure following extrusion allowswater vapor to expand and the ensuing entraPment of gas creates abuoyant food particle. The additional cost of producing floating feeds mustbe carefully compared to the advantages of using a floating feed. Manycatfish producers prefer the floating feeds because they can observe the fishfeeding. This aids in pond management and reduces feed wastage due tooverfeeding and loss of pellets that sink into the bottom muds. Recentstudies with catfish have shown that feeding 15([l of the ration as floatingfeed and 85% as sinking feed gives better feed utilization and is moreeconomical than feeding either alone.Although the extrusion of feeds may result in the destruction of certainvitamins, amino acids, and fats, the lost materials can be rePlaced by spraycoatingthe pellets before packaging. Color may also be added at this time.A moist, pelleted fish feed containing 30-35% water can be made withspecial ingredients and equipment. No heat is required in pelleting moistfeeds. Mold inhibitors, hygroscopic chemicals, or refrigeration must be usedto protect moist feeds against spoilage. After extrusion the pellets arequick-frozen and stored at -14'F. If properly handled, the pellets willremain separate without lumping. Moist pelleted feed spoils rapidly whenthawed and a major loss of vitamins will result within a few hours.Moist feeds cost more to manufacture, ship, and store than dry pelletedfeeds because they must be kept frozen. But they are beneficial in feedingfish that do not accept dry formulated feeds. Fingerlings of some speciesprefer the soft moist feeds because they are similar in texture to naturalfeeds. Moist feeds have been used successfully as an intermediate stage inconverting fish from natural food to dry formula feeds.Salmon producers are the major users of moist feeds. The Oregon moistpellet can be obtained at a competitive price from several commercial feedcompanies in the northwest.Open- and Closed-Formulated FeedsThere are open and closed formula feeds. An open-formula feed is one forwhich the complete formula is disclosed. Generally, such feeds have beendeveloped by state or federal agencies or universities. An open-formulafeed has the following advantages.(t) fne producer knows exactly what is in the feed, including the levelof vitamin supplementation.

236 FISH HAI'CHERY MANAGEMENT(2) Because the same formulation and quality of ingredients are used, thefeed will be consistent from one production season to the next.(3) Competitive bidding is possible for the specified feed.(A) fne feed can be monitored through a quality-control program'In using open-formula feeds, however, the buyer assumes full responsibilityfor feed performance because the manufacturer has followed contractedinstructions. This requires the buyer to have concise manufacturing andformula specifications, which must be updated periodically. Formula specificationsfor various diets are presented in Appendix F'A closed-formula feed is one in which the feed formulation is not disclosedto the buyer. These feeds are sold by private manufacturers and arealso referred to as "brand name" or proprietary feeds. The advantages ofthese feeds follow.(1) The manufacturer is responsible for the formulation'(2) The feed is generally a shelf item available at any time.(S) fhe diet may be lower in cost due to large-quantity production andthe option of ingredient substitution.(A) f ne manufacturer is liable for problems of poor production related tothe diet.However, the buyer has no control of the feed quality and the content ofthe feed largely is unknown. There may be unexpected variations betweenbatches of feed due to ingredient substitutions or formulation changes'Handling and Storing ProceduresFormulated fish feeds contain high levels of protein and oil with little fiber'These feeds are soft, fragile, and prone to rapid deterioration, especially ifoptimum handling and storage are not provided.Normally, the feeds are packaged in multiwalled paper bags to protectthe flavor, aroma, and color. The bags also reduce exposure to air, moisture,and contamination. Plastic liners are used in bags for feeds containingoil levels over l2% to eliminate oil seepage through the paper bags and toretard moisture uptake.Many fish producers receive their feed in bulk, storing it in large bulkbins (Figure 74). Whether feed is in bags or bulk, proPer handling andstorage procedures must be followed to protect the quality of the feed. Becausefish feeds are very fragile in comparison to feeds for other animals,up to 3% fines can be expected from normal handling. Excess fines are theresult of rough handling or poor physical characteristics of the feed. Do not

NUTRITION AND FEEDING 2371.",if:3* *FICURE 74. Bulk storage of pelleted fish feeds. Dust and "fines" are screened outand collected (arrow), and can be repelleted. This type of storage is preferred tobins that require augering the feed up into a truck, because augering breaks upthe pellets. (FWS photo.)throw, walk on, or stand on bagged feed. A motorized belt-type bag conveyorcauses the least damage to bagged feed. close-spaced roller gravityconveyers work well, but the wide-spaced rollers or wheel rollers used forboxes are not suitable for bags and cause breakage of the granules and pellets.For handling bulk feed, a bucket elevator is preferred, followed by airlift systems; screw-type augers are least satisfactory.If proper storage conditions are not maintained, fish feed will spoil rapidly.During storage several factors can cause deterioration of the feed:

238 FISH HATCHERY MANAGEMENTphysical conditions (moisture, heat, light) ; oxidation; micro-organisms(molds, bacteria, yeast) ; and enzymatic action.Feed in bags or bulk should be stored in a cool, dry area. Low humiditymust be maintained because moisture enhances mold growth and attractsinsects. Molds, which grow when the moisture is l37o or above, cause feedspoilage and may produce toxins. High temperatures may cause rancidityof oils and deterioration of vitamins. Rancid oils can be toxic, may destroyother nutrients, will cause off-flavor of the feed, and will produce an undesirableflavor in fish eating the feed. The storage area should be keptclean and adequately ventilated. The stored feed should be protected fromrodents, insects, and contamination.Ideal conditions for storing bagged dry feed include stacking the bagsnot over ten high on pallets so the bags are 3 to 4 inches off the floor.Space should be provided between the stacks for air circulation and rodentcontrol. Low relative humidityreduce the rate of deterioration in feeds.The recommended maximumand low temperature in the storage areastorage time for dry pelleted feeds is90-100 days. If less than optimal storage conditions exist, the storage timeshould be shortened.Bulk feed should be stored in clean bins free of contaminants or spoiledfeed. The bins must be in good condition to protect the feed from waterand weather elements. Bins located in shaded areas remain cooler. Bins canbe fitted with a screening unit on the discharge to remove dust and finesfrom the pellets. In many cases the fines can be returned to the feed millfor repelleting or be used to fertilize ponds.Moist pellets should be stored in the freezer at temperatures below 0'Funtil they are to be fed, then thawed just prior to feeding.Feed EaaluationThe performance of feeds often is measured to evaluate or compare them.The measurements used to evaluate feeds at production hatcheries are: (1.)fish growth (weight and length) ; (2) feed conversion; (3) cost to rear apound of fish; (4) protein and calories required to rear a pound of fish; and(5) mortality and dietary deficiency symptoms.FeedingFeeding once was considered a simple task and was usually assigned to theleast experienced fish culturist. The chore consisted of merely feeding all

NUTRITION AND FEEDINGthat the fish would consume, and then giving a little more to assure anabundant supply. Even though given more feed than necessary, the fishoften were underfed because much of the feed was lost as it dispersed inthe water.Nutrition is not solely a matter of feed composition. While it is true thatfish cannot grow if essential elements are lacking in the feed, it is equallytrue that a feed cannot efficiently produce fish unless it can be consumed.The conversion of food into fish flesh is the measure that commonly is usedto judge the efficiency of a feeding program in a hatchery. If the conversionfactor is to be regarded as a measure of efficiency, what can be doneto insure good food conversions?The most common errors in hatcheries are either to overfeed or to underfeed.Overfeeding is wasteful in terms of unconsumed food, butunderfeeding is just as wasteful in terms of lost production. To obtain maximumproduction and feed efficiency during a growing season, careful attentionmust be given, on a daily basis, to the amount of food the fish arereceiving.The quantity of food required is expressed conveniently in terms of percentbody weight per day. Because the metabolic rate per unit weight offish decreases as the fish grow larger, the percent of body weight to be fedper day also decreases.Feeding Guides for SalmonidsThere are several methods for estimating feeding rates. Although differingin complexity, all produce efficient results if properly used.Table 25 may be used to estimate the amount of dry pelleted feed neededfor rainbow trout. For a given fish size, the amount of food increaseswith increasing water temperature; for a given water temperature theamount of feed decreases with increasing fish size.Table 26 was developed by Oregon Fish and Wildlife Department for estimatingthe amount of moist feed to give to coldwater species. A higherpercent of body weight must be fed than in the case of dry pellets becauseof the greater water content in moist feed.Feeding tables provide a guide for determining the amount of feed togive salmonids. In general, these yield good results. However, there are situationsin which the amounts should be increased or reduced. When thewater begins to warm in the spring, the fish indicate an accelerated metabolismby their increased activity and by the vigor with which they feed.At this time of the year, when the photoperiod also is increasing, it is possibleto feed in excess of (up to twice) the amounts in the tables and obtain

240 FlsH HAT('HFRY MANAGLMI.N ITesln 25. RECoMMENDED AMOUNTS oF DRy FEED FoR RATNBOW TRoul pER DAy.'I.EMPERA.I.URESoF DIFFEREN'I.(OR POUNDS FEED PER IOO PoUNDS oF FISH), INI 976. )WATERIEMPERAI'URI,l.F)2,542+NUMBER OF FISH PER POL]NI), q,J.')-30430488.3APPROXIMATE SIZE IN INCHESUNDER I t2 23tlu.337.uI7.ut9.736373u39404l4243444546474849505l5253545556575859606l626364o.)6667682.72.72.93.03.23.33.53.63.84.04,14.34.54.75.25.45.45.65.86.16.36.77.07.37.57.88.18.48.79.09.39.69.92.22.32.12.52.62.82.83.0ll. I3.33.(;3.83.94.34.54.54.95.15.35.55. tii6.06.36.57.07.57.t19.19.4t.7l.u2.02.22.22.22.42.52.52.72.83.03.03.23.53.63.83.94.24.:l4.85.05.15.35.55.75.96.16.36.66.91.31.41.5t.7t.7l.ul.tJ1.92.02.12.22.32.52.72.82.rl2.93.03.23.3:t.53.63.7lJ.94.14.3.1.54.7.{.95.15.3551.01.1| .'2l.iJI .lJ1.41.4L,11.51.6t.7t.7l.tr1.92.(l2.12.12.22.:l2.12.52.62.72.Il3.0ll. I3.23.,1l|.53.63.ti3.94.0

NL]'fRI'I'ION AND FEEDING24IGIVENASPERCENTBODYWEIGHT,FoRDIFFERENTSIZEGROUPSHL,LDINWATE,RRELATION TO FISH SIZE AND WATER TEMPERATURL,. (SOURCL,: LEI'I'RITZ AND I'T]WIS19.7-I 1.61 1.6-7.35NUMBER OT' FISH PER POUND7.35-4.944.94-3.47APPROXIMATE SIZE IN INCHES3.472.53Under2.535-6 6-7 7-8 8-9 9- l0 l0+WATER'T!]MPERA I'T]RE("F)0.80.90.90.91.0l.lt.21.21.31.31.4i.41.51.51.71.7l.tJ1.92.02.02.12.22.32.42.52.62.72.82.93.03.13.20.70.70.lt0.ti0.90.90.91.01.01.11.21.21.31.31.4l.Dl.Jl.J1.61.61.71.81.91.92.02.02.12.12.22.22.32.42.50.60.60.70.70.80.80.80.90.91.01.01.0t.ll.lt.21.3i.31.31.41.4l.Jl.Jl-o1.7t.71.81.81.91.92.02.02.12.10.50.50.60.i;0.70.70.70.80.80.90.90.91.01.0l.i1.1l.ll.l1.31.3l.J1.41.4l-ol-J1.61.611t.71.81.81.92.00.50.50.50.60.60.60.60.70.80.80.80.80.90.9t.01.01.0l.ll.lI.It.21.21.31.3t.41.4l.J1.51.6t.t)1.61.71.80.40.40.50.50.50.50.50.60.60.70.70.70.80.80.90.90.91.01.01.01.0l.l1.2t.21.31.31.41.41.51.51.61.61.7li6373839404l42434445464849505152535+5556575859606l62636465666768

242 FISH HATCHERY MANAGEMENTTenr-E 26. Rr,COMMENDED AMOUNTS oF oREGoN Morsr pELLET FEED FoR sAL.WEIGH.| PER DAY (POUNDS FEED PE,R lOO POUNDS oF FISH), RELATED To FISH SIZLUNPUBLISHED.)NTIMBER OF FISH PLR P0L]NI)WA'I I]RI'EMPERA'I'LIRFiFls rAR r 600 120 305600 120 305 230230 180- 1,10 l 15-180 l'10 I 15 903.2 2.9l|.5 3.23.9 3.5'1.3 3.u4.7 .1. I5.I 4.45.5 4.u(i.0 5.26..1 5.66.9 (;.07.3 6..17.7 6.7u.0 7.0rJ.3 7.38.(i 7.6tt.g 7.99.3 r,t.29.(i u.5{).9 U.u10.'2 9,110.5 9.32.62.83.03.2l:|.53.84.2,1.b5.05..15.ll(t. If'..16.6(i.87.07.37.67. rl8.18.32..)2.52.72.93. Il|. 'll.t. tJ,1. I+.,4.65.25.55. rl(i.06.'2(i.,1.6.76.97.17.37.52.0'2.'2'2.4'2.t)2.83.13.7,t.0141.75.05.25.65.8(t. I6.36.56.76.91.9 L82.t 2.02.3 2.22.5',2.42.7',2.62.9 2.tl:1.2 3.03.5 3.33.8 3.5.1.1 3.84.1 ,1. I1.7 ,t.ll4.9 ,+.55.0 +.75.2 4.85.3 5.05.5 5.25.7 5..15.9 5.66.1 5.8(i.il 5.9l.(il.u2.02.22.62.93.1iJ. 'l3.6:J. tt.1.01.1tl,1..6.1.u5.05.25.,15.5excellent conversions and weight gains by the fish. Taking advantage ofsuch situations increases the efficiency and production of a hatchery. Bythe same reasoning, as the temperature starts to fall, metabolism isdepressed and less food than the amounts listed in the tables still willresult in maximum efficiency of food conversion.As mentioned in Chapter 2, salmonids increase their length at a constantrate during their first lj years or so of life, so long as they are raised at aconstant temperature (see page 61). The rate of length increase (inches perday or month), of course, varies with temperature. For a given temperature,the amount of daily feed needed can be calculated from knowledge of fishgrowth and conversion at that temperature from the following formula:Percent body weight to feed daily - conversionx3xlzxl00

N.UTRII'ION AND FEF,DING'213MONIDS (BASED ON COHO SALMON) FED TWICE EACH DAY, GIVEN AS PERCEN'T BODYAND WAIER TEMPERATURE. (SOLtnCs, ORECUN FISH AND WILDLIFE DEPARIMENTNUMBER OF FISH PER POUND90- 75- 6575 65 55554539 34'f l_2945- 39-29-25.5WATERTEM PERA-I'I] RT("l l1.51.71.92.12.22.52.72.9tJ. I3.33.53.73.u,1. t),1. I,1. iJt1.1.64.u5.05.11.31.5t.71.92.12.32.52.72.83.0il.'23.33.53.63.ttlJ.9,1. I,t.5.\.7t.2I ..11.6l.u2.02.22.:l2.52.72.tl3.03.23.33.5lJ.63.u3.94.14.5l.ll.ilI ..11.6].u2.02.22.52.7'2.93.03.23.,r3.53.73.83.9.1.1,1.i1I.0L',21.31.51.71.92.12.3'2.12.6'2.82.!)3.1:1.23.5:1. (i3.73.94.04.1L0 0.9I .l 1.0t.'2 l. l1.4 1.3l.fi 1.5l.u t.72.0 1.92.1 2.02.3 2.22.5',2.32.7 2.52.U',2.73.0 2.8:l.l 2.93.2 3.I3.4 3.23.5 lt.43.6 3.53.8 3.63.9 3.7,1.0 3.fl0.90.91.0t.2l .11.6l.uL92.1'2.',22.12.62.72. fl3.03.1:1.23.33.lr3.6401,I42434146,1849505l5253545556575u59tt0Here, -\Z equals the daily increase in length in inthes, and Z equals thelength in inches at the present time.To use this equation, an average monthly growth in inches is establishedfrom previous years' records for the same temperature. The daily increasein length is determined by dividing the average monthly growth by thenumber of days in the month. The daily growth then can be used to projectfish size to any date needed. An expected feed conversion is obtainedfrom previous hatchery records or calculated from the caloric content ofthe feed (see page 225).For example, on April 13, we have 210,000 fish on hand. Their feedingrate was last established on April 1, when fish were 20 pounds per 1,000fish, or 3.68 inches. We need to adjust the feeding rate again, knowingfrom past records that at this temperature the average length increase per

244 FISH HATCHERY MANAGEMENTTest E 26. coNTTNUED.WATERTEMPERATURE 25.5- 22.5f F) 22.5 20.0NUMBER OF FISH PER POUND20.0-18.0I 8.0- 16.0- 14.0-16.0 14.0 13.0I 1.013.0- 12.0- ANDl2.O I 1.0 FEWER404l4243444546474849505l52535455)o575859600.8 0.80.9 0.81.0 0.91.1 l.l1.3 1.21.5 |.41.6 1.51.8 |.71.9 1.82.1 2.02.3 2.12.4 2.32.6 2.42.7 2.62.8 2.72.9 2.83.1 2.93.2 3.03.3 3.13.4 3.23.5 3.30.70.80.80.9l.l1.3t.41.61.92.02.22.32.42.52.62.82.93.03.13.20.7 0.60.7 0.70.8 0.70.9 0.81.0 0.91.2 1.11.3 1.21.5 1.31.6 1.51.8 1.61.9 1.82.0 1.92.2 2.02.3 2.12.4 2.22.5 2.32.6 2.42.7 2.52.8 2.62.9 2.73.0 2.80.60.60.70.70.81.0l.lt.21.41.5t.71.81.92.02.12.2z.J2.42.52.62.70.50.60.60.70.70.91.0l.l1.3t.41.5l.o1.71.81.92.02.12.22.32.42.50.5 0.40.5 0.50.6 0.50.6 0.60.7 0.60.8 0.80.9 0.rl1.0 0.9l.l I .01.3 I .lt.4 1.31.5 1.41.6 1.51.7 1.61.8 1.71.9 l.tl2.0 1.92.1 2.02.2 2.12.3 2.22.4 2.3day (AZ) is 0.019 inches per day during April, and expected feed conversionis 1.2 pounds of feed per pound of growth. What is our new feedingrate ?Length, April lstGrowth, 13 days x 0.019Length, April l3th3.68 inches (20 pounds/1,000): 0.253.93 inches (24.3 pounds/1,000)210,000 fish x 24.3 pounds/1,000% to feed daily0.017 x 5,103 pounds3x1.2x0.019x100: l.7olo (o.otz)3.93: 5,103 pounds of fish, April l3th: 87 pounds of feed requireddaily, April l3th, for210,000 fish.

NUTRITION AND FEEDING 245The proper use of this method helps assure optimum feeding levels. Itdetermines the feeding level regardless of the caloric content of the feed,because this is considered in the feed conversion.When the water temperature, diet, and species remain constant, allnumerator factors in the feeding formula remain constant. Multiplication ofthe numerator factors establishes a Hatcherv Constant (HC):HC --3 X conversion x AZ x 100.The percent of body weight to feed daily for any length of fish can be obtainedby dividing the Hatchery Constant by the length of fish (I) ininches.Percent of body weight feed daily : +The Hatchery Constant (ffC) ir used in the following example to calculatefeed requirements. We must calculate the amount of feed required on Aprill0th for 20,000 fish averaging 100 pounds per 1,000 fish or 6.3 inches onApril lst. The expected growth during April is 0.60 inches and the feedconversion is 1.2 pounds of feed per pound of growth.Length increase per day (AZ)Length, April lstGrowth, l0 days x 0.020Length, April lOth20,000 fish x 110 pounds/1,000HC:3x1.2x0.020x100Percent body weight to feed2,200 pounds fish x 0.0110.02 inches6.30 inches (100 pounds/1,000 fish)0.206.50 inches (l l0 pounds/1,000 fish)2,200 pounds of fish April lOth7.2t9 : :+: r.r% (o.or r)L 6.5024.2 pounds of feed required onApril l0th for the 20,000 fish.The above method of calculating feed can be used to project the amountof feed required for a raceway or pond for any period of time. Many stationsuse this method to set up feeding programs for the coming month.

246 FISH HATCHERY MANAGEMENTA simplified method to calculate the amount of daily feed is based onmonthly percent gain in fish weight. In conjunction with past records thatestablish both growth in inches and conversion, Table 27 can be used toproject daily feed requirements on a monthly basis. To calculate theamount of feed required for a one month period two values- must be determined:(l) ttre gain in weight for the month; and (2) the percent gain forthe month.(f ) Gain in weight weight of lot on hand at the end of the\2) Percent gainmonth minus the weight of lot onhand the start of the month.monthlv gain in weight x 100weight at start of monthThe feed requirement during the month of July for 100,000 fish averaging100 pounds per 1,000 fish, or 6.30 inches, on July lst can be calculatedin the following manner. The expected growth for the month of July is0.60 inches and the feed conversion is 1.3 pounds of feed per pound ofqrowth.Length, July lstExpected growth, JulYLength, July 3lst100,000 fish x 100 pounds/1,000100,000 fish x 132 pounds/1,000Expected gain in fish weight, July6.30 inches (tO0 pounds/1,000 fish)0.606.90 inches (132 pounds/1,000 fish)10,000 pounds JulY lst13,200 pounds JulY Slst3,200 poundsThe expected gain in fish weight, multiplied by the food conversiondetermines the required pounds of feed for the month'Pounds of feed required for July: 3,200 pounds gain x 1'3 conversion: 4,160 PoundsPercent gain:3,200 pounds gain :32f010,000 pounds on hand JulY ITable 27 shows that at the 30?6 rate of gain, fish should be fed 2.91% ofthe monthly feed total per day during the first 8 days;3.13% during thesecond 8 days; 3.34% during the third 8 days; and 3'57% per day theremaining days of the month'

NUTRITION AND FEEDING 247'f1^srF. 27. PERCENT oF TorAL MONI'HLY FEED TO GIVE TROUT DAILY FOR DIF-FERENT PERCENT GAINS, IF FEED IS TO BE ADJUSTED FOUR TIMES PER MONl'H.(SOURCE: FREEMAN ET AL lghT lEXPEC] I,DDAYSMONTHLYPERCEN'I'WEIGHTGAINI -ll(tJ DAYS]9 lft{8 DAYS)t7 24(tJ DAYS]25 3l17 D^YS]l0203040503.133.002.912.8s2.753.133. 193. l33.093.083.253.313.343.3t111.403.293..133.57l].6,t3.71ti07080901002.692.632.562.502.453.0,r3.002.962.962.933.363.453.483.493.503.903.904.004.064.14ll01201301401502.402.352.312.262.232.912.882.852.842.U l3.513.533.553.563.594.20+.'29,t.334.394.56160t70IttO1902002. l92.t 52.t I2.082.052.U02.782.752.742.7 |3.5u3.593.603.613.634.504.56,1.6 I4.(i(t4.702to2202302402502.011.991.961.93l.9l2.702.692.6t]2.662.633.633.633.6li3.643.65+.76.1.U04. U4,1.894.932602702U02903001.891.U6l.u4l.u l1.792.632.(; I2.602.5t12.563.653.653.653.tt63.684.965.005.0,15.095.12

248 FISH HATCHERY MANAGEMENTThe amounts to feed would be:July l-8; 2.910i x 4,160: l2l pounds/dayJuly 9-16; 3.130i x 4,160:130 pounds/dayJuJy 17 24; 3.34% x 4,160:139 pounds/dayJuly 25-31; 3.S7lo x 4,160:149 pounds/dayUnder normal conditions, adjusting feeding revels four times during themonth should prevent over- or under-feeding. The advantage of thismethod is its simpliciry.Feeding Guides for Coolwater FishesFor many years, fish culture was classified into two major groups. .,coldwater"hatcheries cultured trout and salmon, and "warmwater" hatcheries culturedany fish not a salmonid. Muskellunge, northern pike, walleye, andyellow perch prefer temperatures warmer than those suited for trout, butcolder than those water temperatures most favorable for bass and catfish.The term "coolwater species" has gained general acceptance in referring tothis intermediate group.Pond culture traditionally has been used to rear coolwater species. Thismethod of extensive culture involves providing sufficient quantities ofmicro-organisms and plankton as natural foods through pond fertilizationprograms. If larger fingerlings are to be reared the fry are transferred, whenthey reach approximately 1.5 inches in length, to growing ponds whereminnows are provided for food. A major problem in extensive pond cultureis that the fish culturist is unable to control the food supply, diseases, orother factors. Many times it is extremely difficult to determine the healthand growth of fish in a pond.In recent years the intensive culture of coolwater fishes in tanks hasbeen successful. Zooplankton, primarily Daphnia, are cultured in ponds andeach day a supply is placed in the rearing tanks. Fish reared in tanks canbe observed readily and treated for parasites. Fish also can be graded tosize to minimize cannibalism and to provide an accurate inventory.Pennsylvania fisheries workers successfully fed a diet of 100% Daphnia tomuskellunge for up to 5 months with no significant mortality, but after thefish attained a length of approximately 2 inches the Daphnia diet did notappear adequate.Fisheries workers in Pennsylvania and Michigan have reared coolwaterfishes successfully on dry feed. The w-7 dry feed formulated by the unitedStates Fish and wildlife Service specifically for coolwater fishes hasgiven the best results. (See Appendix F for diet formulation.) Starter feed

NU]'RITION AND FEEDINGis distributed in the trough.by automatic feeders set to feed at 5-minute intervalsfrom dawn to dusk (Figures 75 and 76)-Coolwater fish will not pick food pellets off the bottom of the tank so itis necessary to continually present small amounts of feed with an automaticfeeder. In some situations, coolwater fry are started on brine shrimp andthen converted to dry feed. Pennsylvania workers rePort that muskellungeare extremely difficult to rear on artificial feeds. However, the tiger muskie(northern pike male x muskellunge females) adapts readily to dry feeds.Northern pike will accept a dry feed and also adapt to culture in tanks.Walleye fry have been observed feeding on the W-7 diet, but did notsurvive well on it. Anemia developed in advanced fingerlings, indicating adeficiency of some nutrient.Tiger muskie fry aggressively feed on dry feeds. Fry often follow a foodparticle through the entire water column before striking it. Hand-feedingor human presence at the trough does not disrupt feeding activity. However,when the fish attain a length of 5-6 inches, human presence next to atrough or tank can disrupt feeding activity completely. cannibalism generallyis a problem only during the first 10-12 days after initial feeding,when the fish are less than 2-3 inches in length. The removal of weak anddying fry greatly reduces cannibalism.The methods developed for estimating feeding rates for salmonids can beadapted for use with coolwater species. Michigan workers use a HatcheryConstant of 40 to calculate feeding rates for tiger muskellunge raised in70"F water.Feeding Guides forWarmwater FishesCATFISHNewly hatched catfish fry live on nutrients from the yolk sac for 3-10 days,depending upon water temperatures, after which they accePt food from avariety of sources. Generally, feed for trough-feeding of fry should be smallin particle size, high in animal protein, and high in fat. Salmonid rationsare well suited for this purpose. Palatability of lower-quality feed isenhanced by having a high percentage of fish meal, fish oil, chopped liver,egg yolk, or other ingredients that serve as attractants.bverfeeding in the troughs should be avoided and adequate water flowsmust be maintained to avoid fouling the water. The fry should betransferred to ponds with high zooplankton densities as soon as possible toefficiently utilize the natural food source'Supplemental feeding of fry in ponds should begin soon after stocking. A

250 FISH HATCHERY MANAGEMENTFIcunt 75. In recent years, intensive culture of coolwater fishes in tanks hasbeen successful. The tanks are covered partially with black plastic to avoid disturbingthe fish. Automatic feeders provide a continuous supply of dry feed fromdawn to dusk at 5-minute intervals. (Courtesy Pennsylvania Fish Commission.)FIGURE 76. Walleye fingerlings are reared successfully in tanks, with automaticfeeders to dispense dry feed. The fish first are started feeding on live brineshrimp or zooplankton and then are converted to dry feed. (Courtesy PennsylvaniaFish Commission.)

NUTRITION AND FEEDINC 251high-quality, 36()/i protein catfish feed (Appendix F) is an adequate supplementalfeed for fry and small fingerlings as they will get a large portion oftheir nutrients from natural pond organisms.Feed first should be pelleted or extruded before it is reduced to smallerparticle sizes. Fat sprayed onto the feed after processing reduces the loss ofwater- soluble vitamins.Growth of channel catfish fingerlings is similar with either sinking orfloating pellets, provided that the nutrient contents are the same. Floatingfeeds are a valuable management tool to help determine the effects of lowdissolved oxygen content and low or high water temperature on feeding,general vigor, and health of fish during the feeding season. It also is helpfulin determining amounts of feed to give fish in special culture systemssuch as cage feeding, raceway feeding, and ponds having abundant rootedvegetation.Table 28 presents a feeding guide for channel catfish in ponds, andTable 29 offers one for catfish in raceways. The pond feed is a supplemental,361iprotein diet; that for raceways is a complete formulation. See AppendixF for ingredients.Low dissolved oxygen levels depress feeding activity of catfish, and fishshould not be fed in early morning for this reason. Neither should they befed late in the day because their increased metabolic oxygen requirementduring active feeding and digestion will coincide with the period of lowdissolved oxygen in the pond during the night and early morning. Thebest times to feed are between mid-morning and mid-afternoon.The optimal temperature for catfish growth is approximately 85"F; astemperature decreases, food consumption decreases proportionally. Generally,catfish do not feed consistently in ponds when the water temPeraturedrops below 60"F; below 50"F they will feed, but at greatly reducedlevels and frequencies. Below (i0'F, the efficiency of digestion and metabolismdrops markedly.During colder months, feed catfish only on warm days and only what thefish will consume readily. A recommended guide for winter feeding of catfishin ponds is to feed the fish 0.75-1'li of their estimated weight dailyonlv when the water temperature is above 54"F, and not to feed at lowertemperatures.There are no reliable data on the best feeds for catfish in the winter.Catfish do not respond as well to high-protein diets in cool weather as inwarm weather. This may indicate that lower-protein feeds (b"lo* 32'li) aremore economical in cold water. Digestibility of carbohydrates is suppressedeven more at low temperatures than the digestibility of proteins and fats,indicating that high-grain feeds are not utilized by catfish in cool weather.Therefore, winter rations should contain less protein and carbohydratesthan those fed durine the summer.

252 FISH HATCHERY MANAGEMENTasI-E 28. TyprcAL spRrNc-suMMER-FALL suppLEMrNlAL FEEDING scHEDuLr roRCHANNEL CATFISH IN PONDS, BASL,D ON STOCKING RA'I'ES OF 2,O(]O 3.OOO FISH PERecRt.o (souLcE: srtcKNEy AND LovELL 1077.)DATEWA'TLRI'I]MPERAl'UREfl')FISHSIZF,(PouNDslPERCI]NT BODYWEICHl'TO FEII)DAII,Y -April l5April 30Mav 15May ijOJune 15June 30July 15July 30August 15August 30September l5September liOOctober l56tl72788083E48585ti68(iu37l)730.040.060.1 l0. 1(;0.210.280.350.120.600.750.ti9I .01l.l02.O2.52.tl3.03.03.02.u2.52.21.81.61.4l.l'Thefeed allowances are based on rations containing 36rlr protein and approximately 2.tltlkcalories of digestible energy per gram of protein. If feeds of lower protein and enersy concentrationsare used, daily allowances should be increased proportionally."Fish are fed 6 days per week.LARGEMOUTH AND SMALLMOUTH BASSAs long ago as 1924, fish culturists attempted to increase yield and survivalof smallmouth bass by providing a supplemental feed of zooplankton.Ground fresh-fish flesh also was successfully used but costs were prohibitive.These early attempts were discouraging but culturists have continuedto rear bass fry to fingerling size on naturally occurring foods in fertilizedTeslr 29. FEEDTNG RATES (PERCENT BoDy wErcHT FED pER DAy) FoR CHANNELCATFISH FED A COMPLETE FEED (25'I, FLOATING, 75']I SINKING FEED) IN RACEWAYS.(souRCE, KRAMER, cHIN AND MAyo 1976.)WA'I'ERSIZE (INCHES)2_5WEIGHl'(POUNDS)TEMPERATURI 0.00 l-0.004 0.004-0.04 0.04Below 55'FAt 55"FAbove 55'Fl9i3orir5'tl,I ii)2',ln3,il'/i,1.59112"ln

NUTRITION AND I'E,EDINGearthen ponds. This method generally results in low yields and isunpredictable.Interest in supplemental feeding of bass has been renewed in recentyears due to successful experimental use of formulated pelleted feeds withlargemouth bass fingerlings. Attempts to train swim-up bass fry to feedexclusively on formulated feeds or ground fish flesh have been unsuccessful,despite the use of a variety of training techniques. The best success insupplemental feeding has been obtained by rearing bass fry on natural feedto an average length of 2 inches in earthen ponds before they are put onan intensive training program to accept formulated feed. A moist feed, suchas the Oregon moist pellet, or a quality dry feed such as the W-7 coolwaterfish feed may be employed. The success of this Program has been correlatedwith initial fingerling size, coupled with sound management practices.The following steps are suggested for an intensive feeding program withbass:By conventional techniques, rear bass fingerlings on natural feed inearthen ponds to.an average total length of 2.0 inches. Harvest and movefish to raceways and tanks. Grade fish carefully to eliminate "cannibals,"because uniformly sized fingerlings are needed. Stock the tanks at 0.15-0.4pounds per cubic foot of water (3,000-7,500 fingerlings per tank).Treat the fish prophylactically with 4 parts per million acriflavine for 4hours. Heavy parasite infestations may require treatment with formalin or asimilar chemical. Provide ample aeration during treatment'Begin feeding a {-inchfeed granule the following day. Feed at l- to 2-hour intervals, five or more times daily. Feed slowly and carefully becausebass will not pick up sunken food particles from the bottom of the tank.Automatic feeders are excellent for this Purpose.If fish are reluctant to feed, supplement the granule with ground fresh orfrozen fish.Clean tanks twice daily and remove all dead fish daily.Begin feeding a $-inch granule as soon as the fingerlings are feedingwell and able to ingest it.Perform grading as needed to reduce cannibalism.After 10-14 days, 65-75% of the fish should be on feed' Reports of90-95,/o success are not unusual. The fish should double their weight duringthis 2-week period.At 2-3 weeks. remove all nonfeeders and move the fish to ponds or raceways.stock ponds at 10,000 per acre. Feed and maintain fish in a restrictedarea for 2-3 days, then release them to the remainder of the pond.Grow the bass to 4 inches on a ]-inch pellet. Table 30 presents a suggestedfeeding guide that can be used when formulated dry feeds are givento bass fingerlings in raceways or ponds.

254 FtsH HAtcHERY MANAGEMENTTABLE 30. BAss FEED cHAR'r': PERCF,NT BoDy wEtcHt FED PER DAY IN RT\CEWAYCUI-'f URE FOR FORMULATI.]DR\' FI]I]DS." IS()L RCE: KRAN'IER. CHIN r\NI) MAYO l1)7lt.lSIZE IINT]HES]ii-,1\\'UlGHl rPOt'Nt)S\\'A1t_RI I]A,lPLRA I'L'I{t. 0.002 0.002 .01r 0.015- 0.03 0.03-0. (xi0.0(i(;5'F70'F7l"Fu0'l'85"F90"Fl'eed ingsper hour.1..1",5.5",(i.0' ,(t.5",7.l'7.5",,.1.1.0'5.0 ,5.1"5. I)',(i.3".1ll.2' ,2.5'1.0",.1.11',,",5.1"'2..+ ',,,'2.'2"11.0",3.113.rl', "3.9",II .(t',2.0' ,2.0' ,2.2'2.+' ,2.7'I"\^ int", feeding rute; Ioi bodr seight per daySI'RIPED BASSStriped bass fingerlings often are fed supplemental diets in earthen pondswhen zooplankton blooms have deteriorated or larger fish are desired. Thefingerlings are fed a high-protein (40-50",,) salmonid type of formulatedfeed at the rate of 5.0 pounds/acre per day. This is increased gradually to amaximum of 20.0 pounds/acre per day by the time of harvest. The fish arefed 2-6 times daily.When striped bass fingerlings reach a length of approximately 1.5 inchesthey will accept salmonid-type feeds readily. Good success can be anticipatedwhen a training program is followed, such as that described forlargemouth and smallmouth bass. Striped bass fingerlings can be grown toadvanced sizes in ponds, cages, or raceways.Attempts to rear swim-up fry to fingerling size on brine shrimp and formulatedfeeds under intensive cultural conditions have been relativelyunsuccessful.Time of Initial FeedingThere is considerable difference of opinion among fish culturists as to whenfry should receive their initial feeding. The most common practice is tooffer food when the fry swim up. Swim-up occurs when the fry have absorbedenough of their yolk sac to enable them to rise from the bottom of

NUTRITION AND FEEDING 255the trough and maintain a position in the water column. A considerableamount of work has been conducted to determine when various salmonidfry first take food. Brown trout begin feeding food approximately 3l daysafter hatching in 52"F water, while food was first found in the stomachs ofrainbow trout fry 21 days after hatching in 50'F water.The upper alimentary tract of rainbow trout fry remains closed by a tissueplug until several days before swim-up. Thus, feeding of rainbow troutfry before swim-up is useless. Some fish culturists have observed highermortality in brook trout fed early than in those deprived of food for up to5 days after swim-up.Yolk absorption is a useful visual guide to determine the initial feedingof most species of fish. Most studies reported in the literature (Table 3l)indicate that early feeding of fry during swim-up does not provide themwith any advantage over fry that are fed later, after the yolk sac has beenabsorbed. Many culturists start feeding when 50% of the fry are swimmingup because if fry are denied food much beyond yolk-sac absorption, somewill refuse to feed. No doubt, starvation from a lack of food will lead to aweakened fry that cannot feed even when food is abundant.It is apparent that the initial feeding time for warmwater fishes is muchmore critical than for coldwater species because metabolic rates are muchhigher at warmer water temperatures. This will lead to more rapid yolk absorptionand a need for fish to be introduced to feed at an earlier date.Feeding FrequencyThe frequency at which fish should be fed is governed by the size of thefish and how rapidly they consume the feed. When fish are started on feed,it is desirable to give small amounts of small-sized particles at frequent intervals.Several factors influence how quickly fish consume feed. The type offeed, the way it is introduced, and the type of trough or pond in which itis fed all will affect the rate of consumption. Feeds that are heavier thanwater must be fed with more care than those that float. Once a sinkingfeed reaches the bottom many fish will ignore it. To avoid their prolongedexposure to water, sinking feeds should be fed slowly and at greater frequency.Trout and salmon generally are fed small amounts at hourly intervalsthroughout an 8-hour day when they first start to feed. Some fish culturistsfeed fry at half-hourly intervals and gradually reduce the number of feedingsas the fish increase in length. The general practice has been to feedtrout three times a day until they are 5 inches long (20/pound). Largertrout are fed twice daily and broodfish are usually fed once each day.

256 FISH HATcHERY MANAGEMENTTABLE 3I.INITIAL FEEDING TIMES FoR vARIoUS SPECIES oF FISHINITIALWATERFEEDINGTEMPERSPECIES(DAYS POST.HATcHINc)ATURE('F)REMARKSBrook troutZJ_JJ52Several fry had food in gut on23rd day; all fry were feedingon the 35th day.Brown trout3l52Evidence of food in stomach on27th dayl all fry feeding on 3lstduyCutthroat trout2347-51Evidence of food in stomach onl4th day; all fry feeding on 23rdduy.Rainbow trout20-30047Evidence of food in stomach on2lst day (16 days at 50'F).Channel catfishat swrm- up5 to l0 days after hatching,depending on water temperature.Tiger muskie968Food presented at swim-up; mostof yolk sac absorbed after 8days.Northern pike,walleye,muskellungeat swim-up50-704Food presented at swim-up, up tol2 days post-hatching.'Variousreports include a range of initial feeding times and water temperatures. It isimportant to note that in some instances, evidence of food in the stomach did not occur untilseveral days after swim- up.Table 32 presents feeding frequencies for trout and Pacific salmon fingerlings.Successful feeding of dry feeds to coolwater fishes, such as northern pikeand tiger muskie, requires initial feeding of fry at s-minute intervals, atl0-minute intervals when fry are 2 inches long, and at l5-minute intervalswhen they are 4 inches long, from automatic feeders during the daylighthours.A rule of thumb used by some fish culturists is to feed l%r of the bodyweight per feeding. Therefore, if the fish are being fed at a rate of l0% of

NUTRITION AND FEEDING 257TABLE 32.SUGGESTED FEEDING FREqUENCIES FOR SALMONIDS. (SOURCE, WASHING-TON DEPARTMENT OF FISHERIES' UNPUBLISHED']SP!]CI ESFISH SIZE (NUMBER/POUND)tjoo lpt, to soo zso- -rN zs to l0 LARCERTIMES PER DAYCoho salmonFall chinooksalmonTrout66bbody weight, they would receive 10 feedings per day; if they receive l% ofbody weight in feed per day it would be fed in one feeding'Channel catfish reared in raceways produce more gain when fed twicedaily than when they are fed only once daily. In some situations' morethan two feedings per day will not improve the feed consumPtion orgrowth rate in Pond fed catfish.The following statements relate to feeding frequency:The feeding frequency does not significantly influence the mortality offry once they pass the initial feeding stage'Frequently fed fingerlings utilize their feed more efficiently than thosefed less frequently, resulting in better feed conversion'Frequent feeding of fingerlings reduces starvation and stunting of thesmall fish in a group. Generally, more frequent feeding results in greateruniformity in fish size.The accumulation of waste feed on the bottom of a rearing unit due tothe infrequent feeding of large amounts of feed is a principal factor causinginefficient utilization of feed.whenuneaten feed lies on the bottom of the tank, water-soluble nutrientsare leached out, resulting in poor utilization of the feed.In general, the number of feedings per day should be greater for dryfeed than for soft moist feeds.A rule of thumb is that 90%, of the feed should be eaten in 15 minutes orless.Feed SizesThe size of feed particles is critical in the feeding of fish. If particles aretoo large, the fish will not be able to ingest them until the water disintegratesthe feed to an acceptable size. When this occurs, nutrients leachout of the pellet, wasting feed and possibly polluting the water. when the

258 FISH HATCHERY MANAGEMEN'I'TABLE 33.RECOMMENDED SIZES FoR DRY FORMULATED FEEDS GIVEN To TROUTCRANULE ORPELLETSIZEAUSSCRE!]NSIZEWEICH'TPERTHOUSANDFISH StZEN UMBERPERPOUNDStarter granuleNo. I granuleNo. 2 granuleNo. 3 granuleNo. 4 granule{" Rell"t.30-4020 30I 6-20l0- l (t610less than 0.50.5 1.251.25-4.04.0-10.010.0-33.333.3- 100.02,000+2,000-800800 250250 100I 00-3030-10f" Rellets100.0+l0 and fewerdFeed sizes-USFish and Wildlife Service Trout Feed Contract Specifications. SpearfishFisheries Center, Spearfish, South Dakota 57783.particles are too small, the feed dissolves in water and is lost. It is importantfor maximumfeed efficiency to provide an acceptable range of feedsizes for fish during their different growth stages.Granules or crumbles are made in a range of sizes for fingerlings of differentweights (Tables 33-35). Hard pellets are cracked into granules andthe different particle sizes are separated by screening.When the fish are being shifted from a small granule to a larger size, thechange should be gradual rather than abrupt. The change may be made eitherby mixing the two sizes together and feeding them at the same time,or by feeding the two sizes separately, starting with a few feedings of thelarger size each day and gradually increasing the frequency until only thelarger particle is fed.TABLE 34. RECOMMENDED SIZES FoR ABERNATHY DRY PELLE,I.ED FEED GIVEN ToPACIFIC SALMON. (SOURCE: L.c. FOWLER. UNpUBLISHED.ICRAN*ULE OR PELLE,T SIZEFISH sIZE {NUMBER PER POUND)Starter granule-L-inch granule800+800-500f-inchgranule500-200L-inch granule1-inch granule'I:-rn.hrrallAt"''" r_ "'12{-inchpelleta-inch pellet200- I 00100 7575 5050-20Less than 20

NUTRITION AND T'EEDING 259TABLE 35. OPTIMUM FEED PARTICLE SIZES FOR SMALL CHANNEL CATFISH. CRUMBLES OR PELLETS SHOULD BE KEPT TO THE MAXIMUM SIZE THAT THE FISH CANINGEST. (souncn, STIcKNEY AND LovELL 1977.)CRL;MBLE OR PELLET SIZI,00 Crumble (starter)No. I crumbleNo. 3 crumble| -inch pelletFISH SIZF] iINCIIES]Swim-up fry0.5 1.5t.5 2.52.5 6Feeding MethodsAutomatic feeders with timing devices can be used to reduce labor costsand to provide fish with small quantities of feed at frequent intervals. Selffeedersor demand feeders are especially useful in feeding large channelcatfish, particularly during winter months when the fish fed less actively.Automatic feeders have become quite popular for feeding salmonids andcoolwater fishes. However, most pond-reared warmwater fishes are fed byhand. Mobile blower-type feeders often are used to feed warmwater fish inlarge ponds (Figure 77). One study determined that more frequent feedingwith automatic feeders did not increase growth of channel catfish over thosehand-fed twice per day. Because catfish have relatively large stomachs, theymay consume enough food for maximum growth in two feedings.Frcunn 77.pond.Bulk-feeding of formulated pelleted feed to catfish in a large rearing

260 FISH HATCHERY MANAGEMENTBibliographyANDERsoN, Ron.rlo J. 1974. Feeding artificial diets to smallmouth bass. Progressive Fish-Culturist 36(3) : 145-151.ANDREWS, J,urrs W., and Jturuv W. P,qcE. 1975. The effects of frequency of feeding on cultureof catfish. Transactions of the American Fisheries Society 104(2):317321.BEyERLE, GEoxct B. 1975. Summary of attempts to raise walleye fry and fingerlings on artificialdiets, with suggestions on needed research and procedures to be used in futuretests. Progressive Fish-Culturist 37(2) :103-105'BoNN, EoweRo W., WIlr-Iev M. BAILEY, J.tcr D. BAYLESS, KIM E. ERIcKSoN, and RoBERTE. SrEvtNs. 1976. Guidelines for striped bass culture. Striped Bass Committee, SouthernDivision, American Fisheries Society, Bethesda, Maryland. 103 p.Bnnlr, J. R. 197i. Growth responses of young sockeye salmon lonrcrhlnrhus nerka) to differentdiets and plans of nutrition. Journal of the Fisheries Research Board of Canada28 ( 10) :1635-l 643.1971. Satiation time, aPPetite, and maximum food intake of sockeye salmon (Ozcorhynchusnerka). Jovnal of the Fisheries Research Board of Canada 28(3):409-415.BUTERBAUGH, G,lrnN L., and HexvEv WILLOUGHBY. 1967. A feeding guide for brook, brownand rainbow trout. Progressive Fish-Culturist 29(4):210-215.CHE5HIRE, W. F., and K. L. STEELE. 1972. Hatchery rearing of walleyes using artificial food.Progressive Fish-Culturist 34(2) :96-99.Dewer, SHrN-rcHIRo, and SutzuNont IDEDA. 1973. Studies of digestive enzymes of rainbowtrout after hatching and the effect of dietary change on the activities of digestive enzymesin the juvenile stage. Bulletin of the Japanese Society of Scientific Fisheries39(7):819-823.DELoNc, DoNer-o C., Jonrv E. Helvrn, and EnwtN T. Mnnrz. 1958. Nutrition of salmonidfishes. VL Protein requirements of chinook salmon at two water temPeratures. Journalof Nutrition 65 (4):589-599.DupREE, Henny K. 1976. Sone practical feeding and management techniques for fish farmers.Pages 77-83 rz Proceedings of the 1976 Fish Farming Conference and Annual Conventionof the Catfish Farmers of Texas, Texas Agricultural and Mining University, CollegeStation, Texas.O. L. GREEN, and Ktnutr E. SNEED. 1970. The growth and survival of fingerlingchannel catfish fed complete and incomplete feeds in ponds and troughs. ProgressiveFish- Culturist 3212) :85-92.ELLIoTT, J. M. 1975. Weight of food and time required to satiate brown trout, Salmo trutta.Freshwater Biology 5:51-64.FowLER, L. G. 1973. Tests of three vitamin supplementation levels in the Abernathy diet. ProgressiveFish-Culturist 35(4) :197-198.and J. L. BANKs. 1976. Animal and vegetable substitutes for fish meal in the Abernathydiet. Progressive Fish-Culturist 38(3):123-126.and J. L. BANKS. 1976. Fish meal and wheat germ meal substitutes in the Abernathydiet, 1974. Progressive Fish-Culturist 38(3):127-130.and Rocln E. Bunnows. 1971. The Abernathy salmon diet. Progressive Fish-Culturist 33{2\:67-75.FREEMAN, R. I., D. C. Hesxnll, D. L. LoNcAcRr, and E. W' SrlLEs. 1967. Calculations ofamounts to feed in trout hatcheries. Progressive Fish-Culturist 29(4):194-209'GRAFF, DELAN9 R. 1968. The successful feeding of a dry diet to esocids. Progressive Fish-Culturist 30(3): 152.and LrRoy SoRENSoN. i970. The successful feeding of a dry diet to esocids. ProgressiveFish-Culturist 32(l) :31-35.

NUTRITION AND FEEDING 261HAl.\'ftR, JouN7l:3 p.E., editor. l1)72. Fish nutrition. Academic Press, New York and London.Hasull'toro, Y. l97rr. Nutritional requirements of warmwater fish. Proceedings of the 1)thInternational Congress of Nutrition, Mexico 3:l5tl 175.HestlNcs, W. H. 1973. Phase feeding for catfish. Progressive Fish-Culturist 35('1):lf)5-11)6.and H,qnnv K. DUPREE. 1969. Formula feeds for channel catfish. Prosressive Fish-Culturist 3l (4):lu7 l1)(i.HII'ron, J.W., C.Y. CJo, and S. J. Slrucln. 1977. Factors affecting the stability of supplementalascorbic acid in practical trout diets. .Journal of the Fisheries Research Board ofCanada 34(5) :(j83-(tU7.HoRAK, DONe,lo. 1975. Nutritional fish diseases and symptoms. Colorado Division ofWildlife, Fishery Information Leaflet no. 2!). 5 p.Hutllou, WallecE F. 19(;3. Oregon pellets. Progressive Fish-Culturist 25(,1):175 1U0.Jor Wellts, THoMAs B. McKet. 1959. Development of the Oregon pellet diets. OregonFish Commission, Research Briefs, Portland, Oregon 7(l):Z>t-5t;.HuRLrY, D. A., and E. L. BRANNoN. 196!). Effects of feeding before and after yolk absorptionon the growth of sockeye salmon. International Pacific Salmon Fisheries Cornmrssron,Progress Report 21, New West Minster, British Columbia. l9 p.INSLEE, THEoPHILUS D. 1977. Starting smallmouth bass fry and fingerlings on prepared diets.Project completion report (l'H +ftZ), Fish Cultural Development Center, San Marcos,'Iexas. 7 p.KRAMER, CHIN and M,+yO, Incorporated.CDB Project Number 102-010-006. Seattle, Washington.1976. Statewide fish hatchery program, Illinois,L,ttrttltntoN, DALE. l!)77. Feeds and feeding. Spearfish In-Service Training School, US Fishand Wildlife Service, Spearfish, South Dakota. (Mt-e".)L[]u D. J., and G. B. PUTNAM. l1)73.'l'he response of rainbow trout to varying protein/energyratios in a test diet. Journal of Nutrition 103(ti) :1)16-1)22.Lrttnttz, Eenr-, and Ronl:nl C. Ltwrs. l!)76. Trout and salmon culture (hatchery methods).California Department of Fish and Game, Fish Bulletin 164. l!)7 p.Locrr:, Devlo O., and S'rlNlr,r P. Lrrvsco'r'r. 1969. A new dry diet for landlocked Atlanticsalmon and lake trout. Progressive Fish-Culturist 3l(l):3 10.LaJVEt-t-, ToM. l!)79. Diet, management, environment affect fish food consumption. CommercialFish Farmer and Aquaculture News 2((i):l|3-35.107!). Fish farming industry becomes a rich source of animal protein. CommercialFish Farmer and Aquaculture News 3(l):'19 50.McCnenEN, Josnlu P., and Rosrnr G. Prprn. Undated. The use of length-weight tables withNeclt-,channel catfish. US Fish and Wildlife Service, San Marcos, Texas. 6 p. (Typed report.)Trtt O. 197,1. Rearing of walleye fingerlings in an intensive culture using Oregonmoist pellets as an artificial diet. Progressive Fish-Culturist 36(l):59-fil.1976. Intensive culture of fingerling walleyes on formulated feeds. Progressive Fish-Culturist 3tl(2):90 :)1.-. 1976. Rearing largemouth bass yearlings on artificial diets. Wildlife In-Service NoteNaTroNelllliS, Ohio Department of Natural Resources, Division of Wildlife, Columbus. 6 p.RESEARCH Cout'lcrr-, Susa:OrrrrurrrEE oN FrsH NuTn|rroN.1973. Nutrient requirementsof trout, salmon and catfish. National Academy of Sciences, Washington, D.C.57 p.SUBCOMMIfIUE oN WARMWATER FISHlrs. 1977. Nutrient requirements of warmwaterfishes. National Academy of Sciences, Washington, D.C. 78 p.NELsoN, Jouw T., RosrRr G. Bowrrn, and JoHN D. RonrNsol. 1974. Rearing pellet-fedlargemouth bass in a raceway. Progressive Fish-Culturist 36(2):108 ll0.ORMI, LEo E. 1970. Trout feed formulation and development. Pages 172-192 rn European InlandFisheries Advisory Commission Report of the 1970 Workshop on Fish Feed Tech-

262 FISH HATCHERY MANAGEMENTnology and Nutrition.U.S. Bureau of Sport Fisheries and Wildlife, Resource Publication102, Washington, D.C.and C. A. LEMM. 1974. Trout eye examination procedure. Progressive Fish-Culturist36 (3) : I 65-l 68.PAGE, JIMMY W., and JeuEs W. ANDREWS. 1973. Interactions of dietary levels of protein andenergy on channel catfish \Ictalurus punetatus). Journal of Nutrition 103:1339-ll|46.PALMER, DAVrD D., HAnLeNn E. JouNsorv, LESLIE A. RoBlNsoN, and RocrnE. BuRRows.1951. The effect of retardation of the initial feeding on the growth and suruival of salmonfingerlings. Progressive Fish-Culturist l3(2):55-62.LESLIE A. RoBINSoN, and RocenE. BuRRows. 1951. Feeding frequency: its role inthe rearing of blueback salmon fingerlings in troughs. Progressive Fish-Culturistl3\4):205-212.PEARSoN, W. E. 1968. The nutrition of fish. Hoffmann-LaRoche, Basel, Switzerland. 38 p.PHrLLIps, ARTHUR M., JR. 1970. Trout feeds and feeding. Manual of Fish Culture, Part 3.b.5,Bureau of Sport Fisheries and Wildlife, Washington, D.C. 49 p.SATIA, BENEDTCT P. 1974. quantitative protein requirements of rainbow trout. ProgressiveFish- Culturist 36 (2) :80-85.SCHMIDT, P. J., and E. G. Be.xrn. 1969. Indirect pigmentation of salmon and trout flesh withcanthaxanthin. Journal of the Fisheries Research Board of Canada 26:357-360.SMtrH, R. R. 1971. A method for measuring digestibility and metabolizable energy of fishfeeds. Progressive Fish-Culturist 33(3):132-134SNow, J. R., and J. I. MAXwELL. 1970. Oregon moist Pellet as a production ration for largemouthbass. Progressive Fish-Culturist 32(2):101-102.SpTNELLI, JoHN, and ConR,ro MAHNKEN. 1976. Effect of diets containing dogfish (Sqzalzsacanthias) meal on the mercury content and growth of pen-reared coho salmon (Ozcorhlnchuskisutch). Journal of the Fisheries Research Board of Canada 33(8):1771-1778.S1tcxnrv, R. R., and R. T. Lovlll. 1977. Nutrition and feeding of channel catfish. SouthernCooperative Series, Bulletin 218, Auburn University, Auburn, Alabama. 67 pTIEMEIER. O. W., C. W. Dlvor,, and S. Wr,tnorN.1965. Effects on growth of fingerling channelcatfish of diets containingKansas Academy of Science 68(l):180-186.two energy and two protein levels. Transactions of theTwoNco, TIMoTHY K., and HucH R. MecCnIvuoN. 1976. Significance of the timing of initialfeeding in hatchery rainbow trout, Salmo gairdneri. Journal of the Fisheries ResearchBoard of Canada 33(9):1914-1921.WrwoEr-r-, JouN T. 1976. Feeding frequency for rainbow trout. Commercial Fish Farmer andAquaculture News, 2(4) : l'1-15.J. D. Hunner.o, and D. L. Honax. 1972. Rate of gastric evacuation in rainbow troutfed three pelleted diets. Progressive Fish-Culturist 34(3) : I 56-159.Jluns F. KttcHr,I-1, DAVID O. NoRRIS, Jeuls S. NoRRIs, and Jlrrnr,v w. Folrz.1976. Temperature and rate of gastric evacuation by rainbow trouI, SaLmo gairdneri.Transactions of the American Fisheries Society 105(6):712-717.Wooo, E. M., W. T. Yesurerl, A. N. WOODALI-, and J. E. HALVDR. 1957. The nutrition ofsalmonoid (fishes: chemical and histological) studies of wild and domestic fish. Journalof Nutrition 6l (4) :465-478.

Fish Health ManagementControl of diseases in hatchery fish can be achieved best by a program ofgood management. This involves maintaining the fish in a good environment,with good nutrition and a minimum of stress. However, attemptsshould be made to eradicate the serious diseases from places where they occur.Containment is accomplished by not transferring diseased fish intoareas where the disease does not already exist.Eradication, when feasibleand beneficial, involves the removal of infected fish populations and chemicaldecontamination of facilities and equipment. In some cases, simplykeeping additional disease agents from contaminated waters can result ineffective eradication.Fish tapeworms can be transmitted to people who eat raw fish but, ingeneral, fish diseases are not human health problems. The reasons fordisease control are to prevent costly losses in hatchery production, toprevent transmission of diseases among hatcheries when eggs, fry, andbroodstock are shipped, and to prevent the spread of disease to wild fishwhen hatchery products are stocked out. Although fish diseases themselvesrarely trouble humans, control measures can create a hazard if fish are contaminatedwith drugs or chemicals when they are sold as food.In local disease outbreaks, it is important that treatments begin as soonas possible. If routine disease problems, such as bacterial septicemia, canbe recognized by the hatchery manager, treatment can begin sooner than if263

264 FISH HATCHERY MANAGEMENTa diagnosis is required from a pathology laboratory. Broad-spectrum treatmentsbased on a poor diagnosis are ill-advised, but treatment based onkeen observation and awareness of signs can mean the difference betweenlosing just a few fish or losing tens of thousands.Disease CharacteristicsD isease - C a u s ing Orga nis msOrganisms that cause diseases in fish include viruses, bacteria, fungi, protozoans,and a wide range of invertebrate animals. Generally, they can becategorized as either pathogens or parasites, although the distinction is notalways clear. For our purposes, we consider subcellular and unicellular organisms(viruses, bacteria) to be pathogens. Protozoans and multicellularorganisms (invertebrate animals) are parasites, and can reside either insidethe host (endoparasites) or outside it (ectoparasites). Low numbers of eitherpathogens or parasites do not always cause disease signs in fish.Viruses are neither plant nor animal. They have been particularly successfulin infecting fish. viruses are submicroscopic disease agents that arecompletely dependent upon living cells for their replication. All knownviruses are considered infective agents and often have highly specific requirementsfor a particular host and for certain tissues within that host.Deficiencies or excesses in the major components of the diet (proteins'amino acids, fats, carbohydrates, and fiber) often are the primary cause ofsecondary bacterial, fungal, and parasitic diseases. Fish with a diet deficientin protein or any of the indispensable amino acids will not be healthy andwill be a prime target for infectious agents. The same is true of deficienciesof fatty acids or excesses of digestible carbohydrates' Secondary diseaseagents may infect a fish in which biochemical functions are impaired. Nutritionaldeficiences are discussed in more detail in Chapter 4.Disease RecognitionDisease can be defined briefly as any deviation of the body from its normalor healthy state causing discomfort, sickness, inconvenience, or death.When parasites become numerous on a fish, they may cause changes inbehavior or produce other obvious signs.Individual diseases do not always produce a single sign or characteristicthat is diagnostic in itself. Nevertheless, by observing the signs exhibitedone usually can narrow down tire cause of the trouble to a particular tyPeof causative agent.Some of the obvious changes in behavior of fish suffering frgm a disease,parasite, or other physical affliction a." (t) loss of appetite; (2) abnormal

FISH HEALTH MANAGEMENT 265distribution in a pond or raceway, such as swimming at the surface, alongthe tank sides, or in slack water, or crowding at the head or tail screens;(3) flashing, scraping on the bottom or projecting objects, darting, whirling,or twisting, and loss of equilibrium; and (4) weakness, loss of vitality, andloss of ability to withstand stresses during handling, grading, seining, loading,or transportation.In addition to changes in behavior, disease may produce physical signsand lesions, or be caused by parasites that can be seen by the unaided eye.Signs observed may be external, internal, or both. For microscopic examination,it may be necessary to call in a fish pathologist.Gross external signs of disease include discolored areas on the body;eroded areas or sores on the body, head, or fins; swelling on the body orgills; popeye; hemorrhages; and cysts containing parasites or tumors.Gross internal signs of disease are color changes of organs or tissue (paleliver or kidney or congested organ.); hemorrhages in organs or tissues;swollen or boil-like lesions; changes in the texture of organs or tissues;accumulated fluid in body cavities; and cysts or tumors.If a serious disease problem is suspected, a pathologist should be contactedfor assistance in isolating and identifying the causative agent. If avirus is suspected, contact a laboratory for analysis of tissues.Two other classes of disease are important to fish culturists, in additionto those caused by pathogenic organisms. One is nutritional in origin, andthe other concerns environmental factors, including bad hatchery practicesand poor water quality, that stress the fish.Stress and lts Relationship to DiseaseStress plays a major role in the susceptibility of fish to disease. The differencebetween health and sickness depends on a delicate balance resultingfrom the interactions of the disease agent, the fish, and the environment(Figrr.e 78). For example, although bacteria such as species of Aeromonas,Pseudomonas, and Flexibacter are present continuously in most hatchery watersupplies, disease seldom occurs unless environmental quality or the defensesystems of the fish have deteriorated.Fish in intensive culture are affected continuously by environmental fluctuationsand management practices such as handling, crowding, hauling,and drug treatment. All of these, together with associated fright, can imposesignificant stress on the limited disease defense mechanisms of mostfishes. Table 36 presents a list of infectious diseases together with thestress factors known to be predisposing conditions. In addition to sophisticatedphysiological measurements, behavioral changes, production traits(growth, weight gain or loss, food conversion), morbidity, and mortality arefactors that can be used to evaluate the severity of stresses.

266 FISH HATCHERY MANAGEMEN'I'ABFtcuRE 78. (A) Frequently, a fish population (l) must interact with a pathogen(2) in an unfavorable environment (3) for an epizootic (l-2-3) to occur. (B)Interaction of more than three factors may be required. In carp hemorrhagic septicemia,a chronic virus infection (1) of the common carp (2), followed by exposureto Aeromonas liquefaciens (3) i" a stressful environment (+), *uy be prerequisitesto an epizootic (t-Z-S-l). (Sorrrce, Snieszko 1973.)Whereas some pathogens of fish are highly virulent and cause disease assoon as they invade a fish, most diseases are stress-related. Prevention ofthese diseases best can be done through good hatchery management. Environmentalstresses and associated disease problems are minimized byhigh water quality standards, optimum rearing densities, and adequate nutrition.Management stresses such as handling, stocking, drug treatments, hauling,or rapid temperature fluctuations of more than 5'F frequently are associatedwith the onset of several physiological diseases. Table 37 gives a partiallisting of these fish cultural practices, their associated disease problems,and stress mitigation procedures if known.Disease TreatmentA complete rearing season seldom passes during which fish do not requiretreatment for one disease or another. Every treatment should be considereda serious undertaking, and caution should be taken to avoid disastrous

FISH HEALTH MANACEMENT 267TABLE 36. TNFECTIOUS DISEASESCOMMONI,Y CONSIDERED TO BE STRESS,MEDIA'I'EDIN PACIFIC SALMON, TROUT, CATFISH, COMMON CARP, AND SHAD. (SOL]RCE:WNDEMEYER AND WOOD I971.)STRESS T'ACI'ORSD ISEASIPRLT)ISPoSING'f O I N I, I]C-I'IONFurunculosisBacterial gill diseaseColumnaris (Flexibacter columnaris)Corynebacterial kidney diseaseAeromonad and Pseudomonadhemorrhagic septicemiasVibriosis (V i brio angui llarum)Costia, Trichodina, HexamitaSpring viremia of carpFin and tail rotInfectious hematopoietic necrosis (IHNJCold water diseaseChannel catfish virus diseaseLow oxygen; crowding; handling in the pres'ence of Aeromonas salmonicida; handling amonth prior to an expected epizootic;elevated water temperatures.Crowding; chronic low oxygen (4 pp-);elevated ammonia (1 ppm NH3-N)t parti'culate matter in water.Crowding or handling during warmwaterLowperiods (59"F) if carrier fish are present inthe water supply; for salmonids, a temperatureincrease to about6tl"F if thepathogen is present, even if fish are notcrowded or handled.total water hardness (less than about199 ppm as CaCO3).Protozoaninfections such as Coslia, or l-richotlina;accumulation of organic materialsin water leading to increased bacterial loadin water; particulate matter in water; handling;low oxygen; chronic sublethal exposureto heavy metals, pesticides, or poylchlorinatedbiphenyls (pCS's); for commoncarp, handling after over-wintering.Handlingl dissolved oxygen lower than (ippm, especially at water temperatures of50-51)"F; brackish water of 10 l5ppt.Overcrowding of fry and fingerlings; lowoxygen; excessive size variation amongfish in ponds.Handlingafter over-wintering at low temperatures.Crowding; improper temperaturesl excessivelevels of metabolities in the water; nutritionalimbalances; chronic sublethal exposureto PCB's.Temperature decrease from 50"F to 4ii-55"!'.Temperature decrease (from 50 59'F to45-50"F) if the pathogen is present; highwater flow duringyolk absorption, e.g.,more than five gallons per minute inHeath incubators.Temperature above (itl"F; handling; low oxygen;co-infection wilh F'lexibatler, Aeromonas,or Pseudomonas; crowding.

FISH HATCHERY MANAGEMENT.fABLEIHI]IR:-I7, PHYsIoI,oGIcAL DISI.]ASES, ENVIRONMENTAL I.ACTCIRS IMPLICATED INOCCLTRRI.]NCI], AND RECOMMENI)!]I) MI'I'IGA'IION PROCF,DURL,S. (SOL]RCE:\vED!tN{tiYl.tR ANt) \\,()()D l1)7 1.1t) I S I.]ASI sl Iil..ss l,\c't ()tts lNlpt.t(A1 uDNlt I IGt l lON PR()C}tDt'RI.tSCoagulatcd I olk (whitespo tl"Haulinem()rtalit) )loss" (delayedBlue sac lhydrrcoelembn onalis)Rou{h handling; malachitegreen containingnrore than 0.013", Zn";gas supersatu|ation olI l0' , or ntore; mineraldeficicncy in incubation water.Ilauling; stocking; roughhandlingL)rorvdingi arccurrulationol nitroqenous metitbolicu,astes duc toinadcquate flow pattern s.L-lse "Zn-frcc" malachitegrccn ({).t)lt" zn"); aerate;add CaCl2 roincrcase total hardnessto 50 ppm (as ClaCOr).Add 0.1 0.3' NaCl duringhauling; add CaC12to raise total hardnessto at least 50 pprn{CaCO1).Maintain NH3,N concentration lower than Ippm during egg incuDALION."L,se of nralachite green is not recomnrcnded.results. All drugs and chemicals used to control infectious organisms canbe toxic to fish if concentrations are too high. All treatment calculationsshould be double-checked before being implemented (Appendix G). In humanor veterinary medicine, patients are treated on an individual basisunder carefully controlled conditions, whereas fish populations are treated"en masse," often comprising hundreds of thousands of individuals.Treatment MethodsThere are two classes of treatments for fish disease, prophylactic and therapeutic.Prophylactic treatments are protective or defensive measuresdesigned to prevent an epizootic from occurring. Such treatments are usedprimarily against ectoparasites and stress-mediated bacterial diseases.Therapeutic treatments are begun only after disease signs appear. Whentherapeutic treatments are needed to control external parasites or bacterialgill disease, it may be a good indication of poor hatchery management.In fish diseases, as in human diseases, treatment with various medicationsand chemotherapeutic agents is for the purpose of keeping theanimals alive, i.e., for "buying time," not for killing l009io of the disease

FISH HEALTH MANAGEMENT 269organisms present. Medications hold disease organisms in check by retardingtheir growth or even killing the pathogen but, in the end, it is thefishes' own protective mechanisms that must overcome the disease if thetreatment is to be successful. To cure a disease, not just treat it' the bodymust be helped to do the job itself. To be successful, every fish culturist,farmer, or hobbyist must keep this basic principle in mind every time atreatment is considered.Before treatment is begun, the following questions should be asked;whether or not to treat depends on the answers.l. what is the prognosis, i.e., is the disease treatable and what is the possibilityof a successful treatment?2. Is it feasible to treat the fish where they are, considering the cost,handling, prognosis, etc.?3. Is it worthwhile to treat or will the cost of treating exceed the valueof the fish?4. Are the fish in good enough condition to withstand the treatment?5. Does the loss rate and severity of the disease present warrant treatment?Before any treatment is started, four factors must be considered. The culturistmust know and understand (t) ttt" water source, (2) the fish, (3) thechemical, u"d (4) the disease. Failure to take all these factors into considerationcan result in a complete kill of all of the treated fish, or a failureto control the disease with a resultant loss of many fish and wasted funds.i) Wate, source. The volume of water of the holding or rearing unit to betreated must be calculated accurately before any treatment is applied. Anoverestimation of the water volume means too much chemical will be used,which probably will kill all the fish. An underestimation of the volumemeans not enough chemical will be used, thus the disease-causing organismmay not be controlled. water-quality factors, such as total hardness, pH,and temperature, will increase the activity of some chemicals and decreasethat of others. In ponds, the amount and type of aquatic plants presentalso must be taken into consideration before any chemical is applied.(Z) fisn. Fish of different kinds and ages react differently to the samedrug or chemical. Certain species are much more sensitive to a particularchemical than others. The age of fish also will affect the way they react toa specific treatment.if a particular chemical or drug has never been used to treat fish at thehatchery, it is always a good idea to test it first on a small number of fishbefore an entire pond or holding unit is treated. This can be done in tanksor in small containers such as large plastic wastebaskets'(3) Chemical. The toxicity of the chemical should be known for the particularspecies to be treated. The effect of water chemistry on the toxicityof the chemical also should be known. Some chemicals break down rapidly

270 FISH HATCHERY MANAGEMENTin the presence of sunlight and high temperatures and thus are less likelyto be effective during summer months than during the cooler months of theyear. Mixingchemicals may enhance or intensify the toxicity of one ofthem. Also, certain chemicals are toxic to plants and can cause an oxygendepletion if used in ponds at the wrong time.(4) Disease. Although disease may be a self-evident factor, it is disregardedwidely, much to the regret of many fish culturists. Most of the chemicalsused to treat fish diseases are expensive and generally are effectiveonly against certain groups of organisms. Use of the wrong chemical ordrug usually means that several days to a week may pass before one realizesthe treatment was not effective. During this time, large numbers of fishmay be lost unnecessarily.When it is apparent that a treatment is necessary, the following rulesmust be adherred to:(A) Pretreatment Rulesl. Clean holding unit.2. Accurately determine the water volume and flow rate.3. Choose the correct chemical and double-check concentration figures.4. Prevent leaks in the holding unit if a prolonged dip treatment isinvolved (see below).5. Have aeration devices ready for use if needed.6. Make sure of the route by which chemical solutions are dischargedfrom the holding unit.(B) Treatment Rulesl. Dilute the chemical with water before applying it.2. Make sure the chemical is well-mixed in the units or ponds.3. Keep a close watch on units during treatment period.4. Observe fish closely and frequently during treatment (aeration ofwater may be required).5. Turn on fresh water immediately if fish become distressed.(C) Post Treatment Rulesl. Recheck fish to determine success of treatment.2. Do not stress treated fish for at least 48 hours.Various methods of treatment and drug application have been used inthe control of fish diseases. There is no one specific method that is betterthan others; rather, the method of treatment should be based on the specificsituation encountered.DIP TREATMENTDuring the dip treatments, small numbers of fish are placed in a net anddipped in a strong solution of chemical for a short time' usually 15-45

FISH HEALTH MANAGEMENT 271seconds, that depends on the type of chemical, its concentration, and thespecies of fish being treated. Metal containers should not be used to holdthe treatment solution because some chemicals can react with the metaland form toxic compounds, particularly if the water is acid.This method of treatment is dangerous because the difference betweenan effective dose and a killingdose often is very small. However, if doneproperly, it is very effective for treating small numbers of fish. Other disadvantagesto this method include its high labor costs and stress on the fishdue to handling.PROLONGED BATHFor prolonged-bath treatments, the inflowing water is cut off and the correctamount of chemical is added directly to the unit being treated (AppendixG). After a specified time, the chemical is flushed out quickly with freshwater. This treatment can be used in any unit that has an adequate supplyof fresh water and can be flushed out within 5 to l0 minutes.Several precautions must be observed with this method to prevent seriouslosses: (1) Because the water flow is turned off, the oxygen concentrationof the water may be reduced to the point that the fish are stressed andlosses occur. The more fish per unit volume of water, the more likely this isto occur. Aerators of some type must be installed in the unit being treatedto insure an adequate oxygen supply or must be available if needed. (2)Regardless of the treatment time that is recommended, the fish alwaysshould be observed throughout the treatment and, at the first sign of distress,fresh water must be added quickly. (3) The chemical must be uniformlydistributed throughout the unit to prevent the occurrence of "hotspots" of the chemical. Fish being treated may be killed or severelyinjured by overdoses if they swim through hot spots. Conversely, fish thatavoid these hot spots may not be exposed to a concentration high enoughto be effective. The method used for distributing the chemical throughoutthe unit will depend on the kind of chemical being used, type and size ofunit being treated, and equipment and labor available. Common sensemust be used as it is impossible to lay down hard and fast guidelines thatwill cover every situation.INDEFINITE BATHIndefinite baths usually are used to treat ponds or hauling tanks. A lowconcentration of a chemical is applied and left to dissipate naturally. Thisgenerally is one of the safest methods of treatment. One major drawback,however, is that the large quantities of chemicals required can be exPensiveto the point of being prohibitive. Another drawback relates to the

FISH HATCHERY MANAGEMENTpossible adverse effects on the pond environment. Some treatment chemicalsare algicidal or herbicidaland may kill enough plants to ultimatelycause an oxygen deficit. Other chemicals, such as formalin, may reducedissolved oxygen levels as they degrade.As in prolonged-bath treatments, it is important that the chemical beevenly distributed throughout the culture unit to prevent the occurrence ofhot spots. Special boats are available for applying chemicals to ponds.However, such chemical boats are fairly expensive and are not needed unlesslarge acreages are involved. For dry chemicals that dissolve rapidly inwater, such as copper sulfate or potassium permanganate, burlap or anycoarse-weave bags can be used. The required amount of chemical is putinto a bag and towed behind the boat so that the chemical dissolves in thewake of the boat. Liquids and wettable powders can be applied evenly withhand or power sprayers or can be siphoned over the edge of a boat into theprop wash.As with the prolonged-bath method, there is no one correct way to applya chemical evenly to the unit of water to be treated. Rather, the applicationwill depend on the kind of chemical being used, the equipment available,and the type of unit to be treated.FLUSH TREATMENTFlush treatments are simple, and consist of adding a solution of the treatmentchemical at the upper end of a holding unit and allowing it to flushthrough. It has been used widely at trout and salmon hatcheries, but is seldomused at warmwater hatcheries. It is applicable only with raceways,tanks, troughs, or incubators for which an adequate flow of water is available,so that the chemical is completely flushed through the unit or systemwithin a predetermined time. Highly toxic chemicals should be avoided becausethere is no way to assure a uniform concentration within the unit beingtreated.CONSTANT-FLOW TREATMENTConstant-flow treatments are useful in raceways, tanks, or troughs in situationswhere it is impractical or impossible to shut off the inflowing waterlong enough to use prolonged baths (Appendix G).The volume of water flowing into the unit must be determined accuratelyand a stock solution of the chemical metered into the inflowing water toobtain the desired concentration. Before the metering device or constantflowsiphon that delivers the chemical is started, enough chemical shouldhave been added to the water in the device to give the desired concentration.Upon completion of the desired treatment period, the inflow of chemicalis stopped and the unit is flushed by allowing the water flow to continue.

FISH HL,ALTH MANAGEMEN'I' 273The method by which the chemical is metered into the inflowing waterwill depend on the equipment available and the type of unit to be treated'Although the constant-flow method is very efficient, it can be expensivebecause of the large volumes of water that must be treated'FEEDING AND INJECTIONTreatment of certain diseases, such as systemic bacterial infections and certaininternal parasite infestations, requires that the drug be introduced intothe fish's body. This usually is accomplished with feeds or injections.In the treatment of some diseases, the drug or medication must be fedor, in some way, introduced into the stomach of the sick fish. This can bedone either by incorporating the medication in the food or by weighing outthe correct amount of drug, putting it in a gelatin capsule, and then insertingit into the fish's stomach with a balling gun. This type of treatment isbased on body weight; standard treatments are given in grams of activedrug per 100 pounds of fish per day' in milligrams of active drug perp";i of body weight, or in milligrams of active drug per kilogram of bodyweight. Medicated food may be purchased commerciallY, o-1 prepared atthe hatchery if only small amounts are needed (Appendix H)' Once feedingofmedicatedfoodisbegun,itshouldbecontinuedfortheprescribedtreatment Period.Large and valuable fish, particularly small numbers of them' sometimescan be treated best with injlctions of medication into the body cavity (intraperitoneal)or into the muscle tissue (intramuscular). Most drugs workmole rapidly when injected intraperitoneally. For both types of injections,but particularly intraperitoneal ones, caution must be exercised to insurethat internal organs are not damaged'The most convenient location for intraperitoneal injections is the base ofone of the pelvic fins. The pelvic fin is partially lifted, and the needleplaced at the fin base and inserted until its tip penetrates the body wall.The needle and syringe should be held on a line parallel to the long axis ofthebodyandatabouta45degreeangledownwardtoavoidinterna]organs (ree Chapter 3, Figure 59). One can tell when the body wall hasbeen pentrated by the sudden decrease of pressure against the needle. As,oon u. the tip of the needle is in the body cavity, the required amount ofmedication should be injected rapidly and the needle withdrawn.intramuscular injections, the best location usually is the area immediatelyahead of the dorsal fin. The syringe and needle should be held on a lineparallelwiththelongaxisofthebodyandatabouta45degreeangledownward. The needle is inserted to a depth of about 1 ,o I inch and themedication slowl\ is injected directly into the muscle tissue of the back'Theinjectionmustbedoneslowly,otherwisebackpressurewillforcethemedicationoutofthemusclethroughthechannelcreatedbytheneedle.For

274 FISH HATcHERY MANAGEMENTGeneralInformationon ChemicalsBecause many drugs and chemicals will be federally registered in the futurefor use at fish hatcheries and historically have successfully controlled fishdiseases, much information is provided in the following section. However,many have not been registered at this time by the United States Food andDrug Administration for use with fishes; reference to unregistered drugsand chemicals in this section and in other chapters of this book should notbe construed as approval or endorsement by the United States Fish andWildlifeService. In all cases where chemicals and drugs are discussed,their registration status is indicated.Chemicals purchased for hatchery use should be of United States Pharmaceutical(USe;ttu6", if possible, and stored in amber containers toprevent deterioration by sunlight. The chemical formula should be on thelabel. Treatment compounds must be stored as directed on the label, andlids or caps always should be tight. If chemicals become abnormal in color,texture, etc., they should be discarded. Poisonous chemicals should be handledonly with proper safety precautions.Antibacterial agents currently used to control bacterial infections in fishinclude sulfonamides, nitrofurans, and antibiotics. The basic principle ofchemotherapy is one of selective toxicity. The drug must destroy or eliminatethe pathogen by either bactericidal or bacteriostatic action withoutside reactions to the host.Treatment of some diseases, such as columnaris, ulcer disease, and furunculosis,requires the feeding of drugs. This is accomplished by mixing thedrug with the fish's food. The amount of drug to be fed is relatively smalland thorough mixing is necessary to insure proper distribution in the feed.Fish should be hungry before medicated feed is administered; therefore, itmay be necessary to eliminate a prior feeding to insure that the treatedfood is taken readily.With the development of dry diets it now is possible to buy medicatedfeed containing the drug of choice. Fish of different sizes require use ofvarying amounts of food and drug, and custom milling may be necessary inorder to deliver the proper dosage.When internal medication is begun, it should be maintained until theprescribed treatment period has been completed. It takes approximately 3days to build up an effective drug level within fish. To maintain the druglevel, the fish should receive only medicated food during the treatmentperiod. Generally, once the medication is started, it is continued for 10-12days or until mortality returns to normal, then extended for at least 3 moredays.Drug combinations sometimes are more efficient than single drugs. Thecombination of sulfamerazine and furazolidone (not registered by the Food

FISH HEALTH MANACEMENl 275and Drug Administration)infections.often is used to advantage in treating bacterialChemicals and Their UsesSALT BATHS AND DIPSFish infected with bacterial gill disease or external parasites often produceexcessive amounts of mucus on their gills and body surface. This is a naturalresponse to irritation. The mucus buildup, however, often protects theparasites or bacteria and successful treatment may be difficult. A salt(NaCl) treatment, by one of several means, often is helpful as it stimulatesmucus flow, rids the fish of the excess mucus, and helps expose theparasites and bacteria to subsequent chemical treatment.Salt baths have some direct effectiveness against a few external protozoanparasites, fish lice, and leeches. As a prolonged bath treatment andfor use in hauling tanks, salt is used at 1,000-2,000 parts per million(3S-ZO grams per l0 gallons;283-566 grams per l0 cubic feet). As a diptreatment for leeches and fish lice, it is used at 30,000 parts per million or30/o (2.5 pounds per l0 gallons, 18.7 pounds per l0 cubic feet). Fish are leftin the solution for up to 30 minutes or until they show signs of stress.FORMALINFormalin (registered by the Food and Drug Administration) is one of themost widely used therapeutic agents in fish culture. It is 37% formaldehydeby weight and should be adjusted to contain l0-15% methanol. Methanolhelps to retard formation of paraformaldehyde, which is much more toxicthan formalin. Formalin should be stored at temperatures above 40'F becauseon long standing, and when exposed to temperatures below 40'F,paraformaldehyde is formed. Acceptable formalin is a clear liquid. A whiteprecipitate at the bottom of the container or a cloudy suspension indicatesthat paraformaldehyde is present and the solution should be discarded.Formalin is considered to be 100% active for the purpose of treating fish.It is effective against most ectoparasites, such as species of Trichodina, Costia,and lchthyophthirits (Ich), and monogenetic trematodes. Although it isof little value in treating external fungal or bacterial infections of hatchedfish, high concentrations (1,600-2,000 parts per million for 15 minutes)have controlledfungal infections on eggs of trout and catfish. Cautionshould be used when eggs are treated at these high concentrations. Formalinis used widely on fish as a bath treatment at 125-250 parts per million(4.4-8.8 milliliters per l0 gallons; 32.8-65.5 milliliters per l0 cubic feet) forI hour. However, at these concentrations, water temperature will affect the

276 FISH HATCHERY MANAGE,MENltoxicity of formalin to fish. Above 70'F, formalin becomes more toxic; theconcentration used for channel catfish should not exceed 167 parts per millionfor I hour (S.g ^ilhliters per l0 gallons;43.8 milliliters per l0 cubicfeet). At such high temperatures, concentrations higher than 167 Parts permillion should be used for bluegills or largemouth bass only with caution.In water temperatures above 50"F, salmonids become more sensitive tohigher concentrations of formalin, and treatment levels should not exceed167 parts per million for I hour. At higher temperatures and lower concentrationsof formalin, it may be necessary to repeat the treatment on two ormore successive days to effectively control ectoparasites without damage tothe fish. Aeration should always be provided during bath treatments toprevent low oxygen conditions from developing. At the first sign of stress,fresh water should be added to flush out the treatment.Formalin also can be used effectively as an indefinite treatment of mostfish species in ponds, tanks, and aquaria at 15-25 parts per million if certainprecautions are used. Do not exceed 10 parts per million as an indefinitetreatment for striped bass fingerlings because the 96-hour LC50 (theconcentration that kills 509il of the fish in 96 hours) is only 12 parts permillion. Formalin removes 1 part per million oxygen for each 5 parts permillion formalin within 30-36 hours, and it should be used with extremecaution, particularly during summer months, to minimize the chance of anoxygen depletion in the unit being treated. Formalin also is a very effectivealgicide so it should not be used in ponds with moderate to heavy phytoplanktonblooms. If it is necessary to use formalin in a pond that has aphytoplankton bloom, drain out one-third to one-half of the water prior totreatment. Within l2 to l6 hours after treating, start adding fresh water tobring the pond level back to normal.Fish treated with excessive concentrations of formalin may suffer delayedmortality. Rainbow trout yearlings, channel catfish fry and fingerlings, andbluegill fingerlings often are vulnerable in this way. onset of deaths canoccur anytime within I to 24 hours after treatment but may not occur until48 to 72 hours later, depending on species of fish, size and condition offish, and water temperatures. clinical signs associated with delayed mortalitiesinclude piping at the water surface, gaping mouths, excess mucus' andpale color. Formalin also is toxic to humans but the strong odor and eye irritationusually warn of its presence. A few people develop allergicresponses to formalin'COPPER SULFATECopper sulfate (registered by the Food and Drug Administration only as analgicide) is one of the oldest and most commonly used chemicals in fishculture and is considered to be 100'/o active. It has been applied widely in

.ISH HEALTH MANAGEMENT 277aquatic environments as an algicide and also has been an effective controlfor a variety of ectoparasites, including such protozoans as Trichodina, Costia,Scyphidia (Ambiphrya), and Ich. Its major drawback is that its toxicityto fish varies with water hardness. It is highly toxic in soft water. Coppersulfate never should be used as an algicide or parasite treatment unless thewater hardness is known, or unless a test has been run to determine its toxicityto fish under the circumstances in which it is to be used. Even whereit has been used with previous success, it should be used carefully; in atleast one situation, dilution of a pond by heavy rainfall reduced waterhardness to the point that previously used concentrations of copper sulfatekilled many catfish.Copper sulfate generally is used as an indefinite pond treatment. As arule of thumb, the concentration to use varies with water hardness as follows:at 0-49 parts per million total hardness (TH), do not use unless abioassay is run first; at 50-99 parts per million TH, use no more than0.5-0.75 part per million (t.ZS Z.0Z pounds per acre-foot) ; at 100-149parts per million TH, use 0.75-1.0 part per million Q.OZ-Z.ZZ pounds peracre-foot) ; at 150-200 parts per million TH, use 1.0-2.0 parts per million(Z.ZZ-5.+ pounds per acre-foot). Above 200 parts per million TH, copperrapidly precipitates as insoluble copper carbonate and loses its effectivenessas an algicide and parasiticide. In hard-water situations, a bioassay shouldbe run to determine the effective concentration needed. It may be necessaryto add acetic acid or citric acid to hard water to keep the copper insolution. The commonly used ratio is I part CuSO4 to 3 parts citric acid.Although copper sulfate has been touted as an effective control for certainexternal bacterial infections, such as bacterial gill disease, fin rot andcolumnaris, and fungal infections, it has proven to be ineffective againstthese diseases on warmwater fish. Other chemicals are much better for controllingthese organisms.Copper sulfate should be used with great caution, if at all, in warmwaterfish ponds during the summer, particularly if an algal bloom is present.Copper sulfate is a very potent algicide, and it quickly can cause oxygendepletion by killing the bloom. Therefore, it should be used in hot weatheronly if adequate aeration devices or fresh water are available.POTASSIUM PERMANGANATE (KMNO4)Potassium permanganate (registered by the Food and Drug Administration)is 100'X, active. It is used widely in warmwater fish culture as a control forexternal protozoan parasites, monogenetic trematodes, and external fungaland bacterial infections. Because it does not deplete oxygen levels, KMnOais a safe treatment in warm temperatures and in the presence of algalblooms.

278 FISH HATCHERY MANAGEMENTRecommendations lbr its use vary from 2 parts per million (5'4 poundsp", u.."-foot) to as much as 8 parts per million (21.6 pounds per acre-foot)as an indefinite pond treatment. At 2 parts per million it is not toxic tocatfish or centrarchids, but it can be very toxic at greater concentrationsunless there is a significant amount of organic matter in the water. Therefore,before a concentration higher than 2 parts Per million is used, it isimperative that a bioassay be run with both fish and water from the unit tobe treated. In most situations, it is best to use 2 parts per million eventhough the treatment may have to be reapplied within 24 hours to be effective.It has been recommended that 3 parts per million be used to treat troutwith excessive gill proliferation associated with chronically poor environmentalconditions. However, as in all cases, it is best to test this concentrationon a few of the trout before it is applied to the entire lot'Potassium permanganate imparts a deep wine-red color to water. Uponbreaking down, the color changes to dirty brown. If a color change occursin less than 12 hours after KMnOa has been applied, it may be necessaryto repeat the treatment.Potassium permanganate also is used widely to help alleviate oxygen deficienciesin warmwater ponds. Although it does not add oxygen to thewater, as has been suggested by some, it does help reduce biological oxygendemand by oxidizing organic matter in the pond'qUATERNARY AMMONIUM COMPOUNDSQuaternaryammonium compounds are not registered by the Food andD-rug Administration. Such chemicals as Roccal, Hyamine 3500, and Hyamine1622 are bactericidal but will not kill ectoParasites. They generallyare used for controllingexternal bacterial pathogens and for disinfectinghatcheryequipment.Likemanychemicalsusedinexternaltreatments'they become more toxic at high temperatures and in soft water. Thequaternary ammonium compounds commonly are used to treat salmonidsfor bacterial gill disease. A standing bath of 2 parts per million (active ingredients)of Hyamine 3500 or Roccal for one hour usually is successful'i{yr,'u.r" 1622 has been used by some culturists who find Hyamine 3500too toxic for salmon fingerlings. Treatments should be conducted for 3 or 4consecutive daYs.Quaternary ammonium compounds may be purchased as liquids of variousstrengthr. e SO.f solution is an excellent consistency to use but, whenexposed to air, it may evaPorate, changing the concentration' Hyamine1622 may be purchased as a 100% active-ingredient powder that goes intosolution easily when added to warm water but tends to form a sticky massifwaterispouredoverit'Arespiratorshouldbewornwhenthiscompoundis used.

FISH HEALTH MANAGEMENl 279Hyamine 3500 is a standardized quaternary ammonium compound containinga high percentage of desirable components and very few undesirableones. It has proven very satisfactory for the treatment of externalbacterial infections of trout and salmon. Hyamine 3500 is a 50% solutionand can be used directly, or first diluted to a 10% solution. In either case,Hyamine 3500 should be used at a final dilution of 2 parts per million(based on active ingredients) for I hour.In the case of Roccal, shipments may vary in toxicity to both the fishand the bacteria. Whenever a new supply is received, it should be testedon a few fish before being used in a production unit.Some quaternary ammonium compounds, such as Roccal, have beenused to treat external bacterial infections in salmonids for many years withvarying degrees of success. Their big drawback has been the variable compositionof different lots; they gave good control sometimes, but killed fishat others.The quaternary ammonium compounds have seen little use in warmwaterfish culture, except for the disinfection of equipment, tanks, and troughs.However, these compounds are excellent bactericides and should be effectiveas tank treatments in controllingcatfish.TERRAMYCIN@external bacterial infections ofTerramycin (oxytetracycline) (registered by the Food and Drug Administration)is a broad-spectrum antibiotic widely used to control both externaland systemic bacterial infections of fish. It is available in many formulations,both liquid and powder.As a prolonged-bath treatment in tanks, it is used at 15 parts per millionactive ingredient (0.57 gram active ingredient per l0 gallons;4.25 gramsactive ingredient per l0 cubic feet) for 24 hours. The treatment may haveto be repeated on 2 to 4 successive days.Externalbacterial infections, such as columnaris and bacterial gilldisease in salmonids, often are treated successfully in troughs and tankswith %- to 1-hour exposures to the Terramycin Soluble Powder in solution.One successful treatment uses 1.75 grams of formulation (as it comes fromthe package) per l0 gallons of water. In tanks and troughs, the techniquerequires lowering the water below the normal volume, adding the Terramycin(dissolved in some water), allowing the water to refill to the desired level,and then turning off the flow. Aeration must be provided. Foaming canbe a problem. After the proper length of time, the normal water flow isturned back on and allowed to flush the unit.Where small numbers of large or valuable fish are involved, Terramycincan be injected intraperitoneally or intramuscularly at 25 milligrams perpound of body weight.

280 FISH HATCHERY MANAGEMENTIf it is desirable to administer Terramycin orally for the treatment of systemicbacterial diseases of catfish, it should be fed at 2.5-3.5 grams activeper 100 pounds of fish per day for 7-10 days. If the fish are being fed approximately3% of their body weight daily, it is necessary to incorporate83.3-116.7 grams of active Terramycin per 100 pounds of food. Under nocircumstances should the treatment time be less than 7 days; l0 days isrecommended.For the treatment of furunculosis and other systemic bacterial diseases ofsalmonids, Terramycin should be fed at the rate of 4 grams active in.gredient per 100 pounds of fish per day for l0 days.Occasionally, it may be necessary to add Terramycin to small amounts offood. This may be done by mixing an appropriate amount of TM-50,TM-50D, or Terramycin Soluble Powder in a gelatin solution (40 gramsgelatin to I quart of warm water) and spraying it over the daily food ration.The water-soluble powder concentrate of rerramycin is the easiestform with which to work. This form may be purchased in 4-ouncepreweighed packages, each of which contains 25.6 grams of antibiotic. Asmuch as two packages of this form may be dissolved in I quart of warmgelatin solution.If fry or small fingerlings must be treated, it is possible to combine Ipound of fresh beef liver (run through a blender), I pound of meal-typefeed, 2 raw eggs, and 2.5 grams of active Terramycin into a dough-likeconsistency. Refrigerate and feed as needed.NITROFURANSNitrofuransare not registered by the Food and Drug Administration.Furazolidone (NF-180, Furox-50) and nitrofururone (Frrracin) are closelyrelated compounds that have been widely used to treat bacterial infectionsin warm- and cold-blooded animals. They are available in several differentformulations, but the most common contain either ll% or 4.5g0/o activeingredient (49.9 grams active ingredient per pound of formulation).Furazolidone effectively treats furunculosis and redmouth disease in salmonids,particularly if these pathogens have developed a resistance to Terramycinor sulfonamides. It is fed at the rate of 2.s-4.5 grams activeingredient per 100 pounds of fish per day for l0 days. However, a slightlydifferent method has been used by some workers who feed at the rate of2.5 grams active ingredient per 100 pounds of fish for 3 days, followed by a20'day course of 1.0 gram active ingredient per 100 pounds of fish. Becausefurazolidone breaks down rapidly in wet (meat or fish) diets, it should befed in a dry pelleted feed or mixed fresh for each feedins if a wet diet mustbe used.

FISH HEALTH MANAGEMENT 281For the treatment of Aeromonas, Pseudomonag and Flexibacter sp- infectionsin catfish, the nitrofurans are fed at the rate of 4-5 grams active ingredientper 100 pounds of fish per day for 7-10 days. If the fish undertreatment are being fed at 3% of their body weight daily, it is necessary toincorporate 133-167 grams active ingredient per 100 pounds of food. Fishnever should be fed either of the nitrofurans for less than 7 days.Nitrofurans have been used as a prolonged-bath treatment for externalbacterial infections and as a prophalaxis during the transport of warmwaterfish. The levels recommended vary from 5 to 30 parts per million active ingredient.However, severe losses of channel catfish sac fry and swim-up fryhave occurred during treatment with 15 and 25 parts per million active nitrofurozone.Five parts per million should be adequate. It is suggested thatnitrofurazone not be used to treat channel catfish sac fry or swim-up fry. Ifit must be used, apply only the lowest concentration, with caution.Furanace (p-Ztgg, nitrofurpirinol) is a relatively new nitrofuran that hasbeen used to control bacterial infections of trout and salmon. It also appearseffective against bacterial infections in catfish, although it has beenused only on a limited basis for that species.Continued treatment of catfish is discouraged because furanace may causeinjury to the skin during prolonged exposures. In trout and salmon culture,furanace is used as a bath at I part per million active ingredient (0.038 gramper l0 gallons; 0.283 gram per 10 cubic feet) for 5-10 minutes, or at 0.1 partper million active ingredient (0.OOg8 gram active per 10 gallons; 0.0283gram active per l0 cubic feet) for an indefinite period. It is also fed at100-200 milligrams of active ingredient per 100 pounds of fish for 3-5 days.Thus, if fish are being fed 3% of their body weight daily, it is necessary tohave 3.3-6.7 grams of active ingredient per 100 pounds of food'SULFONAMIDESSulfonamides have been used since 1946 to treat bacterial infections of salmonids,but have been applied rarely to warmwater fish. They are registeredby the Food and Drug Administration.Presently, sulfamerazine and sulfamethazine are the sulfonamides mostwidely used. Generally, they are fed at a therapeutic level of 5-10 grams ofdrug per 100 pounds of fish per day for l0-21 days. Sulfonamides may betoxic to some fish species when the high dosages (10 gta-. per 100 poundsof fish per day ot mo.e) are fed. However, with the possible exception ofbacterial hemorrhagic septicemia caused by Aeromonas hydrophilia or Pseudomonasfluorescens, high drug levels seldom are required.ACRIFLAVINEAcriflavine is not registered by the Food and Drug Administration. A bacteriostat,it has been used widely for many years in the treatment of

282 FISH HATCHERY MANAGEMENTexternal bacterial infections of fish and as a prophylaxis in hauling tanks,but results are not dependable. It is available either as acriflavine neutralor as a hydrochloride salt and is considered 100% active. Generally, it isused at 3-5 parts per million (O.tt-O.tg gram Per l0 gallons;0.85-1.4grams per 10 cubic feet) in hauling tanks and at 5-10 parts.Per million(O.tS-O.lS gram per l0 gallons; 1.4-2.8 grams per 10 cubic feet) in holdingtanks.Cost prohibits the use of acriflavine in large volumes of water, such asponds.CALCIUM HYDROXIDECalcium hydroxide (slaked lime or hydrated lime) is registered by theFood and Drug Administration. It is used as a disinfectant in ponds thathave been drained. Although calcium oxide (quicklime) probably is better,it is more dangerous to handle and less readily available. Calcium hydroxideis used at the rate of 1,000-2,500 pounds Per acre (O.OZ-0.00 pound orl0-26 grams per square foot) spread over the pond bottom.IODOPHORESIodophores are not registered by the Food and Drug Administration.Betadineand wescodyne, non-selective germicides, are iodophores that successfullydisinfect fish eggs. Iodophores are much more effective for this thanother disinfectants such as acriflavin and merthiolate. Green or eyed eggsusually are disinfected in a net dipped into a large tub or a shallow troughwith no inflowing water. After l0 minutes, the eggs should be removed andpromptly rinsed in fresh water. For a more extensive description of the useof iodophores, see Chapter 3.DI-,T-BUTYL TIN OXIDEDiz-butyl tin oxide (di-z-butyl tin laureate) is not registered by the Foodand Drug Administration. It is effective against adult tapeworms in the lumenof the intestinal tract, and should be equally so against nematodes andspiny-headed worms, when given orally at the rate of l14 milligrams perpound of fish or fed for 5 days at 0.3% of food (0'3 pound per 100 poundsof food).MASOTEN@Masoten (Oyto*) is registered by the Food and Drug Administration, andcan be obtained in a variety of formulations; most common is the 80%wettable powder (w.P.). It is used as an indefinite pond treatment to controlectoparasites such as monogenetic trematodes, anchor parasites, fish

FISH HEALTH MANAGEMENT 283lice, and leeches. The application rate is 0.25 Part Per million active (0.84pound of 80% W.P. per acre-foot). One treatment will suffice for monogenetictrematodes, leeches, and fish lice. For effective control of anchorparasites, Masoten should be applied four times at 5-7-day intervals'Because Masoten breaks down rapidly at high temPeratures and highpH, it may give inconsistent results in summer. If it must be used then, applicationsshould be made early in the morning, and at double strengthwhen water temperatures are above 80"F.E q uipment D ec on tamina tionThe following procedures for the decontamination of hatchery equipment istaken from irout and Salmon Culture by Leitritz and Lewis (tgZO)'Equipment sometimes must be decontaminated. One of the best andcheapest disinfectants is chlorine. A solution of 200 Parts Per million willbe effective in 30-60 minutes; one of 100 parts per million may requireseveral hours for complete sterilization. Chlorine levels are reduced byorganic material such as mud, slime, and plant material; therefore, for fulleffectiveness, it is necessary to thoroughly clean equipment before it isexposed to the solution. A chlorine solution also loses strength when exposedto the air, so it may be necessary to add more chlorine or make up freshsolutions during disinfection.chlorine is toxic to all fish. If troughs, tanks, or ponds are disinfected,the chlorine must be neutralized before it is allowed to drain or to enterwaters containing fish.One gallon of 200 parts per million chlorine solution can be neutralizedby 5.6 grams of sodium thiosulfate. Neutralization can be determined withstarch-iodide chlorine test paper or with orthotolidine solution. A fewdrops of orthotolidineare added to a sample of the solution to be tested. Ifthe sample turns a reddish-brown or yellow color, chlorine is still Present.Absence of color means that the chlorine has been neutralized'Chlorine may be obtained as sodium hypochlorite in either liquid orpowdered (gT'H) form. The latter is the more stable of the two, but it ismore expensive. The amount of chlorine added to water depends on thepercentage of available chlorine in the product used. As an example, HTHpowder may contain either 15,50, or 65% available chlorine. Therefore, thefollowing amounts would be needed to make a 200 parts per million solution:2 ounces of l5% available chlorine HTH powder to 10.5 gallons of water;I ounce of 50% available chlorine HTH powder to 18 gallons of waterlI ounce of 65% available chlorine HTH powder to 23.25 gallons ofwater.

FISH HATCHERY MANAGEMEN'fF aci lity D eco n ta mina tio nIn recent years, as fish production has increased at comparatively highcosts, prevention and control of diseases have assumed major importance.Some diseases are controlled quite easily. For those that presently cannotbe treated, the only successful control is complete elimination of all infectedfish from a hatchery, thorough decontamination of the facility, developmentof a new stock of disease-free fish, and maintenance of disease-freeconditions throughout all future operations. Hatchery decontamination hasbeen successful in removing corynebacteria and IPN virus in many cases.However, this method is practical only at those hatcheries having a controlledwater supply originating in wells or springs that can be kept free offish.ELIMINATION OF FISHDuring decontamination, all dead fish should be destroyed by deep burialand covered with lime. The burial grounds should be so located that leachingcannot recontaminate the hatchery water supply. All stray fish left inpipelines will be destroyed by chlorine, but it is important that their carcassesbe retrieved and destroyed.PRELIMINARY OPERATIONSBefore chemical decontamination of the hatchery is started, several preliminaryoperations are necessary. The capacities of all raceways and troughsare measured accurately. The areas of all floor surfaces in the buildings arecalculated, and allowance is made for 3 inches of solution on all floors.Then, the quantity of sodium hypochlorite needed to fill these volumeswith a 200 parts per million solution is computed. It the chlorine solutionwill enter fish-bearing waters after leaving the hatchery, it will have to beneutralized. Commercial sodium thiosulfate, used at the rate of 5.6 gramsfor each gallon of 200 parts per million chlorine solution, will suffice.All loose equipment should be brought from storage rooms, scrubbedthoroughly with warm water and soap, and left near a raceway for laterdecontamination. Such equipment includes buckets, pans, small troughs,tubs, screens, seines, and extra splash boards. During this operation, anyworn-out equipment should be burned or otherwise destroyed. Hatchingand rearing troughs should be scrubbed clean. The sidewalls of all racewaysshould be scrubbed and the bottom raked. Particular attention shouldbe given to removing any remaining fish food, pond scum, or other organicsubstances.

FISH HEAL'IH MANAGEMENTDECONTAMINA'f IONThe actual administration of chlorine varies among hatcheries, so only generalprocedures will be given here. Decontamination methods should assurethat the full strength (200 parts per million) of the chlorine is maintainedfor at least I hour, and that a concentration of not less than 100 parts permillion is maintained for several hours. Many hatcheries are so large thattotal decontamination cannot be completed in one day. Treatment thenmust be carried out by areas or blocks, and started at the upper end of thehatchery.Before chlorine is added, all ponds, raceways, and troughs are drained.Additional dam boards are set in certain sections to hold the water to thevery top of each section. Rearing troughs are plugged, so they will overflow,and drain outlets from the hatchery blocked. The required quantityof chlorine then is added gradually to the incoming water that feeds thehead trough. The solution flows to the various rearing troughs' which areallowed to fill and overflow until there are 3 inches of the chlorine solutionon the floor. The incoming water then is turned off or bypassed. Thechlorine solution is pumped from the floor and sprayed on the sides andbottoms of all tanks and racks, the walls and ceiling, head trough, and anyother dry equipment for I hour. The same procedure must be used in allrooms of every building, with special attention being given to the foodstorage room. Undergroundpipelines must be filled and flushed severaltimes. If the hatchery must be decontaminated in sections, the work shouldbe so planned and timed so that all buildings, springs, supply lines, andraceways contain maximum chlorine at the same time, so that no contaminatedwater can enter parts of the system already treated. While a maximumconcentration of chlorine is being maintained in the raceway system,all loose equipment such as pails, tubs, trays, splashboards, and other materialmay be immersed in the raceways. Care must be taken that woodenequipment is kept submerged.Throughoutthe course of the project, checks should be made on theapproximate chlorine strength with the orthotolidine test or chlorine testpapers. If any section holds a concentration below 100 parts per millionchlorine after I hour, the solution should be fortified with additionalchlorine. Finally, the solution is left in the hatchery until no chlorine canbe detected in the holding unit. This may take several days.MAINTENANCE OFTHE HA'TCHERYAfter a hatchery has been decontaminated and is pathogen-free, recontaminationmust be prevented. The movement of any live fish into the hatcheryshould be forbidden absolutely and production should be restarted onlywith disinfected eggs. The spread of disease can be prevented only by rigid

FISH HATCHERY MANAGEMENlcleanliness. Allshipped-in equipment should be decontaminated thoroughlybefore it is placed in contact with clean hatchery equipment andwater. The liberal use of warm water and soap is recommended. All trucksand equipment should be decontaminated before they enter the hatchery.The drivers and helpers should not be allowed to assist in loading fish. A"KEEP IT CLEAN" motto should be adopted and hatchery staffimpressed with the idea that one slip-up in cleanliness may nullify all previousefforts.Defense Mechanisms of FishesAs with all living organisms, fish stay healthy only if they prevent excessivegrowth of micro-organisms on their external surfaces and invasion oftheir tissues by pathogenic agents. Invasion is inhibited by tissues that providea physical barrier and by natural or acquired internal defense mechanisms.Physical barriers are important, but give variable degrees of protection.Fish eggs are protected by the structurally tough and chemically resistantchorion. However, during oogenesis the egg may become infected or contaminatedwith viruses and bacteria living in the female. Once hatched, thedelicate fry again are vulnerable to invasion.Fishes are protected from injury and invasion of disease agents by theexternal barriers of mucus, scales, and skin. For example, the skin of salmonprotects against fungi by continuously producing and sloughing offinucus, which allows fungi only temporary residence on the host. Mucusalso may contain nonspecific antimicrobial substances, such as lysozyme,specific antibacterial antibodies, and complement-like factors.Gill tissue contains mucus cells that can serve the same purpose as thosein the skin. However, irritants may cause accumulation of mucus on thegill tissue and lead to asphyxiation. This is an example of a defensemechanism that can work against the host.Internal defenses of the fish can be divided into natural nonspecificdefenses and induced defenses. Induced defenses can be either specific ornonspecific. One of the primary natural defense mechanisms is the inflammatoryresponse of the vascular (blood) system. Defense agents in capillaryblood respond to invasion of pathogenic agents and other irritants. Dilationof capillaries increases the supply of humoral and cellular agents atthe focus of infection. The inflammatory response proceeds to dilute, localize,destroy, remove, or replace the agent that stimulated the response.Fish, like most animals, have an important defense mechanism in the formof fixed and wandering phagocytes in the lymphatic and circulatory systems.Phagocytes are cells capable of ingesting bacteria, foreign particles,and other cells. Fish also have natural, noninduced humoral defenses

FISH HEALTH MANAGEMENT 287against infectious disease that are intrinsic to the species and individual.These defenses account for the innate resistance of various species andraces of fish to certain diseases. For example, IHN virus affects sockeyeand chinook salmon and rainbow trout fry, but coho salmon appear resistantto the disease. Rainbow trout are less susceptible to furunculosis thanbrook trout.Fish have immunological capabilities. Under favorable circumstances fishare able to produce gamma globulins and form circulating antibodies inresponse to antigenic stimuli. They also are capable of immunologicalmemory and proliferation of cells involved in the immune response. Theimmune response of cold-blooded animals, unlike that in warm-bloodedones, depends upon environmental temPerature. Lowering of the watertemperature below a fish's optimum usually reduces or delays the period ofimmune response. Other environmental factors that stress fish also canreduce the immune resPonse.Adaptive responses to disease occur in natural populations of fish. Significantheritabilities for resistance to disease exist, and selection to increasedisease resistance in controlled environments can be useful. Intentionallyor unintentionally, specific disease resistance has been increased atmany hatcheries by the continued use of survivors of epizootics asbroodstock. Increases in resistance to furunculosis in selected populationsof brook and brown trout have developed in this way. Potential exists forgenetic selection and breeding to increase disease tolerance in all propagatedfishes but certain risks must be anticipated in any major breeding program.Under controlled environmental conditions, resistance to a single diseaseagent through a breeding program can be expected. However, simultaneousselection for tolerance of several disease agents can be extremely difficult,except perhaps for closely related forms. In any natural population,individual fish may be found that are resistant to most of the commondiseases. Pathogenicity of disease agents varies from year to year and fromlocation to location, probably as a result of environmental changes as wellas strain differences of the disease agents. When environmental conditionsare favorable for a pathogen, the fish that can tolerate its effect have aselective advantage. However, when conditions favor another pathogen,other individual fish may have the advantage. Natural recombination ofthe breeding population assures that these variations are reestablished ineach new generation of the population. Any propagation program must ensurethat this variability is protected to retain stability of the stocks.Managers always run the risk of decreasing the fitness of their stock inselective breeding programs; changes in gene frequencies resulting fromselection for disease resistance may cause undesirable changes in the frequenciesof other genes that are unrelated to disease resistance'

FISH HA'I'CHERY MANAGEMEN'IImmunilation of FishesIn the past few years there has been rapid development in the technologyof fish vaccination, primarily for salmonids. In the 1977 Proceedings oJ' theInternational symposium on Diseases of cultured salmonids, produced by Tavolek,Inc., T. P. T. Evelyn thoroughly reviewed the status of fish immunization;excerpts of his report are presented in this section.Pressures conspiring to make vaccination an attractive and almost inevitableadjunct approach to fish health were probably most acutely felt in theUnited States where it was becoming increasingly clear that reliance on theuse of antimicrobial drugs in fish culture might have to be reduced. First,the list of antibacterial drugs that could legally be used is extremelysmall...and the prospects for enlarging the list were dim. Second, the effectivenessof the few available antibacterial drugs was rapidly being diminishedbecause of the development of antibiotic resistance among thebacterial fish pathoeens. Third, there was the danger that this antibioticresistance might be transmissible to micro-organisms of public health concern,and because of this there was the very real possibility that drugs nowapproved for use in fish culture would have their approval revoked.Finally, viral infections in fish could not be treated with any of the antibioticsavailable.Faced with the foregoing situation, American fish culturists were forcedto consider other measures that might help to ensure the health of theircharges. one obvious approach was immunization. Advantages of immunizationwere several. First, immunization did not generate antibiotic resistantmicro-organisms; second, it could be applied to control viral as well asbacterial diseases; third, it appeared that fish may be vaccinated economicallyand conveniently while still very small; and fourth, protection conferredby vaccination was more durable than that resulting from chemotherapy,and could be expected to persist for considerable periods followingvaccination. Finally, with killed vaccines, at least, the requirements forlicensing the vaccines were less stringent than those required for the registrationof antimicrobial drugs.Unfortunately, the biggest single factor working against the widespreaduse of fish vaccination was the lack of a safe, economical and convenienttechnique for vaccinating large numbers of fish. Recent advances in salmonid immunization are very promising.Vaccination MethodsAttempts at oral vaccination have been unsuccessful, and alternative procedureshave been devised: mass inoculation; infiltration; and spray vaccination.

FISH HEALTH MANAGEMENTThe mass inoculation method works well with fish in the 5-25 gramrange, and individual operators are able to vaccinate 500-1,000 fish perhour. Cost of the technique seems reasonable but the number of fish thatcan be treated is limited by the manpower available for short-term employmentand by the size of the inoculating tables.The infiltration method (hyperosmotic immersion) allows vaccination ofup to 9,000 fish (1,000 to the pound) quickly and safely in approximately 4minutes. The method utilizes a specially prepared buffered hyperosmoticsolution. Through osmosis, fluid is drawn from the fish body during its immersionin the buffered prevaccination solution. The fish are then placedinto a commercially prepared vaccine that replenishes the body fluids andsimultaneously diffuses the vaccine or bacterin into the fish.Fish are spray uaccinated by removing them briefly from the water andspraying them with a vaccine from a sand-blasting spray gun. Antigenicityof the preparations is markedly enhanced by the addition of bentonite, anabsorbent. Spray vaccination against vibriosis protected coho salmon for atleast 125 days. Most importantly, the method appears, like the injectionmethod, to be a srr..essfrrl delivery system for all four bacterins tested (twoVibrio species, Aeromonas salmonicida, and a kidney disease bacterium)'In 1976, two bacterins were licensed for sale and distribution by theUnited States Department of Agriculture. These products are enteric redmouthand Vibrio anguillarum bacterins.Fish Disease Policies and Regulationscurrent disease-control programs are administered by the colorado Riverwildtife council, the Great Lakes Fishery commission, the United statesFish and Wildlife Service, numerous states, and several foreign countries.Most of the state and national programs include important regulations torestrict certain diseases. Very few programs have regulations requiring destructionof diseased fish and only California has provisions for indemnificationof losses sustained in eradication efforts.The last 20 years have seen a gradual change in disease control emphasisfrom treatment to prevention. International, federal, and state legislationhave been passed to minimize the spread of certain contagious diseases offish. The use of legal and voluntary restrictions on the transportation ofdiseased plants and animals, including fish, is not new. In the UnitedStates, the Department of Agriculture has an extensive organization for thereporting and eradication of certain plant and animal diseases. Unfortunately,this program does not cover fish. Both compulsory and voluntaryregulations have been used to fight diseases in other animals. Some diseaseeradication methods are severe, such as the prompt destruction of entire

290 FISH HATCHERY MANAGEMENTherds of cattle in the United States and Great Britain if hoof-and-mouthdisease is discovered in any individual. Pullorum disease of poultry also isdealt with severely, but on a more voluntary basis. Growers have theirflocks checked periodically and destroy populations if any individuals havethe disease. The success of the regulations is shown by the rare occurrencesof these diseases in areas where they are enforced.In 1967, Code of Federal Regulations, Title 50, Chapter 1, Part 13, Importationof Wildlife or Eggs Thereof, was amended. To Section 13.7 wasadded the stipulation that the importation to the United States of salmonidsand their eggs can be done only under appropriate certificationthat they are free of whirling disease and viral hemorrhagic septicemia unlessthey were processed by certain methods or captured commercially inthe open sea. In 1976, Canada passed federal Fish Health Protection Regulations(pC tgZO-2439, l8 November 1976) that reflect concern over thedissemination of infectious fish diseases via international and interprovincialmovement of cultured salmonids. The Canadian regulations deal withall species and hybrids of fish in the family Salmonidae. Both live and deadshipments of fish are covered and a dozen different fish pathogens ordisease conditions are prohibited.Many states have passed restrictive regulations or policies that limit theintroduction of infected or contaminated fish. In 1973, the western states ofthe Colorado River Wildlife Council adopted a Fish Disease Policy thatprohibits the importation into the Colorado River drainage system of fishinfected with one or more of eight disease pathogens. The policy describesstrict inspection and certification procedures that must be passed beforelive fish or eggs may be transported to hatcheries or waters in the drainageof the Colorado River. To support the policy, each of the seven states andthe Fish and Wildlifeintent of the Council.Service passed rules and regulations that support theFish disease control in the Great Lakes Basin is the responsibility of thenatural resource agencies responsible for managing the fisheries resources.The Fish Disease Control Committee of the Great Lakes Fishery Commissionhas developed a program to unify and coordinate the disease-controlefforts of the member agencies. The policy sets forth essential requirementsfor the prevention and control of serious fish diseases, includes a system forinspecting and certifying fish hatcheries, and describes the technical proceduresto be used for inspection and diagnosis. Eight fish diseases arecovered by the program.A fish disease control program should emphasize all aspects of goodhealth, including infectious diseases, nutrition, physiology, and environment.The program should not be an end in itself, but a means of providinga quality product for fishery resource uses. The first step of any programmust be the establishment of long-range goals. These goals may be

FISH HEALTH MANAGEMENT 291broad in concept or may dictate pathogen eradication. The latter is muchmore difficult to achieve, as it is possible to have disease control withoutpathogen eradication. Inspection, quarantine, and subsequent eradicationare proven measures in livestock and poultry husbandry.After the goals of disease control have been established, it is necessary todesign a policy that is compatible with other fishery resource priorities'The backbone of the policy should be a monitoring Program that willdetermine the range of serious fish pathogens and detect new outbreaks ofdisease. Control and containment of fish diseases require the periodic examinationof hatchery populations as well as fish that are free-ranging innatural waters. Good health of hatchery fish extends beyond their culturalconfinement to natural populations which they contact after being stocked.A monitoring program should include:(t) rislhealth laboratories capable of following standardized proceduresused to analyze fish specimens. These may include tests for disease agents,nutritional deficiencies, histology, tissue residues' etc.(2) A co.ps of competent, qualified individuals trained in inspection andlaboratory procedures.(3) A trainlng program in fish health for all persons involved in fish husbandry.(4) Ag.e"-ents between various government agencies and private grouPsto establish lines of communication as well as the storage and cataloging ofdata derived from the monitoring program.(5) Specific guidelines for laboratory procedures to be followed and forqualifications of persons doing the inspections and testing.(O) fne development of specific steps for disease reporting and of a certificationsystem.of action to control or eradicate a reportable disease when it..jtJ.f.".*sWith this in mind, the Fish and Wildlife Service established a policy forfish disease control and developed a plan to implement it. Basically, theplan is designed to classify, suppress, and eradicate certain serious diseasesof salmonids present at facilities within the National Fish Hatchery System.As far as nonsalmonids are concerned, sampling for serious diseases is leftto the discretion of Service biologists. Within the limits of existing technicalcapabilities and knowledge, the plan provides for determining specificpathogen ranges within the National Fish Hatchery System, restrictingdissemination of fish pathogens, and eradicating certain disease agents fromfederal fish hatcheries. The policy also provides a stimulus for research andtraining which should result in significant advances in technical knowledgeconcerning epizootiology, prevention, control, and diagnosis of various fish

FISH HAI'CHERY MANAGEMENTdiseases. The Fish and Wildlife Service Disease Control Proeram serves asa model for other governmental agencies.During an on-site disease inspection at a hatchery, the fish health inspectorwill collect random samples of fish tissue to be sent to a laboratoryfor analysis. The tests to be conducted will vary according to the type ofcertification requested and should follow the standardized procedures ofthe Fish Health Section of the American Fisheries Society (Procedures for theDetcrtion and Identification 0f Fish Pathogens).The inspector takes tissues from a specified number of fish from eachpopulation at the hatchery. In most cases, each fish sampled must bekilled. The minimum sample size from each population will follow a statisticalplan that provides a 95% confidence for detecting a disease agent withan incidence of infection at or greater than 2 or 50/o (Table 38).The sample sizes represent the minimum acceptable number. In situationswhere the presence of a disease agent is suspected strongly, largersamples may be necessary and taken at the discretion of the inspector. Themethod of collecting subsamples from rearing units to obtain a representativesample also is left to the inspector.For all fish except those being inspected for whirling disease, the samplepopulation is determined on the basis of hatchery variables such as species,age, and water source. Generally, two egg shipments of fall-spawning rainbowtrout from the same hatchery received in September and Decemberare considered as a single population; similarly, all spring-spawning rainbowtrout from the same source would be another population. However,TABLE 38. THE MINIMUM sAMpLE stzEs FoR FISH-DISEASE rNSpEcrIoNS. AccoRD-ING TO THE NUMBER OF FISH IN 'THE POPULAI'ION THAT WILL ALLOW A DISEASETO BE DETEC'I'ED IF IT OCCURS IN 2". OR 5'., OF THE POPULATION.SIZE OF SAMPLEPOPI]LA'I'ION SIZI 2 .. INCIDENCE ' ., INCII)ENCE50100250500l,000I,5002,0004,00010,000100,000 and larger4u77tt2l2ul3rlt42143t461471483444525557575u58585u

]ISH HEALTH IVIANAGEMENT 293when fish are held in different water supplies, each group has to be sampledas a separate population. All broodstock of the same species held in asingle water supply can be considered one population.For a whirlingdisease inspection, each species of salmonid on thehatchery between 4 and 8 months old in a single water supply is a separatepopulation. Example: A hatchery containing three species of trout between4 and 8 months old with a single water supply has three sample popula_tions.Wild salmonid broodstocks must be inspected at least once during theperiod that eggs are being obtained for a National Fish Hatchery.All fish on hand at the time of inspection constitute the population andare sampled accordingly. Samples are collected from each tank or rearingunit. Suspect fish (moribund specimens) are collected along with healthyindividuals. Fish should be alive when collected. Necropsy procedures assumethat the same fish may provide tissues for the various laboratory tests(bacterial, viral, parasitic). A modified procedure may be required for verysmall fish. Material to be examined for external parasites must be takenbefore any antiseptic or disinfectant procedures are applied. After the bodyhas been opened aseptically, tissues for bacterial cultures and virus testsare collected. Finally, cartilaginous organs (heads and gill arches) are takenfor whirling disease examination. The samples are stored in sealed plasticbags and placed on wet ice for transfer to the laboratory.Protocol in the receiving laboratory must maintain the identity of allsamples and preclude the dissemination of possible disease agents to othersamples concurrently under examination. In addition, procedures mustprevent contamination of the samples once the testing begins.At least 2 weeks are required for the laboratory analyses to be completed.However, additional time may be required if any complicationsarise that cause some tests to be repeated or extended. Upon completion ofthe tests, a certifying official will issue a report specifying the samplestaken, the laboratory tests conducted, and the findings. The exact type ofreport can vary according to the governmental agency involved and the circumstancesof the inspection. Based on results of the inspection, a certificateof fish health -uy (o. may not) be issued to the agency requesting theinspection. A copy must be given to the hatchery owner or manager.A fish-disease inspection often is trying to a hatchery manager. However,one must remember that the aim of issuing fish disease certificates is to improvesuccess in combating diseases on a national scale. The spread of contagiousdiseases has occurred mainly through the uncontrolled transfer oflive fish and eggs. In this connection, a clean bill of health helps not onlyto protect a hatchery owner from serious diseases that might be introducedby new shipments of fish or eggs, but also to assure that hatchery customersreceive a quality product.

FISH HATCHERY MANAGEMENTDiseases of FishViral DiseasesINFECTIOUS PANCREATIC 11BgPO$IS (IPN)Infectious pancreatic necrosis is a viral disease of salmonids foundthroughout the world. The disease is common in North America and hasbeen spread to other countries, probably via contaminated egg and fishshlpments. It has been reported in all species of trout and salmon' As arule, susceptibility decreases with age' High losses occur in young finger-IingsbutfewdeathsorsignsapPearinfishlongerthan6inches.Someevid"i.",.tgg"sts that well-ied, rapidly growing fish are more vulnerable tothe disease than those less well-nourished'In an IPN epizootic, the first sign usually seen is a sudden increase inmortality. The largest and best appearing fingerlings typically are affectedfirst. Spiraling along the long body axis is a common behavior of fish inlots having high death rates. The spiraling may vary from slow and feebleto rapid and frantic. Convulsive behavior may alternate with periods ofqrri"r."r,." during which victims may lie on the bottom and respire weakly'Death usually occurs shortly after the spiraling behavior develops'Signs include overall darkening of the body, protruding eyes' abdominal,*"liirg, and (at times) hemorrhages in ventral areas including the bases offins'Multiplepetechiaeoccurinthepyloriccaecalarea,andthe,Iiverandspleenarepaleincolor.Thedigestivetractalmostalwaysisvoidoffoodand has a whitish appearance. clear to milky mucoid material occurs in thestomach and anterior intestine and provides a key sign in the presumptiveidentification of IPN disease. Spiraling behavior, a mucus plug in the intestine,andalackofactivefeedingstronglysuggestlPNdisease'However'adefinitive diagnosis requires isolation and identification of the causal agent'This requires isolation of the virus in tissue culture combined with a serumneutralization test with specific immune serum. A positive diagnosis usuallycan be obtained within 24 to 4tl hours in cases where large die-offs occur.lnlectious pancreatic necrosis cannot be treated effectively and avoidancepresents the only effective control measure. This consists of hatching and propagatinglPNvirus-freefishstocksinuncontaminatedwatersupplies.CareInrrrt b" given to exclude sources of contamination such as egg cases' transportvehicles irom other hatcheries, and eggs and fish from uncertified sources.Some hatcheries are forced to oPerate with water from sources containingIPN virus carriers. In these cases, extra eggs should be started to allow forhigh production losses. when an IPN outbreak occurs, strict sanitation canp.".r".,t the spread of the disease to fish in other holding units. If water is."rrr"d, susceptible fish elsewhere in the system usually will contract the infection.survivorsmustbeconsideredtobecarriersofthevirus.

FISH HEALTH MANAGEMENT 295VIRAL HEMORRHAGIC SEPTICEMIA (VHS)Viral hemorrhagic septicemia, also known as Egtved disease, has not beenfound in North America but is a serious hatchery problem in several Europeancountries. Epizootics have been reported in brown trout but VHS primarilyis a disease of rainbow trout. It causes major losses among catchableor marketable trout but seldom is a problem among young fingerlings orbroodfish. The disease spreads from fish to fish through the water supply.Over the years, the disease has been given numerous names by variousGerman, French, and Danish workers. For simplification, the name ViralHemorrhagic Septicemia has been recommended and the abbreviationVHS appears frequently in the literature. In North America, VHS is consideredan exotic disease that, if introduced, would cause severe problemsin American culture of salmonids.Epizootics are characterized by a significant increase in mortality' Affectedfish become lethargic, swim listlessly, avoid water current, and seek theedges of the holding unit. Some individuals drop to the bottom and are reluctantto swim even though they retain their normal upright position. Justprior to death, affected fish behave in a frenzied manner and often swim intight circles along planes that vary from horizontal to vertical. Hyperactivitymay persist for a minute or more, then the fish drop motionless to thebottom. Most die, but others may resume a degree of normal activity for ashort time. Affected trout generally do not eat, although a few fish in aninfected population will feed.Trout with typical VHS become noticably darker as the diseaseprogresses. Exophthalmia can develop to an extreme stage' and the orbitfrequently becomes surrounded by hemorrhagic tissue. Such hemorrhagingis visible externally or may be seen during examination of the roof of themouth. Characteristically,the gills are very pale and show focal hemorrhages.On occasion, the base of ventral fins show hemorrhages. The dorsalfin may be eroded and thickened, but this also is a common feature amonghealthy rainbow trout under crowded conditions so its significance in VHSis not known. There is no food in the gastrointestinal tract and the liver ischaracteristically pale withhyperemic areas. Hemorrhages may occurthroughout the visceral mass, especially around the pyloric caeca. Thespleen becomes hyperemic and considerably swollen. One of the more commonsigns is extensive hemorrhages in swim bladder tissue. Kidneys of affectedfishes show a variable response. During the peak of acute epizootics,the kidneys usually have normal morphology but they may show hyperemia.Occasionally, the kidneys become grossly swollen and posteriorportions may show corrugation. It is not known whether this is a resPonseto the virus or to other complicating factors. Body musculature also showsa variable response; in some fish it appears to be normal but in others

296 FISH HATCHERY MANAGEMENTpetechiae may be present throughout the flesh. As with IPN virus, thecausative agent of VHS must be identified by serological methods involvingcell cultures and immune serum specific for the virus. Fluorescent antibodyprocedures also have been developed and work well.There is evidence that resistance increases with age. Infections usuallyare more severe in fingerlings and yearling fish, whereas fry and broodfishappear to be less susceptible. Brook trout, brown trout, and Atlantic salmonhave been infected experimentally and grayling and whitefish were reportedto be susceptible.Natural transmission occurs through the water, suggesting that virus isprobably shed in feces or urine. There also is some evidence that the viruscan occur on eggs. Survivors of an epizootic become carriers of the virus.This disease usually occurs during the winter and spring; as water temperaturesrise, epizootics subside. Sporadic outbreaks may occur in the summerat water temperatures less than 68'F.Preventive measures against VHS in the United States consist largely ofpreventing the introduction of the virus through importation of infectedeggs or fish. No salmonid eggs or fish may enter the United States legallyunless they have been thoroughly inspected and found free of VHS.As in the case of other viral infections of fish, chemotherapy of VHS isunsuccessful. The only effective measure at present is avoidance, consistingof propagating clean fish in clean hatcheries and controlling the access offish, personnel, animals, and equipment that might introduce the virus.INFECTIOUS HEMATOPOIETIC NECROSIS (IHN)Infectious hematopoietic necrosis, a viral disease of trout and salmon, firstwas recognized in 1967. Recent findings show that the pathogenic agentcausing IHNdisease is morphologically, serologically, physically, andbiochemically indistinguishable from those implicated in viral diseases ofsockeye and chinook salmon. Furthermore, clinical signs of the diseasesand the histopathological lesions are the same. Thus the descriptive nameinfectious hematopoietic necrosis (IHN) disease has been given to all.Diseased fish are lethargic but, as in the case of many viral infections,some individuals will display sporadic whirling or other evidence of hyperactivity.In chronic cases, abdominal swelling, exophthalmia, pale gills,hemorrhages at the base of fins, and dark coloration are typical signs of thedisease. Internally, the liver, spleen, and kidneys usually are pale. Thestomach may be filled with a milk-like fluid and the intestine with awatery, yellow fluid that sometimes includes blood. Pin-point hemorrhagesthroughout the visceral fat tissue and mesenteries often can be seen. In occasionalcases, signs may be absent and fish die of no apparent cause.During the course of an epizootic, a generalized viremia occurs and thevirus can be isolated from almost any tissue for diagnostic purposes. After

FISH HE,AL'I'H MANAGEMEN'Iisolation, positive identification requires neutralization of the virus by aspecific antiserum.Fish that survive an infection become carriers: both sexes shed the virusprimarily with sex products. Gonadal fluids are used in bioassays to detectcarrier populations. Naturaltransmission occurs from infected fish tononinfected fish through the water, or from the exposure of susceptible fryto sex products of carrier adult broodfish. The virus also can be transmittedwith eggs or by the feeding of infected fish products.Only rainbow trout and chinook and sockeye salmon have been shownto be susceptible to IHN. Coho salmon apparently are resistant to thevirus. Resistance increases with age and deaths are highest among youngfry and fingerlings. However, natural outbreaks have occurred in fish rangingfrom yolk-sac fry to 2 years of age. The incubation and course of thedisease are influenced strongly by water temperature. At 50"F, mortalitymay begin 4 to 6 days after exposure. Numbers of dead usually peakwithin 8 to 14 days, but mortality may continue for several weeks if thewater temperature remains near 50"F. Below 50'F, the disease becomes prolongedand chronic. Above 50'F, the incubation time is shorter and thedisease may be acute. Some epizootics have been reported at temperaturesabove 59'F.Outbreaks of IHNdisease have occurred along the Pacific Coast fromthe Sacramento River in California to Kodiak Island, Alaska. Although thevirus may not exist in all populations of sockeye salmon, the virus hasbeen detected in all major salmon production areas. Among chinook salmon,the disease is a particularly serious problem in the Sacramento Riverdrainage; it has been found also in fish of the Columbia River. Outbreaksof IFIN in rainbow trout have been much more restricted. Isolatedhatcheries where carriers and outbreaks were identified are known fromSouth Dakota, Minnesota, Montana, Idaho, Oregon, Washington, Colorado,and West Virginia. AII involved fish or eggs from a known carrierstock. However, there has been no recurrence of the disease at most ofthese hatcheries after the original outbreak. IHN also occurred in Japan insockeye salmon from eggs transported from Alaska.An effective method of control is to maintain the water temperatureabove 59"F while fish are being reared. This principle has been used successfullyto control IHN in chinook salmon along the Sacramento River.However, it is expensive to heat large volumes of water. Furthermore, rearinginfected fish at elevated temperatures does not eliminate the carrierstate.In rainbow trout, IHN virus is believed to be transmitted with eggs as acontaminate. Disinfection of eggs with iodophors usually will destroy thevirus.

298 FISH HATCHERY MANAGEMENTCHANNEL CATFISH VIRUS DISEASE (CCV)In recent years, many outbreaks of channel catfish virus disease (CCV) tra""been reported in the United States, primarily from the major catfish-rearingregion of the mid-South and Southeast. However, epizootics are not limitedto these states and may occur anywhere channel catfish are cultured intensivelyif water temperatures are optimum for the virus. An outbreak in Californialed to a complete embargo on the shipment of catfish into that state.A sudden increase in morbidity usually is the first indication of CCVdisease. The fish swim abnormally, often rotating about the long axis. Thisswimming pattern may become convulsive, after which the fish drop to thebottom and become quiescent. Just before death, affected fish tend to hangvertically with their heads at the water surface. This has been a characteristicbehavioral sign associated with the disease. Any of the following signsmay also be observed: hemorrhagic areas on the fins and abdomen and inthe eye; distension of the abdomen due to fluid accumulation; pale orhemorrhagic gills; hemorrhagic areas in the musculature, liver, kidneys,and spleen; and a distended stomach filled with yellowish mucoid secretion.Definitive diagnosis requires the isolation and identification of theagent with specific immune antiserum.Catfish are the only known susceptible fish. Channel and blue catfishand hybrids between them have been infected experimentally with CCV.Young of the year are extremely vulnerable and losses of more than g0%are common. Age seems to provide some protection. Healthy catfish fingerlingshave developed signs and died within 72 to 78 hours after exposureat water temperatures of 77"F and higher. In most cases, the disease can belinked to predisposing stress factors such as handling, low oxygen concentrations,and coincident bacterial infections. Water temperatures (78'F orabove) play an important part in the occurrence of the disease.At present, the only practical controls for channel catfish virus diseaseare avoidance, isolation, and sanitation. If the disease is diagnosed early,pond disinfection and destruction of infected fish may prevent the spreadto other fish in ponds, troughs, or raceways.HERPESVIRUS DISEASE OF SALMONIDSThe most recent virus to be isolated from cultured salmonids is the herpesvirusdisease. In the United States, broodstock rainbow trout in awestern hatchery have been carriers. This is the only report to date inNorth America, but a similar, if not identical, agent has been the cause ofnatural epizootics occurring annually among fry of landlocked sockeye salmonin Japan. Recently, the virus was isolated from sick and dead adultlandlocked sockeye salmon, also in Japan, but it yet remains to be determinedwhether or not the virus was the cause of death. Experimentally, thevirus has been lethal to rainbow trout fry and fingerlings.

FISH HEALTH MANAGEMENT 299Infected fry become lethargic; some swim erratically and are hyperactive,apparently losing motor control during the terminal stages. Exophthalmiais pronounced and abdominal darkening is common. Hemorrhage may beseen in the eyes of fish with exophthalmia. Abdominal distension is commonand gills are abnormally pale.Internally, ascitic fluid is abundant, and anemia and edema may be evidentin the visceral mass. The liver, spleen, and digestive tract are flaccidand the vascular organs are mottled with areas of hyperemia. The kidneysare pale, though not necessarily swollen. The digestive tract is void of food.Presently, specific immune antiserum has not been developed for definitiveidentification of the virus. Diagnosis, therefore, must be based on clinicalsigns of the disease, histopathological changes, and presumptive tests ofthe agent itself. This requires the services of a pathologist at a wellequippedlaboratory.Fish-to-fish transmission is assumed, because the virus can be isolatedfrom ovarian fluid, and eggs must be considered contaminated if they comefrom an infected source. Rainbow trout and landlocked sockeye salmonthus far are the only known susceptible species. Atlantic salmon, browntrout, and brook trout tested experimentally were refractory. Other speciesof salmon have not been tested.To date, reports of herpesvirus disease have been scattered and effortsshould be made to prevent the spread of this potentially damaging disease.Avoidance is the only certain method of control. Chemotheraphy is ineffective.LYMPHOCYSTIS DISEASELymphocystis disease, although rarely lethal, is of special interest becauseof its wide range of occurrence and presence in so many propagated andfree-ranging fish species. Marine as well as freshwater fishes are susceptible,but the disease has not been reported among salmonids. Among thepropagated freshwater fishes, walleyes and most centrarchids are susceptible.Lymphocystis is a chronic virus-caused disease causing generally granular,wart-like or nodular tissue lesions composed of greatly enlarged hostcells and their covering membrane. Cells of infected tissue may attain asize of a millimeter or more and resemble a spattering of sand-like granulesor, when larger, a raspberry-like appearance (Figure 79).The causative agent of the disease is a virus maintained in susceptiblehost fishes. Healthy fish may be exposed when infected cells burst and thevirus particles are released. This can occur intermittently through the durationof infection, or it can be massive upon death and decomposition of infectedfish. Lymphocystis lesions are persistent and commonly remain forseveral months; some may continue for a year or more.

FISH HATCHERYMANAGEMENTFtcunn 79. Lymphocystic virus disease. Note numerous "lymphocystic tumors"on skin of walleye. (Courtesy Gene Vaughan, National Fish Hatchery, Nashua,New Hampshire.)No method of treatment is known. Fish with the disease should be removedfrom the population to control the spread of the infection.Bacterial DiseasesBACTERIAL GILL DISEASEBacterial gill disease is a typical stress-mediated disease, and probably isthe most common disease of cultured trout and salmon; it also is an occasionaldisease of warmwater and coolwater fish reared in ponds. Suddenlack of appetite, orientation in rows against the water current, lethargy,Ftcunn 80. Furunculosis in brook trout. Note large furuncles on body surface offish infected with Aeromona salmonicida. (Courtesy National Fish Health Labora-tory, Leetown, West Virginia.)

FISH HEAI,TH MANAGEMEN 301flared opercula, riding high in water, and distribution of individualsequidistant from each other are typical signs of fish infected with bacterialgill disease. Gills show proliferation of the epithelium that may result inclubbing and fusing of lamellae or even filaments. Microscopic examinationof affected gill tissue reveals long, thin bacteria arranged in patchesover the epithelium. Necrotic gill tissue may be visibly grayish-white andmany of the filaments may be completely eroded. Often, only the gills onone side are affected.A combination of large numbers of bacteria and gill epithelial proliferationdifferentiates bacterial gill disease from other gill problems. Etiology ofthe disease has not been proven conclusively because induction of thedisease with flexibacteria isolated from diseased fish has not been consistentlyachieved. Other common soil and water bacteria, such as Aeromo'nas sp., also may cause bacterial gill disease'Crowding, mud and silt in the water supply, and dusty starter diets areimportant stress factors that contribute to outbreaks of the disease. Watertemperatures above 56'F are favorable for the bacteria. Yearling and olderfish are less susceptible than fry, but outbreaks can be acute in all ages offish.Water supplies should be kept free of fish, silt, and mud. The accumulationof fish metabolic products due to crowding apparently is the most importantfactor contributing to bacterial gill disease problems, and should beavoided.The most reliable and often-used treatments for bacterial gill disease areRoccal, Hyamine1622 (98.8y0 active), and Hyamine 3500 (50% active).These treatments are not registered by the Food and Drug Administration.The effectiveness and toxicity of these compounds depends on water hardnessand temperature, so caution must be used to prevent losses due toover-treatment and to insure that the treatment is effective. The recommendedtreatment level is I to 2 parts per million of active ingredient inwater for I hour. Prophylactic treatments should be repeated every 7-I4days. If bacterial gill disease is diagnosed, treatment should be repeateddaily for 3 to 4 days.Bacterial gill disease seldom is a problem among warmwater fish, particularlythose being reared in earthen ponds. It occasionally becomes a problemwhen young channel catfish, largemouth bass, bluegills, or redearsunfish are held in crowded conditions in tanks or troughs for extendedperiods. This can be corrected by treating with 1-2 parts per millionRoccal for t hour daily for 3 or 4 days or with 15-25 parts per millionTerramycin for 24 hours. After the problem is under control, the fish populationshould be thinned or the water flow increased. Unless the managementpractice that precipitated the outbreak is corrected, bacterial gilldisease will reappear.

FISH HATCHERY MANAC;EMEN'I'COI,UMNARIS DISEASEThe causative agent of columnaris disease historically has been namedChondrococcus columnaris, or Cytophaga columnaris, but now is classified asFlexibacter columnaris in Bergey's Manual of Determinatiue Bacteriology. Theagents are long, thin, gram-negative bacteria that move in a creeping orflexing action, and that have a peculiar habit of stacking up to form distinctivecolumns, hence the name "columnaris."Columnaris most commonly involves external infections but can occur asan internal systemic infection with no visible external signs. Externally, thedisease starts as small, grayish lesions anywhere on the body or fins; mostcommonly the the lesions occur around the dorsal fin or on the belly. The lesionsrapidly increase in size and become irregular in shape. As the lesionsget larger, the underlying musculature can be exposed. The margins of thelesions, and occasionally the centers, may have a yellowish color due tolarge aggregations of the bacteria. Frequently, lesions may be restricted tothe head or mouth. In Pacific salmon and warmwater fish, particularly catfish,lesions may be confined to the gills. Lesions on the gills are characterizedby yellowish-brown necrotic tissue beginning at the tip of the filamentsand progressing toward the base.Columnaris disease usually is associated with some kind of stress conditionsuch as high water temperature, low oxygen concentration, crowding,and handling. Under appropriate conditions, columnaris may take an explosivecourse and cause catastrophic losses in I or 2 days after the first appearanceof the disease. Therefore, it is incumbent upon the fish culturistto maintain the best possible environmental conditions for the fish and tominimize any stress conditions.Although columnaris disease attacks practically all species of freshwaterfish, catfish are particularly susceptible. In warmwater fish, most outbreaksof columnaris occur when the water temperature is above 68'F, but thedisease can occur at any time of the year. Columnaris disease is common insalmonids held at water temperatures above 59"F. Progress of the diseaseusually is faster at the higher temperatures.Flexibacteria are common inhabitants of soil and water. They commonlyare found on the surface of fishes, particularly on the gills. The stress ofcrowding, handling, spawning, or holding fish at above-normal temperatures,as well as the stress of external injury, facilitates the transmissionand eruption of columnaris disease.Presumptive diagnosis of columnaris is accomplished best by microscopicexamination of wet mounts of scrapings from lesions and detection of manylong slender bacteria (0.5 x l0 micrometers) that move by flexrng orcreeping movements and form "haystacks" or "columns."Preventative measures include maintenance of optimum water temperaturesfor salmonids, reduced handling during warm weather, maintenance

FISH HEAI-TH MANAGHMI]N'I 30:lof the best possible environmental conditions, and avoidance of overcrowdingfish.External infections of columnaris may be treated with:(t) Dlquat (not registered by the Food and Drug Administration) at U.4to 16.8 parts per million (2 4 parts per million active cation) for t hourdaily on 3 or 4 consecutive days.(2) T"..u*ycin (registered by the Food and Drug Administration) as aprolonged bath at l5 parts per million active ingredient (0.57 gram per 10gallons; 4.25 grams per l0 cubic feet) for 24 hours.(3) Furanace for trout and salmon (not registered by the Food and DrugAdministration) as a bath at I part per million active ingredient (0.03ugram per 10 gallons; 0.283 gram per l0 cubic feet) for 5-10 minutes, or at0.1 part per million active ingredient (0.0038 gram per 10 gallon; 0.0283gram per 10 cubic feet) for an indefinite period.(4) Copp". sulfate (registered by the Food and Drug Administration) at0.5 part per million for pond treatments.(5) Potassium permanganate (registered by the Food and Drug Administration),the most effective pond treatment for external columnaris infectionsin warmwater fish, at the rate of 2 parts per million (5.4 pounds peracre-foot). If the color changes in less than l2 hours it may be necessary torepeat the treatment.Internal infections o[ columnaris may be treated with Terramycin or sulfonamides,both registered by the Food and Drug Administration.(1) For channel catfish and other warmwater fish that will take artificialfood, provide medicated feed that will deliver 2.5 3.5 grams Terramycinper 100 pounds of fish per day for 7 to l0 days. For fish being fed 3'll oftheir body n'eight daily, it is necessary to have U3.3-116.7 grams Terramycinper 100 pounds of food. Under no circumstances should the treatmenttime be less than 7 days. For salmonids, Terramycin given orally in thefeed at a rate of 3.5 grams per 100 pounds fish per day for up to l0 days isvery effective in early as well as advanced outbreaks.(2j For salmonids, sulfamerazine and sulfamethazine can be given orallyin the feed at a rate of 5 to 10 grams per 100 pounds of fish per day, butthey are less effective than other drugs.r,l1I)Ll NCr-!. l)r sr.rAS!lPeduncle Disease is the same condition knorvn as coldwater or lowtemperaturedisease. Lesions appear on the fish in similar locations, systemicflexibacteria are present, and the disease occurs at low water temperaturesin the range of 45'to50'F. Affected fish become darkened, and lesionsmay develop on the caudal peduncle or on the isthmus anterior to

FISH HATCHERY MANAGEMENTthe pectoral fins. The caudal fin may be completely destroyed. A peduncledisease lesion usually starts on the caudal peduncle behind the adipose fin,where it causes inflammation, swelling, and gradual erosion. The diseaseprogresses posteriorly and the caudal fin may be eroded. Coho and chumsalmon are the most susceptible and, in sac fry, the yolk sac may beruptured.Peduncle disease or coldwater disease is caused by a flexibacterium,Cytophaga pslchrophilia. The bacteria are water-borne and can be transmittedfrom carrier fish in the water supply. Crowded conditions stimulate adisease outbreak but are not necessary for the disease to aPPear.The best treatment for peduncle disease is the oral administration ofdrugs with food. Sulfasoxazole (Gantrisin) and sulfamethazine (not registeredby the Food and Drug Administration), at 9 grams per 100 poundsfish per day, or oxytetracycline (Terramycin), at 2'5 grams per 100 poundsof fish per day, should be given for l0-14 days. Chemotherapy combinedwith, or followed by, external disinfection with Roccal will give better andlonger lasting results.F'IN ROl'Advanced cases of fin rot can resemble peduncle disease, but in this diseasebacteria are found in fin lesions only and no specific type of bacterium isrecognized as its cause. Signs may occur incidentally in the course ofanother bacterial disease, such as furunculosis. In typical fin rot, fins firstbecome opaque at the margins and then lesions move Progressively towardthe base. Fins become thickened because of proliferation of tissue and, inadvanced cases, may become so frayed that the rays protrude. The entirecaudal fin may be lost, followed by a gradual erosion of the peduncle.Common water bacteria such as Aeromonas hydrophila and Pseudomlnas sp.often are found in lesions of fin rot. Flexibacteria sometimes are mixedwith other types of bacteria. The disease is associated with poor sanitaryconditions that lead to fin abrasion, secondary bacterial infection, and finallyfin rot.The best results from treatments of fin rot infections are obtained with asoluble form of Terramycin added to water at l0 to 50 Parts per million forI hour. Control also may be achieved with Hyamine or Roccal (not registeredby the Food and Drug Administration) in a concentration of I to 2parts per million for I hour.FURUNCULOSISFish furunculosis, a septicemic disease principally of salmonids, has beenknown since 1894. It was first reported in the United States in 1902 and,since then, virtually all trout and salmon hatcheries have either been

FISH HEALTH MANAGEMENT 305contaminated with or exposed to the bacterium at one time or another.The causative agent of the disease is Aeromonas salmonicida. Today, furunculosisis enzootic in many hatcheries but severe outbreaks are rare due toadvances in fish culture, sanitation, and drug therapy. Outbreakshavebeen reported among marine fishes.The disease is characterized by a generalized bacteremia with focalnecrotic lesions in the muscle, often seen as swellings under the skin andnot true furuncles (Figure 80). The swollen skin lesions are filled with pinkfluid containing blood, and necrotic tissue may have a purple or irridescentblue color. These lesions are especially apparent in chronic infections butsimilar lesions may occur from other diseases caused by gram-negative bacteria.Hemorrhaged fin sockets and frayed dorsal fins also are common.The disease frequently occurs as an acute form in which death resultsfrom massive bacteremia before gross lesions can develop. Only a few clinicallysick fish may be seen at any one time in spite of the high death rate.Internally, diseased fish may exhibit small inflamed red lesions calledpetechiae in the lining of the body cavity and especially on the visceral fat.The pericardium usually is filled with bloody fluid and is inflamed. Thespleen, normally dark red in color, often will be a bright cherry-red andswollen. The lower intestine often is highly inflamed and a bloodydischarge can be manually pressed from the vent.A diagnosis of furunculosis can be either presumptive or confirmed.Presumptive diagnosis takes into consideration the frequency of outbreaksin a certain area, presence of typical lesions, and the occurrence of shortgram-negative rods in the lesions, kidneys, spleen, and blood. Confirmationof a presumptive diagnosis can be made only after Aeromonas salmonicidahas been identified as the predominant organism isolated.Furunculosis is endemic in many hatcheries and is so widespread that nonatural waters with resident fish populations should be considered free ofthis disease. The incidence pattern of furunculosis generally follows theseasonal temperature Pattern. Almost twice as many cases are reported inJuly as in any other month. The number of cases drops sharply in August,possibly indicating increased resistance in the remaining fish population ordeath of most of the susceptible fish.Acute cases of furunculosis have incubation periods of 2-4 days with fewapparent signs. Chronic cases usually occur at temperatures below 55"Fand may have an incubation period of one to several weeks, dependingupon the water temperature. Latent cases may develop during lowtemperatureperiods, and flare up with greater severity, displaying manytypical signs, when water temperatures rise.Fish exposed to furunculosis form protective antibodies. Some fish becomeimmune carriers of the disease. Suckers and other nongame fish inthe water supply may become infected and should be considered likely

306 FISH HATCHERY MANAGEMENTreservoirs of infection. Furunculosis may break out in virtually any freshwaterfish population, including warmwater species, if conditions such ashigh temperature and low dissolved oxygen favor the pathogen.Among the eastern salmonids, brook trout are the most susceptible to infection,brown trout are intermediate, and rainbow trout are least susceptible.Atlantic salmon also are susceptible. Furunculosis has been reported inmost of the western salmonids. In addition to salmonids, the disease hasbeen reported in many other fishes, including sea lamprey, yellow perch,common carp, catfish, northern pike, sculpins, goldfish, whitefish, and variousaquarium fishes.Sanitation provides the most important long-range control of furunculosis.If a population of trout at a hatchery is free of furunculosis and if thewater supply does not contain fish that harbor the pathogen, strict sanitationmeasures should be used to prevent the introduction of the disease viaincoming eggs or fish. Eggs received at a hatchery should be disinfectedupon arrival. Iodophors used as recommended are not toxic to eyed eggsbut are highly toxic to fry.Maintenance of favorable environmental conditions for the fish is ofprime importance in preventing furunculosis outbreaks. Proper water temperatures,adequate dissolved oxygen, efficient waste removal, andavoidance of overcrowding must be observed. In areas where the disease isendemic, strains of trout resistant to furunculosis are recommended. However,regardless of the trout strain involved, acute outbreaks of furunculosishave occurred when conditions favored the disease.Sulfamerazine (10 grams per 100 pounds of fish per day) in the diet hasbeen the standard treatment of furunculosis for years. In recent years, becauseof sulfa-resistant strains of A. salmonicida, Terramycin (3.6 gramsTM-50 or TM-50D per 100 pounds of fish per day for l0 days) has becomethe drug of choice. Furazolidone (not registered by the Food andDrug Administration) has been used successfully under experimental conditionsagainst resistant isolates of the bacterium. Furox 50 (also not registered)at 5 grams active ingredient per 100 pounds fish per day has beenused successfully under production conditions with Pacific salmon. Drugsare effective only in the treatment of outbreaks. Recurrences of furunculosisare likely as long as A. salmonicida is present in the hatchery systemand environmental conditions are suitable.ENTERIC REDMOUTH (ERM)Enteric Redmouth disease refers to an infection of trout caused by an entericbacterium, Tersinia ruckeri. Initially, the disease was called Redmouth; laterthe name Hagerman redmouth disease (HnU) was used to differentiatebetween infections caused bv Tcrsinia and those caused by the bacterium

FISH HEALTH MANAGEMENT 307Aeromonas hldrophila. Presently, the Fish Health Section of the AmericanFisheries Society recommends the name Enteric Redmouth. Enteric redmouthdisease occurs in salmonids throughout Canada and much of theUnited States. Outbreaks in Pennsylvania trout and in Maine Atlantic salmonare among the most recent additions to its geographical range.The gram-negative Tersinia ruckeri produce systemic infections that resultin nonspecific signs and pathological changes. The diagnosis of infectionscan be determined only by isolation and identification of the bacterium.Enteric redmouth disease is characterized, by inflammation and erosionof the jaws and palate of salmonids. Trout with ERMtypically becomesluggish, dark in color, and show inflammation of the mouth, opercula,isthmus, and base of fins. Reddening occurs in body fat, and in the posteriorpart of the intestine. The stomach may become filled with a colorlesswatery liquid and the intestine with a yellow fluid (Figure 81). This diseaseoften produces sustained low-level mortality, but can cause large losses.Large-scale epizootics occur if chronically infected fish are stressed duringhauling, or exposed to low dissolved oxygen or other poor environmentalconditions.The disease has been reported in rainbow trout and steelhead, cutthroattrout, and coho, chinook, and Atlantic salmon. The bacterium was isolatedfirst in 1950, from rainbow trout in the Hagerman Valley, Idaho. Evidencesuggests that the spread of the disease is associated with the movement ofinfected fish to uncontaminated waters. Fish-to-fish contact providestransfer of the bacterium to healthy trout.Because spread of the disease can be linked with fish movements, the bestcontrol is avoidance of the pathogen. Fish and eggs should be obtained onlyfrom sources known to be free of ERM contamination. This can be accomplishedby strict sanitary procedures and avoidance of carrier fish.Recent breakthroughs in the possible control of ERM by immunizationhave provided feasible economic procedures for raising trout in waters containingthe bacterium. Bacterins on the market can be administered efficientlyto fry for long-term protection.A combination of drugs sometimes is required to check mortality duringan outbreak. One such combination is sulfamerazine at 6.6 grams per 100pounds fish plus NF-I80 (not registered by the Food and Drug Administration)at 4.4 grams per 100 pounds fish, fed daily for 5 days.MOTILE AEROMONASEPTICEMIA (MAS)Motile aeromonas septicemia is a ubiquitous disease of many freshwaterfish species. It is caused by gram-negative motile bacteria belonging to thegenera Aeromonas and Pseudomanas. Two species frequently isolated in outbreaksare A. hydrobhila and P. fluorescens. A definitive diasnosis of MAS

FISH HATCHERYMANAGEMENTFIcunn 81. Enteric red mouth disease in a rainbow trout. Note hemorrhaging ineye and multiple petechial hemorrhages in liver. The spleen is swollen and a yellowishmucoid plug has been pushed from the intestine. Judged by the pale gillsand watery blood in the body cavity, this fish was anemic. (Courtesy Charlie E.Smith, FWS, Bozeman, Montana.)can be made only if the causative agent is isolated and identified. A tentativediagnosis based only on visible signs can be confused with other similardiseases (Figure 82).When present, the most common signs of MAS are superficial circular orirregular grayish-red ulcerations, with inflammation and erosion in andFrcunr 82. Bacterial septicemia on a goldfish, caused by an infection with Aeromonashydrophila. (Courtesy National Fish Health Laboratory, Leewtown' WestVirginia.

FISH HEALTH MANAGEMENTaround the mouth as in enteric redmouth disease. Fish may have a distendedabdomen filled with a slightly opaque or bloody fluid (dtopsy) or protrudingeyes (exophthalmia) if n.rid accumulates behind the eyeball. Otherfish, minnows in particular, D&y have furuncules like those in furunculosis,which may erupt to the surface, producing deep necrotic craters. Fins alsomay be inflamed (Figure 83).In addition to the presence of fluid in the abdominal cavity, the kidneymay be swollen and soft and the liver may become pale or greenish.Petechiae may be present in the peritoneum and musculature. The lowerintestine and vent often are swollen and inflamed and may contain bloodycontents or discharge. The intestine usually is free of food, but may befilled with a yellow mucus.Motile aeromonas septicemia occasionally takes an acute form in warmwaterfish and severe losses can occur even though fish show few, if any,clinical signs of the disease. In general, most outbreaks in warmwater fishoccur in the spring and summer but the disease may occur at any time ofyear. Largemouth bass and channel catfish are susceptible particularly duringspawning and during the summer if stressed by handling, crowding, orlow oxygen concentrations. Aquariumfish can develop the disease at anytime of the year. Among salmonids, rainbow trout seem to be the most susceptibleand outbreaks are associated with handling stress and crowding ofFtcunu 83. Severe bacterial septicemia in a channel catfish infected with anunknown enteric bacterium.town, West Virginia.)(Courtesy National Fish Health Laboratory, Lee-

310 FISH HATCHERY MANAGEMENTFtcunn 84. Grayish-white necrotic lesions in the kidney of a rainbow trout withbacterial kidney disease. (Courtesy National Fish Health Laboratory, Leetown,West Virginia.)fish. Fish and frogs that recover from the disease usually become carriersand may contaminate water supplies if they are not destroyed. The diseasehas been identified throughout the world and apparently infects anyspecies of freshwater fish under conditions favoring the bacteria.Observation of strict sanitary practices and the elimination of possiblecarrier fish from the water supply are extremely important to the control ofbacterial hemmorhagic septicemia on trout and salmon hatcheries. Forwarmwater fish, everything possible should be done to avoid stressing thefish during warm weather. As a prophylactic measure, broodfish can be injectedwith 25 milligrams active Terramycin per pound of body weight orfed medicated feed before they are handled in the spring.Outbreaks of MAS in channel catfish and other warmwater fish that willeat artificial food can be treated by feeding them 2.5-3.5 grams active Terramycinper 100 pounds of fish for 7-10 days.-Outbreaksin salmonids have been treated successfully by Terramycinfed at 3.6 grams TM-50 per 100 pounds of fish daily for l0 days. Sulfamerazinefed at l0 grams per 100 pounds of fish per day for 10 days also hasbeen used with reasonable success. A combinationof sulfamerazine andNF-180 (not registered by the Food and Drug Administration) has beenvery effective in treating outbreaks on trout hatcheries in the westernUnited States.VIBRIOSISVibriosis is a common systemic disease of marine, estuarine, and (occasionally)freshwater fishes. It is known also under the names of red pest, red

FISH IIEALTH N'IANAGEN'IEN13l lboil, red plague, or salt water furunc:ulosis. Vibrio anguillarum is now consideredto be the etiologic agent of the disease. Although vibriosis generallyis a disease of cultured marine fishes, it also occurs in wild populations. Itcan occur any time of year, even in water temperatures as low as 39'F.However, it is most prevalent in the temperate zones during the warmersummer months and epizootics can be expected when water temperaturesreach 57"F.Signs of the disease usually do not become evident until the fish havebeen in salt water for two weeks or more under crowded conditions. Diminishedfeeding activity is one of the first noticeable signs. Lethargic fishgather around the edges of holding units; others swim in erratic, spinningpatterns. Diseased fish have hemorrhages around the bases of their pectoraland anal fins or a bloody discharge from the vent. When a fish is openedfor necropsy, diffuse pin-point hemorrhages of the intestinal wall and livermay be evident. The spleen frequently is enlarged and may be two to threetimes its normal size.Diagnosis of vibriosis caused by V. anguillarum reqluires isolation of agram-negative, motile, rod-shaped bacterium on salt medium. The organismmay be slightly curved and produces certain biochemical reactionsunder artificial culture. There is no reliable presumptive diagnosis of vibriosisbecause of its similarity to other septicemic diseases caused bygram- negative bac teria.The organism is ubiquitous in marine and brackish waters and infectionsprobably are water-borne and may be spread by contact. Salmonids usuallydie within I week after exposure; fish of all ages are susceptible.Vibriosis is worldwide in its distribution, but it usually is most severe inmariculture operations. Virtually all species of marine and estuarine fishesare susceptible. Among salmonids, pink salmon and chum salmon are themost susceptible but serious epizootics have occurred in coho salmon, rainbowtrout, and Atlantic salmon. Stresses associated with handling, low oxygen,and elevated temperature predispose fish to vibriosis.Prevention of vibriosis depends on good sanitation, no crowding, andminimal handling stress. Immunization is an effective means of combattingthe disease. Bacterins now are available from commercial sources and appearto provide long-term protection. Hyperosmotic procedures utilizingbacterins appear most suitable for large numbers of small fingerlings. Injectionsmay be preferable for larger fish. In theory, long-term selection andbreeding for resistance to the bacterium may be a means of control.Sulfamerazine (registered by the Food and Drug Administration) used atthe rate of 17 grams per 100 pounds of fish per day for l0 days has controlledvibriosis. Terramycin (also registered) at 5.0 to 7.5 grams per 100pounds of fish per day for l0 days also has been successful.

31,2 F'ISH HATCHERY MANAGEMEN'IKIDNEY DISEASEKidneydisease is a chronic insidious infection of salmonid fishes. Thedisease is slow to develop but, once established, it may be difficult to controland virtually impossible to cure.The causative bacterium of kidney disease (Renibacterium salmoninarum)is a small, non-motile, nonacid-fast, gram-Positive diplobacillus.The course of kidney disease is similar to that of a chronic bacteremia.Once the pathogen enters the fish via infected food, or from contact withother infected fish in the water supply, the bacteria multiply slowly in theblood stream. Foci of infection develop in the kidney and in other organssuch as the liver, spleen, and heart (Figu.e 84). White cellular debris collectsin blisters and ulcers that develop in these organs are seen easily. Lesionsdeveloping in the posterior kidney are easiest to spot and may reacha centimeter or more in diameter. Some lesions extend into the musculatureand result in externally visible blisters under the skin. If the diseasehas reached the stage in which gross lesions are apparent, therapeutic treatmenthas little effect (Figu.e 85). At best, drug therapy will only cure lightlyor newly infected fish. This difficulty in the control of kidney disease isthe basis for classifying it as a reportable disease.Although kidney disease first was reported in the United States in 1935,a similar, and probably identical, condition termed "Dee disease" was reportedin Scotland in 1933. The disease has been found in 16 species ofsalmonids in North America. A tendency towards seasonal periodicity hasbeen noted, but the incidence varies at different hatcheries. Chinook, coho,sockeye, and Atlantic salmon and brook trout are highly susceptible, butthe disease is not known among nonsalmonids.Infected or carrier fish are considered to be sources of infection. Experimentally,from I to 3 months have elapsed before mortality began.Historically, diagnosis of kidney disease epizootics has been based on thedemonstration of small, gram-positive diplobacilli in infected tissues. However,the accuracy of such identifications is uncertain and more reliableserological procedures such as fluorescent antibody techniques should beused.Until the sources and modes of infection in hatcheries are known, strictquarantine and antiseptic disposal of infected fish are recommended. Iodophordisinfection of salmonid eggs may be of benefit in preventingtransmission of the organism with eggs, but it is not completely effective.Under laboratory conditions, erythromycin (not registered by the Foodand Drug Administration) given orally at the rate of 4.5 grams per 100pounds of fish per day for three weeks gave the best control but was notcompletely effective. Treatments under field conditions have given similarresults; cures were effected in some lots, but among others the disease

FISH HEALTH MANAGEMENT 313FIcunn 85. External lesions in trout infected with corynebacterial kidney disease.(Courtesy National Fish Health Laboratory, Leetown,West Virginia.)recurred. All published accounts of treatment with sulfonamides report thatmortality from the infection recurred after treatment ceased. Sulfamethazine(registered by the Food and Drug Administration) fed at 2.0 gramsper 100 pounds of fish per day has been successfully used for prophylaxisin Pacific salmon. To date, no sulfonamide-resistant strains of the kidnevdisease bacterium have been reported.' i,liiiiiiry]FIcunE 86. Smallmouth bass with severeexternal fungus infection. (Courtesy G.L. Hoffman, Fish Farming Experimental Station, Stuttgart, Arkansas.)

314 FISH HATCHERY MANAGEMEN'TFungus DiseasesFungi are encountered by all freshwater fishes at one time or another duringtheir lives. Under cultural conditions, certain fungi can be particularlytroublesome. Species of the family Saprolegniaceae commonly are implicatedin fungal diseases of fish and fish eggs. Species of Saprolegnia, Achlla,Aphanomyceq Leptomitus, Phoma, and Pythium have been reported as pathogens.Fungae infestating fish or eggs generally are considered to be secondaryinvaders following injury but, once they start growing on a fish, thelesions usually continue to enlarge and may cause death. Fungi often attackdead fish eggs and spread to adjacent live eggs, killing them. Thesefungi grow on many types of decaying organic matter and are widespreadin nature.The presence of fungal infections on fish or fish eggs is noted by a whitecottony growth. This growth consists of a mass of filaments; these containthe flagellated zoospores that escape to begin infections on other fish oreggs. Unless control measures are taken, the expanding growth ultimatelymay cover every egg in the incubator.Injuries to fish produced by spawning activity or other trauma, and lesionscaused by other infections, often are attacked by fungus. Holdingwarmwater fish in cold water during summer can render fish more susceptibleto fungal infections (Figure 86).Good sanitation and cleanliness are absolutely essential to effective controlof fungi and other parasites under intensive culture conditions. For thecontrol of fungal infections on eggs, there are two methods, one mechanical,the other chemical. The mechanical method is used for controlling fungalinfections on both salmonid and catfish eggs, and involves picking deadand infected eggs at frequent intervals during incubation. This, however, istime-consuming and some healthy eggs may be injured in the process.Good chemical control of fungal infections on eggs can be achieved. Formalinat 1,600 and 2,000 parts per million for 15 minutes will controlfungus on both salmonid and catfish eggs. Do not expose fry to these concentrationsof formalin.In Europe, gill rot, a disease caused by fungi of the genus Branchiomlces,is considered one of the greatest threats to fish culture. Although Europeangill rot is primarily a disease of pike, tench, and carp it has been found inrainbow trout, largemouth bass, smallmouth bass, striped bass, northernpike, pumpkinseed, and guppies in the United States. This disease hasbeen found in Alabama, Arkansas, Florida, Georgia, Missouri, Ohio, RhodeIsland, and Wisconsin.Clinical signs associated with branchiomycosis include pale, whitish gillswith necrotic areas, fish gasping at surface, and high losses.A presumptive diagnosis can be made by microscopic examination of

FISH HEALTH MANAGEMENT 315wet gill tissue (100 x or 440 x) if nonseptate hyphae and spores of thef.rrrgrrs are seen in the capillaries and tissue of the gill lamellae. Suspectmaterial should be sent for a confirmatory diagnosis. Suspect fish should beheld under strict quarantine until the diagnosis is confirmed'There is no control for branchiomycosis excePt destruction of infectedfish and decontamination of facilities.Proto

316 FISH HATCHERY MANAGEMENTFrcuRr tl7. Ichtlobodo (Costia), 400x magnification. (Courtesy G.L. Hoffman, Fish Farming Experimental Station, Stuttgart, Arkansas.)Ichtyobodo can be a serious problem on all species and sizes of warmwaterfish, particularly channel catfish. This flagellate can cause Problems anytimeof year, but is most common on warmwater fish from February toApril.Pond treatments for lchtyobodo that give good results' if they can be usedin the particular situation, include: formalin at I5-25 parts Per million; potassiumpermanganate at 2 parts Per million (may have to berepeated depending on organic load in the pond); or copper sulfate atwhatever concentration can be used safely. For a prolonged bath treatmentfor salmonids or warmwater fish, best results are obtained from formalin at125 to 250 parts per million for up to I hour; the concentration dependson water temperature and species and size of fish to be treated.ICHTHTOPHTHIRIUSIchthyophthirius multifilis, or "Ich," is a large ciliated protozoan exclusivelyparasitic on fish. It probably is the most serious disease of catfish, but alsois a common parasite of other warmwater fishes and can be a serious problemof salmonids. Ich is the only protozoan parasite that can be seen bythe naked eye; when fully grown it may be as large as 1.0 millimeter in diameterand appear as gray-white pustules much like grains of salt. Positiveidentification is based on the finding of a large, ciliated protozoan with ahorseshoe-shaped macronucleus embedded in gills, skin, or fin tissue.The feeding stages, or trophozoites, of Ich are found in the epithelium ofthe skin, fins, and gills (Figures 89 and 90). When mature, the adultparasites drop off the host and attach to the bottom or sides of the pond.Once encysted, they reproduce by multiple fission and, within two to

FISH HEALTH MANAGEMENT3r7Frcuns 88. Ichtyobodo (Costia) infection on a rainbow trout (blue slime disease).(Courtesy G. L. Hoffman, Fish Farming Experimental Station, Stuttgart,Arkansas.)several days, depending upon temperature, each adult may produce up to1,000 ciliated tomites; The tomites burst from the cysts and must find afish host withinabout 24 hours or die. Upon contact with the fish, thetomites penetrate the skin and begin to feed and grow into adults. At optimaltemperatures of 70 to 75"F, the life cycle may take as few as 3 to 4days. The cycle requires 2 weeks at 60'F, more than 5 weeks at 50'F, andmonths at lower temPeratures.Ich is known as "salt and pepper" and "white spot" disease by aquaristsbecause of the gray-white specks that appear on the skin. However, onsome species of warmwater fish, mainly the golden shiner, Ich is found almostexclusively on the gills. On rare occasions, Ich infections on catfishalso may be restricted to the gills. In severe outbreaks, losses may precedeFtcunn 89. SevereIchtfuopthirius itnfection (white spots) in the skin of an Americaneel. (CourtesYNational Fish Health Laboratory, Leetown, West Virginia')

318 FISH HATCHERY MANAGEMENTFIGURE 90. Ichthlophthiriur on a rainbow trout fin, 6x magnification. (CourtesyG. L. Hoffman, Fish Farming Experimental Station, Arkansas.)the appearance of the mature parasites on the fish. Young fish exhibit considerableflashing off the bottom and often show erratic spurts of activity,jumping out of the water and thrashing about, due to irritation caused bythe parasites. Successful treatment of Ich depends upon the elimination ofparasite stages that are free in the water and the prevention of re-infection.Tomites and adult parasites leaving the fish are, therefore, the target oftherapeutic efforts.The best control for lch, as for any disease, is prevention. Hatchery watersupplies always should be kept free of fish. If possible, any warmwaterfish brought onto a hatchery should be quarantined for at least one week at70"F, and coldwater fish for at least 2 weeks at 60"F, to determine if theyare infested with Ich.Ich is difficult to treat because the tissue-inhabiting and encysted formsare resistant to treatment; only the free-swiming forms are vulnerable. Successfultreatment usually is long and expensive. There are several pondtreatments for either warmwater fish or salmonids that can be used successfullyif started in time. Copper sulfate can be used at whatever concentrationis safe in the existing water chemistry. Treatment is repeated on alternatedays; usually from two to four applications are necessary, dependingon water temperature. This is the least expensive treatment and gives good

FISH HEALTH MANAGEMENT 319results on catfish when it can be used safely. Potassium permanganatesometimes is used at 2 parts per million and repeated on alternate days fortwo to four applications. Success is not always good. Formalin at 15-25parts per million can be used on alternate days for two to four applications.The higher concentration gives the best results. This is a very effectivetreatment but is expensive for treating large volumes of water.Prolonged bath or flush treatments can also be used to treat Ich on fishbeing held in tanks, raceways, or troughs. Formalin is effective at L67-250parts per million, depending on water temperature and species and size offish, for up to I hour daily or on alternate days. The number of treatmentsrequired depends on the water temperature.CHILODONELLASpecies of Chilodonella are small, oval, colorless protozoans, 50-70 micrometerslong, which may be found in vast numbers on the skin, fins, and gillsof goldfish, other warmwater species, and salmonids. Under high magnification,faint bands of cilia can be seen over much of the organism (Figure9l). Their optimal water temperature is 40 to 50"F, making it particularlytroublesome on warmwater species during cold weather. Heavily infectedfish are listless, do not feed actively, and may flash. Chilodonella is controlledeasily with any of the following treatments for external protozoanParasrres:(l) Formalin at 125-250 parts per million for I hour in tanks or racesays.(2) Formalin at 15 25 parts perponds.million as an indefinite treatment in(3) Copper sulfate at whatever concentration can be used safely in theexisting water chemistry as an indefinite treatment in ponds.(4) Potassium permanganate at 2 parts per million as an indefinite treatmentin ponds. The treatment may have to be repeated if heavy organicloads are present.EPISTTLISSpecies of Epistylis grow in clumps at the ends of bifurcate, noncontractilestalks (Figures 92 and 93). Under the microscope they appear much like acluster of bluebells growing on a stalk that is attached to the fish by a disc.They commonly are found on the skin but also may occur on gills and incubatingeggs. Flashing actions by the fish during the late morning and lateevening hours are among the first signs of infestations. Some species of Epislyllievidently cause little tissue damage but other strains cause extensivecutaneous lesions. Epistllis should be removed when it causes severe flashingor skin lesions that may serve as openings for fungal or bacterial infections.Epistylis can be extremely difficult to control on warmwater

320 FISH HATCHERY MANAGDMENTFIGURE 91. Chilodonella, 475x magnification. (CourtesyG. L. Hoffman, Fish Farming Experimental Station,Stuttgart, Arkansas.)fish, particularly channel catfish. Epistyl* on salmonids can be controlledwith one treatment of 167 parts per million formalin for I hour if the watertemperature is 55"F or higher, or with 250 parts per million formalin for Ihour repeated twice, if the water temperature is 45"F or lower. For warmwaterfish the following treatments have been used:(t) Sutt (NaCt) at 0.1-1.5% for 3 hours is the best for controlling Epistylison channel catfish. This is suitable only for raceway, tank, or trough treatments,not for ponds.(2) In ponds, use formalin at 15-25 parts per million or potassium permanganateat 2 parts per million. These treatments usually must berepeated two to three times to achieve an effective control.TRICHODINATrichodinidsare saucer-shaped protozoans with cilia around the margin of thebody as they normally are viewed under the microscope. These protozoans live onthe skin, hns, and gills of fish and, when abundant, cause severe irritation andcontinual flashing. Salmon yearlings, if left untreated, develop a tattered appearance.Secondary bacterial infections may develop in untreated cases.

FISH HEALTH MANAGEMENT 321Trichodina on warmwater fish can be controlled with any of the followingtreatments:(t) Copper sulfate as an indefinite pond treatment at whatever concentrationcan be used safely in the existing water chemistry.(2) Potassium permanganate at 2 parts per million as an indefinite pondtreatment.(3) Formalln at l5-25 parts per million as an indefinite pond treatment.(4) Formalin at 125-250 parts per million, depending on water temperatureand species and size of fish, for up to I hour.To control Trichodina on salmonids, formalin at 167-250 parts per millionfor up to I hour usually is successful. If salmonids are sensitive to formalin,a 2-4 parts per million treatment of Diquat for one hour should betested.AMBIPHRTAAmbiphrya (Scyphidia) can occur in large numbers on the skin, fins, andgills of freshwater fish.The organism has a barrel-shaped body with a band of cilia around theunattached end and around the middle of the body, and a ribbon-shaPed14,'i!! ,l:FrcuRE 92. Episttlis, l00x magnification. (courtesy G. H. Hoffman, Fish FarmingExperimental Station, Stuttgart, Arkansas..)

322 FISH HATCHERY MANAGEMENTFIcunn 93. Epistylis sp., living colony from rainbow trout, 690x magnification.(Courtesy Charlie E. Smith, FWS, Bozeman, Montana.)FIcunn 94. Trichophyra sp. on gills of rainbow trout. Note extended food gatheringtentacles, 300x magnification. (Courtesy Charlie E. Smith, FWS, Bozeman,Montana.)

FISH HEAL'I'H MANAGEMENTmacronucleus. They can be especially troublesome on young catfish, centrarchids,and goldfish.Ambiphrya can cause problems anytime of year but most frequentlyoccurs when water quality deteriorates due to excessive amounts of organicmatter or low oxygen levels. This protozoan is not a parasite. It feeds onbacteria and detritus and may develop in high numbers. Heavy infestationson the gills cause the fish to act as if they were suffering from an oxygendeficiency. Large numbers of them can cause a reddening of the skin andfins. Fry and small fish may refuse to feed actively, flash, and becomelistless.Ambiphrya is controlled easily with formalin at 125-250 parts per millionfor up to I hour, or 15-25 parts per million as a pond treatment. Coppersulfate, at whatever concentration can be used safely, or potassium Permanganateat 2 parts per million, also give good results.TRICHOPHRTASpecies of Trichophrya sometimes are found on the gills of fish and cancause serious problems in catfish and occasionally in other warmwaterspecies. They have rounded to pyramid-shaped bodies (30 x 50 micrometers)and are distinguished by food-catching tentacles in the adult stage(Figure 94). Live organisms have a characteristic yellowish-orange oryellowish-brown color that makes them very conspicuous when wet mountsof gill tissue are examined under a microscope at 100x or 440x.Affected fish gills are pale and clubbed, and may be eroded. Infectedfish will be listless, as if they were suffering from an oxygen deficiency.Trichophrya is difficultto control in ponds but satisfactory results can beobtained with copper sulfate at whatever concentration is safe. Pond treatmentswith formalin or potassium permanganate give erratic results. A bathtreatment of 125-250 parts per million formalin for up to I hour usually iseffective, but may have to be repeated the next day.Internal Protoloan DiseasesHEXAMITAHexamita salmonis is the only common flagellated protozoan found in theintestine of trout and salmon. Although the pathogenicity of the organismis questioned by some researchers, most feel it can cause poor growth andelevated mortality in small (2-inch) fish. All species of salmonids are susceptibleto infection. Because there are no well-defined signs, a diagnosis of

FISH HATCHERY MANAGEMEN IFtcunE 95. Hexamita salmonis FIGURE 96. Hennegultasp.hexamitiasis must be made by microscopic examination of gut contentsfrom the anterior portion of the intestine and pyloric caeca. The flagellates(Figure 95) are minute, colorless, pear-shaped organisms that dart rapidlyin every direction. Gross signs of infected fish may include swimming in acork-screw pattern, and a dark emaciated condition commonly called"pin-headed." The protozoan may become abundant in fish that are fedmeat diets, and can cause irritation of the gut lining. With the advent ofprocessed diets, incidence of the disease has greatly declined.Therapy is not recommended nnless Hexamita salmonis is abundant. Fortreatment, leed epsom salt (magnesium sulfate) at the rate of 3nu of the dietfor2or3days.HENNEGUTASeventeen species of Henneguya have been described from a wide variety ofNorth American freshwater fishes. The following remarks are limited to therelationship of these parasites to hatchery-reared species, primarily channelcatfish.

FISH HEALTH MANAGEMENT 325All species of Henneguya are histozoic and localize in specific tissues. Infectionsmay appear as white cysts withinthe gills, barbels, adipose fins,skin, gall bladder, connective tissue of the head, subcutaneous tissues, orsclera and muscles of the eye.Spores of Henneguya grossly resemble spermatoza; they possess. two anteriorpolar capsules and an elongate posterior Process(Figure 96) that mayor may not separate along the sutural plane. The mode of transmission isbelieved to be fish-to-fish; no methods of chemical control are known.Hennegula salminicola has been found in cysts in the body or musculatureof coho, pink, and chinook salmon. Chum salmon also are subject toinfection.In channel catfish, Henneguya infections are categorized with resPect tothe tissue parasitized and the site of spore formation.An intralamellarbranchial form develops cysts within gill lamellae. A cutaneous form causeslarge lesions or pustules within the subcutaneous layers and underlyingmusculature of the skin; a granulomatous form causes large tumor-like lesions.An integumentary form causes white cysts on the external body surface.A gall-bladder form develops within that organ and may obstruct thebile duct. An adipose-fin form localizes solely within the tissue of that fin.Spores from catfish infections are similar morphologically and virtuallyindistinguishable on the basis of shape and dimensions. They closelyresemble H. exilis described in channel catfish.'fheintralamellar form is observed commonly among cultured catfish butdoes not cause deaths. The role of this form as a debilitating agent issuspected but unproven. Spore development occurs within capillaries of gilllamellae or blood vessels of gill filaments. The resultant opaque, sPorefilledcysts may be found in large numbers and are readily observed in wetmounts.-lheinterlamellar form of Henneguya develops spores withinbasal cellsbetween gill lamellae (Figure 97). This form, in contrast to the intralamellarform, has caused large losses among very young channel catfish. Mortalitiesof 95% or more among fingerlings less than 2 weeks old have beenreported. Loss of respiratory function accompanies acute infections. Fishexhibit signs of anoxia, swimming at the surface of ponds with flared gillopercula. Infected fish are unable to tolerate handling. Most attempts totreat with parasiticides have resulted in additional losses'As with other myxosporidean infections, prevention is the only controlmeasure because no chemical treatment is effective. The disease has beenspread from hatchery to hatchery with shipments of infected fingerlings.Confirmation of the interlamellar form in a catfish population may warrantdestruction of the inf'ected fish and decontamination of the rearing facilitiesinvolved.

FISH HA'TCHERY MANAGEMENTFIGURE 97. The interlamellar form of Henneguya with resultant spore-filled cysts(arrow) between gill lamellae. Gill lamellae may become greatly hypertrophiedand lose all of their normal appearance. 175x 6agtrllication. (Courtesy CharlieE. Smith. FWS. Bozeman. Montana.)CERATOMTXACeratomlxa shasta is a serious myxosporidian parasite of salmonids in thewestern United States that causes severe losses of rainbow and cutthroattrout, steelhead, and coho and chinook salmon. Heavy mortalities of adultsalmon have occurred just prior to spawning. Severe hatchery epizootics,resulting in 10091 mortality, were reported as early as 1947 in California.Many epizootics have been reported, including significant losses amongsome wild salmonid populations. Infections also have been found in brookand brown trout, and sockeye and Atlantic salmon.The spores of Ceratomyxa shasta are tiny and elongated and can be foundin great numbers in the lining of the gut and in cysts in the liver, kidney,spleen, and muscle. The disease is contracted by adult salmon upon enteringinfected fresh water. Lake conditions are believed to be vital to thedevelopment of the infective stage of the parasite. The entire life cycle,which is poorly known, may be completed in 20 to 30 days at 53'F. Someresearchers feel that infection will not occur below 50"F.The first signs of infection in domestic rainbow trout include lack of appetite,listlessness, and movement to slack water. The fish may darken andshed fecal casts. The abdomen often swells with ascites. Exophthalmiaoften occurs. The first internal changes appear as small, whitish, opaque

FISH HEAL'I'H MANAGEMEN'I 327areas in the tissue of the large intestine. As the disease progresses, the entireintestine becomes swollen and hemorrhagic.The disease has been transferred by inoculating ascites (containingschizonts, trophozoites, and spores) from infected rainbow trout into thevisceral cavity of noninfected rainbow trout. Fish-to-fish transmission byother methods has failed. Infection seemingly does not depend on theingestion of food organisms or any of the known stages of the parasite. Themode of transmission remains unknown.There is no known treatment for Ceratomyxa shasta, so the parasite shouldbe avoided at all costs. Water supplies known to be contaminated should not beutilized for hatchery purposes without pretreatment. There should be no transferof'eggs, young fish, or adults liom inf'ected to noninfected areas.MTXOSOMAMltxosoma cerebralis is the causative agent of whirling disease, a serious conditionof salmonid fishes. Because of its importance, special emphasisshould be given to it. The disease was endemic in central Europe, but nowis well-established in France, Italy, Czechoslovakia, Poland, the Soviet Union,Denmark, and the United States. It first appeared in the United Statesat a brook trout hatchery in Pennsylvania and has spread as far west asCalifornia and Nevada. The obvious sign of tail-chasing (whirling) becomesevident about 40 to 60 days after infection and may persist for about Iyeaf.The whirling symptom is caused by erosion of the cranial cartilage, particularlyaround the auditory equilibrium organ behind the eye, by the trophozoitephase of the parasite. Infected fingerling trout can become soexhausted by the convulsive whirling behavior that they fall to the bottomand remain on their sides (Figure 98). In general, only young trout (fry tosmall fingerlings) exhibit whirling disease so it has been referred to as a"childhood disease." However, older fish can become infected even thoughthey show no clinical signs. Mortality has varied greatly among epizootics,sometimes minor, sometimes devastating.The complete life cycle of Myxosoma cerebralis has never been established.In the past, it has been thought that the sPores are ingested by fish, andthat the sporoplasm leaves the sPore, penetrates the intestinal mucosa, andmigrates to the cartilage where it resides as the trophozoite. However, thishypothesis has never been verified experimentally and other means of infectionmay be possible. Most recent studies suggest that the sPores are notinfective upon release from the fish, but must be aged in mud for 4-5months.External signs alone are not adequate for positive diagnosis of Myxosomacerebralis infections. Verification requires identification of the spore stage,

328 FISH HATCHERY MANAGEMENTFIcune 98. Characteristic signs of whirling disease in older fish that have survivedthe disease are a sunken cranium, misshapen opercles, and scoliosis of thespine due to the destruction of cartilage (arro*). (Courtesy G. L. Hoffman, FishFarming Experimental Station, Stuttgart, Arkansas.)which may not appear for 4 months after infection. In heavy infections,spores readily can be found in wet mounts or histological sections (Figure99). They are ovoidal (front view) or lenticular (in profile), and have twopyriform polar capsules containing filaments at the anterior end.Because of the seriousness of whirling disease, control and treatmentmeasures must be rigorous. Ideally, all earthen rearing units and water suPpliesshould be converted to concrete, followed by complete decontamination offacilities and equipment with high concentrations of such chemicals as sodiumhyprochlorite or calcium oxide. Allow the treated area to stand 4 weeks, cleanthoroughly, and repeat decontamination. New eggs or fry must be obtained from aknown uncontaminated source and raised in spore-free ponds or raceways for thefirst 8 months.PLEISTOPHORASeveral species of Pbistophora infect hatchery fish. As the name of the classMicrosporidea indicates, these are exceedingly small protozoans. Pleistophoraspores are about the size of large bacteria, 3-6 micrometers long andsomewhat bean shaped. Severe infections have been reported in the gills ofrainbow trout and in the ovaries of golden shiners. In golden shiners, theparasites infest up to about half of the ovary and significantly reduce thefecundity of broodstock populations.The only known control for Pbistophora in rainbow trout is prevention.Rainbow trout or their eggs should not be transferred from infected touninfected hatcheries. Broodstocks known to be infected should be phasedout and the rearing facilities decontamination.

FISH HEALTH MANAGEMENT 329Because there are no known stocks of golden shiners free of Pleistophoraouariae, proper management is the only answer to this problem. The severityof infections increases with age, so only one-year-old broodstock shouldbe used and all older fish destroyed.Trematode Diseases (M onogenetic)Monogenetic trematode parasites of fish can complete their life cycles onfish without involving other species of animals. Although the majority aretoo small to be seen by the naked eye, some species may reach 5 millimetersin length. The posterior organ of attachment, the "haptor," is used inidentification of different genera and species. There often are marginalhooklets around margin of the haptor and either zero' two' or four largeanchor hooks.Species of the family Gyrodactylidae generally are found on the bodyand fins of fish, rarely on the gills. These parasites move around freely'The members of this family give birth to live young similar in appearanceto the adults. They have no eye spots, 16 marginal hooklets, and two largeanchors.Species of the family Dactylogyridae are found commonly on the gills offish. Dactylogyrids lay eggs, and have eye sPots' one pair of anchor hooks,ld'.:l..:&".FiEijnr 99. Stained Myxosoma cerebralis spores in a histological section ofcartilage, 875x magnification. (Courtesy G. L. Hoffman, Fish FarmingExperimental Station, Stuttgart, Arkansas.)I

330 FISH HATCHERY MANAGEMENTand l6 marginal hooklets. Dactylogyrids are common on warmwater fishwhile Gyrodactylids are common on both trout and warmwater species.GTRODACTTLUSSpecies of Gyrodactylzr can be identified by the developing embryo insidethe adult as well as by their lack of eye spots. The haptor has two large anchorhooks and 16 marginal hooklets (Figrr." 100). These worms are socommon on trout that it is unusual to examine fish and not find them. Diagnosisis made from wet mounts of fin tissue or skin scrapings under a microscopeat 35x or l00x magnification (Figure 101). The parasites mayoccur in large numbers and cause skin irritation and lesions. Fish withlarge numbers of GyrodacQlus may appear listless, have frayed fins, andflash frequently. In ponds, they may gather in shallow water in denseschools. On salmonids, these parasites are removed easily by treating thefish with formalin at 167 to 250 parts per million for up to I hour, or at25parts per million in ponds with one or more treatments. Potassium permanganateat 2 to 3 parts per million for I hour should be tested as an alternatetreatment for formalin-sensitive trout.For warmwater fish, excellent results are obtained with Masoten (registeredwith the Food and Drug Administration) at 0.25 part per millionactive ingredient as an indefinite pond treatment. Other good pond treatmentsare copper sulfate at whatever concentration that can be used safely,and formalin at l5-30 parts per million.DACTTLOGTRUSDactylogyrus is but one genus of several dactylogyrids found on warmwaterfish. These worms are particularly serious parasites of cyprinids. Dactylogtrus,a small gill parasite, can be identified by the presence of four eyespots, one pair of anchor hooks, and 16 marginal hooklets (Figure 100).No embryos will be found internally, as these worms lay eggs. Theseparasites feed on blood and can cause serious damage to the gills of warmwaterfish when numerous. Clinical signs easily can be mistaken for thosecaused by an oxygen deficiency or other gill infections. Dactylogyrids easilyare controlled with 0.25 part per million active Masoten, copper sulfateat whatever concentration is safe, or 15-25 parts per million formalin as anindefinite pond treatment. Formalin at 125-250 parts per million for up toI hour is an effective bath treatment for raceways, tanks, or troughs.CLEIDODISCUSCleidodiscus sp. is common on the gills of catfish and a variety of otherwarmwater fish species. Llke Dactlloglrzq it has eye spots, but has four

FISH HEALTH MANAGEMENT 331I2FrcuRE 100. Gyodactylussp. (1)and Dartylogyus sp. (2).rl;{)',tdddFtcur.E 101. Glrodactllus on a rainbow trout(Courtesy G. H. Hoffman, Fish FarmingStuttgart, Arkansas.)fin, 35x magnification.ExperimentalStation,

332 FISH HATCHERY MANAGEMENTFrcuRE 102C leidodiscus sp.large anchor hooks (Figure 102) and lays eggs; unlaid eggs frequently maybe seen within the adult worm. Cleidodiscus is found only on the gillswhere, when numerous, it causes respiratory problems by severely damagingthe tissue. Signs of infection, therefore, are those of gill damage andmay be similar to those seen when oxygen is low.The most effective control is Masoten at 0.25 part per million as a pondtreatment. Other controls include formalin at 15-25 parts per million, 2parts per million potassium permanganate, or copper sulfate at whateverrate can be used safely as an indefinite pond treatment. In raceways, tanks,or troughs, use 125-250 parts per million formalin for up to I hour.Trematode Diseases (Digenetic)Digenetic trematodes require one or more animal hosts, in addition to fish,to complete their life cycles. These parasites can be divided into two majorgroups; (l) those that live in fish as adults, producing eggs that leave thefish to continue the life cycle, and (2) those that penetrate the skin of thefish and live in the fish as larvae, usually encysted in the tissue, until thefish is eaten by the final host.SANGUINICOLABlood flukes(Sanguinicola daaisi) live as adults in arterioles of the gillarches of salmonids and other fish species. These tiny worms lay eggs thatbecome trapped in the capillary beds of the gills and other organs, wherethey develop into miracidia that have a characteristic dark eye spot (Figure103). When fully developed, the ciliated miracidia burst from the gill to beeaten by an operculate snail, the only intermediate host in the life cycle.Cercaria emerge from the snail and penetrate fish to complete the cycle.The control of blood flukes is difficult. It depends upon either continualtreatment of infected water supplies to kill the cercaria, or eradication of

I.'ISH HEALI H MANACEMI.NT 333the intermediate host snails. In most cases, however, blood flukes are debilitatingbut not the cause of serious losses of fish. It is conceivable thatlarge numbers of miracidia leaving the gill at one time could cause a significantloss of blood and damage to the gills. Eggs and developing miracidiaalso interfere with the circulation of blood in the gill capillaries and in thecapillary beds of the kidney and liver.Copepod ParasitesMost copepods in fresh and salt water are an important part of the normaldiet of fish. Certain species, however, are parasitic on fish and the sites oftheir attachment may become ulcerated and provide access for secondaryinfections by fungi and bacteria. Crowded hatchery rearing units provideideal conditions for infestations by copepods because of the dense fish populationsand rich environmental conditions. Under most hatchery conditions,however, serious losses of fish seldom are caused by parasiticcopepods. The stocking of copepod-infested fish has infected wild fish instreams..s$a:, ,$t# Px{'.'*'.oGilY,\*tL *Jary',,,*-.Wrd.3i{..'!i":.,all.,sbJl&trTwfi8ri::s''ii _..,&. -t r "rtrt:;'#s1'"f.l:e lW;. ffu#,,t€'.&:.$,',,*',.;,,,{'l' **!':!.ry,,fq. '''''''';{...r: -.r...4 ..,rk ullii' ie. -sd tf-i; -sl ._*FIcunE 103. Sanguinicola daztisi,2,000x magnification. (Courtesy G. L. Hoffman,Fish Farming Experimental Station, Stuttgart, Arkansas.)

334 FISH HATCHERY MANAGEMENTARGULUSArgulus spp. have been given the common name of fish lice because of theirability to creep about over the surface of the fish. On first glance, theylook like a scale but, on closer examination, are seen to be saucer shapedand flattened against the side of the fish. They have jointed legs and twolarge sucking discs for attachment that may give them the appearance ofhaving large eyes (Figrrte 104). Argulids have an oral sting that pierces theskin of the host fish. They then inject a cytolytic substance, and feed onblood. If these organisms become abundant, even large fish may be killed.Masoten (registered by the Food and Drug Administration) at 0.25 Part Permillion active is used for the treatment of Argulus in ponds. Complete dryingof rearing units will kill eggs, larvae, and adults.LERNAEALernaea spp. are most commonly found on warmwater fish. However, onespecies, Z. elegans, lacks host specificity and even attacks frogs andsalamanders. Heavy infestations have caused massive mortality in carp andgoldfish populations. The parasite penetrates beneath scales and causes alesion at the point of attachment. The damage caused is associated withloss of blood and exposure to secondary infections by fungi, bacteria, andpossibly viruses.Lernaea are long (S-ZZ millimeters) slender copepods which, when attached,give the appearance of a soft sticks with two egg sacs attached atthe distal ends. Actually, the head end is buried in the flesh. This end haslarge, horn-like appendages that aid in identification of the parasite (FigureI 05).Ff cuRE 104. Argulu sp. Frcunr 105 Lernaea sp.

FISH HEALTH MANAGEMEN'I' 335Masoten at 0.25 part Per million active as a pond treatment, repeatedfour times at weekly intervals, gives good control of anchor worms. However,inconsistent results are obtained when water temperatures exceed80"F or when the pH is 9 or higher. During summer months, Masotentreatment should be applied early in the morning and it may be necessaryto increase the concentration to 0.5 part per million active for best results.Packing and Shipping SpecimensSeveral state agencies have laboratories with biologists trained in the diagnosisof fish diseases. In addition, several fish-disease laboratories and anumber of trained hatchery biologists in the United States Fish andwildlife Service are available for help in disease diagnosis. In recent yearsprivate consulting biologists also have set up practices in disease diagnosis.Correct diagnosis depends upon accurate and detailed information regardingthe fish and the conditions under which they were raised, andespecially upon the proper preparation of material that will be shipped to afish-disease laboratory. The more informationlikely that the diagnosis will be correct.If, after a preliminarythat is available, the morediagnosis in the hatchery, some treatment alreadyhas been started, specimens and information nevertheless should be sent toa disease laboratory for verification. Although the symptoms may seem typical,another disease may be present. It is not uncommon to have twodisease conditions present at the same time, one masking the other.Although treatments may be effective for one condition, the other diseasemay still be uncontrolled. Hatchery personnel should furnish the laboratorywith correctly collected and handled material, including all available information,at the earliest possible date. If the required information is not furnishedwith specimens, conclusiae diagnosis ma! not be possible.To facilitate the packing and shipping of proper specimens and information,a comprehensive checklist, such as the Diagnostic Summary Informationform (Figure 106), should be included. All instructions and questionsshould be read carefully. All questions should be answered. If an answercannot be furnished, or a question is not applicable, this should be indicatedin each case. When disease breaks out, specimens should be collectedand preserved before any treatment is given or started. Only a few fishshould be sent for examination, but these should be collected with the utmostcare. Dead fish or fish that appear to be normal are nearly worthless.The most desirable fish are those that show most typically the sings of thedisease in question. Moribund, but still liuing fish are the best for diagnosticpurposes.

336 FtsH HAiCHERY MANACEMEN]DIAGNOSTICSI.]N,IN{ARY INFORNlA'I'IONINS l Rtr(l'l IONS: l'rcparc in duplicatc, rctain onc c()pv at hatcher\'. Ansler all cltrestions,II in(orrnation is not available or not applicablc, pleasc che

FISH HEALTH MANAGEMENT)ra(i. t.tslt c()t.t.l.c t t.l) t()R SHIpNII..N l , IN(XIULA'I I()N ()l' NI!-l)IA. ()R li() I'H (I-ilelish arc srrpcrior lo prcscrvt'cl tish)-Na nl)cad n Nloribrrnrl n Appt'ar slightlv abnorrnal E Ilcalthv n\ot selcctcrl irr anr special rru* n7. I'Rl.\'l()t'S l'RI'.A'l Ntl'lNI (l{'anr)-Na n\rrrnbcr o{ tlcatrrrcnts: Hours -(iht'rnicul(s) usccl:Strlfirncrazinc fl'I crrar.r'r'in fl(lhlororrrvcetin nPN{A fI(lalonrcl nRoccal nlormalin nrlr l)avs-Othcrn.\t()R l.\t.il [,.s-Na EList on a scl):rr:rtc page pickofl bv davs, startine $ith the first dav nrortalities scernalrrtornral. and inclicatc on rvhich davs trcalmcnts wcrc administerecl, if anr'. Nlortaliticssliorrlcl bc listccl as incliviclual tnrughs or t:rnks,:rs rsell as bv lot. If cxperimental treatrlrcntsalc gircn, a scparate list ol rnrtalities in thc control troush should be itrcludecl.t). (;t_NF.Rr\l '\PP!-ARAN(lF--Na nNorrnal nSlLrugish !l"lashing E()t Ire r:Ncrvorrs and scarv nlloating listlcsslcr' trSrvirnrning upsidc trdo*rr or on the sideSpiraling or corkscrervingN{aking spasmocli( m()\'emcntsSinking (() the bottomRubbing against thc bottonln nnnI0. ,\PPr,;il r'r,.-Na flNorrnal ! Reclucecl E Refusc lood flI I. ARR.\N(;F-NII-N'I'IN \\',\'I'I.]R-NA LJNorrn:rl l)istribution n()asprna lor air !Schoolins nOrorvcling nater inlet nNc:rr .ttrhccFloating tou'ards outletDistribrrtion a( c\'('n rlistnnce. onc fish fir>rrt atrother, and facing water currcnt fl12. B()l)\'st Rl.ACl.-Na nNormal n /Bluish f ilm: in patchc, n .,. all over E/(]rarish-whitc, p,,t.h", n ,r. tuft,t n Srvollcn arcas;ts fumncles nl)ccp opcn lcsions uirh pus and bloocl n/Shallorv red ulcers: srnall E 1".g. !,/Nc.r.tic are:rs: ,"1,u.u,. n confluent n g."l' E 1,. b.,rrtn Eon hcari n all ovcr n lips and heacl especiallr' !/(]r:rrtulations: glass bcad-like n pcarl-like n or, fi., non boclr n variable in size !ntrFrcunr 106.Continued.

338 FISH HATCHERY MANAGEMENTI 2. B()l)\' St.Rt'A(ll'.-(lontinued:/Pi'poi.t pi,rplc, ! (lvsts n /l'inpoi't spots: lhite ! t'r black n,/l,arasircs: r'erv small, barcll visible, sofi E or longer, harcl fl (oftcn rrith srvallolltailaPPearance)/Irish abtrqrrnullv rlark: cntire br>dr'! r'ertain bocir ,r"u, fl Indicatc whcrc-(]r.r'th n or \\'arts I I.rcstrlar n prolifcrating fl u" "ttfot"n13. IrINS-Na !protrttdine froln: \'ent n nostrils nm()uth n eills flcol.r: fish b,,dr n ."d n bla'k flN.rnral E S*.llen n Necrotic ! !-r,r,ed!Bluish-whitc ! l'*istecl n Flroded !/Spots prescnt: ,uhitc! black n /Bl.ocl-s5ot n Parasitc present nl+. CAtrl),\I- Pl.I)LrN(,1.}.-Na !Sliehrlv Srgollcn E llluish-\\'tritc E Necrotic !\'".r S*.,11.,r n lultsus-like tulis prcsent n Inflarncd n15. (;ll.l-S-Na floovcrs opcn ..,rr" n Su'ollcn n Covercd with mucus, trthan norntallr'P:rtchcs: rvhite E br.rrrrt n g.or' n(ilr t.xANIINI..D (rNI)!lR \1I(IROS(]()PF-)food and dirt particlesFilarncnts ancl I-anrcllae: Swollen fl fused E club-shapcd Eballooned n(l()ttonv tufis present flSrnall gralish-whitc otriects: on filarncnts ! on lamcllae n(iolor o{ gills: dcep red n pale rcd Ihernorrhagic n16. NII-1S(ltrLA'l-trR!--Na Ebctween filaments fl benteen lamellae !Pale Pink nS,,res n or Iiuruncles ! fillcd uith..,d p,,,, n Srnall red,p.',t E.,,rcr fl1\\'tll detinctl ] ,,r filled with .r""-t n .,. .h".,r' fl contents{ .t.,. nHarrl cvsts likc sand grains: srnall nla.g" flblack nor 1'ellw flFrcun n 106.Continued.

F'ISH HEAI,TH MANAGEME,N'I' 33917. F-\'r.S-Na EN.rrnal n .puq.," n \\'hite: lens fl or ."rt,". nl inr spot i,r l.ns n Red spots in ..r.t"o EI'opevc n One erc missins n Bolh cves missing nIf a nccrlle is inserted in thc cve sockct and the cvc is pressed rvhile flsh head is under$ater, gas bubbles ! ,,. .rpu,1,l. fluid ! escapes.llJ. IX)D\' CAVI l'\'-Na !..\ppcars ,r,r.,nrl EExcessivc fluid present n,/l lrrid: (lolorlcss n ()paque ! Bloodv n,/l)r'escnt in linrng: Sp.rts nor Hcmorrhap;es E/\\'orrns: lapc-likc n or Rouncl n /Small (lrsts n19. IN I't S'IINAL 'I'RA(] f-Na flNormal nl)rnpt.v IFilled with food n/Fillcd with mucus: Colorless ! Yellow fl Reddish !Hind gut bloodv n Blood in vent n Stomach op",t"d nRound u'.rrns prcsent fl!'lat u'orms prcsent E20. t.lVFlR-Na flNormal n Rcd ! Yellow fl Bro*. n Pate EColor oI'coffee rvith .."o- ! Marbled ! Sp.rtty fl/Cvsts: Small n .,r- La.g. I/(lall Bladder Bile: (]reenish-vellow n \f'aterv Clear !or llluish-Black n21. SPLET-N-Na !Red EBlack-red n I'alc n Spottv nShrivelled ! SH'ollcn n Lu*pv n Grossly Enlarged E22. PYI-()RIC CAF-CA-Na flNorrnal !Worms inside EFuscd together nBloodshot !FIcunn 106.Swollen nContinued.

lJ40}ISH HA'I CHERY MANAGENlI]N]23. KIt)Nt\'-Na nN,,r rrral f] /l'irrp,,int Spots: ()rar n or White !(irar pustules: Hou rnanr':Snrall nLa.gc E\{hcre located:(lreamv consistcncv n(lhccsr

FISH HE,AI,'IH MANAGEMT]N1 341oxygen usually provide room for expansion. A general precaution is to usea double bag system, one bag filled and sealed within another. It is best toship a minimum number of specimens. Sick flsh and coldwater fish, such astrout, require greater volumes of water than healthy or warmwater fish.Twenty volumes of water for each volume of fish usually will be adequatefor healthy fish, but greater volumes should be provided for sick fish. Duringextreme hot or cold weather, insulated containers may be required.Expanded polystyrene picnic hampers provide good insulation but are relativelyfragile and require protection against damage. They should bepacked, therefore, in a protective corrugated cardboard box or other container.Coldwater fish usually ship better if ice is provided. The ice shouldbe packed in double plastic bags so that it will not leak when it melts.S hipping Preseraed SpecimensPreservatives typically are corrosive and odorous' Containers should be unbreakableand absorbent material should be provided in the event leakagedoes occurs. A good procedure is to fix the fish in a proper fixative for aday or two, then place the preserved fish, with a very small volume of fixative,in a plastic bag. The sealed bag should be placed within a secondplastic bag, which also should be sealed. This durable package has minimalweight. Select representative specimens. Examine them carefully to supplydata in the order given in the Diagnostic Summary Information form.Bouin's solution is a preferred fixative. Its recipe is: picric acid(da.rgero.rs), 17.2 grams; distilled water, 1,430 milliliters; formalin, 475 milliliters;glacial acetic acid, 95 milliliters. NOTE: picric acid explodes whenrapidly heated. Handle accordingly. Weigh picric acid and place crystals ina pyrex container large enough to hold 2 liters (2,000 milliliters) and adddistilled water. Heat on a stove. Stir occasionally until all crystals are dissolved.Do not boil the solution. When crystals have dissolved, remove thesolution from the stove and cool it completely. Add the formalin and glacialacetic acid to the cooled solution. Stir briefly and pour the mixtureinto a jar. This solution will keep well, but should be protected fromfreezing.Volume of the fixative should be at least five to ten times that of thefish or tissue. (Thus, put only one 6-inch fish in a pint of fixative.) Fishand tissues should be left in the fixative for at least 24 hours, and then thefixing solution replaced with 65(/0 ethyl alcohol. However, if alcohol is notavailable, retain the specimens in Bouin's fluid.To facilitate fixation, fish, regardless of size, should be slit down the abdomenfrom the anus to the gills. The air bladder should be pulled out andbroken to permit fixation of the kidney. The kidney of 6-inch or larger fishshould be split along its entire length. The intestines and other organs

342 FISH HATCHERY MANAGEM EN.Tshould be slit if the fish are larger than fingerlings. It also is desirable tocut the skin along the back of the fish. If the fish are larger than 6 inches,the cranial cap should be opened to facilitate fixation of the brain. Theimportance of these incisions cannot be overemphasized. If the fish are toolarge to ship whole, cut pieces from individual tissues (gill, heart, liver,etc.), and especially any lesions observed. These pieces should not be largerthan one-half inch square and one-quarter inch thick.Commercial formalin (containing about 40% formaldehyde) also can beused for preserving specimens and should be mixed with nine parts of waterto make approximately a 10% formalin solution.Unless the lesions are very clear and obvious, always preserve severalhealthy specimens of the same size and age as the sick fish, and send themat the same time in a separate container. This important step often determineswhether or not the disease can be diagnosed.Fish Disease LeafletsThe Fish Disease Leaflet (FDL) series is issued by the United States Fishand Wildlife Service in order to meet the needs of hatchery personnel forspecific information on fish diseases. Each Fish Disease Leaflet treats a particulardisease or parasite, and gives a brief history of the disease, its etiology,clinical signs, diagnosis, geographic range, occurrence, and methods ofcontrol. As new information becomes available, the Fish Disease Leafletsare revised. They are distributed from the Library, National FisheriesCenter (Leetown), Route 3, Box 41, Kearneysville, West Virginia 25430. Inthe following list, leaflets that have been superseded by more recent onesare omitted.FDL-I.FDL-2.FDL-5FDL-6.FDL-9.FDL-13.Infectious pancreatic necrosis (tpN) of salmonid fishes. KenWolf. 1966. 4 p.Parasites of fresh water fish. II. Protozoa. 3. Ichthyophthirus mul'tifilis.Fred P. MeYer. 1974.5 P-Parasites of fresh water fish. IV. Miscellaneous. Parasites of catfishes.Fred P. Meyer. 1966. 7 P.Viral hemorrhagic septicemia of rainbow trout. Ken Wolf'1972.8 p.Approved procedure for determining absence of viral hemorrhagicsepticemia and whirling disease in certain fish and fishproducts. G. L. Hoffman, S. F. Snieszko, and Ken Wolf. 1970.7p.Lymphocystis disease of fish. Ken Wolf. 1968. 4 p.

FISH HEALTH MANAGEMENT 343FDL-I5.Blue-sac disease of fish. Ken Wolf' 1969' 4 p'FDL-19. Bacterial gill disease of freshwater fishes. S. F. Snieszko. 1970.FDL-20.FDL-21.FDL-22.FDL-24.FDL-25.FDL-27.4p.Parasites of freshwater fishes. II. Protozoa. l. Microsporida offishes. R. E. Putz. 1969. 4 P.Parasites of freshwater fish. I. Fungi. l. Fungi (Saprolegnia arldrelatives) of fish and fish eggs. Glenn L' Hoffman' 1969' 6 p'White-spot disease of fish eggs and fry' Ken Wolf' 1970' 3 p'Ulcer disease in trout. Robert G. Piper' 1970' 3 p'Fin rot, cold water disease, and peduncle disease of salmonidfishes. G. L. Bullock and S. F. Snieszko' 1970' 3 p'Approved procedure for determining absence of infectious pancreaticnecrosis (IPN) virus in certain fish and fish products'Donald F. Amend and Gary Wedemeyer' 1970' 4 p'FDL-28. Control and treatment of parasitic diseases of fresh water fishes'Glenn L. Hoffman. 1970.7 P.FDL-3 l. Approved procedure for determining absence of infectioushematopoietic necrosis (Iff N) i" salmonid fishes' Donald F'Amend. 1970. 4 P.FDL-32. Visceral granuloma and nephrocalcinosis. Roger L. Herman.r97r.2 P.FDL-34. Soft-egg disease of fishes. Ken Wolf. 197 l' I p'FDL-35. Fish virology: procedures and preparation of materials for plaquingfish viruses in normal atmosphere. Ken Wolf and M' C'QuimbY. 1973. l3 P.FDL-36. Nutritional (di"tary) gill disease and other less known gilldiseases of freshwater fishes. S. F. Snieszko' 1974' 2 p'FDL-37. Rhabdovirus disease of northern pike fry. Ken Wolf' 1974' 4 p'FDL-38. Stress as a predisposing factor in fish diseases' Gary A'Wedemeyer and James W. Wood. 1974' 8 p'FDL-39. Infectious hematopoietic necrosis (IHN) vtus disease. DonaldF. Amend. 1974.6 P.FDL-40. Diseases of freshwater fishes caused by bacteria of the generaAeromonas, Pseudomonas, and Vibrio. S' F' Snieszko and G' L'Bullock. 1976. 10 P.FDL-41. Bacterial kidney disease of salmonid fishes. G. L. Bullock, H.M. StuckeY, and Ken Wolf. 1975' 7 P'FDL-43. Fish furunculosis. s. F. Snieszko and G. L. Bullock. 1975. l0 p.FDL-44. Herpesvirus disease of salmonids. Ken Wolf, Tokuo Sano, andTakahisa Kimura. 1975' 8 P'FDL-45. Columnaris disease of fishes. s. F. Snieszko and G. L. Bullock.1976. 10 P.

344 FISH HATCHL,RY MANAGEMENTFDL-46.Parasites of freshwater fishes. IV. Miscellaneous. The anchorparasite (Lernaea elegans) and related species. G. L. Hoffman'1976. 13 p.FDL-47. Whirling disease of trout. G. L. Hoffman. 1976. 10 p.FDL-48.l-DL-49.Copepod parasites of freshwater fish: Ergasilus, Achtheres, andSalmincola. G. L. Hoffman. 1977. l0 p.Argulus, a branchiuran parasite of freshwater fishes. G. L. Hoffman.1977. 9 p.FDL-50. Vibriosis in fish. G. L. Bullock. 1977. ll p.FDL-51. Spring viremia of carp. Winfried Ahne and Ken Wolf. 1977.ll p.FDL-52. Channel catfish virus disease. John A. Plumb. 1977. 8 p.FDL-53. Diseases and parasites of fishes: an annotated list of books andsymposia, with a list of core journals on fish diseases, and a listof Fish Disease Leaflets. Joyce A. Mann. l97t). 77 p.FDL-54. Pasteurellosis of fishes. G. L. Bullock. 1978. 7 p.FDL-55. Mycobacteriosis (tuberculosis) of fishes. S. F. Snieszko. 1978.FDL-56.!, P.Meningitis in fish caused by an asporogenous anaerobic bacterium.D. H. Lewis and Lanny R. Udey. l97ti' 5 p.FDL-57. Enteric redmouth disease of salmonids. G. L. Bullock and S. F.Snieszko. l!)79. 7 P.FDL-5U. Ceratomyxa shasta in salmonids. K. A. Johnson, J. E. Sanders,andJ. L. Fryer. 1979. ll p.BibliographyALLISoN, R. 1957. A preliminary note on the use of di-n-butyl tin oxide to remove tapewormsAvENo,Anlecul,n,from fish. Progressive Fish-Culturist l9(3):l2l]-130' 192.D. F. 1976. Prevention and control of viral diseases of salmonids. Journal of theFisheries Research Board of Canada 33(4,2):1059 1066.and A. J. Ross. 1970. Experimental control of columnaris disease with a new nitrofurandrug, P l73l{. Progressive Fish-Culturist 112{l\:19-2r.and L. Svtru.1974. Pathophysiology of infectious hematopoietic necrosis virusdisease in rainbow trout (Salmo gairdneri): early changes in blood and aspects of theimmune response after injection of IHNof Canada 31 (8):137l-1378.virus. Journal of the Fisheries Research BoardE. 1970. Textbook of fish diseases. Translation by D. A. Conroy and R. L. Hermanof Taschenbuch der Fisthkrankheiten, 1961. T.F.H.New Jersey. 1302 p.Publications, Neptune City,ANDERSoN, B. G., and D. L. MITcHUM. 1974. Atlas of trout histology. WyomingFish Department Bulletin 13. I l0 p.Game and

FISH HEALTH MANAGEMENT 345ANDERSoN, D. P. 1974. Fish immunology.239 p.T.F.H. Publications, Neptune City, New Jersey.AN'rIPA, R., and D. F. AutNo. 1977. Immunization of Pacific salmon: comparison of intraperitonealinjection and hyperosmotic infiltration of Vibrio anguilarum and Aeromonas salmonicidabacterins. Journal of the Fisheries Research Board of Canada 34(2):203-208.Beurn, O. N. 1959. Parasites of freshwater fish and the biological basis for their control. Bul-Brll,letin of the State Scientific Research Institute for Lake and River Fish, Leningrad,USSR, volume 49.226 p. English translation as Office of Technical Service 6l 31056,Department of Commerce, Washington, D.C.G. R. 1977. Aspects of defense mechanisms in salmonids. Pages 56-71 in Proceedings ofthe international symposium on diseases of cultured salmonids. Tavolek, Redmond,Washington.BucuerveN, R. E., and N. E. GIBBoNS. 1974. Bergey's manual of determinative bacteriology,tlth edition. Williams and Wilkins, Baltimore, Maryland.Bur-locx, Gxeueu L. 1971. The identification of fish pathogenic bacteria. T.F.H. Publications,Jersey City, New Jersey. 4l p.and DteNr CoLLls. 1969. Oxytetracycline sensitivity of selected fish pathogens. USBureau of Sport F'isheries and Wildlife, Technical Paper 32.DevIo A. Cotttov.and S. F. SNtEszKo. 1971. Bacterial diseases of fishes. T.F.H. Publications,Jersey City, New Jersey. 151 p.and J. A. Mcl-eucsI-rn-. 1970. Advances in knowledge concerning bacteria pathogenicto fishes (tgS+ tS0A). American Fisheries Society Special Publication 5:231-242.Devts, H. S. 1953. Culture and diseases of game fishes. University of California Press, Berkeley.332 p.DocrEL, V. A., G. K. Pnnusntvsrt, and YU. K. PoLYANSKI. 1961. Parasitology of fishes.Oliver and Boyd, Edinburgh and London.Du.;rN, C. vAN. 1973. Diseases of fishes, 3rd edition. Charles Thomas, Springfield, Illinois.EHLINGER, N. F. 1964. Selective breeding of trout for resistance to furunculosis. New YorkFish and GameJournal l1(2):7U 90.1977. Selective breeding of trout for resistance to furunculosis. New York Fish andGame Journal 21 (l) :25-36.EvELyN, T. P. T. 1977. Immunization of salmonids. Pages l6l 176 iz Proceedings of theInternational Symposium on Diseases of Cultured Salmonids. Tavolek, Seattle, Washrngton.Fr3eu, N. N., T. L. WELLBORN, and J. P. NAFTEL. 1970. An acute viral disease of channel catfish.US Fish and Wildlife Service Technical Paper 43.FRyrR, J. L., J. S Rr-rHovEc, G. L. Trnnrr', J. S. McMIcHAEL, and K. S. PILCHER. 1976.Vaccination for control of infectious diseases in Pacific salmon. Fish PathologyI 0 (2) :1 55-l 64.FuJIHARA, M. P., and R. E. Nexlren-t. 1971. Antibody production and immune responses ofrainbow trout and coho salmon to Chondrococcus columnaris. Iournal of the FisheriesResearch Board of Canada 28(9):1253-125t{.Gerntson, R. L., and R. W. GouLD. 1976. AFS 67. Vibrio immunization studies. FederalAid Progress Reports, Fisheries (PL u9-304), US Fish and Wildlife Service,Washington, D.C.GnrrnrN, P. J. 1954. The nature of bacteria pathogenic to fish. 'Iransactions of the AmericanFisheries Society 83:241-253.S. F. SNrEszKo, and S. B. Fntooll. 1952. A more comprehensive description of Barteriumsalmonicida. Transactions of the American Fisheries Society tl2:129-13{1.Gxtzzrr., J. M., and W. A. RocERs. 1976. Anatomy and histology of the channel catfish.Agricultural Experimental Station, Auburn University, Auburn, Alabama. 04 p.

346 FISH HATCHERY MANAGEMENTHterlrwtlt-, C. M., lII. 1975. Immune response and antibody characterization of the channelcatfish (Ictalurus punctatus) to a naturallyWildlife Senice Technical Paper 85.HERMAN, RocERpathogenic bacterium and virus. US Fish andLEE. 1968. Fish furunculosis 1952-1966. Transactions of the AmericanFisheries Society 97 (3) :22 l-230.- 1970. Prevention and control of fish diseases in hatcheries. American Fisheries SocietySpecial Publication 5:3-15.HEsrER, E. F. 1973. Fish Health: A nationwide survey of problems and needs. ProgressiveFish-Culturist 35(1) : I 1-18.HoFFMAN, Glr,NN L. 1967. Parasites of North American freshwater fishes. University of CaliforniaPress, Berkeley. 486 p.1970. Control and treatment of parasitic diseases of freshwater fishes. US Bureau ofSport Fisheries and Wildlife, Fish Disease Leaflet 28. 7 p.1976. Fish diseases and parasites in relation to the environment. Fish Pathology10(2):123-128.and F. P. MEYER. 1974. Parasites of freshwater fishes: a review of their control andtreatment. T.F.H. Publications, Neptune City, New Jersey.224 p.JoHNsoN, HARLAN E., C. D. ADAMS, and R. J. McElnerH. 1955. A new method of treatingsalmon eggs and fry with malachite green. Progressive Fish-Culturist 17\2):76-78.LEITRITZ, E. and R. C. LlwIs.1976. Trout and salmon culture (hatchery methods). CaliforniaDepartment of Fish and Game, Fish Bulletin 164.LEwts, W. M., and M. BENDER. 1960. Heavy mortality of golden shiners during harvest due toa bacterium of the genus Aeromonas. Progressive Fish-Culturistand -.22ll):ll-14.1960. Free-living ability of a warmwater fish pathogen of the genus Aeromonasand factors contributingCulturist n$) :124-126.to its infection of the golden shiner. Progressive Fish-LovELL, R. T. 1975. Nutritional deficiencies in intensively cultured catfish. Pages 721 731 inW. E. Ribelin and G. Migaki, editors. The pathology of fishes. University of WisconsinPress, Madison.MAJoR, R. D., J. P. McCRaRrN, and C. E. SMITH. 1975. Histopathological changes in channelcatfish (Ictalurus punclatus) experimentallyand naturally infected with channel catfishvirus disease. Journal of the Fisheries Research Board of Canada 32(4):563 567.McCRenrN, J. P., M. L. Lervoolr, G. L. HorrlreN, and F. P. MEvER. 1975. Variation inresponse of channel catfish to Hennegula sp. infections (Protozoa: Myxosporidea). Journalof Wildlife Diseases I l:2-7.Mevnx,F. T. WRIcHT, and R. M. JoNES. 1974. Bibliography of the diseases and parasites ofthe channel catfish (lctalurus punclatus Rafinesque). Wildlife Disease Number 65. (Microfiche.)F. P. 1964. Field treatment of Aeromonas liquefaciens infections in golden shiners. ProgressiveFish-Culturist 26(l) :33-35.1966. A new control for the anchor parasite, Lernaea clprinacea. Progressive Fish-Culturist 28(l) :33-39.1966. A review of the parasites and diseases of fishes in warmwater ponds in NorthAmerica. Pages 290-318 rz Proceedings of the Food and Agricultural Organization ofthe United Nations World Symposium on Warmwater Pond Fish Culture, Rome, Vol.5.1969. Dylox as a control for ectoparasites of fish. Proceedings of the Annual Confer'ence Southeastern Association of Game and Fish Commissioners 22:392-396.and J. D. Corren. 1964. Description and treatment of a Pseudomonas infection inwhite catfish. Applied Microbiology I 2 (3) :201-203.

FISH HEALTH MANAGEMENT 347Pluur, J. A. 1972. Channel catfish virus disease in southerr' United States. Proceeding of theAnnual Conference Southeastern Association of Game and Fish Commissioners25:489-493.Purz,-. 1972. Effects of temperature on mortality of fingerling channel catfish (Ictalurus lunctatus)experimentally infected with channel catfish virus. Journal of the Fisheries ResearchBoard of Canada 30(4):568-570., EDIToR. 1979. Principal diseases of farm-raised catfish. Southern Cooperative SeriesNumber 225.R. R., G. L. Hornrr.tet, and C. E. DuNBAR. 1965. Two new species of Plistophora (Microsporidea)from North American fish with a synopsis of Microsporidea of freshwaterand euryhaline fishes. Journal of Protozoology l2l2):228 236.RErcHrNsecH-KLTNKE, HEINz-HERMANN, and E. ElrlN.vertebrates. Academic Press, New York. 600 p.1965. The principal diseases of lowerRocK, L. F., and H. M. NELsoN. 1965. Channel catfish and gizzard shad mortality caused byAeromonas liquefaciens Progressive Fish-Culturist 27(3) :138-141.S,tNorns, J. E., and J. L. FRYER. 1980. Renibacterium salmoninarum gen. nov., sp. nov., thecausative agent of bacterial kidney disease in salmonid fishes. International Journal ofSystematic Bacteriology 30:496-502.Strltru, L. S., and G. R. BELL. 1975. A practical guide to the anatomy and physiology ofSNIrszxo,Pacific salmon. Canada Department of Fisheries and Oceans Miscellaneous SpecialPublication 27.S. F. 1973. Recent advances in scientific knowledge and developments pertaining todiseases of fishes. Advances in Veterinary Science and Comparative Medicine17:291-314.editor. 1970. A symposium on diseases of fishes and shellfishes. AmericanFisheries SocietySpecial Publication 5.525 p.Suluurnrrlr, R. C. 1964. A new microsporidian parasite from the golden shiner, Notemigonuserysoleucas- Transactions of the American Fisheries Society 93(1):6-10.VEGINA, R., and R. Drsnocsnns.1971. Incidence of Aeromonas hldrophila in the perch, Percaflauescens Mitchell. Canadian Journal of Microbiology 17: 1 101-l 1 I 4.WEDEMEvER, G. A. 1970. The role of stress in the disease resistance of fishes. AmercianFisheries Society Special Publication5:3(F34.F. P. MEYER, and L. Slrtru. 1976. Environmental stress and fish diseases. T.F.H. Publications,Nepturn City, New Jersey. 192 p.and J. W. WooD.1974. Stress as a predisposing factor in fish diseases. US Fish andWildlife Sewice, Fish Disease Leaflet 38. 8 p.WELLBoRN, THoMAS L. 1967. Trichodina (Ciliutu' Urceolariidae) of freshwater fishes of thesoutheastern United States. Journal of Protozoology l4(3):399-412.1979. Control and therapy. Pages 61-85 lz Principal diseases of farm-raised catfish.Southern Cooperative Series Number 225.and WILUEn A. RocERS. 1966. A key to the common parasitic protozoans of NorthAmerican fishes. Zoology-Entomology Department Series, Fisheries No. 4, AgriculturalExperimental Station, Auburn University, Auburn, Alabama. 17 p. (mimeo.)Wooo, J. W. 1974. Diseases of Pacific salmon: their prevention and treatment,2nd edition.Washington Department of Fisheries, Seattle.

Transportation of LiveFishesOne extremely important aspect of fish culture and fisheries managementis the transportation of live fishes from the hatchery to waters in whichthey are to be planted. The objective of this function is to transport asmany fish as possible with minimal loss and in an economical manner. Thisoften involves hauling large numbers of fish in a small amount of water,and, depending upon the time involved, can result in extensive detenorationof water quality. Sometimes fish arrive at the planting site in poorphysiological condition due to hauling stresses, and may die at the time ofplanting or shortly thereafter.Transportation EquipmentVehiclesFish are transported in a variety of ways, ranging from plastic containersshipped via the postal service to complex diesel truck-trailer units. Airplanesand seagoing vessels are used to a limited degree (Fig.rre 107). Theextensive stocking of Lake Powell by airplane with rainbow trout andlargemouth bass involved a large, coordinated effort involving severalhatcheries and numerous Dersonnel.348

]'RANSPOR'I'A'IION OF LIVE FISHES 349Ftc;unn 107.Airplane stocking of trout in a remote lakeMaine Department of Inland Fisheries and Wildlife.)(Courtesy Bill Cross,Frcunr l0U. Fish distribution tank mounted on a gooseneck trailer. This unitcan be pulled by a pickup truck.

350 FISH HATCHERY MANAGEMENTTrucks are the principal means of transporting fish. Most hatcheriescurrently use vehicles near 18,000 pounds gross vehicle weight (GVW)'However, units from 6,000 to over 45,000 pounds GVW often are used formoving fish.Automatic transmissions are becoming common in all trucks. Automaticshifting reduces engine lugging or overspeeding, and allows the driver toconcentrate on defensive driving rather than on shifting gears'Diesel engines also are gaining in popularity. Minimal service and longlife are attractive features but the high initial cost is a major disadvantage.Cab-over trucks are popular in many areas especially where a short turningradius is important. Conventional-cab trucks generally are quieter, havebetter directional stability, and a less choppy ride because of their longerwheelbase.A relatively new and promising innovation in warmwater fish transportationis the combined use of gooseneck trailers and pickup trucks. Theseunits are low in cost yet very versatile (Figure 108).Tank DesignMost new fish-distribution tanks are constructed of fiber glass or aluminum,but plywood, redwood, stainless steel, glass, galvanized iron, andsheet metal all have been utilized in the past.Aluminum is lightweight, corrosion-resistant, and easily mass-produced.Alloys in the range 3003H14 to 6061T6 will not cause water-quality problems.Fiber glass is molded easily into strong, lightweight tanks and can berepaired readily. Its smooth surface is simple to clean and sanitize. Aluminumand fiber glass appear equallT well-suited for fish-transport tanks.Most tanks constructed in recent years are insulated, usually with styrofoam,fiberglass, urethane, or corkboard. Styrofoam and urethane are Preferredmaterials because of their superior insulating qualities and theminimal effect that moisture has on them. A well-insulated tank miminizesthe need for elaborate temperature-control systems and small amounts ofice can be used to control the limited heat nses.Circulation is needed to maintain well-aerated water in all parts of thetank. Transportation success is related to tank shape, water circulation pattern,aerator type, and other design criteria'The ff factor is the basis for comparing insulation materials. It is theamount of heat, expressed in BTU's, transmitted in I hour through Isquare foot of material I inch thick for each degree Fahrenheit of temperaturedifference between two surfaces of a material. The lower the ff factor,the better the insulating quality. The following is a list of insulating materialsand their respective -K factors:

TRANSPORTA'I'ION OF LIVL, F'ISHES 351Expanded vermiculiteOakPineCorkStyrofoamFiber glassUrethane1.601.180.740.290.280.250.18"fhe K values indicate that pine must be 4 times as thick as urethane togive the same insulating quality. Generally, combinations of various materialsare used in fabricating distribution tanks.The distribution tank in Figure 109 is constructed with marine plywood,insulated with styrofoam and covered inside and out with fiber glass. Unitsvary in size and may contain several compartments.Warmwater distribution tanks generally are compartmented. Compartmentsfacilitate fish stocking at several different sites on a single trip, permitseparation of species, and act as baffles to prevent water surges. Thenumber of compartments used in tanks ranges from two to eight, four beingmost common. Tanks in current use have 300-700-gallon capacities,averaging about 450 gallons. However, 1,200-gallon tanks occasionally areused to transport catchable size catfish, trout, and bass.Although most tanks presently in use are rectangular, the trend in recentyears has been towards elliptical tanks, such as those used to transportmilk. This shape has several advantages.FIGURE 109. Fiberglass distribution tank with four compartments, each with anelectric aerator (p..o*). Additional oxygen is provided through carbon rods ormicropore tubing on the bottom of the tank. (M.Ne.r.ry National Fish Hatchery,FWS.)

352 FISH HATCHERY NlANAC; EMEN.'f(1) "V"-shaped, elliptical, or partially round tanks promote better mixingand circulation of water as the size of the tank increases.(2) Polyurethane insulation, which has the best insulating qualities, lendsitself ideally to a round or oval tank. It can be injected easily within thewalls of the tank.(3) These tanks can be constructed with few structural members andwithout sharp corners that might injure fish.(4J Rapid ejection of fish is facilitated by an elliptical tank.(5) Lowering the water level in these tanks reduces surface area and simplifiesthe removal of fish with dip nets. The rounded bottom also contributesin this respect.(6) As this shape of tank is widely used by bulk liquid transport companies,thev are mass-produced and readily available.(Z) f nis shape conforms to a truck chassis and holds the center of gravitytowards the area oI greatest strength.(8) Construction weight is iess than that of rectangular tanks of the samecapacity.CirculationCirculation systems are of various sizes and designs; all have plumbing addedfor the pickup and discharge of water. Suction lines to the pumps lieon the bottom of the tank and are covered by perforated screens. Water iscarried to the pumps and then forced through overhead spray headsmounted above the waterline. In most systems, oxygen is introduced in oneof the suction lines just ahead of the pump. This usually is controlled by amedical gas-flow meter; because of the danger involved in handling andtransporting bottled oxygen, care must be taken to follow all prescribedsafety procedures.Self-priming pumps powered by gasoline engines are used to circulatewater in many distribution units. Pumps may be close-coupled or flexiblycoupled. Althoughthe former type is more compact, it tends to transferheat to the water. Depending upon ambient air temperature, close-coupledpumps may increase the temperature of 400 gallons of water by about 7"Fan hour, whereas flexible coupling will reduce heat transfer to approximately3'F per hour.Pipes used in conjunction with pumps usually are black or galvanizedsteel. Althoughsteel is durable, threads may rust, and replacement ormodification following installation may prove difficult. Aluminum pipe alsohas been used in systems of this type, but its advantages and disadvantagesare reportedly similar to those of steel except aluminum pipe does not rust.Because of the ease of installation, plastic pipe should be considered for

TRANSPORI'ATION OF LIVE FISHES 353use. It is noncorrosive, lightweight, and easy to assemble, modify, andremove.Friction reduces water flow through a circulation system if there is anexcess of pipe fittings. Further, the diameter of piping should not be reducedwithin the system except at the spray devices.Generators and electric pumps or aerators sometimes are used, especiallyon larger trucks or trailers with multiple tanks. This eliminates the needfor many small engines with all their fuel and maintenance problems. Heatand noise problems are minimized by placing the generator on the rear ofthe unit.A method of circulating water with 12-volt mechanical aerators uses carbonrods and micropore tubing for dispensing oxygen (Figu.e 110). Aeratorsalone may not be sufficient to provide the oxygen needed to transportlarge loads of fish, but a supplemental oxygenation system can increase thecarrying capacity of the transportation tank. Some advantages of aeratorsystems over gasoline-driven water pump systems are:(l) Temperature increases from aerators are less than l'F per hour, comparedwith 2.5'F with pumps.(2) Aerators and the oxygen injection system can operate independently.There are advantages to carrying small sizes of certain species of fish onoxygen alone. Oxygen also can be used as a temporary backup system ifaerators fail.(3) Usually, aerators have fewer maintenance problems.(4) Costs of recirculating equipment and aerators strongly favor aerators.(5) Use of aerators eliminates the space required between the tank andtruck cab for pumps and plumbing, so the overall truck length can bereduced to assure safer weight distribution. The empty weight of a truckwith a 1,250-gallon tank equipped with aerators is 14,000 pounds-2,000pounds less than a similar unit operating with pumps and refrigeratron.The most efficient tanks have the highest water circulation rates, but circulationrates must be balanced with water capacity. Pumping or aeratingsystems should be able to circulate at least 409i of the tank water perminute when 8-9-inch salmonids are hauled, though lesser rates are appropriatefor smaller fish.AerationThe purpose of aeration during transport is to provide oxygen and toreduce the concentration of carbon dioxide. The exchange of gasesbetween water and the atmosphere is a recognized and important problemin transporting fish. Transport water must contain adequate oxygen, pH

FISH HATCHERYMANAGEMENTFIcunn 110. Aerator-oxygen system designed and tested by FWS personnel atAlchesay National Fish Hatchery, New Mexico. (l) Aerators mounted on top ofan aluminum tank. Note the electrical line for the l2-volt system. (2) Aeratorwith a dual manifold extending through the false bottom of a tank. Water ispulled through manifold (M) ana discharged through aerator (e). (g) Aerator inoperation. Water is aerated and circulated and carbon dioxide is removed. (4)The false bottom of the tank has been removed to show micropore tubing(arrow) which disperses oxygen into the water. Note bubbling of oxygen throughthe water. (Photos courtesy Alchesay National Fish Hatchery, FWS.)levels must remain within a tolerable range, and toxic levels of dissolvedammonia and carbon dioxide must be suppressed. A partial solution to thiscomplex problem is aeration by sprays, baffles, screens, venturi units,compressed gas liberation, agitators, or air blowers. Bottled gaseous orliquid oxygen is liberated within tanks in a variety of ways, including perforatedrubber tubing, carborundum stones, carbon rods, and microporetubing, or is injected directly into the recirculation system.Recent aeration innovations include a miniature water wheel that aerateswater during transport and the Fresh-flo@ aerator. The latter is commerciallyavailable in ten sizes. The system depends upon centrifugal forcecreated by a high speed motor-driven impellor that pulls water into a systemof vanes, producing the turbulence needed to mix water with air,while concurrently rernoving carbon dioxide. This aerator has been highlysatisfactory for transportation of warmwater fish and salmonids.

TRANSPORTATION OF LIVE FISHESThe formation of scum and foam on the surface of transport water mayresult from drug usage or excessive mucus produced by large numbers offish hauled over long distances. Excessive foaming interferes with observationof fish during transit and inhibits aeration. To alleviate this problem, a10,)l solution of Dow Corning's Antifoam AF emulsion should be used atthe rate of 25 milliliters per 100 gallons of water. For maximum effectiveness,the compound should be mixed in before drugs are added or fishloaded. Antifoam is nontoxic to fish.Water QualityOxygenThe most important single factor in transporting fish is providing an adequatelevel of dissolved oxygen. However, an abundance of oxygen withina tank does not necessarily indicate that the fish are in good condition.The ability of fish to use oxygen depends on their tolerance to stress, watertemperature, pH, and concentrations of carbon dioxide and metabolicproducts such as ammonia.The importance of supplying sufficient quantities of oxygen to fish indistribution tanks cannot be overemphasized. Failure to do so results insevere stress due to hypoxia and a subsequent buildup of blood lactic acid,and may contribute to a delayed fish mortality. Ample oxygen suPPressesharmful effects of ammonia and carbon dioxide. Dissolved-oxygen contentof transport water preferably should be greater than 7 parts per million,but less than saturation. Generally, as long as the oxygen concentration isat least 6 parts per million, salmonids have ample oxygen; however' shouldcarbon dioxide levels increase' more oxygen is required by the fish' Oxygenconsumption by fish increases dramatically during handling and loadinginto the transportation tank. For this reason, additional o*yg".t (asmuch as twice the flow normally required) should be provided during loadingand the first hour of hauling. The oxygen flow can be reduced to normallevels (to provide 6 parts per million in the water) after this acclimationperiod, when the fish have become settled and oxygen consumptionhas stabilized (see Slrass, page 358)'The addition of certain chemicals such as hydrogen peroxide has beeneffective in increasing the oxygen concentration in water. However, a morepractical and economical method is to introduce oxygen directly from pressurizedcylinders into the circulating water.Control of water temperature, starving fish before they are transported,and the addition of chemicals and anesthetics to the water have reducedhauling stress.

356 FISH HATCHERY MANAGEMENTTemperatureInsulation and ice have been used to control the temperature of transportwater. Ice sometimes is difficultto find during a delivery trip and cancause damage to fish and tanks if used in large pieces. The main advantageof ice is its simplicity;that can break down.it involves no mechanical refrigeration equipmentRefrigeration units are being used increasingly to mechanically controlwater temperature. Such units are expensive and require careful maintenance.Large units easily justify the cost of refrigeration but small systemsrequire additional development before they become economical (Figure111).Because temperature is such an important factor, it should be continuouslymonitored and controlled. Electric thermometers are readily availableand inexpensive, and provide monitoring of temperature from the truck cab.Temperature strongly influences oxygen consumption by fish; the lowerthe temperature, the lower the oxygen consumption. For each l'F rise intemperature, the fish load should be reduced by about 5.60/o; conversely, foreach l"F decrease in temperature, the load can be increased about 5.6%.Thus, if a distribution tank will safely hold 1,000 pounds of 9-inch trout in52"F water, an increase in temperature to 57"F decreases the permissibleload by 27 .8olo (5' x 5.56%), o, to 722 pounds. If the water temperature isdecreased from 52'F to 47"F, the load-can be increased by 27.8% to 1,278pounds.***tFtcunn 111. Aluminum elliptical tank with refrigeration unit mounted at thefront. Aeration is by gas-driven pumps and pure oxygen. Note air scoops (arro*)for CO2 removal on front and rear of tanks. (Ennis NationalFWS.)Fish Hatchery,

]'RANSPORTATION OF LIVE FISHES 357AmmoniaWhen fish are transported in distribution tanks, their excretory productsaccumulate in the water. Ammonia is the main metabolic product of fishand is excreted through the gills. Total ammonia concentrations can reachl0 parts per million (pp-) or higher in fish distribution tanks dependingon the fish load and duration of the haul. Exposure to ll to 12 parts permillion total ammonia (O.tg to 0. l4 ppm un-ionized ammonia) for 6 hoursand longer adversely affects trout and can reduce stamina.Temperature and time of last feeding are important factors regulatingammonia excretion. For example, trout held in water at 34'F excrete 66'/uless ammonia than those held in 51'F water. and fish starved for 63 hoursbefore shipment produce half as much ammonia as recently fed fish. Smallfish should be starved for at least two days prior to shipping. Fish largerthan 4 inches should be starved at least 48 hours; those 8 inches and largershould be starved 72 hours. If they are not, large losses may occur.Water temperature during shipping should be as low as can be toleratedby the fish being handled. Low temperatures not only reduce ammoniaproduction, but oxygen consumption as well.The effects of metabolic waste products and related substances on warmwaterfish during transportation have received little attention, but most fishculturists agree that excretory products, mucus, and regurgitated food degradewater quality and stress the fish. Cannibalistic species, such as largemouthbass, walleye, and northern pike, obviously should not be starved.Although proper grading for size of fish will reduce cannibalism, it doesnot eliminate it.Carbon DioxideElevated carbon dioxide concentrations are detrimental to fish and can bea limiting factor in fish transportation. A product of fish and bacterialrespiration, CO2 acidifies transport water. Although this reduces the percentageof un-ionized ammonia in the water, it also reduces the oxygencarryingcapacity of fish blood. Fish may succumb if CO2 levels are high,even though oxygen levels are seemingly adequate. Trout appear totolerate carbon dioxide at levels less than 15.0 parts per million in thepresence of reasonable oxygen and temperature, but become distressedwhen carbon dioxide levels approach 25.0 parts per million.Fish transported in distribution tanks are exposed to gradually increasingconcentrations of carbon dioxide. Unless aeration is adequate, CO2 levelsmay exceed 20-30 parts per million. In general, for each milliliter ofoxygen a fish consumes, it produces approximately 0.9 milliliters of CO2.If the CO2 level increases rapidly, as with heavy fish loads, fish become

358 FISH HATCHERY MANAGEMENTdistressed. However, elevated concentrations of CO2 can be tolerated if therate of buildup is slow-Adequate ventilation, such as air scoops provide (Figure 111), is a neceslidson the units can result in asity for distribution units. Tight covers orbuildup of CO2 which will stress the fish. Aeration of the water will reduceconcentrations of dissolved CO2, if there is adequate ventilation. As menfoaming,which inhibits aerationtioned previously, antifoam agents reduceand contributes to the buildup of CO2.BuffersRapid changes in pH stress fish, but buffers can be used to stabilize the*ui", pH Jrrring fish transport. The organic buffer trishydroxymethylaminomethaneis quite effective in fresh and salt water. It is highly soluble,stable, and easily applied. This buffer has been used on 29 species of fishwith no deleterious effects. Levels of 5-10 grams per gallon are recommendedfor routine transport of fish. The least promising buffers for fishtanks have been inorganic compounds such as phosphates'Handling, Loading' and StockingStressStress associated with loading, hauling, and stocking can be severe andresult in immediate or delayed mortality. When fish are handled vigorouslywhile being loaded into distribution units, they become hyperactive.They increase their oxygen consumption and metabolic excretion. The firsthour of confinement in the unit is critical. oxygen consumption remainselevated for 30-60, minutes then gradually declines as fish becomeacclimated. If insfficientoxlgen is present during this adjustment period, fishmaydeuelopan\xlgendebt.Theproblemmaybealleviatedifoxygenisintroduced into the distribution tank l0 to l5 minutes before fish areloaded, especially if the water has a low dissolved oxygen content' Whenfish are in the unit, the water should be cooled. After the first hour of thetrip, the oxygen flow may be gradually decreased, depending on the conditionof the fish.The total hardness should be raised in waters used to hold fish duringhandling and shipping. The addition of 0'l-0'3% salt and enough calciumchloride to raise the total hardness to 50 parts per million is recommendedfor soft waters. Calcium chloride need not be added to harder waters'which already contain sufficient calcium'Striped bass are commonly transported and handled in a l'0% salt solution.Fingerlings should be held in tanks for 24 hours after harvest to allow

TRANSPORTATION OF LIVE FISHES 359them to recover from stress before they are loaded. The fish aPPear totolerate handling and transportation much better in saline solutions'The numbers of bacteria in a warmwater fish transport system should bekept at a minimum level. Acriflavin at 1.0-2.0 Parts Per million (pp-),Furacin at 5.0 ppm, and Combiotic at 15.0 PPm are effective bacteriostatsduring transport. Although varying degrees of success have been attainedwith the above compounds, sulfamerazine and terramycin are the only bactericidescurrently registered for use on food fish.AnestheticsExperimentation with anesthetics and their effects on fish was most activeduring the 1950's. The main benefit of anesthetics is to reduce the metabolicactivity of fish, which results in lower oxygen consumption, less carbondioxide production, and reduced excretion of nitrogenous wastes. Suchdrugs made it possible to transPort trout at two to three times the normalweight per volume of water. Their tranquilizing effects also reduce injuryto large or excitable fish when they are handled.Considerable care must be taken to assure that proper dosages ofanesthetics are used. Deep sedation (Table 39) is best for transported fish.Deeper anesthesia produces partial to total loss of equilibrium, and fishmay settle to the bottom, become overcrowded, and suffocate. If pumps areused to recycle water, anesthetized fish may be pulled against the intakescreen, preventing proPer water circulation.Methanetricainesulfonate (MS-222) in a concentration of 0'1 gramMS-222 per gallon of water, aPPears to be useful in transporting fish.Reduced mortality of threadfin shad has been attained when the fish werehauled in a l%r salt solution containing 1.0 gram MS-222 per gallon ofwater. Concentrations of 0.5 and 1.0 gram MS-222 per gallon of water arenot suitable for routine use in the transportation of salmon becauseanesthetized salmon have both a high oxygen consumPtion and a longrecovery time.Golden shiners have been transported successfully in 8.5 parts per millionsodium seconal and smallmouth bass in 8'5 parts per million sodiumamytol. A pressurized air system was used in conjunction with the drugs.However, caution is advised because drugs tend to lose their strength attemperatures above 50"F. Fathead minnows have been transported safely in2.3 parts per million sodium seconal at 50'F. California Department of Fishand Game personnel have reduced oxygen consumption by transported fishwith 8.5 parts per million sodium amytol. Oklahoma state Personnel successfullyuse a mixture of 2.0 parts Per million guinaldine and 0.25% saltfor transporting a variety of fish.

360 FISH HA'TCHERY MANAGEMENTTABLE 39. CLASSIFICATION OF THE BEHAVIORAL CHANGES THAT OCCUR IN FISHES'fC)DURING ANES'THESIA. LEVE,LS OT ANE,STHESIA CONSIDEREI) VAI-UABL!]FISHERIES WORK ARE ITALICIZED. (SOURCE: McFARLAND ll)(i0)DEFINABL!] LEVELS OF ANESTHESIASTATE PLANE WORD EqUIVALENTS BEHAVIORAL RESPONSTS OF FISHIIilUIIVNormalLight sedationDeep sedationPartial loss ofequilibriumTotal loss ofequi libriumLoss of reflexreactiait!Medullary collapseReactive to external stimuli, equilibriumand muscle tone normal.Slight loss of reaction to external stimuli(visual and tactile).No reaction to external stimuli exceptstrong pressure; slight decreased opercularrate.Partial loss of muscle tone; reaction onlyonly to very strong tactile and vibrationalstimuli; rheotaxis present, butswimming capabilities seriously disrupted;increased opercular rate.Total loss of muscle tone; reaction only todeep pressure stimuli; opercular ratedecreased below normal.Total loss of reactivity; respiratory ratevery slow; heart rate slow.Respiratory movements cease, followedseveral minutes later by cardiac arrest.Carrying CapacityThe weight of fish that can be safely transported in a distribution unitdepends on the efficiency of the aeration system, duration of the haul, watertemperature, fish size, and fish species.If environmental conditions are constant, the carrying capacity of a distributionunit depends upon fish size. Fewer pounds of small fish can betransported per gallon of water than of large fish. It has been suggestedthat the maximum permissible weight of trout in a given distribution tankis directly proportional to their length. Thus, if a tank can safely hold 100pounds of 2-inch trout, it could hold 200 pounds of 4-inch trout, and 300pounds of 6-inch trout.Reported loading rates for fishes vary widely among hatcheries, andmaximum carrying capacities of different types of transportation units havenot been determined.Fish loadings have been calculated and reported inconsistently. In theinterests of uniform reporting by fish culturists, it is suggested that loadingdensities be calculated by the water-displacement method. This is based on

TRANSPOR'IATION OF LIVE FISHES 361TABLE 40. PROXIMATE, AMOUNT OF WATER DISPLACED BY A KNOWN WEIGHT OF FISH.ALL FIGURES ROUNDED TO NEAREST WHOLE NUMBER. (SOUNCT' MCCRAREN ANDJONES 1978).wFjcH|ot ! ISHil.B)wAlllRI)lsPLAClll)icrrl)WI.]IGH'I' WA'I'I.]R WI]IGH'IoF I'ISII DISPLACI.]D OF FISH(I,B) (GAL] (LBJWA'I'ERD ISPLACEI)(GALI100200300,100500600700u00900l,0001,100I,2001,300I,.100l2243(;4t(;072u.t96l0u120t:12t+4156l6u1,500I,600I,700I,U00l,9002,0002,1002,2002,3002,4002,5002,6002,7001801922042t6'22t12402522642762lltit300:lt'2:1242,U002,9003,0003,1003,2003,3003,4003,5003,6003,7003,8003,900,1,00033tt34lt36037'2:lu439(t,10u+2043244+456468480the actual volume of the distribution tank being used, the weight of fishbeing transported, and the volume of water displaced by the fish'Table 40 provides the water displacements for various weights of fish. Asan example, what would be the loading density of 800 pounds of fish transportedin a 500-gallon tank?Loading density(pounds per gallon)Loading densityLoading densitypounds of fishtank capacity - water displaced by fish(gallons)(gallons)800500-961.98 pounds per gallon]'ROUT AND SALMONNormalcarrying capacity for 1.S-inch and 2.5-inch chinook salmon is0.5-1.0, and 1.0 2.0 pounds per gallon, respectively. The carrying capacityfor 4-5-inch coho salmon is 2.0 3.0 pounds per gallon of water.Under ideal conditions, the maximum load of 8-ll-inch rainbow trout is2.5-3.5 pounds per gallon of water for 8 to l0 hours. Similar loading ratesare appropriate for brook, brown, and lake trout of the same size.

362 FISH HATCHERY MANAGEMENTCHANNEL CATFISHChannel catfish have been safely transported at loadings presented inTable 41. Experience will dictate whether or not the suggested loadings aresuitable for varying situations. If the trip exceeds 16 hours, it is recommendedthat a complete water change be made during hauling'Catfish also may be transported as sac fry and in the swim-up stage'Most transfers of these stages should be of relatively short duration. Oxygensystems alone are satisfactory when fry are hauled, and have some advantagesover the use of pumps because suction and spraying turbulence iseliminated. If pumps and spray systems are used, the pump should beoperated at a rate low enough to minimize roiling of water in the compartments.Sac fry, 5,000 per 1.5 gallons of water, have been shipped successfullyin l-cubic-foot plastic bags for up to 36 hours. water temPeratureshould be maintained at the same level fry experienced in the hatchery'Although it may be advantageous to gradually cool the water for shippingsome warmwater species, it is not recommended for channel catfish fry.Fingerlings of l-6 inches ship well for 36 hours. As with salmonids, thenumber and weight of fish transported varies in proportionto the size ofthe fish and duration of the shipment.The following guidelines may be of value for hauling channel catfish:(t) Four pounds of l6-inch catfish can be transported per gallon of waterat 65'F.(2) Loading rates can be increased by 250k for each 10'F decrease in watertemperature, and reduced proportionatelyfor an increase in temperature.(g) es flsh length increases, the pounds of fish per gallon of water can beincreased proportionally. For example, a tank holding I pound of 4-inchTABLE 4I. POUNDS OF CATFISH THAT CAN BE TRANSPORTED PER GALLON OF 65'FWATER. (souRcE, MILLARD AND MccRAREN, UNPUBLISHED)NO. OF FISHPER POUNDIRANSIT PERIOD IN HOURSl2l61.02.04.050125250500l,00010,0006.305.905.003.452.952.20t./Jt.250.205.554.804.12.502.201.751.651.000.204.803.452.952.051.801.501.250.700.20

TRANSPORTATION OF LIVE FISHES 363TABLE42. POUNDS oF CENTRARCHIDS THAT CAN BE DISTRIBUTED PER GALLON oFWATER AT TEMPERATURES RANGING BETWEEN 65'AND 1]5'F. (AFTER WILSON I950.)UNO. OF FISHSIZEAPPROXIMA'I'I] NOPOUNDS OF FISHPER LB.(INCHES)OF FISH PER CAL,PER GAL.25.O100.0400.01.000.04.03.02.01.025.067.0200.0333.01.000.660.500.33aAlthoughhours at these rates.time is not given by Wilson, the literature indicates minimal problems up to l6catfish will safely hold 2 poundsgallon of water.(+) If tne transportation timebe decreased by 25%.of 8-inch, or 4 pounds of l6-inch fish perexceeds 12 hours, the loading rate should(S) If tne transportation time exceeds 16 hours, loading rates should bedecreased by 50% or a complete water change should be arranged.(6) During the winter, hauling temperatures of 45-50'F are preferred,whereas 60-70'F are preferable during summer months.LARGEMOUTH BASS, BLUEGILL, AND OTHER CENTRARCHIDSIn keeping with current stocking requirements, centrarchids are transportedprimarily as small fingerlings at light densities (faUte +Z).Largemouth bass fingerlings of 6-10 inches can be transported at 2.0pounds per gallon of water for up to l0 hours without loss. This loadingrate was used when several southwestern hatcheries transported largerlargemouth bass fingerlings and most trips were considered highly successful.Aeration was provided by aerators and bottled oxygen introduced at0.144.21 cubic foot per minute.STRIPED BASSThe Fish and Wildlife Service in the southeastern United States hauledstriped bass averaging 1,000 per pound at a rate of 0.15 pounds per gallonof water for up to l0 hours with few problems. Fingerlings averaging fiveper pound were transported at rates of 1.5 pounds per gallon for l0 hoursand,0.75 pounds per gallon for 15 hours. Recirculation systems and agitatorsboth have been used successfully. The recommended water temperaturefor hauling striped bass is 55'-65'F. Successful short hauls have beenmade at higher temperatures.Striped bass averaging 500 per pound have been successfully transportedat loadings approaching 0.5 pound per gallon for periods of 19 to 24 hours.

FISH HATCHERY MANAGEMENTTASLE ,13. pouNr)s ()I,'I'HA'INoRIHltl{N PIKE ANI) WALLEYLCAN I]I.] C]ARRIED PF]RGALLON OI.' WAI'ER A'I 'f!]MPERATURL,S BITWEEN 55' 'fO (i5"F ISOURCE: RAYMOND A,PH I I,I-IPS, PERSoNAI, C]OMM TJN IL]A'IION,]N(). ()t IrlsllSIZI.]POT]NI)S OI:I IIA\SI I' PI,]RI()I)PIR I,Ril N( ll llsI'ISH IF,I{ GAIiI{OL'RS(i0.05(X).01,000.0lJ. ()2.t)1.01.300.(i(i0.55lJ.0It.011.0Striped bass fry I or 2 days old have been shipped successfully in plasticbags. Very little mortality has been experienced in transporting fry for 48hours at numbers up to 40,000 per gallon of water. Striped bass less than 2months old exhibit considerable tolerance when abruptly transferred intowaters with temperatures of 44'F to 76"F and salinities of 4 to l2 parts perthousand.This species normally is transported and handled in a 1.0% reconstitutedsea-salt solution to reduce stress. Striped bass do not require temperingwhen transferred either from fresh water to l% saline or from saline to freshwater.NORTHERN PIKE. MUSKELLUNGE, AND WALLEYETable 43 suggests loading rates that have proved successful for northernpike and walleye.Muskellunge fry often are transported in small screen boxes placed inthe tank of a distribution truck. Fry also have been transported successfullyin plastic bags inflated with oxygen. Fingerlings are transported in tanks,either of 250 or 500 gallons capacity; oxygen is bubbled into the tanks butno water circulation is attempted. About 0.5 pound of l0 l4-inch fingerlingscan be carried per gallon of water, and l-2 parts Per million acriflavineis added to the tank to reduce bacterial erowth.Stocking FishIt has been an established practice to acclimate fish from the temPeratureof the transportation unit to that of the environment into which they arestocked, a process called tempering. In the past, temperature was the mainreason given for tempering fish. There is some doubt, however, that temperatureis the only factor involved. Evidence in many cases has failed todemonstrate a temperature shock even though there was a difference of asmuch as 30'F; changes in water chemistry and dissolved gas levels may bemore important than temperature changes. The fish may be subjected to

Flcuno 112. Plastic bag shipment of fish. The container should be at least 4-milplastic and preferably thicker for catfish and large sunfish. (t) fn" proper weightof fish is combined with the required amount of water. (Z) fisn then are pouredinto the plastic shipping bag. Any chemicals such as anesthetics or buffersshould be added to the water before the fish are introduced. (3) The bag is thenfilled with oxygen. All the air is first forced out of the bag, which is then refilledwith oxygen through a small hole at the top of the bag, or the bag can bebunched tightly around the oxygen hose. Approximately 75% of the volume ofthe bag should be oxygen. The bag then is heat-sealed or the top is twistedtightly and secured with a heavy-duty rubber band. (4) Because cool water cansupport more fish than warm water, the water temperature in the shipping containershould be kept as cool as the fish will tolerate. If ice is needed it may beplaced directly with the fish or in separate bags (arto*) next to the fish container.In this way the fish and water are cooled simultaneously. (S)Polyurethane foam inch thick is excellent insulation for shipping, but it isfheavier and less efficient than foam. (0) fn" package then is sealed and properlylabelled for shipment. (Photos courtesy Don Toney, Willow Beach NationalFish Hatchery, FWS.)I865

FISH HATCHERY MANAGEMEN'fTeslr 44. RECoMMENDED LOAl)tNcs AND TREATMENIS PER SHIPPING uNIl l'()llRAINBOW OR BROOK'TROU'T (3OO PER POUND),.TH!] CON'I.AINIiR A.|MOSPHI.]RI.] ISBLAIR. FISH AND WILDLIFE SERVICI.], UNPUBLISHTD.)SPEC I ESN LI M II I,]Rot' trlstl CON I AINI.]R lNs( 1.,\ I I()\(l)\2)(:r )(+)(s)((i)(n)Largemouth bassLargemouth bassLargemouth bassBluegillBluegillBluegillRainbow or brooktrou tRainbow or brooktrou t0-100105 150l 55-5000- 100I 05-300305 n000 3{i00- ll(x)l-gallon cubitainerI -gallon cubitainerl2 x 2(i-inch,.1-milplastic bagl-gallon cubitainerl-gallon cubitainerl2 x 2U-inch, .1-milplastic bagl2 x 2U-inch,-1-milplastic bagl2 x 24-inch,-l-milplastic bagN oneNoneNoneN oneNoneNoneNewspaperRigid polyurethanefoamcarbon dioxide and oxygen tensions in the shipping water that are notpresent in the natural environment. Osmotic shock can be a very seriousproblem, particularly if fish reared in hatcheries with buffered water fromlimestone formations are stocked into dilute acidic waters.Addition of receiving water to the fish distribution tank before fish areunloaded requires effort, but the benefits will more than justify the effortin many situations. As fish are gradually changed from hauling water to receivingwater, they have an opportunity to make some adjustments to theirfuture environment. Flowine water also aids in removinq fish from the tankwith minimum stress.Shipping Fish In Small ContainersPolyethylene bottles have been used to transport small trout, especially byhorseback to back-country areas. After the bottle is filled with water, fish,ice, and oxygen, it is placed in an insulated container for shipment.Plastic bags frequently are used to ship small numbers of tropical fish,warmwater fish, and trout (Figure 112). UPon arrival at the destination theplastic bags should be allowed to float unopened in a shaded area of the receivingwater supply for about 30 minutes to acclimate the fish.There are varying and sometimes conflicting opinions regarding fishloads, water volume, the use of buffers, and container sizes to be used inshipping fish. Some suggested shipping loads are presented in Table 44.The following excerpts from private communications collected at the

TRANSPORTATION OF LIVE FISHESLARGEMOUTHBASS (I,5OO FISH PER POUND), BLUEGILLS (2,IOO PER POUND), ANDPURE OXYGEN. SHIPPING TIME SHOULD NOT EXCEED 21 HOURS. (SOURCE: ALAN B'PARTS PI]RCRAMSMILLILITERSCAI,I-ONSOF WA'TERPoUNI)SOF ICEMILI,IONACRI I'I,AVINfRIS BU!'f!]Rti.li pHTERl'IARYAMYL ALCOHoLSPI]CIES0.50.51.5(,0U2.52.5'2.5U(;Itr01.54.5(l)\2)(:)0.50. ir1.5(,U(.r'2.52.52.5U6Iu0l.lr4.5(r)(s)(6)1.0t'20t23.017)0.7540t22.0Warmwater Fish Cultural Development Center, San Marcos, Texas, mayalso be of interest to fish culturists faced with determining a suitable protocolfor container shipment of fish. All comments relate to containers withone atmosphere of pure oxygen:. Good survival was achieved shipping 100 bluegill sunfish (t,200 fishper pound) in j gallon of water. If shipment is 30 hours or less, we believeit safe to ship 200 fish in j gallon of water in a one-gallon cubitainer.. We had excellent survival on mail distribution. We used ; gallonwater per one-gallon cubitainer, an oxygen overlay, and largemouth bassgoing 900 per pound. Duration of shipment was 24 hours.. Amyl alcohol slightly increased survival time for all species testedwhen used at rates of 2.0-3.0 ml per gallon of water. This chemical aPPearsto tranquilize the fish, thereby reducing metabolism.. . . When shipping in plastic bags we seldom use ice with largemouth bass,and never with northern pike and walleye.. . . We load each bag or box with 50,000 northern pike fry, 70,000 walleyefry, or up to 600 small largemouth bass fingerlings. We have experiencedmortalities in shipments when using V-bottom plastic bags. All species willhold for 24 hours but we prefer to get the fish out of the bag in 4-10hours.. . . Catfish sac fry were shipped by air from Dallas to Honolulu, Hawaii,for several years with good success. We used l-cubic-footplastic cubitainerswith 12 pounds of water to 6 ounces of fry. Shipments arrivingwithin 24 hours usually had losses of 5'lo or less.

368 FISH HATCHERY MANAGEMENTBibliographyAnonymous. ltltl13. 'rransportation of live fish. English translation by H. Jacobson, takenfrom the International Fishery Exposition, Berlin lUll0. Bulletin of the US Fish Commission2:1)5-102.l1)ll1). Distribution highlights in Pennsylvania. Progressive Fish-Culturist (43):34-35.l!)50. A note regarding air shipment of largemouth bass fingerlings from Oklahoma toColorado. Progressive Fish-Culturist l2(l):2ti.-. 1955. Test of planting walleye fry by plane. Progressive Fish-culturist l7(3):128.l1)71. Live hauler. Catfish Farmer ll(5):lt) 21.1973. "300,000 fingerlings per load." Fish Farming Industries,4(2):31.Bencoclx, W. H., and G. Ptls.t . l9(i7. An evaluation of water conditioning systems for fish distributiontanks. Colorado Department of Fish, Game and Parks Special Report l6:l-9.Besu, S. P. 1959. Active respiration of fish in relation to ambient concentrations of oxygenand carbon dioxide. Journal of the Fisheries Research Board of Canada 1612):175-212.B!.AMISH, F. H. W. l!)64. Influence of starvation on standard and routine oxygen cousumption.'fransactionsof the American Fisheries Society tl13(l):103 107.Bl,lt-, G. R. l9(t,1. A guide to the properties, characteristics and uses of some general anestheticsfor fish. Fisheries Research Board of Canada Bulletin l4tl.Bl:zot:x, Fn.q.n-cts H. 1957. Sodium seconal as a sedative for fish. Prosressive Fish-CulturistlS)(3):130.BrTzrn, R,tr.lH, and AllnEo BunrvH,qlr. 1954. A fish distribution unit. Prosressive Fish-Culturist l(i(l):35.BLACK,E.C.,andI.BARRE'I'1.1957.Increaseinlevelsoflacticacidinthebloodofcutthroatand steelhead trout following handling and live transportation. Canadian Fish Culturist20:13-24.BoNx, EowenoW., Wn.l.rAM M. BArLEy, JAcK D. BAvLESS, KrM E. ERrcKSoN, and RoBERi.E. S.tttvLNS. l1)7(i. Guidelines for striped bass culture. Striped Bass Committee, SouthernDivision, American Fisheries Society, Bethesda, Maryland. 103 p.Bnocxwev, D. R. 1950. Metabolic products and their effects. Progressive Fish-Culturistr2Q):t27 t2t).Bunnorvs, R. E. 1937. More about fish planting. Progressive Fish-Culturist (Z+),ZI-ZZ.BURloN, D., and A. SPTHAR. 1!)71. A re-evaluation of the anerobic end products of freshwaterfish exposed to environmental hypoxia. Comparative Biochemistry and Physiology40A:l)'15 954.C,a.rl.t.ctLl:t, CH,cRI-Es W., JR. l9(i7. Hyperactivity, blood lactic acid and mortality in channelcatfish. Pages UgU-g15 in lowa State University AgriculturalExperiment Station, Research Bulletin 551, Ames.and Home EconomicalCctt-t-tNs, Jeurs L., and ANont;w M. HuLSEY. l{)67. Reduction of threadfin shad hauling mortalityby the use of MS-222 and common salt. Proceedings of the Annual ConferenceSoutheastern Association of Game and Fish Commissioners 18:522-524.CcterleNtt, T. H. 1947. Fish distribution units. Progressive Fish-Culturist 9(4):193-202.CuLLER, C. F. 1935. "Comments from our readers." Progressive Fish-Culturist (7):7 x.f)avrs, Jelte,s T. 1971. Handling and transporting egg, fry, and fish. Proceeding of theConference on Production and Marketing of Catfish in the Tennessee Valley, Tennes,see Valley Administrations:40-42.Dorrl, Joun, O. LLoyD Mrruleu,S. F. SNrlszxo, and Gl:oRcE N. WASHBURN. 1956. Raisingbait fishes. US Fish and Wildlife Service Circular 35:124.DowNINC, K. M., and J. C. MtnxnNs.l1)55. The influence of dissolved-oxygen concentrationon the toxicity of un-ionized ammonia to rainbow trout. Annals of Applied Biology13:2111.

TRANSPORTATION OF LIVE FISHES 369Eoov. F. 8.. and R. I. G. Mou.c,rn.l9(i!). Some effect of carbon dioxide on the blood ofrainbow Lrout, Salmo gairdneri Richardson. Journal of Fish Biology 1 (4):lll'l 1172.FALCoNER, D. D.1964. Practical trout transport techniques. Progressive Fish-Culturist26(2):51 58.Ft.rsr, C. N., and C. E. Hecrr.:. l1)4t1. Colorado's glass fish tank. Progressive Fish-Culturistl0(1.):29 30.FRoMM, P. O., and J. R. Gtt-t-rt tt. l1)6tt. Effect of ambient ammonia on blood ammonia andnitrogen excretion of rainbow trout, Sa/mo gairdneri. Comparative Biochemistry andPhysiology 26:ttU7 U(.Xi.FRy, F. E. J. 1957. Ihe aquatic respiration of fish. Pages I (i3 lz M. E. Brown, editor. Physiologyof fishes, volume l. Academic Press, New York.and K. Nonnts.1962. The transportation of live fish. Pages 595 609 in GeorgeBorgstrom, editor. Fish as food, volume 2, nutrition, sanitation and utilization.Academic Press, New York.Fuqua, Cuenlcs L., and HUBERT C. ToPEL. 1939. 'fransportation of channel catfish eggs andfry. Progressive Fish-Culturist (46):11,- 21.Gent.lcx, LEwIs R. 1950.'Ihe helicopter in fish-planting operations in Olympic NationalPark. Progressive Fish-Culrurist IZQ\:72 7n.GREENE, A. F. C. l!)56. Oxygen equipment for fish transportation. Progressive Fish-Culturistl8(l):,{7 4u.HASKELL, D. C. 19,11. An investigation on the use of oxygen in transporting trout. Transactionsof the American Fisheries Society 70:1,tr!) l(i0.and R. O. DAVIES. l95ti. Carbon dioxide as a limiting factor in transportation. NewYork Fish and Game Journal 5 (2) : I 75- I tt3.HEFFERNAN, BrRNeno E. 1973. Intensive catfish culture "cuts its teeth" in Kansas. Fish FarmingIndustries 4(5):tt I l.HENEGAR, DelrHoLDrR,HoRioN,Irezewa,L., and DoN.qt.o C. DUERRE. 1964. Modified California fish distribution unitsfor North Dakota. Progressive Fish-Culturist 26(4):lu8 11)0.C. F. l90ti. A method of transporting live fishes. Bulletin of the US Bureau ofFisheries 28(2): 1005 1007.H. F. 1956. An evaluation of some physical and mechanical factors important inreducing delayed mortality of hatchery reared rainbow trout. Progressive Fish-Culturistl8(l):3-14.Y. 1970. Characteristics of respiration of fish considered from the arterio-venousdifference of oxygen content. Bulletin of the .Japanese Society of Scientific Fisheries36\6):57 l-577 .JoHNSoN, F. C. 1972. Fish transportation improvement-phase II. !'inal report prepared forState of Washington, Department of Fisheries, Olympia. (ili p.JoHNSoN, Ltttn D. 1972. Musky survival. Wisconsin Conservation Bulletin, May June:li 9.JouNsoN, S. K. 1979. Transport of live fish. Report FDDL Fl4, fexas Agricultural ExperimentalService, f)epartment of Wildlife and Fisheries Science, College Station, Iexas.l3 p.KsIt-, W. M. 1935. Better stocking methods. Progressive Fish-Culturist (1)):l (i.KrN-csBLIRy, O. R. 1949. The diffusion of oxygen in fish tanks. Progressive Fish-Culturist1l \l ):21.KLoNTZ, G. W. 1964. Anesthesia of fishes. Pages l'1 l6 iz Proceedings of the symposium onLtecu,experimental animal anesthesiology, Brooks Air Force Base.G. C. 1939. Artificial propogation of brook trout and rainbow trout with notes onthree other species. US Department of Interior, Fisheries Document 955, Washington,D.C.74 p.Llrevln, LoRIN. 1939. A new water aerator. Progressive Fish-Culturist (.151:54 56.

370 FISH HATCHERY MANAGEMENTLEI'IRIiz, E,ent,, and RoBtRI C. Llwrs. l!)76. Trout and salmon culture (hatchery methods).California Department of Fish and Game, Fish Bulletin lti,l. l!)7 p.Lrwrs, Wlr.lteltM., and MIcHAul. BUNDER. l{)60. Heavy mortality of golden shiners duringharvest due to a bacterium of the genus Aeromonas. Progressive Fish-Culturist22(t\:tt t4.Llclyo, R. l9(il.'Ihe toxicity of ammonia to rainbow trout. Water and Waste TreatmentJournal 8:'278-279.Met,ov, CHARI.LS R. 1963. Hauling channel catfish fingerlings. Progressive Fish-Culturist25Q):2ll 212.M.+nelHl, V.8., N. V. Hutlcot-, and S. G. PAlrt.. lS)75. Hydrogen peroxide as a source ofoxygen supply in the transport of fish fry. Progressive Fish-Culturist l7('Z):117.MAX$,11.1., JouN M., and Rriscnr W. Tsolslll.Fish-Culturist 27(:l):l l5 120.l9(i5. Lake Powell stocking story. ProgressiveMAZLTRANIcn, JottN J. l1)71. Basic fish husbandry distribution. US Bureau of Sport Fisheriesand Wildlife, Washington, D.C. 53 p. (Mimeo.)McCRARTN, J. P., and R. W. Jorvts. l97tl. Suggested approach to computing and reportingloading densities for fish transport units. Progressive Fish-Culturist 4()(+):l(i!1.and J,tcx L. Mtt,t,,cRIr. l1)7ti. Transportation of warmwater fishes. Pages 43 tttt inManual of fish culture, Section G, US Fish and Wildlife Service, Washington, D.C.McFARLAND, W. N. 1960. The use of anesthetics for the handling and the transport of fishes.California Fish and Game .16(4):407 431.ME!rnAN, W. R., and L. REVgr'. l(Xi2. The effect of tricane methane sulfonate (VtS Zzz)and/or chilled water on oxygen consumption of sockeye salmon fry. Progressive Fish-Culturist 2,1(,1) : I tl5- I tl7.MEyFrR, FRED P., KERMI'r E. SNEED, and PAUL T. Escrtvr:yr:n, editors. l!)71J. Second report tothe fish farmers. US Bureau of Sport Fisheries and Wildlife, Resource Publication ll3,US Fish and Wildlife Service, Washington, D.C. 123 p.MooRE, 't. J. ltJU7. Report on a successful attempt to introduce living soles to America. Bulletinof the US l'ish Commission 7(t):t 7.Moss, D. D., and D. C. Scoi r. l9(il. Dissolved oxygen requirements for three species of fish.Transactions of the American Fisheries Society !)0(,1):377 393.MlLLrtR, R. B. 1951. Survival of hatchery-reared cutthroat trout in an Alberta stream. Trans'actions of the American Fisheries Society tll:35 42.NoRRIS, K. S., F. Bnocelo,and F. CALANDRINO. 1960. A survey of fish transportationmethods and equipment. California Fish and Game 46(l):5 lJ3.OLsoN, K. R., and P. O. Fncllrv. l1)71. Excretion of urea by two teleosts exposed to differentOLson, RelruOsloRN,concentrations of ambient ammonia. Comparative Biochemistry and Physiology40A(41:{)l)l)-1007.\52):l(i-17H. 1940. Air conditioning fish distribution tanks. Progressive Fish-CulturistP. E. 1951. Some experiments on the use of thiouracil as an aid in holding andtransporting fish. Progressive Fish-Culturist l3\2) :7 5-78.OlwEl.t., W. S., and J. V. MERRINER. 1975. Survival and growth of juvenile striped bass,Morone saxalilis, in a factorial experiment with temperature, salinity and age. Transactionsof the American Fisheries Society 104(3):560-5(i(i.PHlLLIps, A. M., and D. R. BR()cKwAY. 1954. Effect of starvation, water temperature andsodium amytal on the metabolic rate of brook trout. Progressive Fish-Culturistl6(21:65-(iti.Purt.llls, ARTHIIR M., JR. ltxi(;. Outline of courses given at In-Service Training School, Cortland,New York, part B, methods for trout culture. US Fish and Wildlife Service, Cortland,New York. 100 p.

TRANSPORTATION OF LIVE FISHES37IP11wt:t.t-, NATHAN A. 1970. Striped bass in air shipment. Progressive Fish-Culturist:i2(l):18pp.Rtlst:, At-. l1)53. Use of hypnotic drugs in transporting trout. California Department of Fishand Game, Sacramento. l0 p. (Mimeo.)ScHt:t.rz, F. H. l1)5(t. Transfer of anesthetized pike and yellow walleye. Canadian Fish Culturistll|:l 5.SEALT, A. lt)10. The successful transference ofblackbass into the Philippine Island with noteson the transportation of live fish long distances. Philippine Journal of Science, SectionB s(3):151] 150.SHttBl.EY, W. H. 1927. History of fish planted in California. California Fish and Gamel3(3):lft3 17,1.SlrrrH, CHnnt-t!r E. l97tl. 'I'ransportation of salmonid fishes. Pages 9 ,11 in Manual of fish culture,Section G, US Fish and Wildlife Service, Washington, D.C.Svl'rs, H. W. 1929. The excretion of ammonia and urea by the gills of fish. Journal of BiologicalChemistry t)l :7'27- 742.Sr.row, J. R., R. O..JttNts, and W. A. RocERs. 1964. Training manual for warmwater fish culture.US Bureau of Sport Fisheries and Wildlife, National Fish Hatchery, Marion, Alabama.460p.SRINIVASAN, R., P. I. CH,lcrtl,and A. P. V,q.Ls,\N. l[)55. A preliminary note on the utility ofsodium phosphate in the transport of fingerlings of Indian carps. Indian Journal ofFisheries'2\l) :77 tl:1.Sl()NE, LrvrNGSt()N. ll]74. Report on shad hatching operations. US Commission of Fish andFisheries, Commissioner's Report, Appendix C:413 '11(i.Svxt;s, J,ruts E. 1950. A method of transporting fingerling shad. Progressive Fish-Culturistl2 (3): l5ll 151).-. 1951. The transfer of adult shad. Progressive Fish-Culturist l3(l):45 l{i.'I'RIJSSELL,R. P. 1972.'fhe percent of un-ionized ammonia in aqueous ammonia solutions atdifferent pH levels and temperatures. Journalof the Fisheries Research Board of Canada2!)(10):1505-1507Wet t l, Dlxclrv. Undated. Use of electric and hydraulic systems on fish transportation rrnits inPennsylvania. Pennsylvania Fish Commission, Benner Springs Research Station.3 p.(Mimeo.)WuBB, RoBI.tR'r T. l95ti. Distribution of bluegill treated with tricaine methanesulfonate(MS 222). Progressive Fish-Culturist 2012)1;!l 72WEr)fMEvER, C.l!)72.Some physiological consequences of handling stress in the juvenile cohosalmon (Oncorhlnchus kisutch) and steelhead trout (Sa/no gairdneri). Journal of theFisheries Research Board of Canada 2!(12):1780 17U3.and.l.Woo. l1)7,1. Stress as a predisposing factor in fish diseases. US Fish andWildlife Service, Fish Disease Leaflet Number 3tl. tl prWrirBE, A. H., A. M. McG.tvocx, A. C. Fut-t-l:n, and H. C. Menctts. l1)3'1. The ability ofat different hydrogen ion concentrations. Phys-freshwater fish to extract oxygeniological Zoology 7(:l):.{ll5 .1'1U.WILS()N, AI.BERT J. 1950. Distributiont2A\.2rr '2t.).units for warmwater fish. Progressive Fish-Culturist

Appendices

AppendixEnglish-Metric andTemperature ConversionTablesTesr,B A-1.ENGLISH-METRICCoNVERSIoNS.ENcLlsHI inch0.39 inchI foot (12 inches)I yard (3 feet)1.09 yardsMETRtcLength: 2.54 centimeters: I centimeter (10 millimeters): 30.5 centimeters: 0.91 meters: I -"tet (100 centimeters)AreaI square inch: 6'45 square centimeters0.15 square inch: I square centimeterI square foot (144 square inches) : 929 square centimetersI square yard (9 square feet) : 0'84 square meters1.20 square yards : I square meter (10,000 square centimeters)I acre (4,840 square yards) : 0'40 hectares2.47 acres: I hectare (10,000 square meters)VolumeI acre-foot (43,500 cublc feet) : 1,233'6 cubic metersWeightI English ton (2,000 pounds) : 0.91 metric tonl.l0 English tons: I metric ton (t,000 kilograms)Flou rateI cubic foot/second0.035 cubic foot/second::28.32 liters/secondI liter/secondI cubic foot/minute: 28.32 liters/minute0.035 cubic foot/minute : I liter/minuteI gallon/minute0.264 gallons/minute: 3.785 liters/minute: I liter/minute375

376 FtsH HATcHF,Ry N,rANAcFtMriNTTasle A-2. TEM'ERA TuRES-FAHRLNHLIT lo cEN.f IGRADL,. T.EMpIRA r Lr RL rNDEGREES FAHRENHEI'T IS EXPRISSED IN TH!] I,[ T COI,UMN AND IN ],HI]'I'OP ROW:THE CORRESPONDINC; TL,MPFTRATLRE IN DF,cRF,LS cENt'rcR,\Dlt rs IN TIlu r]()t)\'oF'IABLE.r !.Nr P.'F.30.1050(i070u01)0l.I 0.(i 0.0/t..[ 5.0 5.(tI0.0 I0.(i I t.II 5.(; I (i. I 16.7'21. |'2t .7'22.226.7 27.2 27.832.'2 32.1J :Jl.l tr0.(t l.I(i. I (;.7I L7 t').')t7 .'2 | 7.u22.8 23.32ii.3 2u.1)13.1) 3.1.1t.7 2.')7.7 7.uI 2.8 I ll.3I u.i.t I it.t)23.1) 21.129.1 30.0it5.0 3rl.(l'2.t13.i]u.3 u.1)13.1) 11. II1)..1 20.025.0 25.ri30.(' 3t.t3(i. I 3(i.73.1)I]. I15.020. {i2{r. Ilt.7t7 .'2Tesle A-4. voLUMErr{rc AND wF,rcHr EqurvAr-ENr.s oF wAfER rN MErRrc r\ND(SOURCE: CHARLES L. SOWARDS UNPUBLISIlED,) EXEMPLI,. ,LO FIND ,I'HE WI,IGH f INcoLUMN; THEN READ HORIZONTALLY ro FIND 3.7rirl IN iHE.,KILOCRAM" cor_uMN.GRAM OF WAI'ER A'T.1"C AND oN AN AI'MOSPHERIC PRESSURE O[ 7(J0 MM M!,RCT]RY,u)(z)(s)(4)(s)(6)(7)(8)(e)(r o)(l l)(rz)(l 3)CLTBICYARL)1.3090.001I0.0370.0050.0010.00 rCTiB I (IOO'T CTiBIC INCH GAI,I,ON Qr: R r PI \'I35.:l6l0.03527I0. I iJ,10.0330.0170.01 (;0.0010.001(i I,095('1.01)0.0(i I1(i,(i5(iI,72tl'23157.752 u.uu27.71l.lJ051 .7:12I0.0(;l2(t,1.50.2( 4201 .9u7 .4tlI0.'250.1250.120.00110.0070.00.1I ,05tJ 2, I lri1.05u 2.I l(i0.(x) I 0.002807.1) l,(i I6'29.!t',251).1t5+ut20.5 I0..1ti 0.960.031 0.0(i20.03 0.0(i0.017 0.0i]50.001 0.002

c()i\"v!lllstoNlAIll.l.s 377T,qst-E A-3. TEMPERATURES-cEN l'lcRADE TO FAHRENHL,Il . TEMPERA TURE lNDEGREES CENI'IGRADE IS TXPRESSED IN THE LEF'I'COLUMN AND IN THF]'I'OP ROW;]'HE CORRESPONDING TEMPEI{A'fURE IN DEGREES FAHRENHEIT IS IN'fHE BODY OFTABI,E,lr.:rrr,'C. 0 I l) li0I0'2\)30112.0 33.u50.0 51.8(tu.0 (il).ltu(i.0u7.lJllir.(i 37.,1;3.(i 55..17 t.t; 73.,11.il).(i 1) l.-1l|1).2 .1 I.0 .12.rJ .1.1.6 ,1(i.,1 {u.257.2 59.0 60.1t (i2.(i (i.1.,1 (,6.'275.'2 77 .0 7ft.U l.t0.(i 1J2..1 U.1.21)3.2 1)5.0For intermediate temperatures or those exceeding the range of the tables, the following formulasmay be used:F: l.tlxC+1]2,^F32r:l.t]ENGLISH SYSr!lMS. Al-1. FIGUILIIS ON A HORIZON',I',A LINII ARIi, FlqLIVALllNl'VALLiESKILOGRAMS OII ONI.] GAI,I,ON OIi WA'f!]II, I.'IND ]'HI] NUMBL,It ONF] IN'fHI" "GALLON'MI]'I'RIC CON4PLI'fA'I'IONS WERF] BAST.]D ON I LI'fF,II BIlINC; TH!] VOI,L]ME OIT I KILO-F'I,LIII)()trNcl('r. RIC\1 !t I I.tRt.l t LR ()ttK I l.( )Ci R]\ Ntt\tIt-l.ll.Il llR0R CRAN{ ()tiNcr[. \\ r ] POtrN I)33,ft:r-133. u50.03'12.'r,tl53957.5t2u:l'2l{i15.3(iI0.{)(i0.55.10.03,1I0.0010.7 6+0.02|i0.00+0.001r,000I0.0017 t;+.52l.i.ll I 73.7 rJ50.9'1(i0.,17 30..15.10.0i10.02u0.0 I (i0.001I,0(x),0001,000I7(i,1,55928,3223,7 r.t5lr+6.247:l.l'153. tt29.572fi.ltir16.37I35,',27:l'.15.270.0352(i,9371197.7133.-1ll:1.:J.11(i.(i7l()1.0.12I0.57 t'0.031r,),'205 (1)2.201 lz)o.oo2 (:)l,(ill3.(i (+){i2..1211(5)f1.335 (r;)2.0ft.1 0)1.0+'2 (rJ)I (e)0.0(is (r o)0.0(i2 (l l)o.ou(j (l 2)0.002 (r 3)

AppendixAmmonia IonizationTABLE B I. PERCEN.'I. UN IONIZED AMMONIA {NH3) IN AQUEoUS AMMoNIAI]MERSON. I1)7'I. AQTIEOL]S AMMONIAEQUII,IBRIUM CAI,CULATIONS, TECHNICALlruprnetunt,"C5.04.03.00.0pH 1.06.06.16.26.36.46.56.66.76.86.97.07.17.27.37.47.67.77.87au.08.18.28.38.48.5u.68.78.8u.99.00.008270.01040.013 I0.01650.02080.02610.03290.04140.05210.06560.08260.1040.l3l0.1650.2070.2610.32tt0.4t30.5l90.6520.8201.031.291.622.032.553.l93.984.966.l67.640.008990.01l30.01430.01790.02260.02840.03580.04510.0567o.o7t40.0u980.1l3o.t 420.1790.2250.2840.3570.4490.5640.7090.891t.t2t.4l1.762.212.773.464.315.376.67u.250.009770.01230.01550.01950.02450.03090.03890.04900.06l60.07760.09770.1230.1550.1950.2450.3080.3u80.4880.6130.7700.968|.221.53l.9l2.403.003.754.675.817.208.900.01060.01340.01680.02120.02670.03360.04220.05320.06690.08430.1060.1330.1680.21I0.2660.3350.4210.5290.6650.8361.05l.321.652.072.603.254.065.056.287.789.600.01l 50.01450.01830.02300.01890.03640.04590.05770.07270.09150.1l50.1450.182o.2290.2890.3630.4570.5740.7220.907l.l4l.43t.792.252.813.524.395.466.788.39r 0.30.01250.01570.01980.02490.03140.03950.04970.06260.07880.09920.1250.1570.1980.2490.3l30.3940.4950.6230.7830.9831.231.551.942.433.043.804.745.907.319.03ll.l378

AMMONIA IONIZATION 37!)sol-tlrl()Ns. (souRCE: 'f HURSfoN, ROBER] v., R()S!TMARIE RUSS(), AND KtNNE.fHREPORT 7.1 I, MON'fANA S'I'A'fF] TINIVERSI'fY, BoZEMAN. MON.fANA.)pH6.07.0rsv prnnru Rr.'Cu.0 9.010.06.0b_l6.26.:l6.46.56.66.76.86.97.07.17.47.67.77.Il7.98.08.18.28.llu.,18.58.68.78.88.99.00.01360.01 7 I0.02150.02700.03400.04290.0s390.06790.08550.lOtt0.1350.1700.2t40.2700.3390.4270.5370.6750.848t.o71.341.682. l02.633.294.1t5.t26.367.889.72I 1.90.0t470.01 u50.02330.02930.03690.04640.05850.07360.09260.t t70.1470.1t]50.2320.2920.361]Q.4620.5820.7310.9 l9l. l51.451.822.2112.853.5(;4.145.536.86ti.4810.5l2.rl0.01590.02000.02520.03170.04000.05030.06330.07!)70.1000.1260.1590.2000.2520.31 60.3980.5010.6290.7910.9941.251.57l.962.163.0tt3.tt44.7 !)5.967.399.12tl.213.70.01720.02t70.02730.03440.04320.05440.06850.08620.1090.1370.1720.2 l60.2720.3420.4310.5420.61i l0.u56| .071.35L692.122.663.324.15s. l66.427.959.u012.0| 4.70.0 l860.02350.02950.03720.04680.05tt90.07.110.09330.1t70.1480.1860.2340.2910.3700.4660.5860.7360.925l.l61..{(tl.ti32.292.873.5r14.+75.566.91tJ.5410.512.9t 5.70.02010.025,10.03 t 90.0,1020.05060.06370.08010.1010.t270.1600.2010.25110.3 l rl0.4000.5040.63110.796l.001.261.58t.972.173.093.U64.825.997.429.t7ll.lll3.tit 6.u

380 FISH HATCHERY MANAGEMENTTanlr B-1. coN'ilNUEDrEMPriR q t ttRE.'CpH 12.0 t 3.0 14.0 15.0 16.0 17.06.06.16.26.36.4tt.50.021u0.027 40.03450.04340.05470.06880.02350.02960.03730.04690.05900.07430.02540.03 l90.04020.05060.06370.08020.027 40.03450.04340.05460.06870.0u650.02950.03720.04680.05890.07410.09330.03 l80.04010.05040.06350.07990. l0l(t.66.76.tt6.97.00.08660.1090.1370.1730.2t70.09350.1 l80.1,180. I u(t0.2350. l0l0.1270.1600.2010.2530.1090.1370.1720.2t70.2730.1 l70.1480.1860.2340.29.10.1270.1590.2000.2520.3177.17.27.37.50.2730.3440.4330.5440.6840.2950.3710.4670.5u70.7:]tt0.3 l90.4010.5040.6330.7960.3440.4:120.5430.6830.8590.3700.4660.5860.7360.9250.3990.5020.63 r0.7930.9967.67.77.8,.,98.00.ti59l.0tri1.36|.702.130.927l. l61.46l.ull2.30l 001.261.58l.9u2.181.081.351.702.).32.67I .161.461.832.292.87t.25| .57t.972.473.0uti. I8.28.3ti.4tt.52.673.344. l65. l9t.442.873.594.4u5.586.923.t03.tt 74.825.997.133.334.165. 1tJ6.+47.973.584.475.566.918.543.854.805.977.409. l4u.68.7tt.utJ.99.07.9u9.84l2.l| 4.717.98.5ti10. i)t2.9t 5.719.09.18I 1.3l3.tr16.820.29.83t2.l| +.717.92l .510.5t2.9L:)./19.022.8tt.213.8t6.720.224.1

AMMONIA IONIZA'I'ION 381I'EMPERATURE,.C23.02t.020.019.0I U.0pH 22.06.06.16.2(i.36.46.56.66.76.tl6.97.07.17.27.37.47.57.67.77.tl7.!)tt.08.18.28.38.48.5u.68.78.8t].99.00.03430.04310.05430.06840.08600.1080.1360.1720.2l60.2720.3420.4300.5400.6790.u54l.o71.35L692.122.653.314.t45. 156.407.939.7t1t2.0t 4.717.82r.125.50.03690.04650.05850.07360.09260.1t70.1470.1850.2320.2920.3680.4630.5820.7310.919l.l51.451.822.282.853.564.445.536.86lJ.4910.5l2.u15.6l tt.922.727.00.03970.05000.06290.07920.09970.1250.1580.1990.2500.3i50.3960.4980.6260.7860.9uu1.241.561.952.443.063.824.765.927.349.07tt.213.716.620.024.028.40.04270.05380.06770.08520.1070.1350.r700.21+0.2690.3380.4250.5350.6730.8451.061.331.672.102.633.284.l05.l06.347.869.69I 1.914.517.621.225.329.90.04590.05780.07270.09160.1150.1450.1830.2300.2890.3640.4570.5750.7230.908t.t41.431.802.252.823.524.395.476.798.3910.312.7I J_.)18.722.526.731.50.04930.06210.07820.09840.1240.1560.1960.2470.3l00.3900.4910.6170.7760.975t.221.541.932.413.023.774.705.857.258.96I 1.013.516.419.u23.728.233.0

382 FISH HATCHERY MANAGEMENTTenln B-1.coNTINUEDrtUPrn,,rtUnt,'CpH 24.0 26.0 27.0 28.0 29.0 30.06.06.16.26.36.4o-36.66.76.86.97.07.27.47.57.67.77.87.98.08.18.28.38.48.58.68.78.88.99.00.05300.06670.08390.1060.1330.1670.21r0.2650.3330.4190.5270.6630.8331.05l.3ll.oJ2.O72.s93.244.045.036.269.561t-l14.4t7.421.O25.r29.634.60.05690.07160.09010.1130.1430.1800.2260.2840.3580.4500.5660.7110.894t.12t.4l1.772.222.773.474.335.386.698.2710.212.515.318.522.226.43l.l36.30.06100.07680.09670.t220.1530.1930.2420.3050.3840.4830.6070.7630.958|.20I .511.892.372.973.714.635./D7.t48.8210.913.316.219.623.427.832.737.90.06540.08240.1040.1300.1640.2070.2600.3270.41 I0.5170.6510.8181.031.29|.622.032.543. 183.974.94o.lJ7.629.40I 1.6t4.lt1 020.724.729.234.239.60.07010.08830.1110.1400.1760.2210.2790.3510.4410.5540.6970.8761.101.38t.732.t73.404.245.286.568.1210.012.315.018.22l .826.030.735.841.20.0752 0.08050.0946 0.1010.1 l9 0.1280.150 0.1600.189 0.2020.237 0.2540.299 0.3200.376 0.4020,472 0.5060.594 0.6360.747 0.7990.938 1.001.18 1.261.48 I .58l .85 1.982.32 2.482.91 3.l l3.63 3.884.53 4.845.64 6.017.00 7.468.65 L2l10.7 11.313.0 13.815.9 16.8r9.2 20.323.0 24.327.4 28.832.2 33.737.4 39.042.9 44.6

Appendix CVolumes and Capacities ofCircular TanksTABLE C-l.WATER VOLUMES (cuBIC FEE'r) AND CAPACITIES (US cer-loNs) oF clRcuLAR TANKS FILLED lo A l-Foor DEPTH.o'0"TANKDIAM DTER(FEET)VOLUME(CUBICFEEl)CAPACITY(GALLONS]TAN KDIAMETI]R(rEET)VOLUME(cuBlcFEEl.]CAPACITY(cALl.oNS)1.001.502.002.503.003.504.004.50s.005.506.006.507.007.508.008.509.009.5010.010.50.785| .773. l4,1.9 I7.079.6212.615.919.623.u28.333.23U.544.250. I56.lt63.670.978.586.65.8713.223.536.752.972.094.0ll9t471782t22482Uu33037642447653058u641I 1.0I 1.512.012.513.0l3.ir14.0l4.s15.0I ).)16.016.5t7.0t7.5l8.0l8.irr 9.019.520.095.0104l13t23133143154165t771892012t4227241254269284299:J l47tl7778459lu9931,070I,150|,2401,3201,.1 01,5001,6001,700l,u00l,9002,0102,1202,2:lO2,350dFor water depths less or greatel than I foot, multiply the tabulated volumes and capacitiesbyrthe actual depth in feet."For tanks larser than 20 feetone-half its diameter by four.times the volume of a l5-foot tank'Forintermediate tank sizes,volune x 7.411.Ain diameter, multiplythe volume and capacity of a tank30-foot diameter tank, for example, has a volume of fourvolume::i.la x(j diameter)'x water depth; capacity:

Appendi* DUse of Weirs to MeasureFlowThe discharge of water through a hatchery channel can be measured easilyif a Cippoletti or a rectangular weir (Figure O-t) is built into the channel.The only measurement needed is that of the water head behind the weir;the head is the height the water surface above the crest of the weir itself.Reference of this head to a calibration chart (Table D-l ) gives thecorresponding discharge in gallons per minute.Water-flow determinations will be inaccurate if the head is measured atthe wrong point or if the weir has not been constructed carefully. The followingconsiderations must be met if weir operation is to be successful.(l) The head must be measured at a point sufficiently far behind theweir. Near the weir, the water level drops as water begins its fall over theweir crest. The head never should be measured closer to the weir than2 j times the depth of water flowing over the crest. For example, if 2inches of water are flowing over the weir crest, the head should be measured5 inches or more behind the weir. A practical measuring technique isto drive a stake into the channel bottom so that its top is exactly level withthe weir crest. Then, the head can be measured with a thin ruler as thedepth of water over the stake. A ruler also can be mounted permanently onthe side of a vertical channel wall behind the weir, if such a wall has beenconstruc ted.(2) The weir crest must be exactly level and the weir faces exactly vertical,or the standard head-to-discharge calibrations will not apply.ll84

WEIRSoo\/ooo \l+2"O\-^rv^^TlOLvvLv EDGES TO rv BE uL vut CUTI\ SM00TH,SMOOTH, STRAIGHTAND I 2"1TO EXACT DIMENSIONS.oHOLES FOR lOdGALVAN IZED NAILSAT 4" 4"O.C.l:llTloItlo o o o o'o o o o olloFtcunr D-1. (f"p) Diagram of a Cippoletti weir plate. It should be cut fromNo. 8 or No. 10 galvanized iron plate. The trapezoidal notch must be cut to theexact dimensions as shown. Flow rates with this weir will be twice the valuesshown in Table D-1. (Bottom) A rectangular weir installed to measure waterflow at the discharge of a fish hatchery. A sight gauge (insert) with a float in analuminum cylinder is used to measure water depth over the crest of the weir. Itmust be positioned at a distance at least 2.5 times the depth of the water flowingover the weir.

FISH HATCHERY MANAGEMENTTABLED_I.RELATIONBETWEENHEADANDDISCHARGEFORCIPPOLETTIANDREC.TANGULARWEIRS.DISCHARGEVALUESASSUMEAI.FOO.I.-LONGWEIRCREST;FoRSHORTERORLONGERCRES'[S,MUL'I.IPLYTHESEVALUESBYTHEAC'l.UAt,I,ENGTH_il "i1_HEAD(INCHES)0.2500.5000.7501.001.251.50t.7 52.002.252.502.753.003.253.503.754.00DISCHARGE(CALLONSPER MINUTE)5r.0014.023.036.050.066.0ti4.0102l'221431651882t2237263290HEAD(INCHES)4.254.50+.7 55.005.255.506.006.',256.506.757.007.257.507.75u.00DISCHARGL'(CALLONSPER MINUTEJ3t734(t37s40543(;46u50053356760163667270u7457U3u20HEAD(INCHES)tt.258.508.759.009.259.509.7510.010.310.5l0.ttI 1.0I 1.3l 1.5II.ti12.0DISCHARC;E(GAI-LONSPI]R MINUTE]u(;090093997ul,020l,0fi01,100I ,1501,1901,230l,2tt0I,320I,3701,410I,4601,510(g) fne weir crest, formed with a metal Plate, must be leak-proof' sharpor square-edged, and no thicker than |-inch'The distance of the weircrest above the bottom of the channel should be at least 2| times the waterhead on the weir to minimize aPproach water velocities'(a) eir must have access to the underside of falling water as it flows overthe weir crest. otherwise, air pressure may force water against the downstreamface of the weir, increasing the rate of discharge above the flowrates indicated in Table D-l'(S) fne channel above the weir must be straight, level' and clean toensuresmoothwaterflow.Sedimentanddebrisshouldnotbeallowedtocollect on or behind the weir.

FAppendix I ''Hatch"ry Codes forDesignating Fish LotsTABLE E-1. coDES FoR UNIrlt SfA'tES NATIONAL FlsH HATCHERIESCOT)I. IIATCHER} CODE HA I CH!lR'tAbAcAIAbernathy, WashingtonAlchesay, ArizonaAllegheny, PennsylvaniaCfCtCrawford, NebraskaCreston, MontanaBT)BsBIBdtsmCHBaldhill Dam, North DakotaBerkshire, M assashusettsBerlin, New HampshireBowden, West VirginiaBozeman, Mon tanaCarbon Hill, AlabamaDHDtDsECEdEnEtE,WDale Hollow,'I'ennesseeDexter, New Mexicol)worshak, IdahoFiagle Creek, OregonEdenton, North CarolinaEnnis, MontanaEntiat, WashingtonErwin, TennesseeCarson, WashingtonCdCF't,rChCmCnCBCedar Bluff, KansasChattahoochee f orest, Gcor giaCheraw, South CarolinaCohutta, GeorgiaColeman, CaliforniaCorning, ArkansasCraig Brook, MaineFfGDCPGnGI,Gl'Frankfort, KentuckyGarrison Dam, North DakotaGavins Point, South DakotaCenoa, WisconsinGreen l-ake, MaineGreers l'erry, Arkansas387

388 r'lsH HA'rcHERy MANAGEMENTTasLn E-1.coNirNUEDcroDE HAI'CH},R\ cot)E HA'fCHI]RYHgHLHbHFHkHagerman, IdahoHarrison Lake, VirginiaHebron, OhioHiau,atha Forest, MichiganHott hkiss, C olorad,.OrPBPCPFPfOrangeburg, South CarolinaPaint Bank. V irginiaPendills Creek, MichiganPisgah Forest, North CarolinaPittsford, VermontIDIRJsJHJRKkInks l)am, TexasIron River, WisconsrnJackson, WyomingJones Hole, tltahJordan River, Mir higanKooskia, Idahcra. Quilcene, Washingtona" Quinault, WahingtonSMSrSnSfSCSan Marcos, 'fexasSaratoga, WyomingSenecaville, C)hioSpcarfish, South DakotaSpring Creek, WashingtonLhI.MLml,vLeLrLWLahontan, NevadaLake MilL, Wisr onsinLamar, PennsvlvaniaLeadville, ColoradoLeave'nworth, WashingtonLeeto$ r). West VirginiirLittle White Salmon, WashingtonTCTsTpUvVCIehama Colusa, CaliforniaTishomingo, OklahonaTupelo, MississippiUvalde, TexasValley City, North DakotaMk Makah, WashingtonMS Mammoth Springs, ArkansasMN McNenny, South DakotaML McKinney l-ake, North CarolinaMr Meridian. MississippiMs Mesr uler,', Ntu Mexir oMC Miles City, MontanaMl Millen, GeorgiaNs Nashua, New HampshireNi Natchitoches, LouisranaNL New London, MinnesotaNo Neosho, MissouriNf Norfork, ArkansasNA North Attleboro, MassachusettsWhWmWSWlWRWsWdWCWBWtWkWvYkWalhalla, South CarolinaWarm Springs, GeorgiaWarm Springs, OregonWelaka, FloridaWhite River, VermontWhite Sulphur Springs,West VirginiaWillard, WashingtonWilliams Creek, ArizonaWillow Beach, ArizonaWinthrop, WashingtonWolf Creek, KentuckyWytheville, VirginiaYakima, Washington

HA'I'CHF,RY CODL,5Tesl,n E-2.Two-LEr"tER srATE ABBREVIATToNS.ALAKAZARCACOCTDEDCFLGAHIIDILINIAKSKYLAMF:,MDMAMIMNMSMOAlabamaAlaskaArizonaArkansasCaliforniaColoradoConnecticu tDelawareDistrict of ColumbiaFloridaGeorgiaGuamH awaiiIdahoIllinoisI ndianaIowaKansasKentuckyLouisianaMaineMarylandM assac hu settsMichiganMinnesotaMississippiMissouriM1'NBNVNHNJNMNYNONT)OHOKORPAPRRISCSD.I'N'lxUTVTVIWIWYMontanaNebraskaNevadaNew HampshireNew JerseyNeu'MexicoNew YorkNorth CarolinaNorth Dakota0hioOklahomaOregonPen nsylvaniaPuerto RicoRhode IslandSouth CarolinaSouth DakotaTen nessee'l ex asUtahVermontVirginiaVirgin IslandsWashingtonWest VirginiaWisconsinWyoming

trAppendix fNutritional Diseases andDiet FormulationsTasl-n F-1. NLITRI t IONAL DISEASES IN t'lsH. THE FOLLOWING IS PRESEN'fED AS ADIAGNOS'I'IC GUIDE. ALI, SICNS OBSERVI']DtN T'ISH ARE LUMPED 'I'OGI]'fHER ANDSOME DISORDERS MAY NO'f APPLY 'I'O A PAR'|ICULAR FISH SPECIES, (SOURCE:HORAK l1)75.)NI'I RI!]N I'SIGNS OF DI.]I;ICII']NC\' OR l, \ C lrSSPro teinCrude ProleinAmino atidsFat390Signs of deficiency: poor growth; reduced activity; fish remain nearthe water surfacc; increased vulnerability to parasites'Signs ol excess: ntoderate to slight growth retardation'Si!n, nf deficiency: deficiency of any essential amino acid can cdu5ereduced or no growth; lens cataract may result from a deficiency olany essential amino acid except arginine; lordosis or scoliosis mayresult from less than 0.2"" tryptophanin the diet; blacktail syndrome.loss of equilibrium will result from less than 0 fl" ' lysine inthe diet.Signs of excess: inhibited growth results fron excess leucine; dietaryinefficiencv may result from extreme ratios of phenylalanine totyrosine, high levels of either phenylalanine or tyrosine' and valinegreater than ll",Signs of deficiency: poor growth, as essential amino acids must beused for energy; necrosis of the caudal fin; fatty pale liver; fin erosion;dermal depigmentation; edema; increased mitochondrial swelling; mortality; stress'induced violent swimming motion with littleforward movement, follou'ed by motionless floating for I 5 minutesbefore recovery; slightly reduced hemoglobin; anemia; liver andkidney degeneration; soreback; high mortality may occur lrom cornor soy oil in diets at near-freezing temperatures'Signs of excess: plugged intestine; liver and kidney degeneratton;"deathmay result from hard fat (beef); pale, swollen' yellow-brown'

NU RI'TIONAL DISEASES AND DIETS 391TABLE F-1.cuN'nNUL,t,N U'I'R I I.]N'TFat \continued)CarbohydrateV itam insVitanin AVitamin DVitanin EVitanin KThiamine (B)SIGNS OF DEFICIENCY OR EXCI]SSfatty infiltrated liver; pigmented insoluble fat (ceroid) in liver;water edema; amenia; fatty infiltrated kidney and spleen; reducedweight gain with no increase in carcass fat.Signs of deficency: reduced survival of stocked fish; decreased liverglycogen from carbohydrate-free diet; slow growth, as amino acidsare used for energy.Signs of excess: glycogen-infiltrated, pale, swollen liver; fattyinfiltratedkidneys; degenerated pancreatic islets; poor growth;edema; elevated blood glucose; death from overfeeding or fromdigestible carbohydrate greater than 20"r of diet.Signs of deficency: serous fluid in abdominal cavity; edema; exophthalmus;hemorrhage of anterior chamber of the eye, base offins, and kidneys; light-colored body; poor appetite; poor growth;eye cataracts; anemia; drying and hardening of mucous-secretingtissue; clubbed gills; high mortality; bent gill operculum. (VitaminA is destroled by rancid fats.\Signs of excess: enlargement of liver and spleen; retarded growth;skin lesions; epithelial keratinization; abnormal bone formation andfusion of vertebrae; necrosis of caudal fin; elevated levels of bodyfat and cholesteroll lowered hematocrit.Signs of deficency: elevated feed conversion; slightly increasednumber of blood cells; impaired absorption of calcium and phosphorousfrom intestine.Signs of excess: impaired growth; decalcification, especially of ribs;lethargy; dark coloration; elevated blood serum calcium caused bydoses of Dl.|.Signs of deficency: serous fluid in abdominal cavity; ceroid in liver,spleen, and kidney; fragility of red blood cells; poor growth; poorfood conversion; cell degeneration; sterility; excessive mortality;clubbed gills; soreback; general feed rancidity, as vitamin E is astrong antioxidant. VitaminE is involved with selenium and vitaminC for normal reproduction, and may be involved with embryomembrane permeability and hatchability of fish eggs. It is destroyedby rancid fats. Fortification of E can prevent anemia causedby rancidity of the feed.Signs of excess: no growth; toxic liver reaction; death; accumulationof vitamin E in ovary.Signs of deficency: anemia; pale liver, spleen, and gills; hemorrhagicgills, eyes, base of fins, and vascular tissues; death.Signs of excess: none.Signs of deficiency: poor appetite; muscle atrophy; vascular degeneration;convulsions; rolling whirling motioni extreme nervousness andno recovery from excitement; instability and loss of equilibrium;weakness; edema; poor appetite; poor growth;retracted head;sometimes a purple sheen to the body; melanosis in older fish;excessive mortality; anemia; corneal opacities; paralysis of dorsaland oectoral fins.

392 FISH HATCHERY MANAGEMENTTABLE F-1.coNrrNUED.NUTRIEN'fSIGNS OI' DE!'ICIENCY oR EXCESSVitamins \continued)Riboflailn (82)Pyidotine (86)Signs of excess: none.Signs of deficiency: corneal vascularizationi cloudy lens and cataract;hemorrhagic eyes, nose, or operculum; photophobia; incoordination;abnormal pigmentation of iris; striated constructions ofabdominal wall; dark coloration; poor appetite; anemia; completecessation of growth; dermatitis; high mortality.Signs of excess: none.Signs of deficiency: nervous disorders; epileptiform convulsions;hyperirritability; atexia; loss of appetite; edema of peritoneal cavitywith colorless serous fluid; rapid onset of rigor mortis; rapid jerkybreathing; flexing of opercles; iridescent blue-green coloration onback; heavy mortality; retarded growth; indifference to light. (Ahigh tryptophan diet increases requirement for pyridoxine.)Signs of excess: none.Pantothenic acidSigns of deficiency: clubbed gills; necrosis; scarring and cellular atrophyof gills; gill exudate; general "mumpy" appearance; erodedopercles; pinhead; prostration; loss of appetite; lethargy; poorgrowth; high mortality; eroded fins; disruption of blood cell formatlon.BiotinSigns of excess: none.Signs of deficiency: loss of appetite; lesions in colon; dark coloration(blue slime film that sloughs off in patches); muscle atrophy; spasticconvulsions; anemia; skin lesions; reduced stamina; contractedcaudal fin; poor growth; elevated feed conversion; small liver size;abnormally pale liver.Signs of excess: depression of growth; excessive levels can be coun-C ho lineteracted by adding folic acid or niacin.Signs of deficiency: poor food conversion; hemorrhagic kidney andintestine; exophthalmia; extended abdomen; light-colored body;poor growth; fatty infiltrated livers; increased gastric emptyingtime; anemia.Vitamin By2Signs of excess: none.Signs of deficiency: Poor appetite; erratic and low hemoglobin; fraementationof erythrocytes with many immature forms; proteinmetabolism disruption; poor growth; poor food conversron.NiacinSigns of excess: none.Signs of deficiency: loss of appetite; poor food conversion; lesions incolon; jerky or difficult motion; weakness; reduced coordination;mortality from handling stress; edema of stomach and colon; musclespasms while resting; tetanyi sensitivity to sunlight and sunburn;poor growth; swollen but not clubbed gills; flared opercles;anemia; lethargy; skin hemorrhage; high mortality.Signs of excess: none.Ascorbic aeid(ritamin C)Signs of deficiency: scoliosis; lordosis; abnormal opercles; impairedformation of collagen; inpaired wound healing; abnormal cartilage;twisted, spiraled, deformed cartilage of gill filaments; clubbed gills;hyperplasia of jaw and muscle; deformed vertebrae; eye lesions;

NUTRITIONAL DISEASES AND DIETS 393TasLL, F-1.coNTTNUITDN T-'I'R I EN'ISICNS OF DEF'ICIENCY OR EXCESSVitamins (continued)?'olic acid(uitanin I!)Inosi to IM ineralsToxins and chemicalshemorrhagic skin, liver, kidney, intestine, and muscle; retardedgrowth; loss of appetite; increased mortality; eventual anemia.Signs of excess: none.Signs of deficiency: lethargy; fragility of fins, especially caudal; darkcoloration; reduced resistance to disease; poor growth; no aPPetite;infraction of spleen; serous fluid in abdominal cavity; sluggishswimmingi loss of caudal fin; exophthalmia.Signs of excess: none.Signs of deficiency; distended stomach; increased gastric emPtyingtimei skin lesions; fragile fins; loss of caudal fin; poor growth; poorappetite; edema; dark color; anemia; high mortality; white-coloredliver.Signs of excess: none.Signs of deficiency: hyperemia on floor of mouth; protrusions at branchialjunction; thryoid tumor; exophthalmia; renal calculi (kidneystones).Signs of excess: scoliosis; lordosis; blacktaili eroded caudal fin; muscularatrophy; paralysis if there is dissolved lead in the water at'tparts per billion (no toxic effects with lead up to tl,(XX) parts permillion in dry feed) ; growth retardation; pigmentation changeswhen coppcr is greater than I mg/g in dry diet (100 to 200 timesthe daily requircment).Signs of deficiency: none.Signs of excess: Hepatocellular carcinoma after l2 20 months withtannic acid at 7.5 4tt0 mg/100 g in dry feed; loss of appetite;grossly visible sundan-ophilic substance in liver; decreased availabilityof lysine uhen greater than 0.04",' free gossypol (yellow pigmentfrom glands of cottonseed meal) is in feed; trypsin inhibitionresulting frorr low heat-treated soybean meal; liver cell carcinomas;palc yellow or creamy-colored livers; gill epitheliumdisruptionresulting from aflatoxin-contaminated oilseed meals (especially cottonseed)with as little as 0.1 0.5 parts pcr billion aflatoxin Bl, or7.5 mg carbarson/100 g dry feed; feed with greater than l3', moistureencourages mold growth which produces the toxin; gill diseaseresulting from DD'I'at7.ir mg/100 g dry diet; cataract caused byiiO mg/100 mg dry diet of thioacetamide lor l2 months; brokenbacksyndrome; retarded growth produced by toxaphene rn waterat greater than 70 parts per thousand; retarded ammonia detoxication enzymes affected by dieldrin greater than 0.13(i parts per millionin feed; inhibit€d mobilization of liver glycogen and cortisolproduction in fish under stress and endrin greater than 0.2 in leed;stimulated thyroid when greater than 0.tl parts per million DDT or2.0 parts per million l)D!l is in feed, or 2,'t-D in the water; lou'eredegg hatching; abnormal fry anernia; mortality; reduced growth;dark, lethargic fish when greater than 0.2-0.5 parts per million Aroclor125'1 is in feed; yellow-colored flesh when (i",, corn gluten mealis in feed.tJ

394 FISH HATCHERY MANAGEMENTTABLE F-2. DRy rROUT FEEDS DEVELopED By IHL, US TISH AND wILDLIFE SERVICE. VALUES ARE PERCEN]'OF FEED BY WEIGHT. MP = MINIMUM PROTEIN.STARTLRPRODUC'TIONDIE'TfINGERLINGDIETSDIE'I'INGREDIENTSD7 PR 6 PR9Fish meal (MP 60'1,,)Soybean meal, dehulled seedsFlour (MP 50'li,)Meal (MP 47.5'1,)Corn gluten meal (MP 60'1,,)Wheat middlings, standardYeast, dehydrated brewer's or torulaBlood meal (MP lJ0'1,,)Whey, dehydratedFish solubles, condensed (MP 50'1,,)Fermentation solubles, dehydratedAlfalfa meal, dehydratedSoybean oilFish oilVitamin premix no.304Choline chloride, 50'l',Mineral mixtureb45l5l06v555.)|5 19.35l0l0630.4 0.40.2 0.20.05 0.1t352013.35l06350.40.20.125t7.35l0ttJ50.40.20.1"See Table F tl.'Mine.al mixture (gru-. p", pound): ZnSOa, tt4; FeSOa'7H20,22.5; CuSOa, 1.75;MnSOa, 94; KIOq, 0.l3tl; inert carrier, 251.137.

NU'I'RITIONAL DISEASES AND DIETS 395Tesrn F-3. DRy 'rRour FEEDS DEVELOpED By coLoRADo DIVtsroN oF wILDLTFE.VALUES ARE PRECENT OF FEED BY WEIGHT. MP : MINIMUM PRO'I'EIN.STARTER DIE'I'S !INGERLINC DIE'I'S REGULARPRODItC TtONINGREDIENTS SD:] SDsA PRl DIEl'Fish meal (MP 60'11,)3lSoybean meal, dehulled seedsFlour (MP 5o')i,)Meal (MP 47.5'li)Corn gluten meal (MP OO'1,)Wheat middlings, standardWheat germ mealYeast, dehydrated brewer'sBlood meal (MP U0'li')Whey, dehydratedFish solubles, condensedFermentation solubles, dehydratedAlfalfa meal, dehydratedPoultry feathers, hydrolyzedFish oilVitamin premix no. 304Choline chlorideSalt, trace mineralizedD5l3.tt4.57l056U0.50.2I551.37zl055u60.50.2Il019.83.53l063510.50.2l0o15.u5.5IJJ+0.50.223.u5l02.5l0l0(i.53.50.50.2Idsee Table F-ti.DMu*i-rzinccontent 0.005'li,

396 FISH HATCHERY MANAGEMENTT,\sLr: F .1. DRy sAt,MON lEtDs DEVELoPED BY THE US l'rsn AND wn.Dr.n'E sERvICE, VALUES ARI.] PR!]CEN'I' OI FEED BY WEIGH'f . MP : MINIMT-iM PROI'EIN.s t AR il,tRI)tu fI'INLJI']RI INCI)II'I SINGRI.]DII;N'ISSIJFish meal (MP (j0",)Cottonseed meal, dehulled (UlWheat middlings, standardWheat gernr mealYeast, dehydratcd breu'er'sBlood meal (MP u0',)Whey, dehydratedShrimp, c.rnnery residuc mealBrcwer's grains, dehydratedSoy bean oilF ish oilVitamin premix no. 130"Choline chlorideMineral nixturel'+s,;', I+()t0ti.,15rlli5l00..10.'2)7l013.3ti5l0lrt0,10.+0.'20.IJIl0I (t.355,,]l0.10.+0.20.1"See Table F fl. Inositol must be added to the vitamin premix for use in salmon leeds at alevel of tJ grams per pound of premix.'Mineralmixturc (gru-. p"r pound): ZnS()a, tl.1; FeSOa' 7H2O, 22.ri; CuSO1, 1.75;MnSOa, 1).1; KIC)1, 0.l3tl; inert carrier, 25l.i37.

NUTRITIONAL DISEASES AND DIETS 397'IasLE F-5.Molsl sALMoN I'EEDS I-}EVEI,OPED BY OREGON STATE UNIVERSII'Y ANDoRIiGoN DF]PAR'| MEN'I OIWF,IGHl'.!ISH AND WTLDLII'!]. VALTJES ART PRECL,N'I' OF FEED BYIN(iRI]I)II.]N I()Rl.GONS I'AR'I'[,RNIASHoM3oREGONS I'AR I'ERPELLE'I'oP2Meal mixHerrins meald"aFish meal"Whcat germ mealWhey, dehydratedCottonseed mcal, dehulled'Shrimp or c.ab -.'aldCorn distiller's dried solublesVitamin prcmix'Wet mixII una vls('era"Turbot, salmon viscera, hcrringsWet fishnltJHerring oil'Choline chloridc (liquid, 70", product)l0l0l0l01.5100.5'2\)it74J1.530(i.00.5oMinimum'H".rirg70'lir orotein: maximum 3'li, NaCl.meal (minimum 70'li protein; maximum 3'll' NaCl) must be used as 100')1, of thefish meal in each batch rf-+-, + -, and -inch fpellets, and at no less than 509i of the fishmeal in each batch of large pellets. Hake (minimum 68(li' protein), anchovy (domestic orPeruvian, minimum65'li' protein), or menhaden (minimum 60(){r protein) may be used as theremaining portion of the fish meal for larger pellets, provided the total fish meal is increasedto 30'ti, of the diet (31')i' if menhaden us used).'Prepress solvent-extracted; minimum 48.5'li, protein; maximum 0.055'lo free gossypol.dMaximum3'i" NaCl; minimum25'lir protein (not counted as fish meal in protein calculations).'See Table F-tl, Oregon salmon premix./Noheads or gills; with livers, pasteurized.8'Turbot, pasteurized salmon viscera (no heads or gills), or pasteurized herring.al-i-it"dto tuna viscera, herring, "bottom fish" (whole or fillet scrap), salmon viscera, dogfish,and hake, with the following provisions: (l) two or more must be used in combination,with no one exceeding l5'io of the total diet; (2) j - and j-inchpellets shall contain at least7.5(li, tuna viscera, but no fillet scrap.'stabilizedwith 0.3('l1' BHA-BHT (l:l); less than 3.0')i, free fatty acids, and not alkalinereprocessed.

398 FISH HATCHERY MANAGEMENTTeslr F-6.MINIMUMDRY CATFISHPROTEIN.FEEDS. VALUES ARE PRECEN'| OF FEED BY WEIGHT' MP :nr E osoINGRE,DINNl'SFish meal (MP 60'10Soybean meal, dehulled seeds(uP +a'ri,)(MP 49'li,)Corn gluten meal (MP 60'li')Wheat middlings, standardBlood meal (l,tP tlO'tl')Alfalfa meal, dehYdratedMeat and bone mealCorn, yellow, dentDistillers dried grains with solublesDried distillers solublesRice branRice mill dustWheat, grain, groundCottonsJed meal, dehulledFeather mealAnimaltallowDicalcium PhosPhateTrace mineralized saltVitamin Pr"mi*'Choline chloride, 50'l'(tvtp +ti S"")26l9cl5524.91.5+.50.50.50.1t0s',2202r.47.55zI0.50.50.1It)352U.f;52.5J0.250.50.1aFeed I was developed by the departments of Biology and Grain Sci11c1' Kansas stateUniversity. Feed 2 was d"'"lop"d bv the Depa'tm:lt:f Fttl"tt".:";"J;i"O l}i:^O^1:.:::l::'::Nil',T'T"J:fi,r. *u. d","lop"d bf the Skidaway Institute of oceanographv andcoastal plain Station, savannah, Georgia. Feed ,! was developed by the uS Fish and wildlifeService's Fish Farming Experimental Station' Stuttgart' Arkansas''See Table F-[], catfish Premixl220J82510It)5Io.50.1

NUTRITIONAL DISEASES AND DIEl'STasI-E F-7. cooI-wAfER DRY !-tsH FIED (w 7) DEVELoPED FOR l'RY AND FINGERLINGS BY THN US FISH AND WILDLIFE SERVICI. VALLIES ARE PERCE,N,f OF FEEI) BYWEIGHI. MP = MtNIMUM PRO'|EIN.IN(;I{Ut)ILrN fSl-ish meal (Uf OS",150Soybean flour, dehulled seeds (MP +tt.5",,)l0Wheat middlings, standard5.1Fish solubles, condensed (ltp S0",,)l0Blood meal (MP t10", )lrYeast, dehydrated brewer's5Whey, dehydrated5Fish oilIVitamin premix no.30d0.6Choline chloride, 50",,0.3asee l'able F U. Vitamin premix (no.30) is used at 1.5x the level used in trout feedsTABLE F-8.spECIFIcAfloNs FoR vITAMINPREMIXLS FOR CA'fFISH, 'TROUT, ANDSAI,MON FL,EDS, VALUES ARE AMoUNTS PERPOUND OF PREMIX4.hCA'I'FISII,TROUl'ORI.]GON SALMONVI1"{MINL'NI'I'SPREMIXPRUMIX NO. 30PR!]M I XVitamin A'Vitamin BdVitarnin E'Vitamin K/Ascorbic acidBiotinBrzFolic acidI nositolN iacindh-rantothenateryrloox rneRiboflavinI nlamlne"IUIUIUmgcmgmgmggcgmgcmg500,00090,0004,600900Il02.160v:tl0l,800l.ul,rJ00750,00050,00040,000I,25075402.5l,00025t23,500(i4.000I 5,2005+527Itl1.838565.7:1.25351.677tldDiluent used to bring the total amount to one pound must be a cereal product.'Levels in this vitamin premix are calculated to supply the recommended amounts rn acomplete feed.tPul-itut"or acetate./Stabilized."Alpha tocopherol acetateJ Menadione sodium bisulfite complex.SNiacinamide .io-calcirm.tHCl./Mononitrate.

400 FISH HATCHERY MANAGEMENTTasLE F-9. RECOMMENDED AMOUNTS oF vITAMINS IN FISH FEEDS. vALUEs AREAMOUNTS PER POUND OF FEED, AND INCLUDE TOTAL AMOUNTS FROMINGREDIENTS AND VITAMIN PREMIXESO. (SOURCE: NATIONAL ACADEMY OI' SCI-ENCES.)WARMWA'IER FISH FEI.]DSSU P PI,!]M I]NI'ALCOMPLI]TESALMONIDVI'I'AMINDIETDIETI'EEDSVitamin AVitamin D3Vitamin E'Vitamin KAscorbic acidBiotinBrzCholineFolic acidInositolNiacinPantothenic acidPyridoxineRiboflavinThiamineIUIUIUmgmgmgmgmgmgmgmgmgmgmgmg1,00010052.323U0.0052000Ul355J02,500450234.5450.050.012502.34550I9q1,000R,l5,10500.50.011,5002.520075205105-These amounts do not allow for processing or storage losses but give the total vitaminscontributed from all sources. Other amounts may be more appropriate under various conditrons.'R:required, amount not determined.'Requirementis affected directly by the amount and type of unsaturated fat fed.

AppendixChemical Treatments:Calculations and ConstantFlow DeliveryHatchery systems often receive prolonged-bath or constant-flow chemicaltreatments that adjust water quality or control diseases. In prolonged-bathtreatments (without water flow), chemicals are,spread over the surface ofthe water body, and mixed throughout its volume, by hand or machine.Many hatchery tanks and most ponds, particularly large ones, are treatedstatically. In constant-flow treatments, chemicals are metered at one pointinto continously renewed water supplies; the turbulence of the movingwater accomplishes the mixing. Constant-flow treatments typically are usedin intensive culture when even a temporary halt in the supply of freshwater might cause fish mortality because of oxygen depletion or wasteaccumulation.Chemical applications normally are couched in terms of final concentrations;a pond treatment of 2 parts per million rotenone means the wholepond should contain this concentration after application. Concentrations,in turn, typically are weight ratios: weight of chemical in solution (orsuspension) per weight of solvent (usually water). The ratio may beexpressed in terms either of unit solvent weight or of unit solute weight.Ten pounds chemical per ton of water, and one pound chemical per 200pounds water (1:200), both represent the same concentration. Even when aconcentration is expressed in terms of volume or capacity (pounds/acrefoot;milligrams/liter), it is the equivalent weight of that volume of waterthat is implied.401

402 FISH HATCHERY MANAGEMENTCalculations for Prolonged-Bath TreatmentsThe basic formulacapacity(volume) ofwater tobe treatedxfor computing the amount of chemical needed is:finalconcentrationcorrectiondesired x factor(pp-)strength of chemical (decimal)-weight ofchemicalneededThe units of measure and the correction factor (Table G-l) that correlatesvolume with weight vary with the size of the unit to be treated. The chemicalstrength is the fraction of a chemical preparation that is active ingredientwhen purchased; ppm is parts per million.For example, in smaller hatchery units, gallon capacities usually areused. Chemicals typically are measured in grams because small amountsare usually needed, and metric balances are more accurate than Englishones in this range. The correction factor is 0.0038 (grams/gallon).Examples:(l) Ho* much Dylox (50%r active ingredient) is needed for a 0.25 ppmtreatment of a 390-eallon tank?390x0.25x0.0038 : 0.74 grams Dylox0.50(2) How much copper sulfate (100([ active ingredient) is needed for al:6,000 treatment of that 390-eallon tank?390x167x0.0038 : 247 grams CuSO,1.00Tasln G-I. coRRECTIoN FACTORS usED TO CONVERT voLUME oR cApActry roWEIGH'I- IN CALCULATIONS OF CHEMICAL CONCEN'I'RATION.Units Correction Factorgrams (or milliliters)/gallongrams (or milliliters)/cubic footgrams (or milliliters)/cubic yardounces (fluid)/cubic footounces (fluid)/cubic yardounces (weight)/cubic footounces (weight)/cubic yardpounds/cubic footpounds/cubic yardpounds/acre- foot0.0037tt0.0282u0.7(;36f;0.000960.025850.001000.026940.000060.0016u2.7 t8l

CHEMICAL TREATMENTS 403For ponds, volumes usually are known in acre-feet (surface area in acresx average depth in feet). Relatively large amounts of chemicals areneeded for treatment, and these usually can be weighed in pounds. Thecorrection factor is 2.7 (pounds/acre-footper part per million).Example: How much of chemical Alor a 2-ppm treatment of a 2.0-acre pond(60"0 active ingredient) is neededthat averages 2.5 feet deep?Volume : !.Q as1g5 X 2.5 feet : 5.0 acre-feet;t_t#-: 45 pounds of chemical ACalculations for Constant-Flow TreatmentsThe weight of chemical needed for constant-flow treatments is computedjust as for prolonged-bath treatments. However, in this case the volume(capacity) of water to be treated is equal to the flow rate times the treatmenttime (for example, l0 gallons per minute x 30 minutes). Correctionfactors are the same. The formula is:flow treatment final correctionrate X time Xconcentrationx factorchemical strength (decimal fraction)Example: A trough receiving a water flow of six gallons per minute is toreceive a l-hour (60-minute) constant-flow treatment of chemical B (10090active strength) at a concentration of 5 ppm. How many grams of chemicalB must be dispensed to maintain the treatment concentration?6.0x60x5.0x0.0038 : 6.84 srams of chemical B.1.00Constant-Flow Deliverv of Chemicalsweight ofchemicalneededOf the variety of constant-flow devices that have been adapted tohatchery use, commercial chicken waterers are the most reliable (Figurec-l).All such devices deliver only liquids. Dry chemicals first must be putinto solution before they can be dispensed. If the amount of dry chemicalneeded already has been computed by the formula given in the previoussection, it only is necessary to determine the amount of liquid thatwill be dispensed from the chicken waterer over the period of treatment.This is done by simple proportion. For example, if the constant-flow devicedelivers 20 milliliters per minute and the treatment is to be 60minutes long, 1,200 milliliters will be delivered in all. This is the water

404 FISH HATCHERY MANAGEMENTFIGURE G-1. A constant-flow device for dispensing liquid chemicals. (1) The devicemust be positioned over the water inflow to the fish-rearing unit, to insureuniform mixing of the chemicals in the water. (2) The device can be made froma conventional chicken waterer. Note siphon in place (arrow).volume into which the predetermined weight of chemical should be dissolvedbefore treatment begins.If a 300-gallon tank were receiving a l0-gallon-per-minute water flow,it would take at least 30 minutes (300 - l0) for water in the tank to bereplaced. It would take this long for any chemical to reach a desiredconcentration in the tank. Thus, muCh of the treatment would be wasted.To avoid such waste, it is best to pretreat the tank. The water flowis shut off briefly, and chemical is quickly added to establish the finalconcentration required (according to the formula for static treatmentabove). Then the water flow is resumed and chemical metering is begunwith the constant-flow device.After all the chemical has been dispensed, some time will be requiredfor the last of it to be flushed from the treated tank. Partial draining ofthe tank will flush much of the chemical from the unit. Fish should bewatched for signs of stress after, as well as during, the treatment period.If effluent from the tank has to be treated for public-health reasons, suchtreatment should be continued until all the chemical has disappearedfrom the system.

Appendix HDrug Coatings forFeed PelletsEither gelatin or soy oil may be used as drug carriers for coating feed pellets.A representative sample of pellets should be checked for adequatecoatings before the operation is terminated.Gelatin: 125 grams gelatin in 3.0 quarts water per 100 pounds of pellets.(l) Slowty dissolve the gelatin into hot tap water.(Z) Stir the drug into the gelatin solution until all lumps are gone'(g) Slowly add the drug-gelatin mixture to pellets as they are stirred byhand or in a small cement mixer. To avoid pellet breakage, stir gently andonly long enough to assure an even drug coating.Soy oil: 2-3 pounds per 100 pounds of pellets.(t) trli" drug evenly in warm (100-120" F) oil.(Z) pour or spray mixture over pellets.405

TAppendix ILength-Weight TablesGuide to Selecting a Condition Factor (C) Table toMatch a Species of FishConditionfactor(C x to 7) Table Species1,500 I-l Muskellunge (1,OOO), tiger muskellunge (1,600)2,000 l-2 Northern pike (l,gtt)2,500 I-3 Lake trout (ZJZS)3,000 l-4 Chinook salmon (Z,gSg), walleye (3,000), channelcatfish (Z,ezz)3,500 I-5 Westslope cutthroat trout (3,559), coho salmon\3,737), steelhead (3,405)4,000 I-O Rainbow, brook, and brown trout (4,055 acceptedrainbow trout C factor)4,500 I-7 Largemouth bass (4,606)5,000 I-8The body form of some fishes remains nearly constant until the fish becomesexually mature. Therefore, the table can be used for fish longerthan l0 inches, or shorter than I inch, if the decimal point is moved as followsin the tables:Columns1and42 and, 53and6406Fish shorter than 1 inchMove three spaces to leftMove one space to leftMove three spaces to rightFish longer than 70 inchesMove three spaces to rightMove one space to rightMove three spaces to left

LENGTH,WEIGHT'TABLESTABLE I- I. LENG,TH-WE,IGHT RELATIONSHIPS FOR FISH WITH C: I,5OO X IO 7WEIGHI'/I,OOOFISH (I,B)LENCTH(INCHES)FISH/POUNDWEIGHl'(GRAMS)LENGTH(cM)FISH/KILOCRAM0.i500.1540.l5u0.I fi20.1660.1700.17 40.1780.1820.Iu60.1900.1940. lgtt0.2020.2060.2 l00.2140.21tt0.2220.2260.2300.2310.2380.2420.2460.2500.2540.2580.2620.2660.2700.2740.2780.2820.2860.2900.2940.2980.3020.3060.3 l00.3140.3180.3220.3260.3301.00001.00u8I .01751.02601.03441.04261.05071.05871.06661.07431.08201.0u951.0970l. 1043l.lll5l.ll87|.1257t.13271 .1396l. l 464l.l53l1.15981.1663t.t728l. l 7931.18561.1919l.l9ul1.2043t.2t04r.2t64t.2224t.2283t.2:142t.24001.245t)| .25151.257 |1.26271.2683t.2738t.27921.2846L29001.29531.30066666.6646493.50u6329. I I 76172.8446024.t025882.3595747 .t375617.9885494.5 I 65376.3555263.t725154.6525050.5204950.5 l 24854.383476t.9224672.9t+4587.t72,1504.5234424.7974347.8444273.523420 I .6994t32.2504065.0ri I4000.02 I3937.0293U75.9903816.8153759.4203703.72s3649.6563597.1443546. l 2 I3496.5253448.2973401.3U23355.72633 I 1.2803267.9953225.8283 I 84.7353144.67 63105.6123067.5063030.3240.06u00.06990.07170.07350.07530.077 |0.07890.08070.08260.08440.0u620.08800.08980.09 I (i0.09340.09530.09710.09890. I 0070. I 0250.10430.10610. I 0800. l 0980.11160.11340.11520.1 l 700.1 l8u0.t2070.t2250.12430.12610.t2790.t2970.13150. l 3340.13520. I 3700. I 3880. l 4060.t4240.t4420.14610.t 47I0.14972.5402.5622.5842.6062.6272.6482.6692.6U92.7092.7292.7182.7672.7862.8052.8232.8412.8592.8772.8952.9122.9292.9462.9(t32.9792.9953.01 I3.0273.0433.0593.0743.0903.1053.1203.1353.1503.1643.1793.1933.2073.2213.2353.2493.2633.2773.2903.30314697.46ir14315.7 l9I 3953.30 I13608.77713280.8591296rJ.37112670.250123rJ5.531t2tt3.:124I 1852.U24I l 603.293I 1364.051r1134.47710913.99610702.074r0498.227l 0302.000t0112.9779930.7629754.9969585.3489421.4969263. I 529l 10.043ttg(i1.9148U 1 U.5238679.6528545.0tt211414.62582UU.0908l 65.3058046. I 057930.3327817.8487708.50117602.1847498.7547398.09u7300. I I 37204.6887 ttt.723702t.1296932.8 l368,16.6916762.6tt46680.7 I I

408 FISH HATCHERY MANAGEMENl'Tasr-E I- I c: l,5oo x to ', coNTINUl,oWI'ICHl'/1,000FISH (Lts]t.!.Nc t HiINCHES]Fl SH/P()trNt)WEI(;H'III;RAMS]I-!]NG]'HicMtFISH,/Kil.ocRAM0.3340.33n0.3,120.3.r(i0.3500.35,10.35u0.3620.3(;(;0.3700.37'10.37rl0.3820.llu60.3900.39,10.39lt0.4020.40(i0.,1 I00.,11.10.,1I u0.1220.42(i0..1300..1340.43r't0.4120.,1,1(i0.,1500.,15,1.0.45u0.4(i20.46(;0.,1700.17 +0.4780.,rti20..ru60.,1900.,1940.,19u0.50.10.5t20.5200.5281.305r.tl.lll l01.3162I .lJ2 l31.32(i3I .311.1.11.33(i1I .11.1 I 3I .1J.1(t3l 351 ll 3560l.ll(t0tl1.365(i1.3703I .3751t.3797I .38.14l.iJu901.393(t1.3{)tt2L,+027t.4072| .4t t71.,11(il1.,r20(;1.4.24!ll.429llI .43361.,13tt0|.11221..1,1(i51.45071.,15501 .,r5911.4633t.,t67 4|.17 t61.47 57t.1797l.4ulllJl.4u7lJI ..19 I rlI ..1.97u1.5057I .5135|.5212299,1.03 32{)513.6012923.1)9ti2I.t90. 1952857.t6+21124.8tto2793.:lt72762.15'22732.2(;l2702.72:l2673.8172615.52326t7.8'222590.(i9,12564.t23253u.0912512.5832187.5822+6:1.07,t2439.0.\421t 5.47 ll2392.3642il(t9.(ttlu'23+7.1:ltl21125.(i0l2it01.t672283.t212262.4632',242.t72'2222.2+l2202.6622t83.+252t6,1.5'2121,15.9412127.6782t09.7232092.0(r92071.7072057.6312040.834202.1.310200rJ.050lgti4. I 271953. r 251923.07 ttI1193.9,110. l5l 50. 1r;330.15510.15(i90.l5url0. I (i060. r (t2.10.16+20. I (t(i00.l67tt0. I 6960. l 7150. 17330. I 7510.17(;90.t7870. l lJ050. I u230.1 ti,120. l8fiO0. I ttTrl0.I u9(i0.l9l,r0. l 9320. I 9500.19(;90.lgrJ70.20050.20230.20410.20590.20770.209(t0.21 l40.2t320.21500.21(ilJ0.21u(;0.22040.22230.22410.22590.22860.23220.23590.23953.3173.330i].IJ433.35(i11.3693.3 U23. iJ943.4073.4193.,1323.4+43.45(;3.4(i93.,tu l1J..1933.5053.5163.52rJ3.5.103.5513.r(i33.57 +3.5fJ(tl|.5973.60r13.(; l9lJ.(ilJ0:J. (i'1 Il|.(i523.6633.67 'lll.(t853.61)63.70(i3.7 t73.7273.7311:1.74tliJ.7 583.7693.7793.7li93.ti0,r3.82,rll.8.143.u64(t(i00.7036522.5t)0(i.1,16.3016:171.7776298.95 762'27.7856I5U.199(;090. l5(i6023.5985958..17 75ti94.7505ti32.37 1577 t..)01571t .4925652.9145595.5235539.281)5,+8,1.t725430. I '115:177.t645:125.',2t I527 ,4.254522,t.2585t75.2075127.0635079.8095033.41tl4987.Uft7,1943.1334U99.1 954tJ56.0314u l 3.(i2 I477 | .9454730.1)U.t.{(t90.7 t 9,1(t5 l. I 37,16r2.21545 7 3.93u.153(i.29344!)9.26'2,14(t2.ti32,1.r26.98,1437 4.246.t305.lJ9tt4239.6524t7 5.4t8

LRNGTH,WEIGHT TABI,ESTasr.n I- I(,': I,r;00 X IO 7, CONTINUEDWEIGHl /1,000 LENGl'HF lst{/WEIGHTI,ENGTHFISH/(I NCHES)POL]Nt)iGRAMS](CM]KII,OCRAM0.53(i0.5,140.5520.5600.5(itt0.57(i0.5tt.10.5920.(i000.ft0u0.til 60.(i2.t0.(t320.(;,100.6,1r,]0. (iir(i0.fi(i40.67',20.(;800.(itltt0.(i960.70.10.7 t20.7'200.72lt0.73(i0.7 +40.7520.7600.7(trJ0.7760.7840.79')0.u000.u0fl0.u l (t0.1t2.10.8320.11400.ti4r,t0.u5(;0.8(t,10.8720.uu00.lltill0.u96l .528lJ1.53(i.t1.5,139I .55131.55U71.5{i59r .5732L5U0ll1.5u7+1.59,r..1I .(i0 I '11.6083l.6l5ll.(i2 I 1)1.628(iI .(i3r3I .(t.t I Il.(;,ll.t5l.(i550l.(;(il 5L6(i79l .(;7411l (;U0(iL(rtt(t1)I .693 Il.(t99il1.7051t.7tt51.7 t7 5| .72',t51.7295L7 35,11 .7,1 l3| .747'21.7530t.7 587| .76+5|.77011.77 stll.7tll 4t.78701.7926I .798Il U0lJ(iL8090I .814.{I1t65.(i73I 838.237Ittll.r;96t785.7 17l7(;0.56(;I 7116. I 1'1t7 t2.332I (tttg.l92I 66(t.(i70I (i4,1.7 40I (i23.3u01602.5(i81582.2tr3l5(;2.50.1| 5+:l.2t +1524.31)51506.021)14u8.I 00l 470.5931,153.4931,13(i.7U71,120.4(i0I '10.r.500l3118.894I l]7 3.(i:12135u.70113.14.0921329.793l3 I 5.79ir1302.089I 28U.(t(t(i1275.5t6t262.6:12I 250.0061237.(i301225.19(il2l3.ir9ttI 20 I .929I 190.4U2I 179.251I I (;U.230| | 57 .+14I 1,1(;.795l 136.370I t26.t3'2l I I (i.0780.24310.24ft80.25040.25400.257 t;0.26130.2(;,r90.26850.27220.27 stl0.27940.2u300.28670.29030.29390.297(i0.30120.30.1r10.308'10.31210.31r;70.31930.32300.32660.33020.333r10.33750.3.il l0.:14470.341140.35200.35560.35920.3(i290.36650.37010.373n0.377 +0.38 l00.3ti.1(t0.38ti30.39190.39550.39920.402t|0..10(t.13.8833.9023.9213.9403.9593.97 u3.9964.0144.0324.0504.06r14.0u54.1024.1204.t37'1.15.14.t7 |4.t87+.'20,t4.2204.2364.2534.2694.2ti54.3004.3164.3324.:1474.3631.37 rl4.3934.40r1,t.+2:l,1.43u4.451]4.4674.+82.1.49(t4.51 I4.525.1.5394.553+.5674.5tt I4.5954.6094l 13.0984052.61.13993.88 I3936.82(i38u 1.3793827.47 |3775.04137',24.0273671.3743626.0283578.9373533.05334Ut|.323444.7283402.20 l3360.7 l I3320.22 I32u0.69532.12.099320.1..1003 l6 7.569313 I .574309n.38u30(;1.984302U.362995.42029(;3.21 I2931 .6Utt2900.|t2u2870.6t228,11.01tJ2812.0282783.6242755.7Utt2728.503270t .7532675.52|12649.797262+.5612599.80 I257 ir.5042551.t 572528.2482505.26,12482.6912160.527

410 FISH HATCHERY MANACEMENTTABLE I-1.c: l,5oox lo 7, CoNTINUEDWEIGHT/1,000FISH (LB)LENG'TH(INCHES)FISH/POUNDwutcHr'(GRAMS)LENGTH(cM)IISH/KILoGRAM0.9040.9120.9200.9280.9360.9440.9520.96t)0.9680.9760.9840.9921.0001.0801.1601.2401.3201.400l 4801.5601.6401.7201.8001.8tto1.9602.0402.1202.2002.2802.3602.1402.5202.6002.6tiO2.7602.8402.9203.0003.0803.1603.2403.3203.4003.4U03.5603.640I .8198t.82521.83051.tt3581.84101.8463l.85151.8566l .u6l81.8669t.87201.8770I .8821I .93 l01.977 52.02202.06462.t0542.t44tl2. I 8282.2t952.25502.28942.32282.35532.38702.4t782.44782.477 |2.50582.533u2.561l2.58802.61422.64002.66532.69012.71442.73832.76ttl2.78492.80772.U3002.85212.873tt2.tig5lI 106.20 I109(;.49u10u6.9631077.5931068.382r059.3281050.427104 I .(i731033.06,1I 024.596l0 16.266100u.07 I1000.000925.927862.072u0tt.455757.5807 | 4.291675.68 I641.031609.762581.401555.562531 .92 I510.2 t 0490.20247 |.704454.552438.603123.735409.U42396.{J3l384.621373. I 40362.324352.1 l8342.47 |333.339324.6U 1316.46130u.6,17301 .2 l0294.12:l2U7.3612U0.904274.7300.41000.41370.4t730.42090.42460.42820.43 l80.435,10.43910.44270.44630.45000.45360.4u990.52620.56250.59U70.63500.67130.70760.74390.78020.81650.85270.utt900.92530.96 l60.9979l 03421.07051.1067I .1430l. l 793| .2156I .25 l91.28821.3245l.360111.3970I .43331.46961.50591.54221.57851.6 l4uI .65 l04.6224.6364.6494.6634.6764.6894.7034.7 t64.7294.7424.7554.7684.7804.9055.0235.1365.2445.3485.4485.54+5.6375.72t15.8155.9005.9836.0636.1416.2176.2926.3656.43(i6.5056.5736.6406.7066.7706.U336.8956.9557.0157.0747.1317. I ttti7.24+7.2997.3542438.75324t7.3602396.3402375.6822355.3772335.4t723 I 5.79 l2296.4932277.5t42258.8462',240.4812222.+t:)2201.6202041 .3 l8l 900.54 I1777.9281670.177| 571.7401489.620I 4 I 3.230l 344.293l2tt 1.7691224.802I t7 2.684I 124.tt2010u0.709I 039.9281002.1 l3966.952934.t74903.546li7 4.862847.9+4822.632791t.78rl776.28775ir.0l 9734.8tt5715.798697.676680.450664.053648.429633.5226 l 9.286605.676

LENG'IH.WEIGHT TABI,ES4t1TaeI-n I-1.C = I,5OO X IO /, CONTINUDDWEIGHT/I,000LENGTHr.ISH/WEICHl'LING I'HFI SHr'FrsH (LB)(I NCHES]POL]NI)(CRAMS){CM]KI Lo(;RAM3.7203.ti003.t1803.9604.0404.1204.2004.2IJ04.3604.4404.5204.600.t.(;804.7604.U404.9205.0005.4005.8006.200(t.(t007.0007.4007.8008.200u.6009.0009.,1009.ti0010.20010.(;00I 1.000I 1.,100I 1.800t2.20012.(i0013.000I 3.4001 3.u0014.20014.(;0015.000l 5.40015.l.t00I (t.200I 6.6002.91622.93692.!)5742.97762.9975'.1.0t723.036(t3.05573.07.1(;3.09333.1 I lu3.130 I3.1,18 I3. I (i5{)3.183(i3.20103.21ti33.30193.3U 153.,r5753.511033.(t0033.6ft7(t:1.7 J253.795',23.85603.1) 1493.9720,1.027 (;1.08I (;.1. I iJ4ll.1.1 ti57.1.2358.1.2ti.1ti,1.:l:127,1.37954.42544.47034.5l,ti.i1.557 t)4.59994.6,1164.(;8254.72',274.7622.1.tiOl I268.8222(t3. I (il:]257 .374252.5302+7.52!l2+'2.72323tt. 100233.ri49229.362225.',23022t.2+.)2 l 7.3962 t ll.(i792 l0.08rl2(Xt.(t I (t203.25(i200.000I U5. I tt5172.+t.tI (i I .2{)0l5 I .515| +2.857135.13512tt.205121 .9s lI t(;.27!)Ill.ul106.3n3102.0,119tJ.0ll994.34090.90987.72081.746l3l .9(t779.3(i576.9',2371.6277'2.,46+70.42:)(ilJ.4936(i.(i67(;,r.935(;3.2916t.72860.2+lI .(iu7lJ| .72:l(i1.75991.7!t62l.ll325l tlrtttt]1.90501.9'11lJ1.977 62.01:J92.05022.0ti(i52.t'2282.15912. l 9532.2:lt(;2.2(tti02.tL+!112.(i30u2.81232.99373.17513.35663.53803.719,13.90094.0823,1.263tt,\.,+4524.6266'1.tJ0lJ I,1.9U{)55. 1 7095.:15245.5331.15.7 t5'25.ti9(;7(i.078I(i.25956.4,1106.62216.80396.98537.lt'677..1+827.52967.,\077.,1607 .5t'27.5(t37.6t47.6647.7t37 .76',27.lJ l 07.8577.{)047.1)507.!)1)6t].041tt.0u(ift.Il|I8.t748.3r,t7lJ.5r.t1)8.782u.9(t71).1.159.31(i9..ltt I9.(t.10t).79,19.9.1.110.0u9I 0.23010.36710.r0110.(i3210.759I0.tJultI 1.005I l 12.1I 1.2,t0I l 355I 1.4(i61t.576I l.(ift.1I 1.790I l.tigt]I 1.99(t12.09612.195592.(i5051t0. 17.15(;U.2I I556.7:125.15.70u535.11252,1.9195 l 5. 10rl505.656,196.545,187 .7 5747!1.',27 +47 I .Oti2.1(;li. I (i.1455.509.1,11J. I021+0.92140u.2633U0. 1 07355.5IJ4334.034ll14.946297.!t22282.6412(ilt.rJ56256.3522.1,1.95u234.53522+.1162216.140207.gr]4200.4'21193.3811I tt(;.u3llI1J0.707t7 +.970169.5rJ7t64.52+1 59.756I 55.255I 5l .0021.1(i.975143.158l 39.533136.0811l 32.UOu

412 FISH HATCHERY MANAGEMENTTaglr I- I. C : l,.5oo x lo 7, colrttxurowErcHl /1.000l-ltNc IrlFISH/wutcH t'LI]NG fHFISH,F.IS}I (LB] (INCHES] PoI]ND iGRAMs] {cM] KII,oCRAMI 7.000t7.4001 7.800I8.200l ll.(;00l 9.00019.,10019.u0020.20020.6002l .00021.4002l.lJ0022.20022.il)023.00023..10023.u0021.20021.(i1|l)2r;.00025.rJ0026.(i0027.100211.20029.00029.110030.(i003l.40032.20033.00033.U00ll4.(;0035.4003(i.20037.00037.u(X)3rJ.600iJ9.400.1.0.200.11 .000.11 .80042.(i00.1.3..10011.200,15.0004. tilJ931.8770.r.9 I .t I4.950ri4.98665.022r5.05715.09I (i5.t2575. I 5935. I 9255.22525.25765.2U9(i5.3211ri.352.15.3U325.+1375..1.11195.4.7 .175.501t25.5(; I lJ5.(il tt25.67405.72875.78235.83505.ttu(iu5.937(i5.1)8 7(i(i.03(itt(t.0IJ52(r. l32l.i6.17976.22596.27 I5(i.il16.1(t.3(i0(i6.,10126.1473(t.,tu9u(t.53 I 76.5731(i.6 l 406.(i5,t'1(t.6943su.u2,r57 .17 |56. I 805,1.9455:1.7 6452.6:1251.54650.50549.505,tu.5.1,147.61946.72!'45.87245.0.15+4.24t143.+7 842.7 35+2.0t7+1.322,10.650,10.0003u.7(;03 7.59.1IJ6.,t9635.'1(i IlJ.t.4tlll33.55 732.6803l.ll,{731.05630.30329.5U62u.90228.2.\!)27.62427.02726.45525.90725.38I21.87 624.39023.9232:1.17,t2:l.04122.62422.2227.7Itl7.U925u.0739u.255.1rJ.436lJtr.6 I tj28.7997u.9u l I9. I 6259.34,109.525,t9.70699.8r,iu3l0.0697t0.2512I0..132(i10.(; I 40l0.7!)5510.97(i9l 1.1583r 1.339u| | .702712.0650r2.+285t2.7!\:l13.154213.5 t 7l13.I.i8001,1.242t1| 1.60571,1.96u615.331.115.(t94ilr6.0572I (t.,120 Il 6.7829t7.I+5817.50It7t7.87 t6I tJ.23,1,1l rJ.5973l8.9(;0219.323019.6ti5920.0.11Ju20.'11t7t2.292r 2.3tJti12.482t2.57 512.66612.756t 2.8,t512.93313.01913.10513.I81)t3.272I 3.35413..13613.516I 3.595I 3.673I lJ.75 t13.827I ll.90llr ii.97ti| 4.12(it +.271)t,1.412I .1.551| 1.6871,1.821| 4.952l5.0lt215.209l 5.333I 5.456t s.577| 5.69715.8I ,t15.93016.0,1,1l(t.15616.267l(i.lJ7(i16.4tt,1I (t.59 II 6.(t9(i16.u00l 6.902t7.001l 29.61t.1126.7021 23.1]55l2l. 133I I u.52ul 16.033I I 3.ft,10I I 1.3.1.1109. l 40t07.02110,1.9{.}2IOii.020101.12999.30797.55095.ti5394.2t592.63191.100lJ9.6l9u8. t tt5t]5.,r50lJ2.Uti0110.,1(t07 8.t7Il7 6.02173.9Ii072.0+070.2r16U.16(i(i6. u0765.22563.7 t762.27 760.90 l59.5IJ.15u.32357.tl,t55.9555.1.ti,r I53.7 7 |s2.712al./:t2s0.79tt49.87 84U.99 1

LENG'I'H.WE,IG HT TABLES 413Tasln I- |C = 1,500 X IO 7, CONl'INUEt)wElcH'I)1,000LENG'f HI'ISH/WEIGH'It,LNG f HFISFI/FIsH {I,B)(INCHES)POt] N I)(c; RA Nr sltcM)KII,OGR;\M45.U0046.60047.400,18.20049.000,19.80050.60051.40052.20053.00053.U0054.60055.4005ri.20057.00057.8005tt.60059.40060.2006l .000ft l.80062.60063.40064.20065.00065.ti0066.60067.40068.20069.00069.U0070.60071..10072.20073.00073.80074.6007 5.10076.20077.OOO77.80078.(;0079.40080.2008l .00081.800(i.733til6.77276.U l l3(t.u49.16.1il17 r6.92+46.9612(i.!t!) 77.033u7.0(i9(t7. l 0507. l 4007 .174.77.20!)l7.24327.27697.31037.:143'l7.37627.,10t{l7.44t07.47:107.50477.53(; l7 .56737.59827.62897.65937.68957 .7 t947 .74927.77877.807!l7.83707.tt(;5tt7.89+,\7.922!)7.951 I7.9791u.00(t9u.03,168.0(i2011.08938. I 16,1u. 1432tt.l7002 l.ti3,121.45!)2t.09720.74720.40820.01t0I 9.76319..r5519.15718.86ul t].5rJ7I tit.3 I 5I8.051t7.79+t7.51117.30117.0(i51 (;. U3516.61 I16.393l6.tul| 5.!t74| 5.77:ll it.57 615.3U515. lgrJ15.0 l 5| 4.837I 4.(t(til1,1.,19314.:1271,1. I (;41.1.006I ll.tt5013.(i99I 3.55013.,105I 3.26313.12312.98712.u5:]12.72312.5!t412.'16912.34612.225'20.771521.137421.50032 Ltlfi3222.226022.5uu922.951lJ23.31+723.67752+.010124.,103u2,\.766125.129025.,191925.n541126.2t7626.5tt0526.9,13427.3063'27.66912tt.03202tr.3941)28.757829.t20629.483529.846430.209230.572 I110.935031.29793l .660732.023(i32.38(i53',2.7 4!t4:t:l.t t2'2l)3.4 75133.u3IJ034.20093,1.563734.92(i(i35.289535.65233(;.01523(;.378 l36.741037. l03rl17.10417.203r 7.301t7.39717..1{)3l7.5rJrlt7.682t7 .77,117.86(;t7 .957I11.047lll.l36t8.221lll.3l II rJ.39r.iI U..1ullI tl.ir(illl8.(;52I U.73(iI U.lil uI U.900I ll.gr] I19.0(t2t9.t12t9.221l 9.299t9.:177I 9.455l9.5ll I19.60719.683l1).75u19.832I9.90(tr 9.97920.05220.t2420. l9(i20.2t'720.llllu20.40u20.47820.5,+720.6 l620.6U120.752.1U. l3(;17.309'lfi.5 I I.15.7iJ941.9924,+.2(i!),1.3.570,1.2.u9142.2:1441.59740.!)7I.i40.37l.i39.79539.22ti38.(i77lJlt. 1.1237.62137.1 l536.(;2')3(i. 1,1135.(i7335.2 l rJ3+.77331.3.1033.91 733.50533.102'32.70!)3'2.326ll l.!)5 I3l.5lJ5'31.2',27ll0. u7 730.535110.2002t).lt7lJ29.55329.231)28.9322ti.(ilJ I28.3372u.0+927 .7(;(i27.48!)27.2t72(i.951

4t4FISH HATCHERY MANAGEMENTTenlr, I-1. c: l,5oo r ro-7, coNTINUEDWEIGHl /1,000FlsH (r,B)LENC;'I'H{tNCH lis)I'ISH/PoUNDwurc;H f(GRANlS)I-ENC'I HiCM]I.ISH/KII,OCRANI82.ft00u3.,10084.200ti5.00085.U008(t.(;00tt7.40088.20089.000u9.u0090.6009l .40092.20093.00093.U009,1.(;0095.40096.20097.00097.tt009u.(t0099.400102.000I10.000l I u.000l2(i.000134.000142.000150.000U. I {)6ir8.22298.2.1!) I8.'27 5lu.30108.32(i7u.35238.37778.4030tt.4 2 ti l8.45308.47788.5025ti.5270t|.5514It.5 75(iu.59978.6237It.647 (t1.t.6713u.(i94tlti.7 I tt3u.79lJ69.0l7tt9.231ll9.,tr3ir49.63109.ti 19010.000012.107I 1.990r t.u7(;I t.7(;5I l.(i55| | .547| | .41'2I l.3lttJt 1.23(ill.l3ttI t.03tt10.94 Il0.ll,1(tl0.7 53I 0.(;(i I10.57 I10.'tu210.39510.30910.22510. I ,1210.0609.u049.091u..17 57.9:177.4637.042(t.6(;737..1(;(i7:J 7.IJ2963tt. 1925r38.55533ti.91tt2Itg.2t] I I39.(;440.10.00(il.i40.3(;9740.73264l .09554 t.45tt31t .8'21'242. I IJ.11+'2.s+70,12.909r.t43.'2727411.63 5(t,13.99tJ44.1.3tt I li4+.724',2,15.0u71't6.2661+.r1).n95I53.523t]57 .t 5',)6(i0.7u 13(t4.4100(;tt.03uu20.u t 1)20.utr(i20.9ir321.0192l .0852l . 150'21.2152t.')7!',)'21.3112t.4072t.47 |2l .5:J42l .5962 l.(i592t.7212l.78',)21.8,132I .90,121.9(i52',2.02522.08522.t,1+22.:136')2.90523.4+723.96(i21. \(t:l2.1.9.1025.4002(t.(;9026.4312(i. I fJil'25.!tJ725.69525.,+5725.2212,1.99(i'24.77|')'1.5s024.311.124.t2121.|.1) I I23.70(i23.50323.30523.10922.!ll72'2.72t122.51222.351)'22.17\)21.(il420.0+'2I u.6ullt7 .'197l 6.452I 5.525| 4.697

LENGTH-WEIGHT TABLES4t5TABLE I-2.LENG f H-wElGHT RELA I IONSHIPS FOR FISH WITH C' = 2,000 r l0 7\{ !]c H'I11,000IISH ILI]]I-ENGl'H(r NcH!.slFI SHiPOL]NDwutcil lI,T]NG'I'HFISH/(G RAMS) (CM)KII,OGRAM0.2000.2040.20n0.2t'20.2 l60.2'200.2'210.2280.23')0.2iJ(t0.2400.'24.10.2.180.2520.25(i0.2(i00.2{i,10.2(ill0.27',20.'27 (;0.2ttO0.2u'10.2nu0.29'20.21Xt0.3000.30'10.30u0.3 l20.ll I (i0.3200.32.10.32|.t0.3320.33(t0.r.|.100.3.1,1.0.3.1ti0.3520.35(i0.ii{i00.3(i.10.3(tu0.37'20.37 (;0.3n01.0(x)01.006(iI .0132I .01{xi1.02601.03231 .03u5I .0,1.1{il 0ir071 .05(i71.0(;271.0(iu51.0743I .0801l.0r.t5uI .091.rl 0t)70Ll02lI . 1071)Ll llll|l.1lu7L 12,t0l. I 2{)2I .1 l.|.11l.l lJg{i| .t +47l 1.1{)uI . 1s.iltI.t59ul.t6,t7I . I (ilxt| .t7.t5I . l79lJI .l lJ10I . 1UUtiI . l9:.]5Lll)rJl1.202nt.207 ,tl.2l l1)I .2 I {t,1.1.2209t.2'25.+1.22!)u1.23421.23U6ir000.000,1901 .961.1rJ07.(i1)5,17 I (t.91i.1.1629.633,15,15.4(il4164.29:l.1lllt5.1)7 3.1310.:152.\'2:17.2974 I 6ri.(i7(i.101)tt.37 l.1032.2(t1)39(ift.2(i(ill90(t.2(i2lJu,t(i. I (i637 tt7. tJ923731.35(i367 (i.,1U.13(i23.202357 | .,++',23521 . l,1l:t+72.'.2373424.67 23378.3{)33333.3,1r13289..1r.t9321ti.76!)3205.1,r.1ll I (i.1.57 33 I 25.01 (i30tt(i..13(i30.r8.71){i3012.0(i.1'21t7 (;.'20721).1l lglJ290(i.993287:1.5792U.10.1)252n09.0052777.79,1'27+7.',26927 t7 .,+ltl26UU.I lJu26irl).59 I261] 1.5950.09070.09250.09.130.09620.09800.099r10.10160.lOli,l0. I 0520. I 0700. l0l.t1)0.11070.11250.1 l '130. n610.11790.111)70.t2l(t0. 123,10.t2520.12700.12lJtJ0. 130(t0. l 3240.13,130.13610. I 3790. I 3970.14150. l.llJlJ0. 1,1510.1.1700. l,1tiu0.150(i0. 152.10. 15'120.15(i00.15780. l 5970.1(;150.1(ill:J0.16510. l (;690. I (itt70.170i)0.t7242.5,102.557'2.5732.5902.606'2.6222.(illtl2.6532.(;692.(iu42.6992.7 t+2.7'2!)'2.7,+:l2.7582.772'2.7862.8002.tt I 42.8282.U,112.U5ir2.U6rl2.UU l2.U952.90lt2.9202.93112.9,t62.95n2.97 |2.9n32.{)953.0073.0203.0313.0.133.0553.0673.07 tt3.0903.1013.1123. l 2,13.1353.1.16I 1023.1021080(i.96ir10599.1 ,11I 0399. l 601020(;.58610021.012{)8,t2.0ri69669.'1029502.(i{) l93,11 .62{}1) I U5.93ll903r;.348trttu9.(i I7[i7.1U.5 I6u6l l .8208479.3328350.11s982'26.2198105.2.r.(;7987.78r7873.672776'2.777(i54.9(t l7550.09u74,\8.07073.18.766725',2.0707 l 57.ti9 I7066. I 2 I(i976.68068U9.,r(t96ti0'1.414t'721.134(;6,10.45365(; l.,102(i,1u.1.2I I6,r08.8l3(i1.i35. l,1u(i2(i3. 1606192.71i56t23.977(;0r;6.6U45990.U'1u5926.,13,158(;3.3u75U01.6(i4

416 FISH HATCHERY MANAGEMENTTABLE I-2 C : 2,000 X IO /, CONTINUEIJWEIGI'I1'/l,000}ISH (LB)LENG'I'H(rNcHus)F'ISH/POUNI)Wr-I G HT(CRANISILT]NGTH(cM)F ISH/Kr l-ocRAM0.31140.3utJ0.3920.3960.4000.4040.'1080.4t20.,1160.4200.4240.4280.4:120.43fi0.,t,t00.4440.,1,1r10.4520.4560.4600.4640.,t(iti0.4720.47 t;0.,1800.4t|40.4url0.4920.4960.5000.50u0.51(;0.5210.5320.5400.5.{ti0.5560.5{t40.5720.5u00.5urJ0.5960.6040.6120.fi200.6211t.2429|.24721.2515t.25571.25991.2(;.111.2683|.27211.27651.2u06l.2tt.r.6l.2ftu71.29271.29661.30061.3045l.ll0u4l .3123I .il I (t21.3200l.iJ23ut.3276L331,r1.335 I1.33891.3426L3,1{i31.3,1991.3536t.35721.3(t4,1r .37151.378(it.llti561.39251.39931.40(; I1.,11 2tl1.,1t 95l.4260l.'132(i1.4390|.445+I ..t5 I ti1.458 l1.46,13260.1.l tt32577.3362551.0372525.26!)2500.0 I 62475.26,42150.9972427.2012,103.ti61J23U0.96923511.5072336..1652314.ti3 I2293.5942272.7,t32252.26tt2232.15!l22t2.4062 I 92.9992173.9292155.1Uft2 r 3(;.7nt]2l I u.6602100.85(i20u3.3'1920(i(i. 13220.19. l9(i2032.5362016.1452000.0001968.50,119IJ7.9851908.3911I u79.70 1I U5 I .854I82.1.u 1I1798.563177:t.052t7 48.254I7 24.t 4 |1700.{iu3l(i77.tii561(;55.(t331633.991r (t I 2.907I 592.36 I0.t7420. I 7600.17780. I 7960.1lll40. I 8320.1tt5l0. r 8690.1 uu70. l 9050. I 9230.19410. I 9600. I 9780. 199(t0.20I40.20320.20500.206u0.20870.2 t 050.2t230.21,110.21590.2\770.2 I950.22t40.22320.22500.226u0.230,r0.23410.23770.2.1I 30.244!)0.24860.25220.255r10.25950.2(i3l0.26670.270:)0.27,100.'277 60.28t20.28493.1573.l6ti3.1793.IU93.2003.21 I3.'2213.23',23.2'123.2r3iJ.2(;33.2733.2ti311.21)33.303l|.3 I 33.3233.3 311.3,133.353ll.llft23.3723.3It23.31) 1i-r.,10 I3.,t I 03..1193..12{)3.,13{.}3.+473.4663.4u,1.3.5023.5 l93.b373.5543.57 |3.5rJgii.(t053.6223.6393.6553.6713.{il.tti:1.70,t3.71957 +t.2:lor6u2.0,13s624.0(i(;55(i7.2511551 I .rfl(i5,157.01 (;5403.51(i5351.055r299.(i0252.19. 1295 l9{).6095l5t.0t(;5 r 03.3205056.5005010.53r,19(;,5.395+921 .051),\877.5t24831.727.t792.(il.ilt+7 5t .37 |17 t0.7 58,1670.U.1-0,1.(i3 i .5U(i.1592.992'1555.031+517.61)5,r.1tr0.9694444.83'2.1,t09.23u.133{).lJ0 t,t272.5201207.2894 | 4 4.02:l40rJ2.(i33,1023.03i139(i5.1.19390U.90(;3r.i5,1.23 73u0l .07537,19.3(;l3(t91).03,1u(i50.0,11ll(t02.3 2u3 555.8.173510.550

LENGl'H,WEIGHT TABLL,S 4t7Test-l: I-2. c : 2,00{) r t0 7, coN f INUI,DWEICII'I'/'1.000ttslt tLBl[.EN-G I l liINC]HI,]S]t lsH/PoLI N I)WEIGH'I(c RAMS]I,I.]N(; THiCM]!'ISH/KILOGRAN{0.(i3(t0.64.10.6520.(t(i00.(i(i80.(i7(;0.(ttt.10.(i1)20.7000.70f10.71(;0.72,+0.7320.7 +tl0.7,1n0.75(i0.7(i.10.77',20.7I.J00.7nu0.71)(t0.u010.ti l20.tt200.tt2u0. ulJ(i0.lJ+'10.8520.8(i00.u{il10.tt 7 (t0.lltt,t0.l.J920.1)000.90IJ0.91(i0.92'10.9320.9.100.!).ru0.1)5(;0.1xt.10.!)720.9800.1)utJ0.91)(i1.,1705I.+7 67L,1ti2lJI..tl.ttrul .19.1.tt1.50071.50(;(iI .5125l.5lu3L524 11.529u1.535'11.511 Il 5.1(i7|.552',2t.55771.5(;32l 5(ilt71.57 +l1.571).11.58.17l.5t)001.5953l 6005l.(i057I .(t I09l.6l(t0| .621],I .(t2(i Il.(i3 I 2L(ill(i2l.(i,1.1 Il.(;'1(i II.(i5I0l.(i55tt1.6607l.(i(i55l .(i703l.{i75 Il.(;71)1.]L(ill,t5I .(i81)2l.(t9it!)L(i9851.7031t.7077| 57'2.',.13 |I 552.7{)9t53:1.7 +71515.15(i1.1{)7.011|47L29lt1,1(;1.99314.15.092| +28.577l.1 l 2.'11)5l 39(;.(i53138L221I lJ(;(i. I 2(t1351.357133(i.90.1t:12'2.7 57I ll0u.1)0(t121)5.1|'lllt28'2.057l2(i1).0.12t'256.',287t243.7 87l2lt I .533l2l1).51ut2(\7 .73(;I l1)(;.17nI I ll'1.l.i,10tt7:1.7 t5I t(;'2.797I 152.0U0I l '11.559I l3l.22tJI l2l.0ul|llll.ll7I l0l.32tiI09 l 70{}t08'2.'257I07 2.9(ilJ10(i3.8lt(tI05'1.u5910.1(t.03 11037.1J51l028.ll I llI020..1 I 51012.152100.1.02 20.2uu50.21)21().2!t570.29940.30300.30(i60.ll I0il0.3131)0.lJ 1750.321 I0.32,1ti0.32U'10.33200.33570.:13930.3,1290.11,1(i50.35020.353rJ0.:157,10.361 I0.36.170.3(iu30.37190.ll75ri0.37920.3IJ280.3tt(i50.39010.39370.39730.40 l00.40.1(i0..101t20.'11 l90..1I550.,r l9l0.,+2'270.426'10.4:1000.,13 ll(t0..137 30.,1,r01)0..1.1450..1,1.u 10..151133.7353.7513.7(t(i3.782'J.7973.8l23.8',273.U.123.u5(;3.lJ7l3.Ult(i3.9003.91,13.9293.9.1113.1)573.1)713.9f1.13.99u,1.0 I 2,1.0254.01191.0524.0(;54.07 rl4.092'1.1054.1lu,r.l 30,1. 1,13,1. I 5(i.1. I (ill+. 1til,1. 1934.206+.'21t14.2:10.t.'2+:l+.25s,1.267+.'27 ll4.291,1.:10'2.1.31.1,\.3'264.33r1ll4(i(i.1.1933,123.1J1|333lJ 1.3293l|,t0.il,t'13300.3'1032(il.2tililJ22i.].131)31 u5.u7uIt 1.1!)..f(i93 I I lJ.ttti23071).09030.15.0(i7:101 I .7lilJ2979.2'2tl29,t7.11(irr2!lt(;.17 72Uu5.(i+ I2I.i5.73 u2826.1492797.75,127 (t1).(;3(i27 ,\2.07I2715.0(i326u8. r;7,12662.51)tJ2rt37.l l926t',2.\2:l25U7.59(i25(i3.52 52539.f19rJ251(i.7032,11)3.92u247 | .5612.1.19.5922428.009240(i. u0423rJ5.9(i62l.t(i5.,1.u(i21J,15.3 5.12325.5(i3230(i. I 0222U6.9(t,12',268.t 4'22249.(;')(;2231 ..11 I2213.4Uu

418 FISH HATCHERY MANAGEMENTTABLE I-2 C: 2,000 X IO 7, CONTINUE,DwEICH',r/I,000FISH (I,BILI]N(;TH(INCH I.]S)I'rsH/POUN DWEICHT(GRAMS)I,INGTH(CM)FISH/KILOGRAM1.0401.1201.2001.2801.3601..1,t01.520l.(i00l.6tr0l.7601.8,f01.9202.(XX)2.0tiO2.l (i0'2.2+02.3',202.,1002.,tttO2.5(;02.6102.7202.8002.tttt02.9603.0,103.1203.2003.21103.3(i0:J.,t.103.5203.6003.6803.7(i03.U.103.920.1.0004.0rJ04. I {i01.2404.320,1.400,t.,1tit04.5(i0,1.6,10| .73',25t.77 58l.8l7 l1.tt5(i(il 89,t5I .9lJ I0I .96612.0000'2.032t12.06,1{i2.095,1'2.1'25l1'2.15442.I lt2u2.2lll4'2.',2:17+2.26:17'2.289+2.li 1,1(i2.33922.3633'2.3U702.,110 I2.+il2!l2.,t55'22.477 |2.491362.5lgtt2.54072.561 I2.5U 13'2.t 012').62(i72.(i,1002.(i590'2.(i7 77').0962'2.7t4+2.73'24').7 501'2.7(;762.78492.80202.u l fl92.tr35(i2.8521961 .539u92.85{)tt3 3.33778t.254735.29969,1.449657.900(;25.006595.24456U. I ltuir,13.,1|t4520. tt39500.006,t80.775.r62.9(i9.1,16.43543 L04 1,116.(i7340:l.23',2390.631378.7943ri7.653357. l.tti:l+7.22t13117.11.1332tr.953320.51 lt312.505304.8U3297.624290.7032U4.096277.7t1:)271.7142(;5.9(i2260.421255.t07250.005245. I 032,10.3U9235.lt542li l.4fJ(;2',27.'277'22.1.2t92l {).302215.lt2l0.+7170.50ti00.54430.5u060.61690.65320.6n950.7'2570.76200.79u30.tt3460.87090.90720.!)4350.9797l .0160l .0523l.0l.ilJ(;L 12.19I . l6l2L1975l.233tr|.27001.3063|.3+',261.3789| .415'2l.45l5l.4ti78r.52401.5603l.ir966l .(i321)l.ftft921.70551.74ttlt.77ll0l.u l4:lI .8irO(il.uu(t9|.9232I .959ir1.995It2.0:l'212.06lt32.10.164.,1004.51 I4.6154.716+.812,1.9054.9945.0805.1635.2445.3'225.39tt5.4725.5445.6145.61135.7505.f] 155.8795.9+26.0036.0636.t2',26.1796.23(t6.29',26.3476.,100(;.4536.5056.5576.6076.6576.7066.7 5,t6.U016.U4ll6.U9ir6.9406.9U57.0307.0747.l177. I (t07.2027.24+2 l 19.u29r 96ti.4l6I tt37.1911722.3t'8162 l .05,1l 530.9981.150.420I 377.900r:11'2.2871252.63uI 198.177I I 48.2531102.323I 059.9271020.67 I9U4.219950.2lJ I9l u.6058tt8.973861.193835.096810.535787.377/t)5..)trf744.8 I 6725.216706.6216Uti.955672.152656. I 48640.889626.323612.405599.0925U6.3,r(i574. I 3i)562.,11355 I . l6tl5,10.35lt529.967519.9675 l0.33r't501.060492.1124tt3.479.\75.l4.l

LENGTH-WEIGHT TABLES 419Teslr I-2.c: 2,ooo t ro 7, coNttNutoWEICHT/1,000 LENCTHFISH (LB)(INCHES)FISH/POUNDwEICH'l'(GRAMS)LENGTH(cM)FISH,'KTLOCRAM4.7204.8004.8804.9605.2005.6006.0006.4006.8007.2007.6008.0008.400u.8009.2009.60010.00010.40010.800I 1.20011.60012.00012.400l 2.80013.20013.60014.000I 4.400l 4.800l 5.200l 5.60016.00016.40016.800t7.200l 7.60018.000I U.400l 8.800l 9.20019.60020.00020.40020.tt0021.20021 .6002.86U,12.88452.90042.9t622.96253.03663.10723.17,183.23963.30193.36203.41993.47 t 03.53033.58303.63423.6840:1.73253.77983.U2593.87093.91493.95794.00004.04t24.08 l64.12134.16024. l 9U34.235u4.27274.30894.34454.:17954.41404.44804.48144.51444.546u4.57894.61044.6,1 l64.67234.70274.73264.76222l 1.869208.337204.922201.617192.308t7 8.572166.667I 56.250147.059138.889l3l .579125.000I 19.048l13.63710lt.ti96104.167100.00096. I 5492.593u9.2tt686.20783.1t3480.64578.t2575.75873.53071.12969..14567.56tt65.79064. I 0362.50060.97659.52458. 1,1056.8 l8).)..) t)o54.34853. I 9252.0835 r.02050.00049.020,+8.07747.t7046.2962. I 4092.17722.21352.24982.35872.540 I2.72t 52.90303.08443.2659:1.4+7 33.62873.81023.99164. I 7304.35,15,1.53 594.71734.U9885.0u025.26165.,14315.62455.U0605.9874ri. l6uu6.35036.53176.71316.U9467.07607 .25747.43897.62037.801rl7.98328.16468.3.16111.527 58.70908.890,19.07 l ll9.2533!).13+79.61619.79767.2867.3277.:1677.1077.5257.7 t37.8928.06,18.2298.3U78.5398.6878.829u.9fi79.1019.2319.3579.,ilil9.6019.71lt9.8329.94410.05310.16010.26510.367l0.46rl10.56710.66,110.759I 0.85310.945l I .035| | .1241t .212I 1.298I I .3U311.466I 1.549I 1.630I1.71011.790I l.{J68I 1.9,15t2.02112.096467.090459.30545t.77 54.1.1.4119423.965393.6U2367.+37344.472324.20!''306. 1 98290.0u227 5.57 I262.+55250.526239.633229.64!)220.463211.983204.132196.I.t,12190.054l 83.7 19177.793t72.2:17t67.017162.105r57.47:l153.099148.961145.041141.322l 3 7.7 1t91 34.42tit31.2271 28.1 761 25.263t22.+79l19.Ul6I t7 .267l 1,1.u24l12.,1lllI10.23110u.070l 05.99 l103.992102.0(;6

420 FISH HATCHERY MANAGEMENTTABLE I-2. c: 2,000 x l0-7, coNTTNUEDWEIGHT/1,000FrsH (LB)I,ENGTHFISH/WEIGHTLENGl'HFISH/(INCHES)POUND(GRAMS){cM)KILOCRAM22.00022.40022.110023.20023.60024.00024.40024.80025.40026.20027.00027.U0028.60029.40030.20031.0003l .80032.60033.40034.20035.00035.tt0036.60037.40038.20039.00039.1t0040.60041.40042.20043.00043.80044.60045.40046.20047.00047.80048.60049.40050.20051.00051.u0052.60053.40054.20055.0004.79144.U2034.u4Utl4.87704.90494.93244.95974.98665.02655.078u5. I 2995.IU0l5.22935.27765.32515.37 t75.4t755.46265.50695.55055.59345.(ill575.67745.7 I tt55.75905.79U95.83tr35.877 |5.91555.95335.99076.02776.06416. I 0026.l35tl6.17106.205u6.24036.27436.30U06.34136.37436.40706.43936.47 t3(;.503045.45544.64343.U6043. I 0342.3734t.66740.98440.32339.3703tt. 16837.03735.97134.96534.01433.1 l232.25u3l .44630.67529.94029.24028.57 |27.93i]27.32226.73826.17825.64125.t2624.63024.t5523.69723.25622.83122.42122.0262t.6452t.27720.92020.57620.24319.92019.60819.30519.0 I I18.72718.450Itt.I829.979010.160410.34 l910.523310.7041tl0.tlti62I 1.06761t.2491I I .521 llI l.u84lt2.2470I 2.609912.972813.335613.698514.061414.4243t4.787 |15.150015.5129l5.u75ti16.238616.601 5I 6.9644t7.3272I 7.690 II8.05301U.41 59r8.778719. 141619.504519.867420.230220.593120.95602l .3 I 8tt2l .681722.044622.407522.770323. l 33223.496 I23.859024.22t824.584724.947612.t70t2.244I 2.3 l612.38u12.4stlt2.528l2.59tt12.666t2.76712.90013.03013.15713.28213.405I 3.52613.644I 3.76013.87513.987I 4.09814.20714.3 l514.42114.52514.628| 4.72914.tt2914.92u15.02515. 12115.2 l615.31015.40315.49415.5tt5| 5.67415.763I 5.85015.937t6.02216.10716. l9 I16.27416.356t6.437lo-t)t/100.2 l098.42196.69495.02793.41(t9 r .85990.35388.896i16.796u4. 1 4681.65279.30377.0847 4.!18773.0007t.tt769.32767.62666.00664.46262.9U96l.5tt l60.23558.94757 .7 1256.52955.39254.30 I53.25252.2425t.27050.33449.4314U.56047.7 t946.90746.12245.36244.62843.91 743.221142.5604l .9134l .28540.67640.0tt4

LENGTH-WEIGHT TABLES 421TesLE I-2.c - 2,ooo . ro /, coNrrNUe DWEIGHT/1,000FISH {LB)LENCTH(lNcHES)FISH/POUNDWEICHT(GRAMS)LENGTH(cM)FISH/KILOGRAM55.tt0056.60057.40058.200s9.000s9.80060.60061.40062.20063.00063.80064.60065.40066.20067.00067.t|0068.60069.40070.20071.0007 1.u0072.60073.4007 4.20075.00075.80076.60077.4007U.20079.00079.800u0.60081.40082.20083.00083.80084.60085.40086.20087.00087.1t0088.60089.40090.2009l .0009l .1i006.53436.56546.59626.62676.65696.68696.71666.74606.77526.U0416.83286.86126.88946.91746.94516.97277.00007.027 |7.05407.08077.t0727.13357. I 5967. I 8557 .2t t27.23687.26227 .28747.3t247.33727.36197.3U647.41087.43507.45907.48297.50677.53027.55377.57707.600 I7.62317.64607.66887.69t47.7 t3tlt7.92117.668t7.422t7.t8216.94916.72216.502l6.2ri716.07715.873| 5.67415.48015.291l 5. l0{;14.925| 4.749| 4.577I 4.40914.24514.08413.92ut3.77 413.624t3.477l 3.33313.19313.055t2.92012.78812.65812.531t2.40712.28512.16512.048I 1.933I l.tt20I1.710l 1.601I 1.494I 1.390tt.287I1.186I 1.08610.98910.n9325.310525.673326.036226.399 I26.76t927.t24827.487727.850628.2t3428.576328.939229.302129.664930.027830.390730.75363l.ll6431.479331.842232.205032.567932.930833.293733.656634.019434.382334.745235. r 08035.470935.833836. I 96736.559536.922437.285337.6,18138.01l038.37393U.736u39.099739.462539.U25440. l 8u340.551 I40.91 ,104t.276941.639tt16.59716.676t6.7 54I 6.83216.90916.98517.06017. 13517.209t7.28217.355t7.42717.499t7.570t7.64117.7 tlt7.780I 7.849t7 .9t7I 7.98518.05218. I l918.18518.25118.31 718.38118.44618.51018.57318.63718.699I 8.762I 8.823I U.88518.94619.007r 9.067t9.t2719.186t9.246I 9.304l 9.363t9.421l 9.479I 9.536l 9.59339.50938.95138.40837.88037.36636.86736.38035.90635.44434.99434.5s534.12733.7 r033.30232.90532.5 l632.t3731.76731.40531.05130.70530.36730.03629.7 t229.39529.08528.78128.48328. I 9227.90727.62727.35327.08426.82026.56226.30826.05925.8 l525.57625.34025. I l024.88324.66024.44124.22724.0t5

422 FISH HATCHERY MANAGEMENTTABLE I-2.c: 2,ooo x lo-7, coNTTNUEDWEIGHT/1,000LENGTHFISH/WEIGHTLENG'I'HFISH/FISH (LB)(INCHES)POUND(CRAMS)(cM)KILOGRAM92.60093.40094.20095.00095.80096.60097.40098.20099.00099.800106.000I 14.000t22.OOO130.000138.000146.000154.000162.000170.000178.000I U6.000194.0007.73627 .75847.78057.80257.82437.84607.86767.889 I7.91057.93178.09278.29138.48098.66248.83659.00419. I 6579.32t79.47279.61909.76 l09.899010.799t0.70710.6 l610.52610.43810.352t0.26710. I tt310. l0l10.0209.4348.7728.1977.6927.2466.8496.4946.1735.8825.6185.3765.15542.002642.365542.728443.091 243.454143.U 17044.t799+4.542744.905645.268548.080751 .709555.338258.966962.595766.224469.U53173.481977.t10680.739484.368 I87.996819.650I 9.706tg.7 6219.81 rlI 9.87419.92919.98,120.03u20.09320.14720.5552l .0602t.51222.00222.44522.87023.2U 123.67724.06124.+3221.79325. I 4323.U0u23.60,123.40423.20623.01 322.82222.63522.+5022.26922.09020.7{)8I 9.3391U.07 I16.959I 5.976I 5.1001,1.3 I 6l 3.609I 2.968i 2.386I1.85311.364

LENG'TH.WEIGH'T TABLES423TABLE I-3. LENG TH-wEtcHT RELATIONSHIPS FoR FISH wlrH c: 2,500 x l0-7WEICHT/1,000_1!!!ulLENG'f H(rNcHES)FISH/POL]NDWEIGHT(GRAMS)LENG'IH(cM)fI SH/KILOCRAM0.2500.2540.2580.2620.2660.2700.2710.2780.2820.2860.2900.29.10.2{)80.3020.30(;0.ll l00.3 I '10.3 I80..1220.32(;0.3300.33.10.33u0.3,120.34fi0.3500.35.10.35u0.3620.3tt(i0.3700.3740.3780.31.t20.3tt(i0.3{)00.39.10.39t10.4020.,10(i0.,1100..11'10..11l.i0.+220.4261.00001.0053l .01061.0157r.02091.02(i0l.03t01.03601.0.1101.04591.05071.05551.06031.06501.0(i971.07'1ll1.07891.0835l.0nlt01.092sr.09701. 101.1I.t05uLl l0lI . I I'1,1LllltTt.t22,9|.127 |l.llll3l. I 355l I lig(iI . 1.11.|7l.l,17ul.t51l.tl 15511l.l59n1.1637|.1677l.l7l(il.l75,ll.l79l)l.lu3ll I fl(i91 .1907I . 19,1,1.4000.0023937.0103875.!1723U l6.79tt3759..1033703.70936,19.6413597. l2rl3546. I 063.1!X;.5 l0344U.21.i33401.36ti3355.7 I 33ll I I .2(i73267.gtt33225.U 163t84.72:ltJ 144.(i6'13105.(i003067.,r1)53030.3132994.023295u.5912923.9u82U90. r U5'2857.t 51'282+.8702793.3Ott2762.4,\:l'27:12.2522702.7 t52(i7ll. u01)26'15.51 52(i 17.til 32ri90.{iu625(t.1. I l5253U.0U.1'25t2.575'2'187.5752463.0672,1119.0:1721t 5.17'22392.35721169.(;U l2347.,1310.11340.11520.11700.1 I tJtt0.t2070.t2250. 12.130.12610. l 2790. I 2970. l3l50.133.10. I 3520. I 3700.138r,]0.I4(Xt0.11'24o.t +420.11610. I 4790.l4{}70. l5l50. I 5330.15510. I irti90. 15880. I 6060. I 6240.16.120. I fitt00.167u0. I 696o.t7 t50. I 7330.17510. l 7690. l 7u70. I u050. I ti230. r lJ'120.1r,triO0.1 uTlt0.1ll9ri0. t 1) l.r0. I1):J22.5402.5532.5672.5U02.5932.ft0(t2.6192.6312.6442.6562.6692.68 I2.693'2.7052.7 t72.7292.7 '102.7522.7642.7752.7862.7972.8092.U202.U312.ll,1l2.8522. U(;32.8742.U842.U952.9052.9152.!t262.9362.9462.9562.1)66'2.9762.{}t}(t2.9953.00s3.0I 53.0243.034urJ 18.480u679.609l]545.0.138414.586u2uu.055I l 65.270u0.16.0707930.11017Ul7.ul37708.4777602.15',27 +98.723739t|.0707300.0n27204.6567l I 1.69s702t.1026932.7U568,16.6646762.660(i6u0.6u86600.6U0(i522.5666.1.16.28I637 1.75u621)t].93ti(;')27.762615It. 1u06090. l 336023.57 45958.45751J9.1.7 305lt32.352577 t.28157 | t.4775652.89r15595.ir0u5539.2735,1U'l. I5(t5.130.1255377.t485325. l 955271.2385224.2465t75.19r

424 FISH HATCHERY MANAGEMENTTenle I-3. c: 2,100 x l07, coN'IINUE,DwErcHl/l,000FrsH (t.B)LENC'I'H(INcHES)FISH/POUNDWEIGHT(GRAMS)LENGTH{cM)FISH/KILOCRAM0.4300.4340.4380.4420.4.160.4500.4540.4580.4620.,1660.1700.47 +0.47tt0.4u20.4n60.4900.,1940.4980.50.10.5120.5200.5280.5360.5410.5520.5600.56lt0.5760.5u,r0.5920.6000.60u0.6160.6240.6320.6400.64u0.6560.6640.6720.6800.6uu0.6960.7040.7 t20.720l.l9ul1.20181.2055|.20921.2t2tlt.2t64|.22001.22361.2272|.2307|.23421.23771.24t2t.2446l.24ti01.25 l s1.2549t.25821.2633l.2fr!)9| .27651.2u30l.2tt951.2958|.30221.308,1I .ll l4(t1.320{J1.32691.3329L33891.34481.35071.35651.3623l.36ftOt.37 371.37931.3u491.390.11.39591.401,11.4068t.4t2l1.4t75|.42282:125.5942304. I 6 I22U3.1 I u2262.457'2242.1662222.2352202.6562 I u3.4 l9216,1.5I 521.15.9362127 .6732109.71t]2092.0632074.7022057.6262040.8302024.305200u.045t984.t27l 953. I 251923.07r1l u93.94 1I U65.673r 838.237l8l 1.5961785.7 t71760.56(;1736. I 1,1t7 t2.332I 689. I 92l 666.6701644.710I 623.3801602.5681582.2t|3I 562.504| 543.2t 4I 524.395l 506.029I 41i8. 100l 470.5931453.,1931436.787l.{20.4(;01,104.500I3t18.8940. l 9500. I 9690. l 9870.20050.20230.20410.20590.20770.20960.21| 40.21320.21500.2 l6ti0.21860.22040.22230.22410.22590.22860.23220.23590.23950.2.1310.24680.25040.25400.25760.26130.26490.26850.27220.27580.27940.2u300.28670.29030.29390.29760.30 l20.30480.30840.31210.31570.3 r 930.32300.32663.0433.0533.0623.0713.0813.0903.0993.1083.1173.1263.1353.t443.1533.1613.1703.1793. 1873. i963.2093.2263.2423.2593.2753.2913.3073.3233.3393.3553.3703.3863.401lJ.4l6ll.43l3.4453.4603.47511.4893.5033.5183.5323.5463.5593.5733.5873.6003.6 l45127.0515079.7975033.4064987.8554943. I 2 I4899. I 844856.0204U 13.609+77 | .9344730.9734690.7074651.1254612.2034573.926,1536.2814499.2504462.8201426.9774374.2464305.8984239.6524t75.4t84l I1i.0984052.6143993.88 l3936.8263881 .3793827.47 |3775.0413724.0273674.3743626.02t13578.9373533.0533488.3323444.7283402.20 I3360.7 l l3320.2213280.6953242.0993204.4003 l 67.5693131.5743096.3t}u3061.984

LENGTH.WEICHT TABLES 425TABLE I-3 C : 2,500 X 1O_7, CONTINUEDwEICHI /1,000LENGTHFISH/WEIGHTLENCl'llFISH/FISH (LB)(rNcHES)POUND(CRAMS)(cM)KILOGRAM0.7280.7360.7440.7520.7600.7680.7760.7840.7920.8000.u0u0.8160.8240.u320.8400.8480.8560.864o.8720.8800.8880.8960.9040.9120.9200.92u0.9360.9440.9520.9600.9680.9760.9840.9921.000l.080l l60t.2401.3201.4001.4801.5601.640t.7201.8001.8801.42801.43321.43841.44351.44861.45371.45871.4637|.46871.47361.4785r.4t|34l 4tt82l.49301.49781.50251.5072l.5ll9I .5166|.52t2r.52581.53031.53491.53941.54391.54U31.5528r.55721.56161.56591.5703t.57 461.57891.58321.58741.62861.6679t.7054t.7 4t31.77 stll.rJ090l.u4 101.87201.90 r 9I .93 l01.9592l 373.632I 358.70 It344.092I 329.793I 3 I 5.7951302.0u9128U.666t27 5.5161262.632I 250.006I 237.6301225.4t{il2 l3.59tt120 l .929I 190.482I 179.251I 16U.2301t57.4t4I I 46.795I l::i6.3701126.t321116.078I I 06.20 II 096.498l 086.9631077.593l 068.382I 059.3281050.427I 04 l 673I 033.064l 024.596I 0 I 6.2661008.071I 000.000925.927862.072806.455757.5807 | 4.29\675.68 I641.031609.76258 I .401555.562531.92 l0.33020.33380.33750.341 I0.34470.34840.35200.35560.35920.3(;290.36650.37010.373u0.37740.38 l00.3u460.3u830.39 l90.39550.39920.40280.40640.41000.4t370.41730.42090.4.2460.42820.43180.435,10.43910.44270.44630.45000.45360.48990.52620.56250.59It70.63500.67 I l]0.70760.7,1390.78020.81650.85273.6273.6403.6543.6673.6U03.(;923.7053.7183.7303.7433.755l:|.7 6tl3.7U03.7923.1J043.8r63.82u3.ti403.8523.86,13.8753.8873.899lJ.9 l03.9213.9333.9443.9553.9663.9773.9ti93.9994.0t04.0214.0324.1374.2364.3324.4234.51 l4.5954.6764.755,1.tt3 I,1.905't.976302lt.3362995.4202963.21 I2931 .6tt82900.u2r12870.6t22841 .0 I lJ2812.02tr2783.6242755.7882728.50:l270t .7 s32675.52:)264!).7!172621.5612599.8012575.5042551.6572528.2482505.2642482.6942460.5272,13ti.7 532417.36(\2396.3402375.6822355.37723i15.+1723 r 5.79 l2296.4932277.5142258.8462210.4812222.4t32204.620204 I .3 l81900.54 It777.92t1t67 0.t77| 574.7401489.620I 413.230I 344.293l 2n l .769t224.802I t7 2.68.+

426 FISH HATCHERY MANAGEMENTTesLB I-3. c: 2..500 ' ro 7, coN.rrNUEoWEIGH'T/I,000LENGTHFISH/WEICH'I'LENGTHI'ISH/FISH (I-B]lINCHES]POUNI)(GRAMS)(cM)KTLOGRAN'1.9602.0402.1202.',2002.2802.3602.4402.5202.6002.6802.7602.ti402.9203.0003.0803.r603.240iJ.3203.4003.,ft103.5603.(i.r03.7',203.8003.titu03.9fi0,1.0,101.1204.2004.2ttO,t.lJ(t04.410+.520.1.6004.(i801.760,t.tt.t.0.1.920s.0005.,1005.U006.200(;.6007.0007.4007.rJ00l.98ft62.0t322.03!122.06.162.0n932.t 1342.til70'2.t6022.l82ll2.20192.22672.21802.26It92.28942.30962.32!t42.34u92.36tt I2.311702.,t0552.+238'2.44182.,15962.177 L2.+914'2.51t42.52822.541112.561 I2.577:)2.59:]lJ2.60902.62462.64002.65522.67032.6tt5l2.6998'2.7t,\,\'2.78502.85212.9t6',2'2.!t7763.036ri3.093,13. 1,181510.210490.',20247 r.70,115+.552.138.603423.735109.84239tt.u3 l3U4.621373.140362.32.1lJ52.l I u342.47 |333.33932,1.681316.461301t.6,17301.2102!)4.t232tt7.3612U0.904274.730268.8222(;ll.l (i3257.7:172ir2.530247.529212.72:)238. I 00233.649'22!t.362225.23{)2',21.2.1:l2 1 7.3962t3.67!)2 l0.OtJu206.61ti203.256200.000185.185172.114l6l .290l5l .515| 4'2.857135.135128.2050.t}8900.92530.96160.99791.03421.0705r . 10(;7I . 1,1301 .17931.2156I .25191.28821.32.151.360u1.39701.43331.46961.50591.5+221.5785I .61,1r1I .65 l01.6873| .7',2:161.7599t.7962l.832irl.u6trl1.9050I .941l|1.!)7762.01392.05022.0u652.12282.15912. I 9532.23162.26Ii02.4+942.630tJ2.8t232.99373.t75l3.35(;(;3.53ti05.04(t5.t l45.1805.24+5.3075.36u5.42t15.187J.J++5.6015.6565.7 l05.7635.ti I ir5.tJ6ft5.9175.9666.015(t.063fi.ll06.\576.2026.2476.292(t.3:](t6.3796.4226.'16.16.50r;6.5466.5876.627(t. (t (t(t6.7066.74+6.7826.8206. U5rl6.u957.0747.2447.1077.5637 .7 t:l7.8577.99(;I t24.8201080.7091039.92t]1002.1 l3966.95293+.17 4903.5,16u 74.862817.941822.632798.78u77 t'.'2117755.01973,r.8857 l5.79tt697.6766U0..150664.0536,18..129633.5226 l9.2rJ6605.676592.(i505tiO.1 745riu.2I556.732545.70r1535.1 t 2524.9 I I515.l0rl505.65(;496.545187 .757179.271171.082,1tt3. I (t.145r.509,1.1U.102110.92140tJ.2(t33ttO. 107355.5tt.133,1.0343 14.9.1(t297.9'.22282.64'L

LENGTH.WEIGHT TABLES 427TABLE I-3.c: 2,..nn x lo 7, coNTINUEDWDIGH'T/1,000LENGTHFISHiWEIGHTLENG'I'HFISH/FISH (LB)(INCHES)POUND(GRAMS](cM)KILOGRAM8.2008.6009.0009.'1009.80010.200r 0.600I 1.000I 1.400l 1.80012.20012.60013.000I 3.4001 3.u00I 4.200I 4.60015.000I 5.4001 5.80016.20016.60017.00017.400l 7.800I 8.20018.60019.00019.4001 9.80020.20020.60021.00021.4002l.ti0022.20022.(;0023.00023.40023.80024.2002,1.60025.00025.80026.60027.+003.20103.25233.30193.35013.39703.44263.,18703.53033.57263.61393.65433.(i93fl3.73253.77043.110753.8,1403.U 7973.91.193.949,r3.9u33,1.0 l6(i4.04944.08l 74.11341.11474.t755.r.20594.235tt4.26534.29454.32:124.35154.37954.407 |4.43444.16t14.48804.5t 144.540,t4.56614.59154.6t674.(i4l 64.69064.73U64.7856l2l.95lI I 6.279lll.lll106.383102.04 I98.0399'1.34090.90987.72084.746u 1 .96779.36576.92374.62772.46+70.42368.49366.66764.93563.29 I61.72860.24158.82.157 .17 |56.18054.9,1553.76452.6325l .54650.ir05,19.50548.544,17.6 I 946.72945.87245.04541.21843.47812.73542.0t74t.322.{0.65040.00038.76037.59436.4963.7 t943.90094.08234.263u4.44524.6266,1.tii0u l4.98955.17095.35245.53385.71525.89676.07816.25956.44106.62246.80396.98537.16677.34827.52967.7 ttl7.89258.07398.2554u.43688.61ti28.79978.91J l l9. I 6259.3,1409.52549.70699.UUtt310.0697t0.251210.432610.6 I 40I 0.795510.9769ll.l583I 1.33981t.702712.0656t2.42858.1318.2618.3878.5098.6288.7448.8578.9679.07.19.1799.2829.3829.4819.5779.6719.7649.8559.944r0.03110.17t0.20210.285I 0.36710.44810.528l 0.60610.68310.75910.83410.90810.98 lI r.053| | .t24I 1.194l 1.263l 1.332I1.400I l 466l r.533l 1.598I I .662| | .726I 1.790I l.9l,t12.03612.155268.856256.352244.958234.535224.962216.140207.98.1200.+21l 93.388I 86.833I 80.707t7 4.970I 69.587164.521159.756155.25515 I .002146.975143.158I 39.533136.088I 32.808129.68.1t26.7 02123.855l2l.l33I I tt.528I16.033I 13.640I I 1.3.14109.140107.o2l104.982103.02010 l.12999.30797.55095.U5391.2 l592.63191.10089.6198U. I 8585.45082.88080..160

428 FISH HATCHERY MANAGEMENTTanr,B I-3.C : 2,5(IO ' IO 7, CONTINUTI,DWEIGHT/1,000FrsH (LB)LENGTHFISH/WEIGHLENGl'HFISH/(INCHES)POUND(CRAMS)(CM)KII,OGRAM28.20029.00029.80030.6003l .40032.20033.00033.80034.60035.40036.20037.00037.80038.60039.40040.20041.0004 r .80042.60043.40044.20045.00045.80046.60047.40048.20049.00049.80050.60051.40052.20053.00053.80054.60055.40056.20057.00057.80058.60059.40060.2006l .0006l .80062.60063.40064.2004.83 l74.87704.92t44.96515.00805.05025.09165. l 3255.17265.2t225.25125.28965.32745.36475.40165.43795.47375.509 l5.54405.57855.61265.64625.67955.7 t245.74495.77705.80885.8402s.87 l35.90215.93265.96275.99266.022r6.05 l46.08046.10916. I 3766.16576. I 937€).22146.2488t.27606.30306.32976.356235.46134.4tt333.55732.68031 .84731.05630.30329.58628.90228.24927.62427.02726.45525.90725.38 l24.87624.39023.92323.47423.04122.62422.2222l .83421.4592t.09720.74720.40820.08019.76319.45519.157l 8.868l 8.58718.3 I 518.05 I17.794l7 .544I 7.30117.06516.83516.61I16.39316.18 I15.974t5.773l5_)/o12.7913t3.t54213.517113.8tt0014.242t1I 4.605714.9686r5.33I415.6943t6.057216.420I16.782917.145817.508717.87 l618.2344I 8.597318.960219.3230l 9.685920.048820.411720.77452t.13742l .500321 .863222.226022.588922.95|t123.314723.677524.040424.403324.766125.129025.491925.854u26.2t7626.580526.943427.306327.669128.03202U.394928.757829. I 206t2.27312.3U8r 2.50012.61I12.72012.827I 2.93313.03613.138l 3.23913.33813.43613.53213.626t3.720l 3.81213.90313.99314.08214.16914.25614.34114.42614.50914.59214.67414.75414.83414.91314.99115.06915.145| 5.221l 5.29615.37 I15.44415.51715.58915.661t5.73215.u0215.87215.94116.010t6.07716.14578.t7tl76.02173.98072.04670.2t I68.46666.80765.22563.71762.27760.90159.5845U.323{t7.l1155.95554.U4153.77 |52.7425t.75250.79849.87848.9914U.13(t47.30946.51 I45.73944.99244.2694',J.57042.t|9142.23441.59740.97840.37u39.79539.22838.67738.14237.62137.1 I 536.62236.14135.67335.21834.77334.340

LENGTH-WEIGHT TABLES 429Tesle I-3. c : 2,500 x lo 7, coNTTNUEDWEIGHT/1,000FISH (LB)LUNCTH(rNcHES)FISH/POU N I)WEIGHI'(cRAMS]LENGTH(cM)FISH/KTLOCRAM65.00065.80066.60067.40068.20069.00069.80070.6007 t.40072.20073.00073.U0074.6007 5.40076.20077.00077.80078.60079.400u0.20081.00081.80082.600t|3.40084.200u5.00085.80086.60087.40088.200u9.00089.80090.60091.40092.20093.00093.tt0094.60095.40096.20097.00097.8009U.60099.400102.000I10.0006.3It256.40U66.43446.46016.48566.5 l0ll6.53596.56086.58556.61006.63436.65tt46.68246.70626.72986.75336.77666.79986.U2286.84566.86836.89086.91326.93556.95766.97957.00147.02317.04467.06607.08737.10857.12967. l 5057 .t7 t37.19207.21257.23307.25337.27357.29367.31367.33357.35337.41697.605915.3U5I 5. 198l 5.015l 4.83714.663I 4.49314.327| 4.16414.006I 3.850r 3.69913.55013.405I 3.26313.12312.987I 2.853t2.72312.594t2.46912.3,16t2.225t2.t07I 1.990I 1.876I t.765I 1.655| | .547| | .442I 1.338I l.2ll(ill.t36I 1.03810.94110.84610.753l 0.66110.57 lt0.48210.39510.30910.225lo.t 4210.0609.8049.09129.483529.846430.209230.572130.93503t.297931.660732.023632.386532.749133.t t2233.475l33.838034.200934.56373,1.926635.289535.652336.015236.37rJ I36.741037.103837.466737.829638. I 92538.555338.9 I 8239.281 I39.644040.006u40.369740.73264l .095541 .45tt34t.821242.t84142.547042.909843.272743.635643.998444.36 l344.724245.087 |46.266449.U951t6.2t2t6.278I 6.34316.409t6.47316.53716.60 I16.664t6.727l6.7tigl6.tt5 II 6.91216.97317.034I 7.09417.153t7.2t3t7 .27 |17.33017.3U8t7.44517.50317.56017.616t7.672t7.72817.7t13I 7.839I 7.89317.94818.00218.05618.10918.162I U.2l5I 8.268I U.320t8.37218.423t8.47 518.526t8.57718.62718.677I 8.83919.31933.91 733.50533. I 0232.70932.32631.9513 1.58531.22730.8 730.53530.20029.87329.55329.23928.93228.63128.33728.04927.76627.48927.21726.95126.69026.13426. I 832s.93725.69525.45725.22424.99624.77 |24.55024.33424.t2l23.91 I23.70623.50323.30523.10922.9t722.72822.54222.35922.1792t.6t420.042

430 FISH HATCHERY MANAGEMENTTABLE I-3. C: 2,s00 x l0-7, CONTINUEDWEIGH'I'/I,000LENGTHFISH/WEICHTLENCTHFISH/FISH (LB)(INCHES)POUNDlGRAMS)(CM)KILOGRAMl I 8.000r 26.000134.000142.000150.000158.000166.000174.000182.000190.000i 98.000206.000214.000222.000230.00023U.000246.0007.78607.95818.12318.28168.43438.58178.72418.86218.99599. l 2589.25219.375 l9.49499.61 l89.72599.83749.94648.4757.9377.4637.0426.6676.3296.0245.7475.4955.2635.0514.8544.6734.5054.3484.2024.06553.523857.t52660.781364.410068.03887 t.667 575.296278.925082.553786. I 82589.81 I 293.439997.0687100.6974I 04.326 I107.9549l I 1.5836tg.7 7620.21420.6332l .03521.4232t.79722.t 5922.5t022.85023.18023.50023.81324.tt724.41424.70424.98725.264r 8.68317.497t6.4521s.s25t4.69713.95313.28 I12.67012.1i3I 1.603l l .l3410.70210.3029.9319.5859.2638.962

LENGTH-WEIGHT TABLES431TABLE I-4. LENGTH-wEIGHT RELATIONSHIpS FoR FISH wtrH c: 3.000 x l07WEIGHT/1,000FISH (LB)LENGTH(INCHES)FISH/POUNDWEIGHT(CRAMS)LENGTH(CM)FISH/KILOGRAM0.3000.3040.3080.3120.3 l60.3200.3240.3280.3320.3360.3400.3410.3480.3520.3560.3600.3640.3680.3720.3760.3800.3840.3880.3920.3960.4000.4040.4080.4120.4 l60.4200.4240.4280.4320.4360.4400.4440.4480.4520.4560.4600.4640.4680.4720.4760.4801.00001.0044r.0088I .0132L0l75t.0217026003020344t.03850426t.0167l.0507|.05471.0587|.0627l 06661.07051.07431.07821.0820l.08581.08951.09331.09701.1006L10431.1079l.l I l5l.ll5ll. I 187|.t222t.1257t.t292t.13271.13621.13961 .1430| .t 464l. l 498l.l53ll. I 565l. I 598l.l63ll. I 6631 16963333.3353289..1763246.7563205. I 3 I3164.56I3125.0043086.4243048.7{J53012.0532976. I 962941 . 1ti22906.9U3287'J.5702840.9162808.9962777.7852747 .26027 t7.3992688. I 802659.5832631 .5872604.r752577.32t12551.0292525.2612500.0092475.2572450.9902427.1942403.8562380.9622358.5002336.45823'14.8252293.5882272.7 372252.2622232.r532212.4002192.9932t73.9232 I 55.1832 I 36.7632 l 81 .6552100.85 l2083.3440.13610. l 3790. I 3970.14150. I 4330.14510. l 4700. l48tii0.l50ri0. I 5240.15420. I 5600. 15780. l 5970.16150. l 6330.16510. 16690. r 6870.17060.t724o.t7 420. I 7600.17780.179(i0.ttll40. l 8330.18510. I 8690. l 8870. I 9050. l 9230.19410. 19600.197t10. I 9960.20 l40.20320.20500.206ri}0.20870.21050.2t230.21410.21590.21772.5402.5512.5622.5732.5842.5952.6062.6t72.6272.6382.64t12.6592.6692.6792.6892.(i992.7092.7 t92.7292.7392.74tl2.7582.7672.7772.7862.7962.8052.8142.8232.8322.8.112.8502.U592.86rJ2.t4772.8U62.U952.9032.9122.9202.9292.9372.9462.9542.9632.97 |7318.73+7252.0437157.8597066.0946976.6526U89.4456804.3916721.4t06640.4306561.3796484. I 8tt6408.7896335. I 256263. I 376 I 92.7666 l 23.9576056.6645990.8285926.4t45t]63.3675801 .6485741.2t 55682.0275624.0475567.23855 I l 5665457.0005403.5005351 .0395299.5ti652.19. I l35 I 99.5945l 5 l .0005103.3095056.48u5010.5204965.379+921.0474877.5004Ull4.7 l5+792.6724751.355+710.7 464670.82846:1t.57 +4592.980

432 FISH HATCHERY MANAGEMENTTanlr I-4.WEICHT/c: 3,ooo ro-7, coNtINUEo"1,000rISH (LB)LENGTHUNcHES)FISH/POUNDWEIGH'I'(GRAMS)LENCTH(cM)FISH/KILOGRAM0.4840.4880.4920.4960.s000.5080.5160.5240.5320.5400.54u0.5560.5640.5720.5tt00.5Iilt0.5960.6040.6120.6200.62u0.6360.6440.6520.6600.66u0.6760.6840.6920.7000.7080.7 t60.7240.7320.7400.7480.7560.7640.7720.7u00.7880.7960.8040.8120.8200.828|.17211l. t 76ll. I 7931.1825l.lu56l. l9l9l.l98r1.2043t.2to4t.2t64t.2224l.22Il3|.2342t.2400t.24stl1.25151.257 |1.26271.26U3t.2738|.2792|.28461.29001.29531.30061.3058l.3ll0l.3162I .32131.3264I .33 l41.3364I .34131.34631.351I1.35601.36081.36561.3703t.37 5l1.37981.38441.38901.39361.3982t.40272066. I 262049. I I I2032.53 l2016.1402000.000I 968.5041937.9U5I 908.398I U79.70 1I 85 I .854I 824.tJ l9l7gt].5631773.052t7 48.254t7 24.t 4l1700.6u31677.856I 655.633I 633.99 Il6l 2.907l 592.36 I| 572.:t3ll 5s2.799r s33.7 471515.1561497.01It47lt.295I 461 .993I 445.092| 428.577| 4t2.435I 396.653l3ul.22ll 366. I 26I 35 l .357I 336.904t:122.7 57130tt.906I 295.3431282.057t269.042t256.287t243.787l23l .533l2l9.5lu1207 .7360.21950.22140.22320.22500.22680.23040.23410.23770.24130.24490.24860.25220.25580.25950.26310.26670.27030.27400.27760.28 l20.28490.28850.29210.2!)570.29940.30300.30660.31030.31390.31750.321I0.324u0.32840.33200.33570.33930.34290.34650.35020.35380.35740.361 I0.36470.36tt30.37190.37562.9792.9872.9953.0033.0123.0273.0433.0593.0743.0903.1053.1203.1353.1503.1643.t7!)3.1933.2073.2213.2353.2493.2633.2773.2903.3033.3173.3303.3433.3563.3693.3823.3943.4073.4203.4323.4443.4563.4693.4813.4933.5053.5163.52u3.5403.5513.5634555.0234517.6884480.9574444.8204409.23u4339.80 I4272.5204207.2894144.0234082.6334023.0333965. I 493908.9063854.2373801 .0753749.36 I3699.0343650.04 I3602.32u3555.tt4735 l 0.5503,166.3933,{23.333338 I .3293340.3443300.340326 1 .2833223. l 393 185.87t]3 I 49.4693l 13.8U23079.0903045.067301 l.7tiu2979.22t12947.3652916.1772tiu5.64l2tt55.7 382826.4492797.7 542769.63627 42.07t)27 15.0(;32688.5742662.598

LENGTH-WEIGHTTABLES 433TABLE I-4. c: 3,000 x t0-7, coNTINUEDWEIGHT/I,000FISH (LB)LENG'TH(INCHES)FISH/POUNDWEIGHT(GRAMS)LENGTH(cMlFISH/KILOGRAM0.8360.8440.u520.8600.86u0.8760.81140.8920.9000.90[t0.9160.9240.9320.9400.9480.9560.9640.9720.9800.98n0.996l.0401.120r.2001.280r.360t.4401.5201.600l.680t.7601.8401.9202.0002.0ttO2.1602.2402.',3202.4002.4802.5602.6402.7202.8002.8802.960t.407 2t.4l17I .416l1.42061.42491.42931.43361.4380|.44221.4465t.45071.4550I .4591r.46331.4674t.47 t61.4757t.4797l.483ttl.4tt78I .491tJ1.5135I .55 l31.5874I .62 l91.6550l.6tt691.7175t.7 472t.77 stl1.u036I .830.'r1.8566I .8U2Il.906llI .93 l01.9545r.977 52.00002.02202.04352.06452.011522.t0542.12532.1448I196.I7u1184.840t173.7 t51t62.797I 152.080I 141.559I 131.2281 I 21 .083lllt.ll7I l0l .3281091.7091082.2571072.968I 063.836l 054.8591046.03 II 037.35 I1028.8131020.4 l51012.1521004.02296 I .539892.859833.33778t.254735.299694.449657.900625.006595.244568. I Uti543.484520.839500.006480.775462.969446.435431.041416.673403.232390.631378.794367.653357. I 48347.22t1337.U430.37920.38280.38650.39010.39370.39730.40 l00.40460.40820.41190.41550.41910.42270.42640.43000.43360.43730.44090.44450.44810.45 l80.47 t70.50800.54430.58060.61690.65320.68950.72570.76200.79830.83460.87090.90720.94350.9797I .01601.05231.0u86t.t249l.l6l2r.19751.2338|.27001.3063|.34263.5743.5863.5973.6083.6193.6303.6413.6523.6633.6743.6853.6963.7063.7173.7273.7383.7483.7583.7693.7793.7893.8443.9404.0324.t204.2044.2854.3634.4384.51 I4.5814.6494.7164.7804.8434.0954.9645.0235.0805.1365.1905.2445.2965.3485.3985.4482637.1 l92612.1232587.5962563.5252539.89825 l 6.7032493.9282471.5612449.592242U.0092406.8042385.9662365.4862345.3542325.5632306. I 022286.9642268.t422249.626223t.4t12213.4882 l 19.829I 968.4 I 61837.19 1t722.368162 I .054l 530.998I 450.420I 377.900t312.2871252.631JI 198.177I 148.2531102.3231059.9271020.67 I984.219950.2819 I 8.605888.973861.193835.096810.535787.377/ o.)-)trJ7 44.816

434 FISH HATCHERY MANAGEMENTTesr.E I-4.c: 3,ooo x ro-7, coNTINUEDWEIGHT/r,000FISH (LB)LENCTH(rNcHEs)FISH/POUNDwEtcH'I'(GRAMS)I,ENCTH(cM)IIISH/KTLOGRAM3.0403.1203.2003.2803.3603.,1403.5203.6003.6t|03.7603.8403.9204.0004.0804.1604.2404.3204.4004.4804.5604.6404.7204.8004.8804.9605.2005.6006.0006.4006.8007.2007.6008.000[t.4008.U009.2009.600r 0.000r0.40010.800I 1.200I 1.60012.000t2.400r 2.800I 3.2002.t6402.18282.20132.2t952.23742.25502.27232.28942.30622.322t12.33922.35532.37 t22.38702.40252.41782.43292.44782.46252.477 |2.49152.50572.519u2.53372.54752.58802.65272.71442.77342.U3012.U8452.93702.98763.03663.0t|403.130 I3.17483.21U33.26063.30193.34223.38153.,1993.15753.49433.530332U.953320.5 l8312.505304.8U3'297.624290.703284.096277.783271.744265.962260.421255.t07250.005245. I 03240.389235.854231.486227.277223.2t9219.3022t 5.5212 l 186920rJ.337204.92220t.6t7I 92.308t78.572I 66.667156.250147.059l 38.889131.579125.000I19.0,18I 13.637108.696104.t67100.00096. I 5492.59389.28686.20783.33480.6.1578.12575.758l.37lt9| .4t 52I .45 l51.48781.52401.56031.59661.63291.66921.7055|.7 4181.7780I .81431.85061.8869t.92321.95951.99582.03212.06ti32.t0462. I 4092.17722.21352.24982.35872.540 I2.72t52.90303.08443.26593.44733.62873.81023.9916.t.l 7304.35454.53594.71734.8988s.08025.26165.4.1315.62455.80605.98745.4965.54+5.5915.6375.6835.7285.7725.8155.8585.9005.9425.9836.0236.0636.1026.1416.1796.2t76.2556.2926.3286.3656.4006.4366.47 |6.5736.7386.U957.0457. 1Uu7.3277.4607.5897.7t37.u337.950tt.0648.t7 +8.2828.3878.4898.5898.6878.7828.876u.967725.2t6706.62168u.955672.t 52656. I 48640.889626.323612.,105599.0925U6.1146574. I 30562.4 l 3551.165540.358529.967519.9675 I 0.338501.060492.t t2483.,179.175.1411467.090459.30545t.77 54+4.489423.965393.6tt2367.437344.472324.209306. I 98290.0u227 5.578262.455250.526239.633229.6,19220.+63211.9U3204.t321 96.U42190.05.1l u3.7 l9177.793t72.237t67.Ot7

LENGTH-WEIGHTABLES 435TABLE I-4.C: i'},000 X IO_7, CONTINUEDWEIGH'I'/I,000LENGTHFI SH/WI.]IGHTLENC'I'HFISH/FISH (LB)(INCH!]S)PoU N t)(GRANlS)(cM)KILOCRAM13.600t 4.00014.4001,1.800I 5.200l 5.60016.000I 6.40016.u00t7.200I 7.600I U.000I 8.4001 tt.ti0019.20019.60020.00020.,10020.80021.2002l .60022.00022.40(l22.tt0023.20023.6002,1.00024.40024.80025..10026.20027.00027.8002U.tt0029.40030.2003 r.0003l.ll0032.60033.'1003.1.20035.00035.80036.60037.4.00118.2003.ir6563.(i0033.63423.6(i7(i3.70033.73253.764 I3.79533.82593.tt5603.UU563.91,193.94373.9720.1.00004.027 t,1.05'1tt4.0u 174. lOtt24.1ll434. I 602.1. 11t574.2109.r..235tt4.26044.2lJ4tl4.30891.3327,1.35(i2,1.391 I,1.4367,1.4U 1.r.4.52524.56824.61044.65194.692(i4.73264.77',204.81074.U,1titJ4.8n634.9233.1.95974.9956ir.030973.53071.4'2t)69.44567.56n65.79064. I 0362.50060.97659.52458. I 4056.11I u55.55654.3.1r153. I 9252.Or]351.02050.000,19.02018.07747.17046.296.15.45514.64343.U6043. I 0342.:17 3lt.667.10.{)tr.1.10.32339.37038.1(;u|17.03735.97134.96534.0143ll.I l232.25831.44630.67 ir29.9402\t.24028.57 |27.93:l27.:12226.73826.t7ta6. l6nll(;.35036.531 76.7llJl6.89.167.07607 .257'17.43fig7.62037.801u7.9u32u. 16,1(;8.3,1(i I8.5'.27 5u.7090n.89049.07 I t|9.25339.,13.179.61619.7 !t769.979010.160410.3,119I 0.523310.704u10.8u(i21l.0676I l .2491I 1.521lJI I .n|.t I12.247012.609912.972813.335{i13.69U514.0(t I 4| 4.42+3t,+.787 |15.150015.5129l5.u75u16.2386I (;.(i0 I 516.9(i4,117.'.12729.0579.1,159.2319.3169.3999.,18 I9.5619.6409.7 l8L7lt49.t]709.9.r,110.0 l 710.0r,t910.160I 0.23010.29910.36710.43 510.50110.56710.63210.69(t10.75910.822l0.uu310.9,15I 1.005I l.06ir1 l .153I 1.269I 1.3{J3I I .,191l 1.603I 1.711l1.81611.91912.02112.t'21t'2.2t!)l2.ll l612.'11I12.50512.59u12.6u9t2.779162.105r57.473153.099l4u.96l1,15.04 lt+t.3'22137.789l34.,l2ll13t.227128.176r25.',26:lt'22.47 !)I 19.8161t7.267I 14.1t2.1I l2.4rJ I110.231108.070105.91) I103.992102.06(;100.21098.,12196.69.195.02793.,11691.u5990.3538U.896r'l(;.796u4. l4(ift 1.65279.30377.08471.98773.0007t.tt769.327(i7.62(i66.00(t64.+6262.9r,]96l.5Ul60.23558.94757 .7 t2

436 FISH HATCHERY MANAGEMENTTesr-E I-4. C: 3,OOO X IO 7, CONTINUEDWEIGHT/|,000FISH (LB)LENGTH(INcHES)FISH/POUNDWEICHT(CRAMS)LENGTH(CM)FISH/KILOGRAM39.00039.80040.6004l .40042.20043.00043.U0044.60045.40046.20047.00047.8004rJ.60049.40050.2005l .00051.80052.60053.40054.200s5.00055.80056.60057.40058.20059.000s9.80060.6006l .40062.20063.00063.U0064.60065.40066.20067.00067.u006U.60069.40070.20071.00071.u0072.60073.4007 4.20075.0005.065u5. I 0025.13415.t6765.20075.23345.26565.29755.32905.36015.39095.421',.)5.45145.481I5.51055.53975.5(ttt55.59705.62525.65325.68095.70U35.73545.76235.78905.8 t 545.8,1155.t]6755.U9ll25.91t]75.9439s.96905.993u6.01856.04296.06716.09126. I l5l6. l 3U76.t6226. 1 U566.20876.23176.25456.277 |6.299625.64125.t2624.63024.15523.69723.25622.83122.42122.02621.6452t.27720.92020.57620.24319.92019.60819.30519.01It8.727I U.450l8.IU2t7.g2l17.66ut7.42217.182I 6.94916.72216.50216.28716.077I 5.873| 5.67415.4U015.29115.106t4.92514.749| 4.577I 4.409| 4.24514.0u413.92ut3.77 413.62+13.477I 3.33317.690118.053018.41 59t8.7787l9.l4t6l 9.5045I 9.867420.230220.593120.956021.31882t.681722.044622.407522.770323.133223.496 l23.859024.221824.584724.947625.310525.673326.036226.399 I26.761927.t24827.4L7727.850628.21:1428.576328.939229.302129.664930.027830.390730.753631.116431.479331.842232.205032.567932.930833.293733.656634.0194t2.867l 2.955I 3.04113.12613.210l 3.293t3.37 5I 3.456I 3.53613.61513.693t3.770I 3.84613.92213.99714.07 || 4.t 4414.2t6I 4.28814.35914.429I 4.499r 4.56u14.636t4.704t4.77 |14.837l 4.903I 4.96915.0331s.098l5.l6l| 5.22415.287I 5.349l 5.41 I15.47 2I 5.532t5.592l 5.65215.71 I| 5.770t 5.u28t 5.u86I 5.944l 6.00156.52955.39254.30 I53.25252.24251.27050.33449.43148.56047 .7 t946.90746.12245.36244.62t143.9t743.22842.56041.9134t.28540.67640.08.139.50938.95138.40837.88037.36636.86736.38035.90635.44434.99434.55534.12733.7 l033.30232.90532.51632.1373t .76731.40531.05130.70530.36730.03629.7 t229.395

LENGTH-WEIGH'T TABLES 437TasI-E I-4. c: 3,ooo x to-/, coNTINUEDWEIGHT/1,000FISH ILB)LENGTH(INCHES)FISH/POUNDWEIGHT(CRAMS)LENGTH(cM)FISH/KIt,OCRAM75.80076.60077.40078.20079.00079.80080.60081.40082.20083.00083.80084.60085.40086.20087.00087.80088.60089.40090.2009l .0009l .80092.60093.40094.20095.00095.80096.60097.40098.20099.00099.800106.000I 14.000122.000130.000138.000146.000154.000I 62.000170.000178.000186.000194.000202.0002 r 0.0002 r 8.0006.32196.34416.36616.38806.40976.43126.45266.47396.49516.51616.53696.55776.57836.59886.61916.63936.65946.67946.69936.71906.73876.75826.77766.79696.816 I6.83516.85416.U7306.89 l86.91046.92907.06967.24327.40887.56737 .71947.86588.00698. I 4328.27518.40308.52708.64758.76488.87908.9904I 3.19313.055r2.920t2.78812.65u12.531t2.407t2.28512.16512.04uI 1.933I 1.82011.710I l .601I 1.494I 1.390l l .287l l.l u6l L08610.98910.893I 0.799t0.70710.616I 0.52610.43tt10.35210.26710. I 83l0.l0l10.020L4348.7728.1977.6927.2466.8496.4946.1735.8825.6185.3765.1554.9504.7624.58734.382334.745235.10u035.470935.[t33836. l 96736.559536.922437.285337.648138.01l03U.37 3938.736839.099739.462539.825440. l8tJ340.551 I40.91404t .276941 .639u42.002642.365542.728443.091 243.454143.817044.t79944.542744.905645.268548.080751.709555.338258.966962.595766.224469.853 I73.481977.1t0680.739484.3681u7.996tt9 r .625695.254398.883016.05ul6.ll416.17016.225l6.2ti lI 6.335I 6.39016.444t6.49716.551I 6.604l 6.65616.70916.7 6l16.81316.u6416.91 516.96617.01617.066l7.l l6I 7.166t7 .21517.26417.31317.361I 7.40917.457I 7.50517.55217.60017.957l 8.39818.81819.22119.60719.97920.33820.6U42 I .01921.3442l .65921.96522.26322.55:l22.83629.08528.78l28.4u328. l 9227.90727.62727.:15327.08+26.82026.56226.30826.05925.U 1 525.57 625.34025.1 l024.88324.66024.44124.22724.0t 523.80823.60,123.40423.20623.0 r 322.82222.63522.15022.26922.09020.79u19.339I U.07 II 6.959I 5.97615.1001,1.3 I 6I 3.609l2.96ttI 2.3861 1.u53I l.3ft,110.9 l410.,19trl0.l l3

438 FISH HATCHERY MANAGEMENTTllg f -4.a,ooo, to-7, coNltNur,o9,=___wItcHT/I,(XX)LENGTHFISH/!VI,ICH'fLENCI'HFISH/FISH (I,B){INCHES)PoUN D(GRAMS)(CM]KILoGRAM226.00023,1.000212.000250.000258.000266.00027 +.000282.000290.00029ti|.0009.09909.20529.30899.4 10.19.50979.60709.70239.79599.uu76lr.97 7 74.+'254.2744.1324.0003.r,t7 63.7593.fi503.5.163..14u3.356102.51 l8106. I .10s109.7(;92l 13.39110I t7 .0267I 20.6555t'24.284',2127.9129I lJ 1.5417135. 170,1'23.tt223.3U 123.64523.9022.t.t 5524.+02'24.64424.Ut| I25.1 I 525.3439.75ir9.4219.1 l0u.ulutt.5.r5u.2tllJu.0.167.U 1 ti7.6027.391r

TABLE I-5LENGTH-WEIGHT TABLES 439LENGTH.WEIGH'I' RL,LAI'IONSHIPS FOR FISH WITH C = 3,500 X IO 7WEIGH'f/1.000I'ISH (LB)LENGl'H(r N cr{ ES)FISH/POU NDWEIGHTlGRAMS)LI,]NC I'H{cM)FISH/'KII-OGRAM0.3500.3540.35rJ0.3620.3660.3700.3740.37u0.3tr20.3860.3900.39.r0.39r10..1020.40(t0.4100.,11,10.'11rJ0.1220.4260.'1300.43'10.,r3r,10.1220.,1'1(t0.'1500..15,10.45r10.1620.4660.4700.1740.47tt0..1ri20.,1tt(i0.49()0.4940..t9ll0.50'10.5120.5200.52r10.53(i0.5.1.10.5520.5(;01.0000r.003lJl.007(tl.0ll:Jl .0150I .0I U7|.02241.02(;01.029(;1.03321.03(i71.0.1031.0,13u1.04731.0507t.05421.0576l .0610L0(tlllt.0677l 07l01.07'13t.077 6l.0rJ09I .0u,t IL0t|7,1L090(;1.09381.0{)70l.l00lL1033I . l0(i,1I . 1095r1.112(tl.l l5{;l.l 187T,T2I7| .1247t.t292L13521.141 II . 1.169| .t 527Ll5U4I . I (;.10I . l (i9{;'2857.t 452r.t2,r.lt6l2793.2982762..134273'2.'213270',2.7062(i73.80026.+5.5072617.8052590.(;7n256.1. 10725311.07(;2512.5(itl2,187.5(tu24ri3.0(t02,139.03024t 5.1652392.35 I2369.(i7r'2:l+7.12+2325.5Uti21.|0.1. I ir.t2283.t t22262.4502'242.t6022'22.2292202.6512l83..111216.1.5102l 'r5.9302t27.6672109.7 t 32092.05r.}2074.6972057.62120.10.ti25202,1.300200u.041198.{. 1271953. 12.5l1)23.07r1l 893.91 II tt(i5.(i7lJIr.r3r'|.237lrJ11.51Xit7 85.7 t70. l5trtt0. l 6060. l 6240. 16,120. l 6600. I 6780. 161)60.17150. I 7330. l 7510. I 7690.t7870.18050. I 8230. I u,r20. l 8600.187n0. I r,t9(i0.191.10. l 9320.1{)s00.19(;90. 19870.20050.20230.20'110.20590.20770.209{i0.21 l40.21320.21500.21(ttt0.21u(i0.220'10.'22230.22410.225{)0.221t60.'23220.2351)0.23950.2.1310.24(;tt0.2ir0.10.25402.5102.5502.b592.5692.57 tl'2.5872.5972.6062.6152.6242.6332.6122.6512.6602.(i692.6782.6tt(t2.695'2.7032.7 t22.7202.72!)'2.737'2.7452.75+2.762'2.770'2.7782.7862.7lt+2.8022.8102.tt I u2.1t2(i2. trt3,12.8112.U492.8572.8(iu2.UU32.U1)ti2.91:J2.9282.!l \22.!t57'2.97|(i298.91 +6227 .7,t26l5tt.l(t0(;090.1 l:i6023.555595tt.'r3rJ589,r.7115832.3365771.26657 | | .+575652.8795595.,r925ir39.25.15.18,1.1415,130. 1095377.1335325. 180527 +.2235224.2305t75.t765127.0355079.7t] I503ll.ll9l.19tt7.ti,t0'19.13.101).1lit99. I (ilJ.1U56.00.r,1u l 3.59.1477 l .1) lrl4730.{X;r4(i90.61)5'1651.1 l34(i I 2. l9l,r573.91r14536.2 70.1+9!1.212,1,1(i2.U09.1,r2(i.9651374.',2.16.130ir.U1)tl.12:i9.(i52.11 75.. 1ti,11 I ll.09u,1052.(i 1.13993.881:.i93(t.82(t

440 FISH HATCHERY MANAGEMENTTABLE I-5. c: 3,500 x lo7, CoNTINUEDWEIGH'I/I,0(x)r.ISH (LB)I,I.,NG1'H(INCHI,S)FISII/POUNDWEIG H'I(G RAMS)I,ENGTII(cM)F'ISH/Krr.ocRAM0.56r]0.5760.5840.5920.6000.60It0.6160.6240.6320.6,100.64u0.6560.66.10.6720.(;tit00.68t10.6960.7040.7 t20.7200.72110.7360.7440.7520.7{;00.7680.7760.7u,10.7920.8000.u080.tr I 60.t|240.8320.u400.tt,180.ri5(i0.8640.8720.8u00.8880.8960.9040.9120.9200.928t.t7 5l1.1806l.lu6ll.l9l51 .1968|.2021L207 1t.21261.2t77t.222tl|.2279t.'2329|.2:17!lt.242\l1.2478t.2527t.257 s1.262:l1.267 || .27 ttl| .27651.28t21.285u1.29041.29,191.29951.3040l.30lt41.3129I .31731.32 l61.32601.3303l.3lJ.1(t1.33{J9l.lt43 I1.3473l .35 l51.35571.359u1.3639l.36ti0t.:1720I .3761l 3801I .31t4 I1760.56(i1736.1 l,rt7 t2.3321 689. I 92166(;.670t644.7101 623.3801602.5(i81 582.2U3r s62.50,115+3.2t4152.1.395l 506.029I 488. 1 001,r70.5931,1s3.4931,136.787| 420.460I 404.500r 388.894l 373.632I 358.70 II 344.092I 329.793I 3 l 5.7951 302.0u91 2uu.666t27 5.5161262.6321250.00(;I 237.6301225.49t'I 2l 3.59ti1201.929I 190.4U2I t79.251l l 68.2301157 .4t 4| | 46.7 95I I 3(;.370t126.t32I I 16.078I106.201I 096.4981 0u6.9631077.5930.25760.26130.26490.26u50.27220.27580.27940.28300.28670.29030.29390.29760.30120.304u0.30840.3 l2l0.31570.31930.32300.32660.113020.333r10.31:1750.3,11 I0.3+470.34840.35200.35560.35920.36290.36650.370 I0.37380.37740.3u 100.38460.3llu30.39 l90.39550.39920.402u0.40640.41000.41370.4t730..12092.9852.9993.013:1.0263.04011.0533.0673.0u0:J.0933.1063.1193.132lJ.l443.1573. I (t93. I tt23.1943.2063.21tl3.2303.2+23.2543.2663.2783.2893.3013.3123.3233.335tJ.3463.3573.36ti3.3793.3903.,1013.41 I3.+223.4333.4433.,1543.,t643.4753.4853.4953.5053.5 I ri38tt 1.37938'27.47 |3775.04r372.\.0273671.:17 43(t26.02u3578.9373533.0533488.3323444.7283+02.2013360.7 l l3i120.2213280.69532'12.099320.1.,100:t I (i7.56931.1t .5743096.38li3061.9n43028.33(i2995.4202963.2 l I2931 .6Ur,]2900.n2r12870.6t22U4 I .01 n2812.02t12783.62.42755.78r12728.503270t .7532675.5232649.7972624.5612599.80 12575.5042551 .6572528.2+tl2s0s.2642482.6942+60.5272438.75324t7.3602396.3402375.682

LENGTH-WEIGH'I' TABLES 441TesI-E I-5. c: 3,500 x lo 7, coNTINUEDwErcHltI,(XX)nsH iLBlI-I]NC'I'II(INCHI.]SiFtslr/POL]NI)WT]IGH I{GRAMSILENGI'HlcM)I IStl/KI I,OGRANI0.9:l(t0.9.1,10.{)520.9(i00.9(t80.97(i0.1)lt,t0.9921.0001.0u0l. I (i0|.2401.3201.,100l.4it01.5(i01.6,10|.7201.ft00t.ti801.9602.0402.t202.2002.2802.3602.4,102.5202.6(X)2.6802.7 (;02.tt.102.9203.0003.0u03.1603.2403.3203.400lJ.4u03.5(i03.6,103.7203.11003.8U03.960l .llti801.39201.3!)591.399r11..10371.,1075I .41 l41.4152I ..11 90t.,15591.,19091.52151.556(;I .5137.1l.(;l7l| .6457|.67 ,1,11.7001t.7261I .75131.77 stl1.7996t.822!)L8,1551.1t676l.uu92I .9IOiJ1.9310l 9512I .97 l01.99042.00952.028',)2.04(i52.06452.0rJ232.09972.1 l(il12.t3372. I 5032.t6672.1ri2lJ2. 198(;2.214:l2.22!172.2419IO(ilt.lJu21059.32ut050.42710,1 I .(;731033.0(i,11024.59riI 0 I (;.2(t(i1008.07 ll 000.000925.927862.072u0(i.455757.5807 t1.291(i75.(i8 I6,11 .031(i09.7(;25ti I ..101555.5(i2ir3l.92l510.210190.20247 t.704454.552438.603+2:1.735.109.842396.tt313u4.(t2l373. 1,10:162.:124352.1 Iu:142.+7 |333.339324.(t8IlJ I (;.'16 I30u.647301.210294.t232U7.3612ri0.904274.730268.8222(;3. I (i3257.737252.5300.4'2,Ui0.42820.,13 l rl0..135,10.43910.4'1270..1,1(;30.45000.4511(t0.,11J990.52(i20.5r;250.59870.63500.(i7 I ll0.70760.74390.7lt020.81650.85',270.88900.92530.96 l (i0.99791.03,121.0705l. l0(;7I . 1,130l. I 79:ll.2l5ri1.2519|.2882t.32451.3(i0u1.39701..11J331.,169(i1.50591.5122l.57rJ5l.(t l,1uI.65t0l.(;t|73t.72361.7599t.79623.52(i3.5363.5,r(;3.5ir53.5653.5753.5rJ53.5953.6043.69r13.7873.8723.95,tr4.032,4.t07.1. I tiO+.'250.1.3 I tt.1.3tt,11.+ltl,1.5 I I4.57 |,1.630.1.(ilili4.7 +44.7994.tt521.9054.{}565.0065.05(;5.1045.t 52ir. l9tl5.2445.2tt95.3335.3 75.1205..\625.5035.5,145.585ir.(i245.(;(i45.7022355.37 /'23.t5.,tt72ll 15.791'22!16.4!l:l'2277.5t,1225rJ.rJ,r(i2240.,1It I2222.4t:l220+.(r2020,11.31111900.5.{ It777.9'281670.t77| 571.7101,189.(;201,113.23013,1.1.293I 2tt I .7(;{)t22+.802I 172.{ttt.11124.n2010u0.7091039.92r11002.1 l3966.952934.17.1903.54(;874.8628+7.tJ+482'2.6327gtt.7Ul.l776.287755.01{)73,1.UU5715.7gr.i697 .076(;tt0.,15066.1.053(;.1tt.,121)(i33.52(i 19.2u(;605.(i7(t592.6505U0. 17456r,].21 I556.73',2

442FISH HATCHERY MANAGEMENTTABLEI-5. c : 3,500 x lo 7, coNTINUEDWEICHTi1,000fISH {LB)LENGTH(INcHLS)!'rsH/POUNDWEIGH'T(CRAMS)LENCTH{cM)FISH/KILOGRAM4.0404.1204.2004.2804.360+.41t)4.5204.6004.6804.7 604.8404.9205.0005.,1005.8006.2006.6007.0007.1007.8008.2008.6009.0009.4009.U0010.20010.600l1.000I 1.40011.80012.200I 2.60013.000l 3.40013.tt0014.200l 4.600l 5.00015.400I 5.80016.20016.60017.00017.,100I 7.U0018.2002.26002.27482.289+2.30392.31u l2.33222.34612.35992.37:152.3U692.40022.413+2.12642.48952.5,t952.60(i82.66t72.7 t442.76522.81,112.86142.907',)2.95162.!)!)+73.03663.07733.117 |3.155u3. l 9363.23053.26663.30193.336i)3.37043.40363.43623.,16813.49953.53033.56063.59053.61983.64863.67703.70503.7325247.529242.723238. I 00233.6,r9229.3€)2225.23022t.243217.396213.6792l0.0uu206.6 I tt203.25(t200.000185.185172.4r4l6l .290151.515142.857I 35.1 35128.205121.951I t6.279lll.lllI 06.383102.0.1198.03994.34090.90987.72084.7468l .96779.36576.92374.62772.46470.+236U.49366.66764.93563.29 I61.72860.2415U.82457 .47 |56. I 8054.945i.83251.86881.9050I .9413|.97762.01392.0s022.086ir2.12282. I 5912. 19s32.23t62.26802.44942.63082.8t232.99373.17513.35663.53803.71943.90094.08234.26384.44524.6266,1.80814.98955. I 7095.35245.53385.7 t525.89676.07816.25956.44 l06.62246.U0396.98537.t6677.3+827.52967.7 tll7.89258.07398.25545.7405.77 t15.8155.8525.8885.92+5.9595.99,16.0296.0636.0976.1306.1636.3236.4766.6216.7616.8957.0247.1487.2687.3847.4977.6077.7t37.8167.917u.0l68.1 l28.2058.2978.3878.4758.5618.6458.72118.U098.8898.9679.0449.1209.194L2679.3409.4119.481545.708535. 1 2524.9195 l 5.108505.656496.545487 .7 57479.27 447 t.0824ii3.164455.509448.t02440.924408.263380. I 07355.58,t334.0343 14.946297.922282.644268.856256.352241.958234.535224.9622 16. 1,10207.984200.421193.388I 86.833180.707t7 4.970I 69.587164.524I 59.756t55.255151.002t 46.97 5143.158l 39.533136.088132.808129.68,1t26.702123.855l2l.l33

LENCTH-WEIGHT TABLES 443TABLE I-5. C: 3,500 X IO_7, CONTINUEDWEIGHT/l,000FISH (LB)LENGTH(INCHES]FISH/POUNDWI]IGHT(GRAMS)LENGTH(CM)rISH/KILOCRAIlI18.60019.000I 9.40019.80020.20020.60021.00021 .40021.80022.20022.60023.00023.40023.80024.20024.60025.00025.80026.60027.40028.20029.00029.80030.60031.40032.20033.00033.80034.60035.40036.20037.00037.80038.60039.40040.20041.00041.80042.60043.40044.20045.00045.80046.60047.40048.2003.75973.7U643.81283.U3883.86453.88983.91493.93963.96403.98U 14.0 l 194.03544.05874.08 I it4.1044,1.12694.14914. I 9294.23584.27794.31914.3596,1.39934.43U34.47674.51444.55144.58794.62384.65924.69401.72844.76224.79564.82854.U6094.89304.92464.955u4.98665.017 |5.04725.07695. I 063). I.J3J5.164153.76452.6',3251 .5,1650.50549.50548.54447.61946.72945.87245.04544.24843.47842.735+2.0174l.32240.65040.0003ti.76037.59436.49635.46134.48333.55732.68031.8473l .05630.30329.58628.90228.24927.62427.02726.45525.90725.38124.87624.39023.92323.47423.0412',2.62422.22221.83421 .45921.09720.7478.43688.61828.79978.98 19. I 6259.3.1409.52549.70699.888310.0697t0.25t2I 0.432610.61 40I 0.795510.976911.1583l l.339811.702712.0656t2.428512.791313.1542l3.5l7l13.8800| 4.21281,1.(i05714.96U615.3314I 5.694316.057216.420116.7U2917.145817.5087t7 .87 t6t8.2314l 8.5973I 8.960219.323019.6U5920.048r120.1t 1720.77452t .137421.500321.86329.5509.6179.6859.7519.8169.U809.944t0.00610.06810.13010.19010.25010.30910.367t0.42510.48210.53910.650l0.7 5910.lJ6610.97 II1.073tt.t741t.273I 1.37 II 1.466I I .561I 1.653tt.7 45I 1.834l 1.92312.01012.096l2.l8lt2.26412.347t2.428l2.50rJ12.5{J8l2.6tt(i12.743t2.820l2.t]95t2.97013.04413. I l7I I tt.52ttI 16.033I 13.640I I 1.344109.1.10107.021I 04.982103.020101.12999.30797.55095.85394.21592.63191.100lt9.6l988. 18585.45082.U80u0.46078.17876.02173.98072.04670.21|68.46666.tt0765.225t'3.71762.27760.90159.5U45rJ.32357.tt455.95554.U4153.77 |52.7425t.75250.79849.87 u4U.991,18.13647.30946.51 I45.739

444 FISH HATCHERY MANAGEMENTTasle I-5. c': lt,.i00 x l0- 7, CONTINUEDWEIGHl'/1,000I-ENGl'HFISH/WEIGH'fLENG'I'HFISTI/FISH {LB)(INCHES)POUNI)(CRAMS)(cM)Krr-ocRAM49.00049.80050.60051.40052.20053.00053.80054.60055.40056.200ir7.00057.80058.60059.40060.2006l .000(; I .80062.60063.,10064.20065.00065.80066.60067.4006U.20069.00069.u0070.60071.40072.20073.00073.U007,1.(i0075.40076.20077.00077.80078.(t0079.40080.200u 1 .000u1.800u2.600tt3.40084.200u5.0005. I 9255.22065.24845.275t)5.30325.33015.35685.3U325.40945.43535.46105..18(;.15.51l65.536(;5.5ft l35.5U5rJ5.(il0l5.63425.(i5815.68l tl5.70535.72875.75l u5.77175.79755.u2015.84255.tt6475.UU(;tt5.90875.93045.95205.97345.99476.015l.l6.0361]6.05766.07836.098{)6.r 1936.139(t6. I 5976.r7 !17(;.19966.219,16.239020.40tt20.0u0I 9.763I 9.45519. l 5718.868I U.5U7ltt.3t5I8.051t7.794t7.5+417.30117.06516.83516.61II (t.393l6.l tll15.974| 5.773I 5.576I 5.38515.l9u15.015t.1.tt371,1.66314.'191]11.327I 4. 16.11,1.006l3.r't50l3.ri99I 3.550I 3.405I 3.263I ll. 12312.98712.u53t2.723t2.59412.4(t9I 2.34612.22512.t07l 1.990I 1.876| | .76522.2',26022.58It922.951 u2:1.3t 4723.677 524.040424.403324.766125. I 29025.49 l I25. n54826.2t7626.5U052ft.9.13427.306327.(;6912ti.032028.394928.757829. I 20629.4tt352!1.846430.2092'30.5721:J0.935031.297931.660732.023632.386532.7 +943:l.t t2233.475l33.838034.200934.563734.92(t(t35.2tt95lt5.(i521]36.01 ir236.37 8lli(t.74 I 037.103u:17.+66737.829638. I 9253fi.5553I l-t. I ttg13.26013.33113.,10113.47013.53813.60613.(;7:J13.7,t013.u06l3.u7ll 3.93513.9991.1.(xili1,1.1 26l4.l tt8| 4.25014.31 I| 4.372I 4.+:1214.+9214.55114.(il014.66ut1.726t,1.7 t33l,{.u401,1.896t4.952I 5.00815.063l5.l ltt15.l7l]| 5.22715.2u015.33,1l5.3tt6I 5.43915.491I 5.543I 5.59515.(t46I 5.697| 5.747| 5.79715.847+4.9!124'1.269.13.570,t2.u9I42.231+1.59740.97u40.37839.79539.22r138.6773lt. 1,1237.62137.115:16.t'2'236.14 135.(i7335.2 I tt34.77:l3.1.3,t03ll.9l 733.50533. I 0232.70!'32.3263l .95131.5853t.22730.87 730.53530.20029.87 329.55329.21)92n.93228.63128.3372li.04927 .76627.48!l27.2t72(i.95126.69026.4342(i. I U325.937

LENGTH-WEIGHT TABLES 445TABLE I-5.c: ll,5oo x lo 7, CONTINUEDWEICHT/r,000LENCl'HfISH/WI]IGHlLENCTHFISH/FISH (LB)(INCHES)POUND(GRAMS)(CM)KILOGRAM85.80086.600u7.40088.20089.00089.1t0090.60091.40092.20093.00093.8009.1.60095.4009fr.20097.00097.rJ009ll.(i0099.,100102.000I 10.000l l tt.000l2(i.000134.000142.000l 50.000158.000166.00017.r.000182.000l 90.00019ri.000206.00021.1.000222.000230.00023n.000246.000254.000262.000270.00027U.0002tt6.000294.000302.0003 10.0003l u.0006.25856.277!)6.29726.3 I (t46.33546.35436.37316.391u6.4104(;.42896.4173(i.465(;6.483u(;.50 l n6.51986.53776.55556.573 l6.62996.79896.95997.1 I lJtt7.26t37.40307.53957 .67 t27.79857.92t98.0,115r't. l 57(i8.27058.3n04u.,18758.5920u.69'108.7 !1.17u.tt9I I8.9n659.071)tr9.17139.2(i l09.3.1909.435.1lt.52029.60359.6854I 1.655| | .547| | .442l 1.338I l.236I I .136l 1.03810.94 l10.84610.75310.66110.57 l10.4u210.39510.309t0.225t0.I,1210.0609.80'19.091lt.47 57.!):177.46:l7.0+2(i.6676.3296.0245.7475..1955.2635.0511.85,1,r.6734.505,1.34tt1.20',2,1.0(i53.9373.tt I 73.70.t3.5973.'1973.4013.lJ I I3.2263.1453U.9l U239.281 I39.6.14040.006840.3697+0.7 32641 .095541 .45834t.82t242.184142.547042.909n+3.272743.635643.998'1,14.36134+.72+245.087116.2664.19.895153.523857.152660.711l364.41006U.038871.667575.29627 tt.925082.553786. 1 u25ttg.8l293.439997.0687100.697,1104.32(;lI 07.9549I I l.5tti|6I 15.2123I lti.tt4l I122.'169u126.0986t29.7273l 33.3560l 36.9818140.6135| 44.2422I 5.89715.946I 5.99516.04,116.09216. I 4016. I 8816.235l 6.283I 6.329I 6.376t6.42316.,16916.5 l 516.56016.60616.65116.697I 6.84017.269t7.67818.069I u.,14,1I U.U0419.150I 9.48519.80tJ20.t2220.42520.72021.0072t.2862l.55rl2t.8',2422.0tt322.33622.58322.82623.06323.29523.52323.74623.9662,1. I8I24.39324.60125.69525.45725.22424.99624.77124.55024.33424.t2123.91I23.70623.50323.30523.10922.!lt722.72822.54222.35922.t792t .6t 120.042I U.68317.4!17I 6.452l 5.525l 4.697I 3.95313.28 lt2.67012. I l3I 1.601]I l. 13410.702l 0.3029.9319.5u59.263u.9(t28.6U0u.4I 5ll. l6ir7.9307.7087.,1997.3007.tt26.933

446 FISH HATCHLRY MANAGEMENTTABLE I-5. c: 3,500 x lo-7, coNTINUEDWEIGHT/1,000FISH (LB)LENGTH(INCHES)FISH/POUNDWEICHT(GRAMS)LENGTH(CM)FISH/KILOGRAM326.000334.000342.000350.0009.76609.84529.923210.00003.0672.9942.9242.857|47 .87 r0I 5 l .4997l 55.1284t58.7 57224.80625.00725.20525.4006.7636.6016.4466.299

LENGTH-WEIGHT TABLES 447TABLE I-6. LENGTH-wEIcHT RELA'IIoNSHIPs FoR FISH wtrH c: 1,000 r l07WEICH'I'/I,OOOfrsH (LB)LENGTH{rNcHES)FISH/POUNI)WEIGHT(GRAMS)I,LNC'I'H{cM)FISH/KILOGRAM0.4000.4040.40u0.4120.4 l60.4200.4240.4280.4320.4360.4400.4.440.44110.4520.4560.4600..16,10.4680.4720.4760.4u00.48.10.4uu0.4920.,1960.5000.5080.5160.5240.5320.5400.5480.5560.5640.5720.5tt00.5880.5960.6040.6120.6200.6280.6360.6410.(i520.66i)1.00001.00331.00661.0099l .0132I .0164I .0196t.02281.0260I .0291].032r11.035,11.0385I .04161.0,r461.0477l.0irO71.05371.05671.0597|.06271.06561.0685t.07 t41.07 +3t.0772l.0lt29l.0uu61.09421.09971.1052l. l 106t.llriOl.l2l3l. I 266l.l3 t 9t.1370| .t 422t .t,t73r.1523l. I 573t.t6'22|.167'2t.1720l. I 769l .l8l72500.00 l2+75.2492450.9U22427.t872,103.u4923tt0.9552358.,r9'12336.45223 I 4.81 rJ2293.5822272.7:tl2252.2562',232.t4722t2.3!t42[)2.91]72l 73.9182t 55.t72136.7572 l l u.6492100.8,162083.11392066. I 2 I2049. 1 U62032.5262016.1352000.0001961J.50.1I 937.985190tt.39nI U79.70 1185 I .rJ5.1I 824.U 191798.563t77 3.0521718.254t7 24.t 4l1700.6rJ3l fi77.85616ir5.633l (i33.9911612.9071592.36 I| 572.331l 552.7991533.7471515.1560.181,10. l 8330.18510. I 8690. r u870. l 9050. I 9230. I 9,110. I 9600. l 9780.19960.20140.20320.20500.206u0.'20870.2l0ir0.21230.21410.21590.2t770.21950.22t +0.22320.22500.226u0.230.10.23410.23770.2.11 30.24+!)0.24860.25220.255r10.25950.2(i310.26670.270:)0.'27 +0o.'277 60.28l20.28490.2ull50.29210.'29570.299.12.5102.5182.5572.5652.5732.5822.5902.5982.606'2.6142.6222.6302.638'2.6462.6532.6612.669'2.6762.68.12.6922.6992.7072.7 t42.7212.72!)2.7362.75l2.7652.7792.7932.8072.8212.8352.8482.8622.8752.8tt82.9012.9t4'2.!)272.9,102.9522.9652.9772.1)893.001551 l .5515,r56.9U05403.48,1535 I .0235299.5 7052.19.09u5199.5U25l 50.9885 I 03.293505(i.4735010.5084965.3674921.0354877.484,ilt34.7034792.6601751.34447 t0.7 344670.U 1(i463 I .56(t4592.969'1555.012+5t7 .6764.1U0.9.154444.8094409.2384339.U0 14272.5204207.2894t +4.023,1082.6334023.03339(;5. I 19390U.90(i3ti5,1.23 73r]0l .075117.19.3613699.03,13(;50.0413602.32u3555. u,1735 10.5503466.3933,12li.li3lJ338 1.32933,10.34,r

448 FISH HATCHERY MANAGEMENTTenr,E I-6.c: 4,ooo x lo 7, CoNTTNUEDWEIGHT/1,000FISH (LB]LENGTH(INCHES)FISH/POUNDWEIGHT(GRAMS)LENGTH(cM)FISH/KILOGRAM0.6680.6760.6840.6920.7000.7080.7160.7240.7320.7400.748u. /5b0.764o.7720.7800.7880.7960.8040.8120.8200.8280.8360.8440.8520.8600.8680.8760.8840.8920.9000.9080.9160.9240.9320.9400.9480.9560.9640.9720.9800.9880.9961.0401.t201.2001.2801.1864l.l9l I1.1958l.2005l .20511.2096t.2t42t.21871.22321.2276r.23201.2364r.2407|.2450|.24931.2536r.257It.2620t.26621.27031.27441.2785t.28261.2866t.2907t.29471.2986l.30261.30651.3104t.3t 42I .318 IL3219l.32571.32951.33331.3370t.3407t.34441.3481I .35 l81.35541.37511.4095t.4422t.47 361497.01I| 479.295146 l 9931445.092t428.5771412.435I 396.653l38l .2211366. I 26l35l .357I 336.9041322.757I 308.906I 295.343t282.0571269.042r256.2871243.787123 L5331219.5181207.736I 196.178I 184.840tt73.7 r5t162.797l 152.080I 141.559I 131.228I l2l .083lill.ll7l 101.3281091.709r082.2571072.9681063.8361054.8591046.03 lI 037.35 I1028.8 l 31020.4 I 5t012.r52ro04.022961.539892.859833.33778t.2540.30300.30660.31030.31390.31750.321I0.32480.32840.33200.33570.33930.34290.34650.35020.35380.35740.361 I0.36470.36830.37190.37560.37920.38280.38650.39010.39370.39730.40100.40460.40820.41 l90.41550.4191o.4227o.42640.43000.43360.43730.44090.44450.44810.4518o.47 t70.50800.54430.58063.0143.0253.0373.0493.0613.O723.0843.0953.1073.1183.t293.1403.l5l3.162c.tt.13.1843.1953.2063.2163.2273.2373.2473.2583.2683.2783.2883.2983.3083.3183.3283.3383.3483.3583.3673.3773.3863.3963.4053.4 l53.4243.4333.4433.4933.5803.6633.7433300.340326 1.2833223.1393 I 85.8783 149.4693l 13.8823079.0903045.06730 I |.7882979.2282947.3652916.r772885.6412855.7382826.4492797 .7 542769.6362742.07827 15.0632688.5742662.5982637.trg26t2.r232587.5962563.5252539.89825 l 6.7032493.928247 r.56r2449.5922428.O092406.8042385.9662365.4862345.3542325.s632306.1022286.9642268.t422249.626223t.4t12213.4882l 19.829l 968.4 l 6I 837. l9 l1722.368

LENGTH-WEIGHT TABLES 449Tesln I-6.c: 4,ooo x lo-/, CoNTINUEDWEIGHT/1,000FISH (LB)LENGTH(rNcHESlFISH/POUNDWEIGHT(CRAMS]LENCTH(CM)FISH/KILOCRAM1.3601.4401.5201.6001.6801.760l 840l.9202.0002.0802.1602.2402.3202.4002.4802.5602.6402.7202.8002.8802.9603.0403.1203.2003.2803.3603.4403.5203.6003.6803.7603.8403.9204.0004.0804.1604.2404.3204.4004.4804.5604.6404.7204.8004.8804.9601.5037r.53261.5605r.587 4I .61341.63861.66311.68691.71001.73251.7544r.77 58t.7967l.8l 7 II .83711.85661.87581.89451.9129I .93101.94871.96611.98322.00002.01652.03282.04882.06452.08012.09542.tt042.t2532.r4002.t5442.r6872. l 8282.t9672.2r042.22402.23742.25062.26372.27662.28942.302r2.3t46735.299694.449657.900625.006595.244568. I 88543.484520.839500.006480.775462.969446.43543 I .041416.673403.232390.631378.794367.653357. I 48347.228337.843328.953320.51 83 I 2.505304.883297.624290.703284.096277.78327 t.7 44265.962260.42r255.t07250.005245.103240.389235.85423 I .486227.277223.2t9219.3022t5.5212l l .869208.337204.92220t.6170.61690.65320.68950.72570.76200.79830.83460.87090.90720.94350.9797l .01601.05231.0886t.t249|.16121.1975l 2338t.27001.3063r.34261.3789t.4t 52l 45l51.48781.52401.56031.59661.63291.6692t.7 055t.7 4t8r.7780l.8l 43l 85061.8869t.92321.95951.99582.03212.06832.t0462.t4092.17722.21352.24983.8 l93.8933.9644.0324.0984.t624.2244.2854.3434.4004.4564.51I4.5644.6t54.6664.7 t64.7644.8124.8594.9054.9504.9945.0375.0805.t225.1635.2045.2445.2835.3225.3615.3985.4365.4725.5085.5445.5805.6145.6495.6835.7 t75.7505.7835.8155.8475.879162 I .054l 530.998| 450.420l 377.900t3t2.2871252.631|I 198. t77I 148.253l 102.323I 059.9271020.67 l9U4.2 l9950.28 I9 l 8.605888.973861.193835.096ti 10.535787.377765.5057 44.816725.216706.621688.955672.t52656. 14tt640.889626.3236t2.405599.092586.346574. l 30562.4t3551.165540.358529.9675 19.9675 10.338501.060492.1t2483.47947 5.t43467.090459.30545t.77 5444.489

450 FISH HATCHERY MANAGEMENTTaer-E I-6(,'= 1,0(X) X IO 7, CONTINUEDwutcH t/1,000LINC1'HI'ISH/WEIGHTLENGI'H!.ISH/Flsl{ (r.BlltNcH Lrs)POU NI)(CjRAMS){cMiK I LOGRA M5.2005.6006.0006.4006.8007.2007.6008.0008.400ti.ti009.2009.60010.00010..r0010.800I 1.2001 l.(;00I 2.00012..r.00l 2.800I 3.2001 3.60014.00014.400l4.ll00I 5.20015.60016.00016.40016.u00t7.20017.600I8.000I t].400I tt.u0019.200I 9.60020.00020.40020.8002t.20021.60022.00022.+0022.U002:1.2002.35132.,1101'2.46622.51gtt2.57 t:l2.62072.66ti42.7 |,\42.75892.80202.U4392.U8,152.9',2402.96253.00003.03663.072:):1.t0723. l4l .13.l74fl'.1.20753.239(t3.27 | I3.30193.33223.36203.39123.41993.44823.47603.503.r3.53033.55693.5U303.60lltl3.63,123.(;5933.6ti.r.0i.i.70n,13.7:1253.75633.779t13.tt0293.82593.84853.8709192.30ftt78.572I 66.667l 56.250I 47.059l3ll.8rJ9131 .579125.000I 19.0.1rJI I 3.(;37l0n.(i96104.1(t7100.0009(i. l 5492.59389.28ritttt.207u3.334u0.ri4578.t2575.75873.5307 L42!)69.4.15fr7.56n65.79064. I 0362.50060.97(;59.5245tt. I 4056.n I rl55.55654.34u53. l 9252.0tt351.02050.000.19.02i)'\8.077+7.t704(i.29(;45.455,14.641143.n6043. I 032.35u 72.5,1012.7',2t 52.901i03.08443.26593.+4733.621173.U 1023.9916.1.171i0,1.35,1i,,1.53 594.7173,1.89Uu5.0n025.26165.,14315.62455.80605.987.16. 168u6.35036.53 r 76.7 l3l6.89467.07607 .257,\7.43U97.62037.801ti7.98328.1(i46u.3,1618.52758.70908. U9049.07 I u9.25339.13479.6 l6 l9.79769.979010.160410.341910.52335.9726.t'226.2646.400tt.53 I6.6576.7786.U957.0087.t177.2237.:1277.4277.5257.6207.7t37.U047.8927.979u.0648.t 478.229ti.30utt.387It.1648.539u.6 I4tJ.6U78.758u.8298.U998.9679.0359. 1019.1669.2319.2959.3579.4199.4U 19.5,119.6019.6599.7IutJ.77 59.1t32423.965393.682367.+37341.47232.1.209306. I 98290.08227 5.57 8262.15s250.526239.633229.619220.,1(i321 1.9U320'4.132196.u.12190.054183.7 I 9t77.793172.237167 .017l62.l0st57.473153.099148.{XilI 45.0.11t4t.3221 37.7U9134.42rJ131.2'27128.176t25.26:1t22.479119.816I t7 .267l I '1.82,1112.481l10.231108.070105.99 I103.992102.066100.21098..1219(;.(i9495.027

LENGTH.WEIGHT TABLES 451Tanlr, I-6.c: ,r,000 x l0 7, coNl'tNUEDWEIGHT/I,00()LI]NGTHFISH/WEIGHTLENGTHFISH/FrsH (LB)(INCHESIPOUND(GRAMS)(cM)KII,OGRAM23.60024.00021.4002.1.80025.40026.20027.00027.8002tit.60029.40030.20i)31.00031.80032.(;0033.,1003.1.20035.00035.U0036.60037.40038.20039.00039.U00.r0.(i004l .40042.20043.00043.U00,14.60045.,10046.20047.000,17.tr004r,t.60049.40050.20051.0005l.ll0052.60053.40054.20055.00055.80056.60057.40058.2003.U9303.9 l.r93.93653.95793.9U96.1.03104.07 l64.llls4. l 5054. I 8891.22654.26354.2999.{.335ri.1.370u4.4054,r..13954.47 ill.{.50624.53Utt4.57094.60264.633r14.6617,1.69514.725'24.754tl4.784',24.lt l3l4.8+t74.U7004.U9794.925(;,t.9529,1.97995.00675.03315.05935.0u525.1109ir. 13635. l6l 45. I 8635.21l05.235.15.259642.3734t.66740.9U440.32339.37038. l6ti:17.03735.97 l34.96534.01,133.1 I 232.25831.,t4630.67529.9402!).24028.57 |27.93327.32226.73826.t7825.64125.12624.63024.t 5523.6!t723.25622.83122.+',)l22.02621.6,r52t.27720.92020.57620.'24:)l 9.92019.60819.30519.01l18.7'27I 8.450IU.l82t7.g2ll 7.668t7..422t7.182I 0.704810.8u62I 1.0676| | .2+9111.5213I 1.8841t2.247012.609912.972t1l 3.335613.69U514.061.1| 4.424311.787 |15. I 50015.512915.875816.238ft16.60 r 516.9644t7.3272I 7.690118.05301U.,1159t8.778719.1,11619.50,1519.867420.230220.593 I20.95602l.3ltlu'2t.68t722.044622.407522.770323. I 33223.496 I23.tit59024.22t82+.58+724.947625.31Oir25.673326.036226.39919.8889.9449.99910.05310.133I 0.23910.34210.44310.54210.640I 0.735I 0.829I 0.922I t.013I 1.102ll.l901t.276I 1.362I 1.446I1.52ull.6l011.69111.770I I .848l 1.92612.002t2.07712.t52t2.22512.29812.370t2.44112.51I12.58012.649t2.7 t712.784I 2.8s 1I 2.91 ttI 2.98213.046l3.l l0l 3.173I 3.23613.29813.35993.41ft91.85990.3538U.896llri.796u4. 1468l .65279.30377.08474.98773.0007t.tt769.32767.62666.00664.46262.9896l .58160.23558.94757 .7 t256.52955.39254.30 I53.25252.2425t.27050.33449.4:J I48.56047 .7 t946.907+6.t2245.3624+.62843.91743.22842.5604 I .91341.28540.67640.0u.139.50938.95138.40837.880

452 FISH HATCHERY MANAGEMENTTeu-E I-6.WEIGHT/1,000FISH {LB)c: 4,ooo to-7, coNTINUED"LENGTH(rNcHES)FISH/POUNI)WEICHT(CRAMS)LENGTH(cM)FISH/KILOCRAM59.00059.80060.6006l .40062.20063.00063.80064.60065.40066.20067.00067.80068.60069.40070.2007l.0007l .80072.60073.40074.20075.00075.80076.60077.40078.20079.00079.80080.6008l .40082.20083.00083.80084.60085.40086.20087.00087.80088.60089.40090.2009l .0009l .80092.60093.40094.20095.0005.28365.30745.33095.35435.37755.40045.42325.44575.46815.49035.51245.53245.55595.57745.59885.62005.64105.66195.68265.70315.723t5.74385.76405.78405.80385.82365.U4325.86265.88205.9012s.92025.93925.95805.976u5.99546.01396.03226.05056.06876.08676. I 0466.12256.14026. l 5786.17546. I 928I 6.949t6.72216.502t6.28716.077l 5.873| 5.674l 5.48015.29115.r0614.92514.74914.577l 4.409| 4.24514.08413.92813.774t3.62413.477I 3.33313.19313.05512.92012.788I 2.65812.531t2.40712.28512.16512.04811.93311.820I1.710I1.601I 1.494I l 390I t.287ll.l86I 1.08610.98910.89310.799t0.70710.61610.52626.761927.t24827.487727.850628.213428.576328.939229.302 I29.664930.027830.390730.75363l.ll6431.479331.842232.205032.567932.930833.293733.656634.019434.3U2334.745235. I 08035.470935.U33836. I 96736.559536.922437.285337.648 I38.01l038.373938.736839.099739.462539.825440. l 88340.551l40.9 r 404l .27694 I .639842.002642.365542.728443.0912I 3.42013.48113.541r 3.600I 3.659t3.7 t7t3.77 5l 3.832I 3.88913.94514.00114.057t4.tt2t4.t67t4.22114.275I 4.32814.381t4.434I 4.48614.53814.589r4.641I 4.691t4.7 42| 4.792t4.84214.89 II 4.940r 4.98915.03715.08615.13315. l8 I| 5.228t5.27 515.322I 5.368t 5.414I 5.460I 5.506r 5.55 Il 5.59615.64 rl 5.685I 5.73037.36636.86736.38035.90635.44434.994J4.JJJ34.t2733.7 l033.30232.90532.51632.13731.76731.4053l.05130.70530.36730.03629.7 1229.39529.08528.78 I2tt.48328. l 9227.90727.62727.35327.08426.82026.56226.30826.05925.81525.57 625.34025.11024.88324.66024.44124.22724.0t523.80823.60423.40423.206

LENG'|H-WEIGHT TABLES 453Tenln I-6.C: 4,OOO X 1O 7, CONTINUEDWEIGHT/1,000FISH (LB]LENGTH(INCHES)FISH/POUNDWEIGHT(CRAMS)LENGTH(cM)FISH/KILOGRAM95.80096.60097.40098.20099.00099.800l 06.000I 14.000122.000130.000138.000146.000154.000162.000170.000l 78.000186.000194.000202.000210.0002 18.000226.000234.000242.000250.000258.000266.00027 4.000282.000290.000298.000306.0003 14.000322.000330.000338.000346.000354.000362.000370.000378.000386.000394.0006.21016.22746.24456.26166.27856.29546.42326.58086.73 l36.87537.01367.t4667.274tl7.39867.51857.63467.74737.u5687.96348.06718.1683t1.26708.36348.45778.5499u.64018.72858.81528.90018.98359.06549. l 45u9.22489.302s9.37899.45419.52819.60099.67279.74359.81329.88 l99.949710.43810.35210.26710.183t0.l0l10.0209.4348.7728.1977.6927.2466.U496.4946.t735.8825.6185.3765.1554.9501.7624.5874.4254.2744.t324.0003.8763.7593.6503.5463.4483.3563.2683.1853.1063.0302.9592.8902.8252.7622.7032.6462.5912.53843.454143.817044.179944.542744.905645.268548.08075 1.709555.338258.966962.595766.2244tig.853173.481977.tt0680.73948,1.36ti l87.996u9l .625695.254398.8830102.5 l 18106. I 405l 09.7692I 13.3980tt7.0267I 20.6555t24.2842t27.9t29131.54t7l 35.1704138.799It42.4279I 46.0566l 49.6853l 53.3 l4lI 56.9428l 60.57 l5I 64.2003l 67.8290t7 t.4577l 75.0865t78.7 | 52t5.77 415.81 815.86115.904| 5.94715.99016.3 l516.71517.098t7.46317.81418.15218.47818.79319.09719.392l9.67tt19.95620.22720.49 I20.74720.9982t.2432l .4832t .7 t72t.94622.t7022.39022.60622.8 l823.02623.23023.43 I23.62IJ23.82224.01324.20124.38624.56924.74824.92625. l 0025.27223.01322.t42222.63522.45022.26922.09020.798I 9.33918.07 I16.95915.97615.10014.3 l613.60912.968I 2.386I 1.853I 1.36410.91 410.498l0.l l39.7559.4219.110u.8 I88.5458.28tt8.0467.8187.6027.3987.2057.0216.8476.6816.5236.3726.2286.0905.95u5.8325.7 115.595

454 FISH HATCHERY MANAGEMENTTABLE I-7. LENcTH-wEtGHT RELATIoNSHIPS FoR FISH wlrH c-,t,st,o' l0 7WEIGHT/I,000FISH (LB)LENG'I'H(INCHES)FISH/PoUNDWEICHT(GRAMS)LENGTH(cM)FISH/KILOGRAM0.4500.4540.45u0.4620.4660.4700.4740.47t10.4820.4ti60.4900.4940.4980.5040.5120.5200.52u0.5360.5440.5520.5600.56u0.5760.5840.5920.6000.6080.6 l60.6240.6320.6400.6480.6560.6640.6720.6800.6880.6960.7040.7 t20.7200.7280.7360.7440.7520.7601.00001.00301.00591.00881.01l7I .0146I .01751.0203t.02321.02601.0288l 03161.03441.03851.04401.04941.05471.06001.06531.07051.07561.08071.08581.090u1.09571.10061.10551.il03l.l l5ll.l1991.12461.1292I . l:139l.l:t851. I 430t.147 5l. I 5201.15651.16091.16531.1696l. I 739t.t7821.1825l. I 8671.19092222.2242202.6452183.4082t64.5042t 45.9252t27.6622109.7072092.0532074.6922057.6t62040.8202024.2952008.0361984.127I 953. I 251923.0781893.941I 865.673I 838.237l8 I 1 .596t785.7 t7I 760.5661736.1 l4t712.3321689. I 92l 666.670t644.7 40I 623.380I 602.568I 582.2831562.504t543.2141524.395l 506.029l 488. I 00I 470.593I 453.493t436.787I 420.460I 404.5001388.894I 373.632I 358.701I 344.092I 329.7931315.7 950.20410.20590.20770.2096o.2tt40.2t320.21500.21680.21U60.22040.22230.22410.22590.22860.23220.23590.23950.24310.24680.25040.25400.25760.26130.26490.26850.27220.27580.27940.28300.28670.29030.29390.29760.30120.30480.30840.312 I0.31570.31930.32300.32660.33020.33380.33750.34110.34472.5402.5482.5552.5622.5702.5772.5842.5922.5992.6062.6132.6202.6272.6382.6522.6652.6792.6922.7062.7 t92.7322.7452.7582.77 |2.7832.7962.8082.8202.8322.8442.8562.8682.8802.8922.9032.91s2.9262.9372.9492.9602.97 |2.9822.9933.0033.0143.0254899. l 564855.9924813.582477 t.9064730.9454690.6844651.1024612.1804573.9064536.2624499.2304462.80 l4426.9534374.246430s.8984239.6524t75.4t841 I 3.0984052.6143993.8813936.8263881 .3793827 .4713775.0413724.0273674.3743626.0283578.9373533.0533488.3323444.7283402.2013360.71l3320.2213280.6953242.0993204.4003 I 67.5693 l3 I .5743096.3883061.9843028.3362995.4202963.21 I2931 .6882900.828

LENGTH.WEIGHT TABLES 455TABLE I-7. c: 4,500 x lo 7, coNTTNUEDWEICHT/I,OOOFISH (LB)LENGTH{INCHES)FIS}I/POUNT)WEIGHT(GRAMS)LI]NGTH(cM)FISH/KILOGRAM0.7680.7760.7840.7920.u000.8080.8160.8240.u320.8400.8480.8560.8640.8720.8800.88rJ0.8960.9040.9120.9200.9280.9360.9440.9520.9600.9680.9760.9840.9921.000l.0ti|01.160|.2401.320l.'t001.4801.5601.6.r01.720r.u00l.lltt01.9602.0402.1202.2002.280r.19501.19921.2033t.207 4t.2t l4| .2154I .219,{|.2234t.2271I .23 l3r.23521.23901.24291.24671.2505|.25131.25801.2618t.26551.2692|.272!l| .2765I .280I1.2837I .28731.29091.294,\1.29U01.30151.3050l.33lJ91.37 I I1..1020I .,111 I 5rl.459ttL'187lI .51351.53891.5635L587.1l .6106I .6331l.(i550t.67611.6972t.7 175I 302.089I 288.6661275.5t6t262.632l 250.0061237.630t225.4961213.5981201.9291190.,11t2| 179.251I 168.230tt57.4t4l 146.795I I 36.3701126.132I I l6.07lll 106.2011096.49uI 086.9631077.593106u.3u21059.32tt1050.127l04l .6731033.06,1I 024.596l 016.2661008.07 Il 000.000925.927862.072lJ0(i.455757.5807 | +.291675.6u 16,t I .031609.762581 .401555.562531 .92 l510.2l0190.20',)471.70+154.552.138.6030.34840.35200.35560.35920.36290.36650.37010.37380.377 +0.38100.3u,160.3u830.39190.39550.39920..102u0.406,10.,11 000..11370.41730..12090.42460.42820.431 u0.,135,10.43910.+.1270.4.r630.45000.,153(i0..1u990.52620. irti250.59870.63 r00.(;7 l30.70760.7.1390.78020.81650.rJ5 270.tt8900.92530.96 I (i0.99791.03,123.0353.0,163.0563.067:1.073.0873.0973.1073.1t73.t273.1373.t 473.1573.t673.1763.1 u63.1953.2053.2t 43.2243.2333.2423.25',2lJ.26l3.2703.271)3.2883.2973.3063.lJ l53.4013.4tIill.5(il3.6363.70f13.7773. u,1.f3.909li.97 l'1.032'1.091.1.1,1u4.',20++.258.1.3 I I4.3632870.6122841.01u2812.0282783.6212755.7882728.503270t.753'2675.5232649.797262+.5612599.U0 12575.5042551.6572528.2482505.2642,\8',2.69'12460.5272.r3U.7532+17.3602396.3102375.6822:155.J7 7'2:135.4t723 I 5.79 I229(i.,1932277.5t4225ti.U.1(i2240.,181'2222.41:l2'201.62020,11.31ul900.ir4l1777.928t670.177I 574.7+0I '1119.(i201,113.2iJO13.14.2{)3l2rJ l .7(i9t22,t.802I t72.681| 12+.82010110.7091039.92l.i1002.1 13966.95 2

FISH HATCHERY MANAGEMENTT,qarn I-7. c r.ir{) . rr,7, coNTlNUEoWEIGHT/I,OOOLENGTHIIIS H/WEIGH'ILENGI'HFISH/'FISH (LB]IINCHES)POU N T)(CRAMS)(CM)KII,OCRAI\,I2.3602.1402.5202.6002.6802.7602.U402.9203.0003.0tt03.1603.2403.3203.4003.4tt03.5603.640:t.7203.U003.UU03.9604.0404.t204.2004.2U0.1.3(i04.4404.5204.6004.6804.760,1.8,101.9205.0005.,1005.8006.2006.(;007.0007.1007.1J00u.2008.(i009.0009.400Lti00|.737 4l.756ti1.77581.7944I .8126l.ll30irl.tt480l.ttft52l.{Ju2I1.u98(tI .9149I .93101.9467t.96',221.977 51.99262.00742.02202.036,12.05062.06452.07842.09202.10ir,l2.t 1872. l3l tt2.l4,tu2.157 t2.t7032.t8282.l9sl2.20742.21952.2311'2.',2894'2.3146'2.3!r7:)2.447112.49(ill2.54302.5U802.63152.67:162.7 t412.75.+02.7926+23.7:15,r09.u4239(i.tt3 I38,1.(t2l373.1,10362.32+352.1 I u:112.47 |333.3932'1.6tll316.,1(i Il|0u.(;47301.2l02!),+.1'2:l2u7.ll(t I2ti0.904271.73026U.822263. I 63257 .737252.5302,\7.52!l242.72323U.1 00233.(i49229.3622',25.23022t.24.)2 l 7.3962 I ll.(;79210.0u8206.616203.25(t200.0001l.t5. I tt5t7 2.+l4161.290r 5l.5l5| 42.857135.13512tt.205121 .951I t6.27!)lll.llll0fi.3u3102.04 Il.070irl 1067l l,1tJo1 .17931.21561.2519l.2uu2|.3215l.1160rl1.3970l..13llll1.469ri1.5059t.5422I .5785I .(i 1,il.tl.(i5101.68731.7'2361.75991.7trc21.u325l.u(iuu1.90501 .9,1 l3| .97762.01392.0s022.0r't(i52.t2282.15912. I 9532.23t62.26U02.44942.ft30ti2.U 1232.99373.17513.35(t(t3.53ti0:1.7 t943.9009.1.0u234.2631.}1.44524.,r l34.462.1.5 I I,t.55ll4.6044.6494.694,1.7 3ti4.780,1.tt2l]4.861.1.0954.9454.9U45.021J5.0615.0995. l3t;5.172s.20u5.2445.2795.3145.34rJ5.3tt25.4155.44t]5..1805.5t25.5445.5765.6075.6375.(i6tt5.ll l 55.9556.0896.2t76.3.1 I6.,159(i.5736.68.1(i.79 l6.8956.9957.093934.t74903.54687,1.tt62n.17.9448',22.63279U.7 U8776.287755.0l973,r. Ult57l5.79tii697.(;76680.,150664.0ir3648.429633.522619.2ti6605.676592.650580.17,156ti.2l l556.732545.70tt535.1 l2524.9 I 9515.r08505.656496.5.15+87 .757+79.27 447 | .082463. I 64455.509.1.1U. 1024.10.92,140u.2tt3380. 107355.5n4334.03,1314.94(i297.922282.64126U.85(t256.:t5',224.1.95r,t234.5115'22+.962

LENG'TH,WEIGHT'I'ABLES 457Tesr-E I-7 c : ,1,.500 r to 7, coN'I INUEDWEIGHT/1,000I,ENG'I'HFISH/WEIGH'TLENGTHFISH/}ISH (LB)(INCHES)PoTIND(CR^MS)(cM)KILOGRAM10.20010.600I 1.000I1.400I 1.800t2.200I 2.60013.000l 3.40013.r.t0014.2001.1.60015.000I 5.400l5.ti00I ft.200l6.ri0017.00017.4001 7.u00I 8.200I tt.(t0019.00019..10019.u0020.20020.6002l .00021.4002 I .t|0022.20022.(;0023.00023.40023.80024.2(X)2.1.(i0025.00025.rJ0026.60027.,1002U.20029.00029.ti0030.600lt 1.4002.83012.U(i(;(i2.90222.93702.97093.00.113.03ft(t3.06n'13.09953.13013. I tt003.1u9.13.21u3:1.24673.27453.3019ll.ll2u93.355'13.3rJ l5'3.4072ll.,1lJ2(;3.4575ll.'1ti2 I3.506.13.53033.5540:1.57:l3.60033.(;21103.6'1541J.667(;3.6U953.71 I I3.7325:1.75373.77463.79533.U 1573.85(i03.U95,13.93,113.1)720.1.0092.1.0.t5u4.0ti l7.1.16998.03994.34090.90987.72084.746u l.9(t779.36576.!t2:l74.62772.46470.1236ti.,19366.667(t.1.91i5tt3.29l61.72860.2415ll.ll2457 .47 |56. l 8054.9.1553.76152.63251.54650.5054{).505.18.5.t.147.61946.72!)45.872,15.04514.2484:1.47842.73541.01741.322,r0.(;5010.0003IJ.7(i0l]7.59,tr3ri.41Xi35..1(i I3.1..18333. ir5 732.(t803l.tt474.6266,1.80ti I4.98955.17095.3524ir.53385.7 t52s.89676.07U 16.25956.44106.6224(;.u0396.98537.t6677.:14827.52!t67.7ttl7.8925tr.0739t|.2554u.43(itt8.61828.7997Ii.9u l I9. I (i259.3.1409.52549.70699.tt88310.069710.2512I 0.432610.61 '1010.795ir10.97(;9I I . l5ti3I l.ll:l9tttt.702712.0(i5(it2.4'28512.7913I 3. 15,1213.5 l7 It 3.tt800| 4.24287.1887.2817.3727.4607.5467.6307.7137.79+7.8737.950rJ.026ti.l0l8.1748.24(i8.3178.387u.,1558.523u.589u.654u.7l98.7828.U458.9068.967lt.0279.0tt(i9. 1,159.2029.2599.3169.3719..1269.'1819.5349.51i79.(i401).ti929.79,r9.n949.993t 0.0u910. I ti3t0.27 610.3(i7t0.457216.140207.984200.421I 93.388l 86.833I 80.707t7 4.970l 69.587164.521I 59.756| 55.255l5l .002146.975143.158I 39.533136.0881 32.80u129.684t26.7021 23.855l2l.li]3l 1 8.52ul r 6.033l 13.6,10I I 1.3.{4109.140107.021I 04.982103.020l0l.l2999.30797.55095.ti5394.21592.6319l . 100u9.619rl8.l85u5.45082.88080.,1(i07U.l7ll76.02173.9{J072.04670.2t1

458 FISH HATCHERY MANAGEMENTTasr,E I-7. c: 4,500 x l0-7, coNTINUEDWEIGHT/1,000FrsH (LB)LENGTH(TNCHES)FIS H/POUNDWEIGHT(GRAMS)I,ENGI'H(cM)FISH/KILoGRAM32.20033.00033.80034.60035.40036.20037.00037.80038.60039.40040.200,11.000.r l .800,r2.60043.40044.20045.000,r5.u00,16.60047.,1004U.20049.00049.u0050.6005l .40052.20053.00053.u005,1.60055.10056.20057.00057.U0058.60059..10060.2006l .00061 .t]0062.60063.,1006.1.20065.00065.r,i0066.60067.4006U.200,1.15 r 64. 1 8574.2t924.2523,1.2848.1.31684.34844.37951.11024.1105+.470:)4.4998.1.521194.55764.58594.61 394.641rt,1.66894.69604.7227'1.74914.77524.U01 I4.8267.1.It520l.8770.1.901fJ.1.92634.9506,1.!17 47,1.99855.02215.04555.06ti7ir.091 65.114.15.13705. 15935.Itll55.203ir5.2',25.)5.2461)5.2(;83ir.289(i5.31075.331631.05630.30329.58628.90228.24927.62427.0272t,.45525.90725.38121.87624.39023.92323.47,\23.04122.62422.22',22 I .tt3421.4592t.09720.74720.,10{J20.0u019.76319..15519.157I 8.8681U.5U718.31 518.05117.7lt4t7 .5+1l 7.301l 7.065I ri.835I (t.(i I I16.31)3l(i.ltJt15.97.115.73r 5.57615.38515. 1gflr5.0I5l.t.u371.1.661i1.r..605 714.96U615.31]l 415.69,13t6.057216.4201I 6.7829l7.l4s8I 7.5087t7 .871618.23.14I 8.597318.9602l 9.323019.f;85920.048u20.41]l720.77452t.t37 't21.50032l .136322',2.226022.5811922.951823.31+7'23.677524.040,!2.r.4033'24.766125. I 29025..191925.115'r8'26.2t762(i.5n0526.943,127.30(ii:]27.(i6{) 12u.03202r,r.39'1928.757829. I 2(Xi29.,18352{).U.1(i.130.209230.572130.9350I 0.54510.632r0.7 t7I 0.80110.8u310.965I 1.0,15| | .12411.202I t.279I 1.355I 1.,129I L503I l.57ftl l.6.1till.7l911.790l 1.859l 1 .92uI 1.99612.063t2.12!t12. t 95t'2.260t2.3',2+12.388t2.,I5l12.51 31',2.575l 2.63612.69(t12.75612.816t2.87 +l2.9il:l12.99113.0.1tJ13.105Ill.l6t13.'21713.272t:1.3'27l3.3rJ I13.,1|613..1U913.5426U.46666.U0765.22563.71762.27760.90159.5ti458.32357.11455.955ir4.84l53.77 |52.7425t.75250.7gti,19.ti78,ru.991,1IJ. I ll(i.17.309.16.51 I,r5.739,1.1.992,14.269-13.57 0'12.11!) I+2.234.11.59710.97 u.10.3 7u39.79539.22lJi.]u.6 7738.12'37.62137.1 l536. (i223(t. I ,1135.673ll5.2l fl37.77.131.3,r033.91733.5053il. 1023'2.70932.32(i

LENGTH.WEIGHT 1'ABLES 459TABLE I-7. c: ,1,500 x 10-/, coNrrNUEDWEICHT/I,000I.ISH {LB)LENCTH(INCHES]FISH/POUNI)\{ EIGHl(GRAMS]LENGl'H(cMlFISH/'KILOGRAM69.00069.f10070.60071.40072.20073.00073.U0074.60075.4007 t'.20077.00077.80078.60079..10080.200u 1.0008l .1100u2.600tt3.,100tJ,t.20085.00i)85.U00i.t6.600tJ7.400tJ8.20089.00089.80090.6009l .40092.20093.00093.t|0094.60095.40096.20097.00097.80098.60099.,100I 02.000I10.0001 l u.000126.00013,1.000142.000r 50.0005.:15245.37305.393.15.1t375.'13395.45395.+7 375..193,15.5 t 305.532.r5.55t75.57095.58995.6081.}5.627 65.64625.6t;175.68325.7 0t,t5.7 196J./.1//5.75565.77315.79125.ti0885.u2635. U.l3 75.U6105.87 U25. ti9535.91235.!)2925.9,1605.9627s.97935.99596.01236.02U76.0.1496.09726.2526(t.400(i6.5,12 r6.677r16.808l6.93371,1.493| 4.327I 4. 16.114.006l 3.850I1J.69913.55013.405I 3.26313.12312.987l2.u5l.it2.72:)12.59,1t2.46!)12.3,1612.225t2.107I 1.990I 1.u76l 1.765I I .655| | .517I t.442I l.33tlI 1.236ll.l36I 1.031t10.9.11r 0.u4(i10.75310.66110.57 I10..182I 0.39510.30910.22510. 1.1210.0609.1t019.0918.47 57.9377 .16:l7.0426.66731.297!)3l .6607112.023632.3U65:12.71!)433.1 t 22:13.475133.83803,1.200934.563 73,1.926(i35.289535.65231J5.015236.378I3(t.741037. 103ti:17.16(i737.829638. I 9253U.55533rJ.9l8239.2U 1 I39.6,1.10.10.006840.369740.7:1264l .09r54I ..15U3'1t.82t2+2.184142.s17042.909t143.2727,r3.6356,13.99U,r4.1.361344.721245.0U7146.266,r49.u95153.523857 .t 526(t0.7ll l364.410068.03fltil 3.595t:1.647I 3.69913.751I 3.80213.u53I 3.90313.95314.00314.052I 4. l0l14. I 50I ,1. l9u11.2+6t+.29,tI ,1.1.t,1 Il ,r.3 tl tJ14..135| 4.48214.52u14.57414.61914.665t4.7 t014.7541,1.799l1.tJ,t31,1.u871,r.9:l I11.971I 5.01715.06015. I 0315.145I5.r8ul 5.230t 5.27115.313l5.l]5415.48715.882l ft.25rlt6.617I 6.961t7 .29")I 7.61 I3l .9513l .5853t.22730.87730.53530.20029.87 329.55329.2392U.9322U.63128.33728.049'27.76627.48927.21726.9512ft.69026.43426. I U325.93725.69525.15725.22,t2.1.99621.77 |24.5502+.33+21.12123.91I23.70623.50323.30523. I 0922.9t722.72822.54222.:15922.17!)2t .61+20.042I u.6U317.19716.,452r s.525l.{.697

FISH HATCHERY MANAGEMENl'Tasln I-7.t: : 4,500 X IO ,, CONTINUEDWEIGH'I'/1,000t-I]NG'I'HIIISH/WEIGHTLENGTHFISH/FISH 1t-B)(INCHES]POUND(CRAMS)(cM)KTLOCRAM158.000l (;(;.00017.1.000I U2.000190.00019rJ.000206.0002l 4.000222.000230.0002:1ti.000246.00025,1.000262.000270.000278.0002U6.00029.r..000302.000310.0003 l8.00032fr.00033,r.000342.000350.00035rJ.000366.00037,1.000382.000390.000398.000,106.000414.000122.000,130.000,138.000,146.0007.05477 .17 tll7.285:)7.39537.50217.(;0597.70707.ri0557.90 l67.9954tt.0ti70u.176(t8.2643u.35028.4343r.i.516rl8.59778.67728.7552rJ.83l tiu.90718.gti I29.05419. l25lt9. I 9649.26609.33451).40209.46n59.53429.59t]99.66289.7251)9.78U 19.tt,19(t9.91039.97036.3296.0245.7475.4955.2635.0514.8544.67:l4.5054.3484.202,tr.06i,3.9373.8173.7043.5973.4973.4013.31 I3.2263. 1453.0672.gtJ42.9242.8572.7932.7322.6742.61rl2.5642.5132.4632.4152.3702.3262.2832.2427 t.667 575.296278.925082.553786. l 82589.81 l293.439997.0687I 00.6974104.3261107.95,t9I I 1.0006tl5.2t2:lll8.84l I122.469t1l 26.0986129.7273I 33.3560l36.9U4ti140.61 35144.2422| 47 .87 t0l5 I .4997I 55. I 284t58.7 572l 62.3859166.0146169.643,1l7 3.272lI 76.90081 U0.5296I 84. I 583187 .787 |l9l .4 I 5u195.0445198.6733202.302017.919t8.2t7I 8.5051 U.78419.05519.31919.576I 9.82620.07020.30u20.54120.76920.99121.20921.42321.6332l .83822.04022.23822.43322.62422.81222.99723.1 U023.35923.53623.7 t023.88124.05024.2t724.38124.54424.70424.86225.01u25.17225.32413.953I 3.2U 1t2.67012. I 13l 1.60311.134t0.702I 0.3029.9319.5U59.2638.9628.6808.41 58.1657.9307.70t17.4997.3007.t126.9336.7 636.6016.4466.2996.i586.0245.8955.7715.6535.5395.4305.3255.2245.127s.0334.943

LENGTH-WEIGHT TABLES461TasI,r I-8. LENGTH-wEIGHT RELATTONSHIps FOR rtsH wtl'H c: .s,000 t t0-7WEIGHT/1,000FISH (LB)LENGTH(INcHES)}.ISH/POUNDWEIGHl'(GRAMS]LENG'I'H(cM)FISH/KILOGRAM0.5000.5060.5 l40.5220.5300.5380.5460.5540.5620.5700.57u0.5860.5940.6020.6100.6180.6260.6340.6420.6500.65tr0.6660.6740.6820.6900.6980.7060.7140.7220.7300.7380.746o.7 54o.7620.7700.7780.7860.7940.8020.8100.8180.8260.8340.8420.8500.8581.0000l.00401.0092I .01451 .0196t.02471.02981.0348l.0397l.044ti1.04951.0543I .05911.063ul.0ti851.0732r.07781.08241.08691 .09 l4l.09591.1003| .t047l.10901. 133l.l 176l 1219i . 12611.1303L1344l .13861.14271.t4671.1508l. l 548l. I 5881.t6271.1667l. I 706t.l7 45l. I 7831. 18211. I 8591.18971.19351.t9722000.00 l1976.285I 945.5261915.7 l0I 886.7941 U58.738183 I .504I 805.0561779.362l 754.389i 730.107I 706.488l 683.s051661.1331639.3481618.127I 597.4481577.2911557.637I 538.4661519.761I 50 I .506l 483.684I 466.2ti| II 449.280t432.670I 4 I 6.436I 400.565I 385.047I 369.8681355.019I 340.4881326.266t3t2.342t298.70712u5.353t272.27 |t259.452l 246.889t234.57 4t222.500I 210.660I 199.0471187.655I t7 6.477l 165.5070.22680.22950.23310.23680.2+040.24400.24770.25 l30.25490.25U50.26220.26580.26940.27310.27670.28030.2tt390.28760.29120.29430.29850.302 I0.30570.309110.31300.31660.32020.32390.32750.331 I0.33470.33840.34200.34560.34930.35290.35650.36020.36380.36740.37 l00.37470.37830.38 l90.38560.38922.5+02.5502.5632.5772.5902.6032.6t62.6282.6412.6532.6662.67I2.6902.7022.7t42.7262.7382.7492.7612.7722.7832.7952.8062.8t72.8282.8392.8502.8602.87 |2.8tJ I2.8922.9022.9 l32.9232.9332.9432.9532.9632.9732.9832.9933.0033.0123.0223.0313.0414109.2424356.9534289. 1,154223.4t04159.6604097.8094037.7703979.463:1922.8173867.7 603814.2283762.157371 I .4893662. I 673614.1393567.355352 l.76ti3477.32t13433.997339 l .7333350.4963310.2503270.9603232.5923195.113315U.4933t22.7033087.7 I 53053.5023020.0392987.3022955.2672923.9122U93.2 l 52U63.1 562833.7 l52804.{J732776.6132748.9t6272t .7662695. l 482669.0452643.4432618.3272593.6842569.50 l

FISH HATCHERY MANAGEMENTTABLE I-8.c: ri,ooo x lo 7, CoNTINUEDwLtcHt /1,000FIST{ (I,BJI,ENCl'H{INCHES]FISH/POL]N I)WEIG H'TiGRAMS)LENGTH(cM)FISH/KTLoGRAM0.[t660.tt7,10.8t|20.8900.89t10.9060.91 ,10.!t220.9300.93u0.9,160.9540.9(i20.9700.97r10.98(;0.99,11.0201.t00l. I ll01.2601.340|.4201.5001.5u01.6601.740l.tt201.9001.9802.0602.1402.2202.3002.3n02.4602.5402.6202.7002.7802.8602.9103.0203.1003.1803.2601.200{)1.204(il.20ti3l.2l l91.2155l.2l9lt.22'271.226:l1.229ul.233lJl.236rJ1.24031.243ut.247'2r.250(tt.2540| .25741.26831.300(iI.33t41.36081.38901.,tl(ilt.+422|.467 +I.,19Iul .515.1r.53831.5605I .58211.603 I1.62361.64361.6631t.68221.7008L71901.7369| .7544t.77161.78841.80491 .82 1l .8371|.85271.8682tt54.7 +0| 141.17 |l 133.7911I 123.602I I I 3.5921103.759I 094.098I 084.605t07 5.275I 066. I 04l 057.0891048.',22+1039.irO71030.93,1I 022.50 ll 0 l 4.205100fi.0.12980.393909.0938+7.461793.655746.273701.230666.672632.917602.4 I 6571.7t!)549.457526.322505.057485.4411467.296450.457434.789420.t71406.510393.707381.685370.376359.71tt349.(i5(t340.t42331 . l3l322.5U6314.47 |306.7540.392u0.396,10.40010.40370.,{0730.41t00.41.1(;0.,11tt20.,121u0.,125i,0.42910.13270.43640..14000.44360.44720.,15090.46270.49900.53520.57 l50.60780.64410.68040.71670.75300.7It920.82550.8(; I rj0.u9810.93,140.97071.00701.04321.0795l. l l5lJ1.15211 .1884t.2247I .2(i l0| .2973l.33351.369ul .,1061|.44241.47873.0503.0603.0693.07u3.0873.0973.1063.1153.t243.1333.1423.1s03.1593.1683.173.1853.1913.2213.3033.3U23.4563.5283.597ll.(t6lJ3.7273.7 tt93.U493.9073.9644.0184.07',24.t244.17 54.2241.2734.3204.3664.4t24.+564.5004.5434.5U44.6264.6664.706+.7 452545.7 6+2522.+622,199.5832+77 .t | 52455.0172433.36924t2.07 |2:lnt .t 4'22:17 0.57:l2350.3552330.17923 10.936229t.7192272.8t82251.2272235.93722t7.9412 l6l .3932001.201l8611.329t7 49.707t6+5.24!)l5ir2.56l1,169.7 59r 395.3421 328.09712ti7.036l2ll 343I 160.340I I I l|.45ttt070.2t7l 030.2 l 0993.08595n.5'1,1926.324896.200867.97384t .47 |8 16.539793.041770.85t1749.8U3730.0 t 97tt.t79693.2rJ8676.27 5

LENGTH-WEIGHT TABLES 463TABLE I-8. C: 5,OOO X IO 7, CONTINUEDWEIGHT/1,000t'rsH (LB)LENCTH{rNcHES)FISH/POUNDWEIGHT(GRAMS)LENGTH(cM)FISH/KILOGRAM3.:1403.4203.5003.5ti03.6603.7403.8203.9003.9U0,1.0604.1404.2204.3004.3804.4604.5401.6204.7004.780,1.8604.9405.1005.5005.9006.3006.7007.1007.5007.9008.3008.7009.1009.5009.90010.30010.700I1.100l 1.500I 1.900I 2.300t2.70o13.100l 3.500I 3.9001,1.300l 4.700l .88331.8982I .9129|.927 41.94161.95571.96951.9u321.99662.00992.02:ll2.03602.048u2.06142.07392.08622.09U42.110.12.122:l2.13412.t4stl2.t6872.22402.27662.32702.37522.42t62.46622.50932.55102.59132.630,12.(i(i8.12.70532.74t32.77632.81052.84392.87652.90832.93952.97013.00003.02933.05813.0u64299.4062!)2.4032U5.71927ll.334273.229267.38526t.785256.4 l5251.261246.3 I 0241 .550236.971232.563228.315224.220220.269216.454212.770209.209205.76520'2.433196.078l8l.8l8169.,192I 58.730t49.254140.8,15l 33.334126.583120.482I1.1.943109.890105.263l0l .01097.0Uu93.,15u90.09086.957li4.034u l .30178.71076.33ri74.07471.94369.93068.0271 .51501 .5513r .58751.6238I .66011.6964t.73271.76901.8053l .84 l5t.877tlI .914l1.95041.98672.02302.05932.09562.13182.16812.20442.24072.31332.494112.67622.85763.03913.22053.40193.58343.7ri,l83.94624.12774.309 l4.49051.67204.1153'15.03495.21635.39775.57925.76065.94206. l 2356.30495.48636.667u4.7844.8224.8594.8964.9324.9675.0035.0375.07 |5.1055.1395.t7 |5.2045.2365.2685.2995.3305.3615.3915.4215.4505.5095.6495.7835.9106.0336.1516.2645.3746.4796.5826.6i1I6.7786.8726.9637.0527. r397.2237.3067.3877.4667.5447.6207.6957 .76ta7.839660.077644.637629.9026 I 5.826602.366589.48 I577.136565.297553.935543.020532.527522.432512.7 t2503.347494.319.185.608477.200469.077461.227453.634446.28u132.278400.840373.665349.940329.048310.510293.950279.066265.6t7253.405242.267232.066222.6892t 4.041206.040I 98.6 l5t9t.707I1t5.263179.238l7 3.593168.292163.30615u.606| 5+.17 0149.975

464 FISH HATCHERY MANAGEMENTTnnu, I-8c: 5,ooo r to 7, CONTINUTDWEIGHT/r,000FrsH (LB)LENCTH(INCHES)TISH/POUNDWEIGHT(GRAMS)LENGTH(cM)FISH/KILOCRAM15.100l 5.500l 5.90016.30016.700I 7.100l 7.500I 7.900i 8.30018.70019.10019.50019.90020.30020.70021.10021 .5002l .90022.30022.70023. l 0023.50023.90024.30024.70025.20026.00026.80027.6002U.40029.20030.00030.8003l.60032.40033.20034.00034.80035.60036.40037.20038.0003t|.80039.60040.4004t.2003. I l4l3.t4t43. I 6823. I 9453.22043.24603.27 | |3.29583.32023.34423.36793.39123.4t423.43703.45943.48 l53.50343.52503.54633.56743.5UU23.60883.62923.64933.66923.693u3.73253.77043.80763.84403.87983.91493.94943.98334.01664.04944.08174.t t344.14474.17554.20594.23584.26534.29454.32324.351566.22564.51662.89361.35059.8805{J.48057 .t 4355.86654.64553.47652.3565t.28250.25149.2614t].30947.39346.5t245.66244.84344.05343.29042.5534t.84l4t.15240.48639.68238.46137.31336.23235.21I34.24633.33332.46731.64530.86430. l 2029.4t228.73628.09027.47226.88226.3 l625.77325.25224.75224.2726.84927.03067.21217.39357.57507 .75647.93798.11938.30078.4822u.6636lii.84509.02659.20799.38939.57089.75229.9337l0.l l5l10.296510.478010.6594l0.u40ul 1.0223| | .2037I 1.4305I 1.793,112.156312.519212.882013.244913.607813.970714.333514.696415.0593| 5.4222I 5.785016.1479I 6.5108l 6.873617.236517.5994t7.9623I 8.325 I1ti.68807.9107.9798.0478.1i48.1808.2458.3098.3718.4338.494u.5548.6148.6728.7308.7878.843u.8998.9539.0089.0619.1 l49.1669.2189.2699.3209.3829.4819.5779.6719.7649.8559.94410.03 Il0.t l710.20210.28510.367l0.44rJ10.52u10.60610.6U310.759I 0.834l0.90rll0.9u lI 1.053t46.OO2142.234138.656I 35.253132.013l 28.925125.978123.163t20.47 |117.894tt5.425I 13.058I 10.785I 08.602106.503104.484t02.541100.66898.86297.t2095.43893.81492.24490.72589.25687.48584.79382.26279.87777.62775.50073.4877 |.57ti69.76668.04466.40464.84263.3516t.92760.56659.26458.0 l656.U2055.67254.57053.5 i0

LENGTH,WEIGHT 1'ABLES 465TABLE I-8. C: 5,OOO X IO 7, CONTINUEDWEICH'I'/1,000FISH (LB)I,ENG'I'H(INcHEs)FISH/POUNDWEICH'I'(CRAMS)LENGTH(cM)FISH/KILOGRAM42.00042.80043.60044.40045.20046.00046.80047.60048.40049.20050.00050.tt005l.60052.40053.2005.1.00054.80055.60056.40057.2005U.00058.tt0059.60060.4006l .20062.00062.80063.60064.40065.200(t6.00066.80067.600(t8.40069.20070.00070.80071.60072.40073.20074.00074.U0075.60076.40077.2007U.0004.37954.40724.43444.46144.48U04.51444.5404,1.56614.59154.61674.6416'1.66624.69064.7 t474.7:1864.76224.78564.U0884.U3174.ti5454.87704.U9931.92144.94344.965 I4.9U665.00u05.02925.0502s.07 l05.09 l65. I l2l5. I 3255. I 5265.t7265. I 9255.21225.23 l85.25t25.27045.28965.30865.327 45.3.1615.36475.383223.U0923.36422.!)3622.52222.1242t.73921.36721.00820.66120.32520.00019.68519.3t]0l9.0tr418.79718.51ttl n.24u17.98617.730t7.482t7.241t7.007t6.77916.556I 6.34016.129| 5.924| 5.72315.52r]15.337l5.l5l| 4.97014.79314.62014.451I 4.286t4.124I 3.966I 3.U 1213.(i6lI ll.5l4l 3.369t3.22tl13.08912.953t2.82119.0509I 9.4 138tlt.7 7 6620. I 39520.502420.86522t.22812l .591021.953922.3t6722.679623.042523.405423.768224.t3t124.491024.856!)25.21{)725.582625.945526.308426.67 t227.0:l4l27.397027.7 59928.t2272U.48562tJ.848529.21l329.57 4229.937 |30.300030.662u3t.02573 1.38U631.751532.t | 4332.477232.ti40133.203033.5(;5u3:1.92873,1.29 t 634.65.{,135. l 07335.3tt02| | .t24ll.l94l 1.263I l 332l 1.400I 1.466I l.533l 1.598I L663| 1.726I 1.790I l.ti52I I .914l 1.97512.036I 2.09612.15512.21412.273l 2.330I 2.28812.444l 2.500t2.55612.61rI 2.666t2.720t2.77 4t2.827l2.tt80l 2.93312.9U513.036l2.0rJ813. l3tll3.l rjg13.239I 3.289l 3.llti813.3U7l 3.436I11.484I 3.532l 3.57913.626I 3.67352.49151.510JI'-JOJ49.65448.77 547.92647.t07,16.3 l545.55044.U0944.09243.39u42.72542.0734t.44040.82640.21t039.65139.08938.54238.01I37.49336.99036.50036.02335.55835.10534.66434.23333.8 l333.40333.00332.6 l332.23r3I .U5931.49531.13930.79130.45130.1 l829.79229.4732!t.t622U.U5628.55728.264

466 FISH HATCHERY MANAGEMENTTest,n I-8.c: 5,ooo r ro 7, coNTINUEDWEIGHT/1,000FrsH it.B)LF]NCTH(rNCH ES)I'ISH/POUNT)WEIGH'I'(GRAMS)LENGTH(cM)FISH/KIl.ocRAM7ti.80079.60080.'100tJ 1.20082.00082.80083.600rJ.r.40085.20086.00086.1100u7.60088..10089.20090.00090.8009l .60092.40093.20094.0009,1.80095.60096..r0097.2009{J.0009n.80099.600104.000I 12.000120.000128.000I 36.000l,{4.000152.000160.000168.000176.0001I.t4.000I 92.000200.00020rJ.0002l 6.000224.000232.000240.00024U.0005.40165.41985.437 95.455tt5.47375.49145.50915.52ri65.54405.56135.57855.59565.61265.629.15.6.1625.66295.67955.69605.7 t245.72875.74495.76 l05.77705.79295.lJ08us.82+55.U4025.92ir06.07326.21456.34966.47!126.60396.723!l6.83996.952 l7.U;077. 166 I7.26857.36U 17.46507.55957 .65t77 .71t77.Il2g77.9l5til 2.690i 2.563l2.4llu12.31512.195t2.077l 1.9621l.848tt.7il7I 1.62uIl 521ll.,1l(tI 1.312ll.2llll.ll1l 1.01310.9 l 7l0.ll2310.73010.63u10.5,1910.46010.373l0.2tru10.204l0.l2l10.0409.6 l58.929It.3337.n l37.3536.9446.5796.2505.9525.6tt25.,1355.2085.0004.ft0u,1.6304.4644.3 l04.1674.03235.743136. I 05936.4fil]u36.1]31737. l 94637 .557437.92033U.2U3238.646139.008939.37 l839.734740.097540..1604,10.823341.18624l .549041.91l912.',27 +8'12.637743.000543.3(t:1443.726344.089244.+52044.81,1945.17817.173650.802354.43 I 05U.059861.688565.3t726U.946072.57 +776.203+79.8322u3.4609tii7.0u9690.7 t tt494.347 |97.975tll 0 l .6046105.2333108.u62 1I 12.490813.720r 3.76613.8 I 2l3.u5u13.90313.94u13.993l4.03tl14.082\ 4.12614. I 6914.213r1.256I 4.299I 4.341l 4.384| 4.426I 4.46814.50914.551I 4.592I 4.63314.67 4t1.7 t1| 4.751| 4.7941.1.tt3415.04915..12615.78516.l28t6.45716.774t7.079t7 .37317.65817.9341 U.202I tJ.46218.715I8.96I19.20 l10.43519.66419.88720. I 0627.97727.69627.42127.t5026.8U62(;.626'26.37|26.t2125.87625.63525.39925.1672.1.93924.7 t524.49624.28024.06823.r'i5923.65523.45323.25523.06122.tr6922.68122.49622.3t122.13521.198l9.68418.37217.22+16.2 l0I 5.3 l0I 4.50413.77 ll13.123t'2.526l 1.9u2I 1.4U2I 1.02310.599t0.2079.8429.5039.186u.890

LENGTH WEIGHT TABLES 467TABLE I-8. c'= .5,000! l07, coNTINUEt)WEIGHT/1,000LI,NC'I'HFISH/WI,ICH II,ENGTHFISH/FISH (LB)(INcHES)POU N t)(GRAMS](cM)KII,OCRAM256.000264.00027'2.0002u0.0002t}u.000296.000304.0003l 2.000320.000328.000336.000344.000352.000360.00036U.00037(;.00038'1.000392.000'100.000408.0004 I 6.000,124.000432.0004,10.000,1.,1tt.000456.000464.000472.0004U0.000488.00049(;.0008.00008.01t258. 16338.2426u.3203u.llg(i7tt.47 l68.54538.(;t77u.6u90ti.7590tt.u2tt0u.u959t].962t]9.02879.09379.t 5779.22099.2tt329.3'1479.'10539..t(i52!1.52449.5n2rl9.6,1069.(;97(i9.75,109.80979.8(;4rl9.91939.97333.9063.7lJtt3.67(;3.5713.+723.37r,13.2893.2053.1253.0.192.97 (;'2.9072.8412.7782.7 t72.(t(t02.6042.5512.5002.45l2.4012.35rl2.3152.2732.',2322.1932.t 552.1 l92.0u32.04!l2.106I l6.l 195I19.74U:ll'23.3770127.0057I 30.6315t3+.'2632I 37.89 I I1,11.5207145.1,t94148.7782I 52.4069l5(;.035(;159.664.r163.2931I tt6.92l uI 70.5506174.t793177.U0u018 l .,136u185.0{i5irI8U.(;9.12I 92.3230r 95.951 7I 99.5804203.2092206.rJ3 7I210..1667214.09ir'l'217.72412'2t.352922.1.981620.32020.52920.73520.93621.13,12l .32u21 .5182t.7052 l.lltt9'22.07022.2+822.42322.59622.761)22.9it323.09tt23.26123.42123.57923.73523.U9024.04221.t922+.34024.487'24.63221.77524.9t725.05725. I 9525.332u.6I2rJ.35l8.1057.8747.6557.4487.2527.066fr.8896.7216.5616.4096.2636.1245.9915.8635.74l5.6245.5t25.4035.3005.2005.1035.0101.9214.tt354.75l4.67 |.1.5934.5 l84.445

GlossaryAbdomenBelly; the ventral side of the fish surrounding the digestiveand reproductive organs.AbdominalAbrasionPertaining to the belly.A spot scraped of skin, mucous membrane, or superficialepithelium.Abscess A localized collection of necrotic debris and white blood cellssurrounded by inflamed tissue.Acclimatization The adaptation of fishes to a new environment or habitator to different climatic conditions.ACre-FOot A water volume equivalent to that covering a surface area ofone acre to a depth of one foot; equal to 326,000 gallons or 2,718,000Acriflavinpounds of water.A mixture of 2,8-diamino-10-methylacridinium chloride andAcute2,8-diaminoacridine. Used as an external disinfectant, especially of livingfish eggs.Activated Sludge Process A system in which organic waste continuallyis circulated in the presence of oxygen and digested by aerobic bacteria.Having a short and relatively severe course; for example, acuteinflammation.Acute Catarrhal Enteritis Saa Infectious Pancreatic Necrosis.469

470 FISH HATCHERY MANAGEMENTAcute ToxicityCausing death or severe damage to an organism by poisoningduring a brief exposure period, normally 96 hours or less. SaeChronic.AdaptationThe process by which individuals (or parts of individuals),populations, or species change in form or function in order to bettersurvive under given or changed environmental conditions. Also theresult of this process.Adipose Fin A small fleshy appendage located posterior to the maindorsal fin; present in Salmonidae and Ictaluridae.Adipose Tissue Tissue capable of storing large amounts of neutral fats.Aerated LagoonAerationA waste treatment pond in which the oxygen requiredfor biological oxidation is supplied by mechanical aerators.The mixing of air and water by wind action or by air forcedthrough water; generally refers to a process by which oxygen is addedto water.Aerobic Referring to a process (for example, respiration) or organism(for example, a bacterium) that requires oxygen.AirThe gases surrounding the earth; consists of approximately 78'ftnitrogen, 2l()ir oxygen, 0.9'lir argon, 0.03'l; carbon dioxide, and minutequantities of helium, krypton, neon, and xenon, plus water vapor.Air Bladder (Swim bladder). An internal, inflatable gas bladder thatenables a fish to regulate its buoyancy.Air StrippingAlevinRemoval of dissolved gases from water to air by agitationof the water to increase the area of air-water contact.A life stage of salmonid fish between hatching and feeding whenthe yolk sac still is present. Equivalent to sac fry in other fishes.Algal BloomA high density or rapid increase in abundance of algae.Algal Toxicosis A poisoning resulting from the uptake or ingestion oftoxins or toxin-producing algae; usually associated with blue-greenalgae or dinoflagellate blooms in fresh or marine water.Alimentary Tract The digestive tract, including all organs from theAliquotAlkalinitymouth to the anal opening.An equal part or sample of a larger quantity.The power of a mineral solution to neutralize hydrogen ions;usually expressed as equivalents of calcium carbonate.Amino Acid A building block for proteins; an organic acid containingone or more amino groups (-NH2) and at least one carboxylic acidgroup (-COOH).AmmoniaThe gas NH1; highly soluble in water; toxic to fish in theun-ionized form, especially at low oxygen tensions.Ammonia Nitrogen Also called total ammonia. The summed weight ofnitrogen in both the ionized (ammonium, NH.,+) and molecular (NH,)forms of dissolved ammonia ( NHn-N plus NH3-N). Ammoniavalues are reported as N (the hydrogen being ignored in analyses).

GLOSSARY47IAmmonium The ionized form of ammonia, NHa+.Anabolism Constructive metabolic processes in living organisms: tissuebuilding and growth.Anadromous Fish Fish that leave the sea and migrate up freshwaterrivers to spawn.AnaerobicAnalAnal FinReferring to a process or organism not requiring oxygen.Pertaining to the anus or vent.The fin on the ventral median line behind the anus.Anal Papilla A protuberance in front of the genital pore and behindthe vent in certain groups of fishes.Anchor Ice Ice that forms from the bottom up in moving water.Anemia A condition characterized by a deficiency of hemoglobin,packed cell volume, or erythrocytes. The more important anemias infish are (l) normocytic anemia caused by acute hemorrhaging, bacterialand viral infection, or metabolic disease; (2) microcytic anemiadue to chronic hemorrhaging, iron deficiency, or deficiency of certainhematopoietic factors; (3) macrocytic anemia resulting from anincrease in hematopoietic activity in the spleen and kidney.AnestheticsChemicals used to relax fish and facilitate the handling andspawning of fish. Commonly used agents include tricane methane sulfonate(MS-222), benzocain, quinaldine, and carbon dioxide.Annulus A yearly mark formed on fish scales when rapid growthresumes after a period (usually in winter) of slow or no growth.Anoxia Reduction of oxygen in the body to levels that can result in tissuedamage.Anterior In front of: toward the head end.Anthelmintic An agent that destroys or expels worm parasites.Antibiotic A chemical produced by living organisms, usually molds orbacteria, capable of inhibiting other organisms.Antibody A specific protein produced by an organism in response to aforeign chemical (antigen) with which it reacts.AntigenA large protein or complex sugar that stimulates the formationof an antibody. Generally, pathogens produce antigens and the hostprotects itself by producing antibodies.Antimicrobial Chemical thatinhibits microorganisms.AntioxidantA substance that chemically protects other compoundsagainst oxidation; for example, vitamin E prevents oxidation and rancidityof fats.Antiseptic A compound that kills or inhibits microorganisms, especiallythose infecting living tissues.AntivitaminAnusSubstance chemically similar to a vitamin that can replacethe vitamin or an essential compound, but cannot perform its role.AquacultureArteryThe external posterior opening of the alimentary tracti the vent.Culture or husbandry of aquatic organisms.A blood vessel carrying blood away from the heart.

472 FISH HATCHERY MANAGEMENTAscites The accumulation of serum-like fluid in the abdomen.Ascorbic Acid Vitamin C, a water-soluble antioxident important for theproduction of connective tissue; deficiencies cause spinal abnormalitiesAsphyxiaand reduce wound-healing capabilities.Suffocation caused by too little oxygen or too much carbondioxide in the blood.Asymptomatic Carrier An individual that shows no signs of a diseasebut harbors and transmits it to others.Atmosphere The envelope of gases surrounding the earth; also, pressureequal to air pressure at sea level, approximately 14.7 pounds persquare inch.Atrophy A degeneration or diminution of a cell or body part due todisuse, defect, or nutritional deficiency.Auditory Referring to the ear or to hearing.Autopsy A medical examination of the body after death to ascertain thecause of death.Available Energy Energy available from nutrients after food is digestedand absorbed.Available Oxygen As used in this text, that oxygen present in thewater in excess of the amount required for minimum maintenance of aspecies, and that can be used for metabolism and growth.Avirulent Not capable of producing disease.Avitaminosis (Hypovitaminosis) A disease caused by deficiency of oneor more vitamins in the diet.Axilla The region just behind the pectoral fin base.BacteremiaThe presence of living bacteria in the blood with or withoutsignificant response by the host.Bacterial Gill Disease A disease usually associated with unfavorableenvironmental conditions followed by secondary invasion of opportunistbacteria. Sae Environmental Gill Disease.Bacterial Hemorrhagic Septicemia A disease caused by many of the.gram-negative rod-shaped bacteria (usually of the genera Aeromonas orPseudomonas) that invade all tissues and blood of the fish. Synonyms:infectious dropsy; red pest; fresh water eel disease; redmouth disease;motile aeromonad septicemia (VnS).Bacterial Kidney Disease An acute to chronic disease of salmonidsBacterincaused by Renibacterium salmoninarum. Synonyms: corynebacterial kidneydisease; Dee's disease; kidney disease.A vaccine prepared from bacteria and inactivated by heat orchemicals in a manner that does not alter the cell antigens.

GLOSSARY 473BacteriocidalBacteriostaticreproduction of bacteria.Having the ability to kill bacteria.Having the ability to inhibit or retard the growth orBacterium (plural: bacteria) One of a large, widely distributed group oftypically one-celled microorganisms, often parasitic or pathogenic.Balanced Diet (feed) A diet that provides adequate nutrients for normalgrowth and reproduction.Bar MarksBarbelVertical color marks on fishes.An elongated fleshy projection, usually of the lips.Basal Metabolic Rate The oxygen consumed by a completely restinganimal per unit weight and time.Basal Metabolism Minimum energy requirements to maintain vitalbody processes.BathBenignBioassayA solution of therapeutic or prophylactic chemicals in which fishare immersed. See Dip; Short Bath; Flush; Long Bath; Constant-FlowTreatment.Not endangering life or health.Any test in which organisms are used to detect or measure thepresence or effect of a chemical or condition.Biochemical Oxygen Demand (nOO) The quantity of dissolved oxygentaken up by nonliving organic matter in the water.Biological Control Control of undesirable animals or plants by meansof predators, parasites, pathogens, or genetic diseases (including sterilization).Biological Oxidation Oxidation of organic matter by organisms in theBiotinpresence of oxygen.Vitamin H, one of the B-complex vitamins.Black Grub Black spots in the skin of fishes caused by metacercaria(larval stages) of the trematodes Lluilifer ambloplitis, Cryptocotyle lingua,and others. Synonym: black-spot disease.Black Spot Usually refers to black cysts of intermediate stages of trematodesin fish. Sae Black Grub.Black-Spot Disease Sar Black Grub.Black-Tail Disease Sae Whirling Disease.Blank EggBlastoporeAn unfertilized egg.Channel leading into a cavity in the egg where fertilizationtakes place and early cell division begins.Blastula A hollow ball of cells, one of the early stages in embryologicaldevelopment.Blood FlagellatesBlue-Sac DiseaseFlagellated protozoan parasites of the blood.A disease of sac fry characterized by opalescence anddistension of the yolk sac with fluid and caused by previous partialasphyxia.

474 FISH HATCHERY MANAGEMENTBlue slime Excessive mucus accumuration on fish, usually caused byskin irritiation due to ectoparasites or malnutrition.Blue-Slime Disease A skin condition associated with a deficiency ofbiotin in the diet.Blue Stone ,Saa Copper Sulfatb.Boil A localized infection of skin and subcutaneous tissue deveropinginto a solitary abscess that drains externally.Bouin's Fluid A mixture of 75 parts saturated picric acid, aqueous solution;25parts formalin (40%, formaldehyde) ; a.rd 5 parts glacial aceticacid. This is widely used for preserving biological materia'I.Brackish water A mixture of fresh and sea water; or water with totalsalt concentrations between 0.05% and 3.0%r.Branchiae (singular: Branchia) Gills, the respiratory organs of fishes.Branchiocraniurn The bony skeleton supporting the gill arches.Branchiomycosis A fungal infection oi if," giit, .uir"a il nrorrtrroo_mlces sp. Synonyms: gill rot; European gill rot.Broodstock Adutt fish retained fo, ,pu*rrr.rg.Buccal Cavity Mouth cavity.Buccal Incubation Incubation of eggs in the mouth; oral incubation.Buffer Chemical that, by taking up or giving up hydrogen ions, sustainspH within a narrow range.calcinosis The deposition of calcium sarts in the tissues without detect_able injury to the affected parts.Calcium Carbonate A relatively insoluble salt, CaCOr, the primaryconstituent of limestone and a common constituent of hard water.Calcium Cyanamide (Lime Nitrogen) CaCN2. Used as a pond disinfec_tant.Calcium Oxide See Lime.calorie The amount of heat required to raise the temperature of onegram of water one degree centierade.carbohydrate Any of the various neutral compounds of carbon, hydrogen,and oxygen, such as sugars, starches, and celluloses, most ofwhich can be utilized as an energy source by animals.Carbon Dioxide A colorless, odoJ"., gas, CO2, resulting from the oxi_dation of carbon-containing substances; highly sorubre in water. Toxicto fish at high levels. Toxicity to fish increases at low revers of oxygen.May be used as an anesthetic.Carbonate The CO3: ion, or any salt formed with it (such as calciumcarbonate, CaCO:;).carcinogen Any agent or substance that produces cancer or acceleratesthe development of cancer.

GLOSSARY 47 5CarnivorousCarrierthe disease.Feeding or preying on animals.An individual harboring a pathogen without indicating signs ofCarrier Host (Transport Host) An animal in which the larval stage of aparasite will live but not develop.Carrying Capacity The population, number, or weight of a species thata given environment can support for a given time.Cartilage A substance more flexible than bone but serving the samepurpose.Catabolism The metabolic breakdown of materials with a resultantrelease of energy.CatadromousCatalystspawn.CataractFish that leave fresh water and mierate to the sea toA substance that speeds up the rate of chemical reaction but isnot itself used up in the reaction.its capsule.Catfish Virus DiseaseCaudalPartial or complete opacity of the crystalline lens of the eye orPertaining to the posterior end.Caudal Fin The tail fin of fish.Sea Channel Catfish Virus Disease.Caudal Peduncle The relatively thin posterior section of the body towhich the caudal fin is attached; region between base of caudal finand base of the last ray of the anal fin.CCVD Channel Catfish Virus Disease.Cecum (plural: Ceca) A blind sac of the alimentary canal, such as apyloric cecum at the posterior end of the stomach.Channel Catfish Virus Disease (CCVO) A disease caused by a herpesvirusthat is infectious to channel catfish and blue catfish.Chemical Coagulation A process in which chemical coagulants are putinto water to form settleable flocs from suspended colloidal solids.Chemical Oxygen Demand (COD) A measure of the chemically oxidizablecomponents in water, determined by the quantity of oxygenconsumed.Chemotherapy(drugs).Chinook Salmon Virus DiseaseChromatophoresChromosomesChronicChronic InflammationCiliaCure or control of a disease by the use of chemicalsColored pigment cells.,.lra Infectious Hematopoietic Necrosis.Structural units of heredity in the nuclei of cells.Occurring or recurring over a long time.Long-lasting inflammation.Movable organelles that project from some cells, used for locomotionof one-celled organisms or to create fluid currents past attachedcells.

476 FISH HATCHERY MANAGEMEN.I.Ciliate Protozoan One-celled animal bearing motile cilia.Circuli The more or less concentric growth marks in a fish scale.clinical Infection An infection or disease generating obvious sympromsand signs of pathology.CloacaThe common cavity into which rectal, urinary, and genital ductsopen. Common opening of intestine and reproductive system of malenematodes.Closed-Formula Feed (Proprietary Feed) A diet for which the formulais known only to the manufacturer.Coelomic Cavity The body cavity containing the internal organs.Coelomic Fluid Fluid inside the body cavity.coelozoic Living in a cavity, usually of the urinary tract or gall bladder.Cold Water Disease Sea Peduncle Disease; Fin Rot Disease.Coldwater Species Generally, fish that spawn in water temperaturesbelow 55'F. The main cultured species are trout and salmon. See CoolwaterSpecies; Warmwater Species.Colloid A substance so finely divided that it stays in suspension inwater, but does not pass through animal membranes.Columnaris Disease An infection, usually of the skin and gills, by Ftexibacter co lumnaris, a my xobacterium.communicable Disease A disease that naturally is transmitted directlyor indirectly from one individual to another.compensation Point That depth at which incident light penetration isjust sufficient for plankton to photosynthetically produce enough oxygento balance their respiration requirements.Complete Diet (Complete Feed) See Balanced Diet.Complicating Disease A disease supervening during the course of analready existing ailment.Compressed Applied to fish, flattened from side to side, as in the caseof a sunfish. Saa Depressed.Conditioned Response Behavior that is the result of experience ortraining.Congenital Disease A disease that is present at birth; may be infectious,nutritional, genetic, or developmental.Congestion Unusual accumulation of blood in tissue; may be active(often called hyperemia) or passive. Passive congestion is the result ofabnormal venus return and is characterized by dark cyanotic blood.Constant-Flow Treatment Continuous automatic metering of a chemicalto flowing water.Contaminationsomething impure or unclean.The presence of material or microorganisms makingControl (Disease) Reduction of mortality or morbidity in a population,usually by use of drugs.

GLOSSARY 477Control (Experimental) Similar test specimens subjected to the sameconditions as the experimental specimens except for the treatmentvariable under study.Control Fish A group of animals given essentially identical treatment tothat of the test grouP, except for the experimental variable.Coolwater Species Generally, fish that sPawn in temperatures between40' and 60'F. The main cultured coolwater species are northern pike,muskellunge, walleye, sauger, and yellow perch. Saa Coldwater Species;Warmwater Species.Copper Sulfate (Blue Stone) Blue stone is copper sulfate pentahydrate(CuSOa'5H20). Effective in the prevention and control of externalCorneaprotozoan parasites, fungal infections, and external bacterial diseases.Highly toxic to fish.Outer covering of the eye.Corynebacterial Kidney Disease Sae Bacterial Kidney Disease.Costiasis An infection of the skin, fins, and gills by flagellated protozoansof the genus Casfia.Cranium The part of the skull enclosing the brain.Cyanocobalamin (Vitamin B12) One of the B-complex vitamins that isinvolved with folic acid in blood-cell production in fish. This vitaminenhances growth in many animals.Cyst, Host A connective tissue capsule, liquid or semi-solid, producedaround a parasite by the host.Cyst, of Parasite Origin A noncellular capsule secreted by a parasite.Cyst, Protozoa A resistant resting or reproductive stage of protozoa.Cytoplasm The contents of a cell, exclusive of the nucleus.Daily Temperature Unit (DTU) Equal to one degree Fahrenheit abovefreezing (32'F) for a 24-hour period.Dechlorination Removal of the residual hypochlorite or chloraminefrom water to allow its use in fish culture. Charcoal is used frequentlybecause it removes much of the hypochlorite and fluoride. Charcoal isinadequate for removing chloramine.Dee's Disease ,Saa Bacterial Kidney Disease.Deficiency A shortage of a substance necessary for health.Deficiency Disease A disease resulting from the lack of one or moreessential constituents of the diet.Denitrification A biochemical reaction in which nitrate (NO, ) lsreduced to NO2, N2O, and nitrogen gas.Density Index The relationship of fish size to the water volume of arearing unit; calculated by the formula:Density Index:(weight of fish) + (fish length X volume of rearing unit).

478 FISH HATCHERY MANAGEMENTDentary Bones The principal or anterior bones of the lower jaw ormandible. They usually bear teeth.DepressedDepth of FishDermalFlattened in the vertical direction, as a flounder.front of the dorsal fin.DermatomycosisDiarrheaDietThe greatest vertical dimension; usually measured just inPertaining to the skin.Any fungus infection of the skin.Profuse discharge of fluid feces.Food regularly provided and consumed.Dietary Fiber Nondigestible carbohydrate.DigestionThe hydrolysis of foods in the digestive tract to simple substancesthat may be absorbed by the body.Diluent A substance used to dissolve and dilute another substance.Dilution Water Refers to the water used to dilute toxicants in aouaticDiPtoxicity studies.Brief immersion of fish into a concentrated solution of a treatment,usually for one minute or less.Diplostomiasis An infection involving larvae of any species of the genusDipterexDiseaseD ip lo s tomum, Trematoda.Saa Dylox.Any departure from health; a particular destructive process inan organ or organism with a specific cause and symptoms.Disease Agent A physical, chemical, or biological factor that causesdisease. Synonyms: etiologic agent; pathogenic agent.Disinfectant An agent that destroys infective agents.Disinfection Destruction of pathogenic microorganisms or their toxins.Dissolved Oxygen The amount of elemental oxygen, 02, in solutionunder existing atmospheric pressure and temperature.Dissolved Solids The residue of all dissolved materials when water isDistalDiurnalevaporated to dryness. Sae Salinity.The remote or extreme end of a structure.Relating to daylight; opposite of nocturnal.Dorsal Pertaining to the back.Dorsal Fin The fin on the back or dorsal side, in front of the adiposeDosefin if the Iatter is present.Drip TreatmentDropsyDry RationA quantity of medication administered at one time.Srr Edema.Sae Constant-Flow Treatment.A diet prepared from air-dried ingredients, formed into distinctparticles and fed to fish.Dylox (Dipte.e*, Masoten) Organophosphate insecticide effective in thecontrol of parasitic copepods.Dysentery Liquid feces containing blood and mucus. Inflammation ofthe colon.

GLOSSARY 479EctodermThe outer layer of cells in an embryo that gives rise to variousorgans.EctoparasiteEdemaEfficacyParasite that lives on the surface of the host.Excessive accumulation of fluid in tissue spaces.Ability to produce effects or intended results.Effluent The discharge from a rearing facility, treatment plant, orindustry.Egg The mature female germ cell, ovum.Egtved Disease Saa Viral Hemorrhagic Septicemia.Emaciation Wasting of the body.Emarginate Fin Fin with the margin containing a shallow notch, as inEmbolithe caudal fin of the rock bass.Abnormal materials carried by the blood stream, such as bloodclots, air bubbles, cancers or other tissue cells, fat, clumps of bacteria,or foreign bodies, until they lodge in a blood vessel and obstruct it.Embryo Developing organism before it is hatched or born.Endocrine A ductless gland or the hormone produced thereiu.Endoparasite A parasite that lives in the host.Endoskeleton The skeleton proper; the inner bony and cartilaginousframework.Energy Capacity to do work.Enteric Redmouth Disease (ERM) A disease, primarily of salmonids,Enteritischaracterized by general bacteremia. Caused by an enteric bacterium,Tersinia ruckeri. Synonym: Hagerman redmouth disease.EnvironmentAny inflammation of the intestinal tract.The sum total of the external conditions that affectgrowth and development of an organism.EnzooticEnzymeEnvironmental Gill Disease Hyperplasia of gill tissue caused by presenceof a pollutant in the water that is a gill irritant. Sea Bacterial GillDisease.A disease that is present in an animal population at all timesbut occurs in few individuals at any given time.A protein that catalyzes biochemical reactions in living organisms.EpidermisEpizooticThe outer layer of the skin.A disease attacking many animals in a population at the sametime; widely diffused and rapidly spreading.EpizootiologyThe study of epizootics; the field of science dealing withrelationships of various factors that determine the frequencies and distributionsof diseases among animals.EradicationERMfrom the environment.Removal of all recognizable units of an infecting agent,Saa Enteric Redmouth Disease.

480 FISH HA'TCHERY MANAGEMENTEsophagus The gullet; a muscular, membranous tube between the pharynxand the stomach.Essential Amino Acids Those amino acids that must be supplied bythe diet and cannot be synthesized within the body.Essential Fatty Acid A fatty acid that must be supplied by the diet.Estuary Water mass where fresh water and sea water mix.Etiologic Agent ,Saa Disease Agent.Etiology The study of the causes of a disease, both direct and predisposing,and the mode of their operation; not synonymous with cause orpathogenesis of disease, but often used to mean pathogenesis.European Gill Rot ,Saa Branchiomycosis.Excretion The process of getting rid or throwing off metabolic wasteproducts by an organism.Exophthalmos Abnormal protrusion of the eyeball from the orbit.Exoskeleton The hard parts on the exterior surfaces, such as scales,scutes, and bony plates.Extended Aeration System A modification of the activated-sludge processin which the retention time is longer than in the conventionalProcess.Extensive Culture Rearing of fish in ponds with low water exchangeand at low densities; the fish utilize primarily natural foods.Eyed Egg The embryo stage at which pigmentation of the eyes becomesvisible through the egg shell.FlF2The first generation of a cross.The second filial generation obtained by random crossing of F1 individuals.Fat An ester composed of fatty acid(s) and glycerol.Fatty Acid Organic acid present in lipids, varying in carbon contentfrom 2 to 34 atoms (C2-C34).FaunaFecundityThe animals inhabiting any region, taken collectively.Number of eggs in a female spawner.Feeding Level The amount of feed offered to fish over a unit time, usuallygiven as percent of fish body weight per day.Fertility Ability to produce viable offspring.Fertilization (t) The union of sperm and egg; (2) addition of nutrientsto a pond to stimulate natural food production.Fin Ray One of the cartilaginous rods that support the membranes ofthe fin.Fin Rot Disease A chronic, necrotic disease of the fins caused by invasionof a myxobacterium into the fin tissue of an unhealthy fish.Fingerling The stage in a fish's life between I inch and the length at Iyear of age.

GLOSSARY48IFixativeA chemical agent chosen to penetrate tissues very soon afterdeath and preserve the cellular components in an insoluble state asnearly life-like as possible.Flagellum (plural: Flagella) Whip-like locomotion organelle of single(usually free-living) cells.FlashingQuick turning movements of fish, especially when fish areannoyed by external parasites, causing a momentary reflection of lightfrom their sides and bellies. when flashing, fish often scrape themselvesagainst objects to rid themselves of the parasites.Flow rndex The relationship of fish size to water inflow (flow rate) of arearing unit; calculated by the formula:Flow Index : (fish weight) - (firn length x water inflow).Flow rate The volume of water moving past a given point in a unit oftime, usually expressed as cubic feet per second (cfs) or gallons perminute (Sp-).Flush A short bath in which the flow of water is not stopped, but a highconcentration of chemical is added at the inlet and passed through thesystem as a pulse.Folic Acid (Folacin) A vitamin of the B complex that is necessary formaturation of red blood cells and synthesis of nucleoproteins; deficiencyresults in anemia.Fomites Inanimate objects (brushes, or dipnets) that may be contaminatedwith and transmit infectious organisms. Sea Vector.Food Conversion A ratio of food intake to body weight gain; more gen_erally, the total weight of all feed given to a lot of fish divided by thetotal weight gain of the fish lot. The units of weight and the timeinterval over which they are measured must be the same. The betterthe conversion, the lower the ratio.Fork Length The distance from the tip of the snout to the fork of thecaudal fin.Forrnalin solution of approximately 87% by weight of formaldehyde gasin water. Effective in the control of external parasites and fungal infectionson fish and eggs. Also used as a tissue fixative.Formulated Feed A combination of ingredients that provides specificamounts of nutrients per weight of feed.Fortification Addition of nutrients to foods.Free Living Not dependent on a host organism.Fresh Water Water containing less than 0.05% total dissolved salts byweight.Fty The stage in a fish's life from the time it hatches until it reaches Iinch in length.Fu4gus Any of a group of primitive plants lacking chlorophyll, includingmolds, rusts, mildews, smuts, and mushrooms. Some kinds areparasitic on fishes.

482 FISH HATCHERY MANAGEMENTFungusDiseaseSaaSaprolegniasis'FuruncleAlocalizedinfectionofskinorsubcutaneoustissuewhichdevelops a solitary abscess that may or may not drain externally'Furunculosis A bacterial disease caused by Aeromonas salmonicida artdcharacterized by the aPPearance of furuncles'Gall Bladder The body vessel containing bile'Gametes Sexual cells: eggs and sperm'Gape The oPening of the mouth'Gas Bladder See Air Bladder'Gas Bubble Disease Gas embolism in various organs and cavities of thefish, caused by supersaturation of gas (mainly nitrogen) in the blood.Gastric Relating to the stomach'Gastritis Inflammation of the stomach'Gastroenteritis Inflammation of the mucosa of the stomach and intes'tines.Gene The unit of inheritance. Genes are located at fixed loci in chromosomesandcanexistinaseriesofalternativeformscalledalleles.GeneticDominantCharacterdonatedbyoneParentthatmasksintheprogeny the recessive character derived from the other parent'GeneticsGenitalThe science of heredity and variation'Pertaining to the reproductive organs'GenusAunitofscientificclassificationthatincludesoneorseveralclosely related species. The scientific name for each organism includesdesignations for genus and species'Geograit ic Distribirtion The geographic areas in which a condition ororganism is known to occur'Gerrniiral Disc The disc-like area of an egg yolk on which cell segmentationfirst aPPears.Gill Arch The U-shaped cartilage that supports the gill filaments'Gill Clefts (Citt Stlts) Spaces between the gills connecting the pharyngealcavity with the gill chamber'GillCoverTheflap-likecoverofthegillandgillchamber;theoperculum.Gill DiseaseGill Filamentsee Bacterial Gill Disease; Environmental Gill Disease'The slender, delicate, fringe-like structure composing thegill.Gill Lamellae The subdivisions of a gill filament where most gas andsomemineralexchangesoccurbetweenbloodandtheoutsidewater.Gill Openings The external openings of the gill chambers' defined bythe oPerculum.Gill Rakers A series of bony appendages, variously arranged along theanterior and often the posterior edges of the gill arches'

GLOSSARY 483Gill RotGillsSea Branchiomycosis.The highly vascular, fleshy filaments used in aquatic respirationand excretion.Globulin One of a group of proteins insoluble in water, but soluble indilute solutions of neutral salts.Glycogen Animal starch, a carbohydrate storage product of animals.Gonadotrophin Hormone produced by pituitary glands to stimulateGonadsGPMsexual maturation.The reproductive organs; testes or ovaries.Gallons per minute.Grading of Fish Sorting of fish by size, usually by some mechanicaldevice.Gram-negative Bacteria Bacteria that lose the purple stain of crystalviolet and retain the counterstain, in the gram staining process.Gram-positive Bacteria Bacteria that retain the purple stain of crystalviolet in the gram staining process.Gross Pathology Pathology that deals with the naked-eye appearanceof tissues.GulletGroup Immunity Immunity enjoyed by a susceptible individual by virtueof membership in a population with enough immune individuals toprevent a disease outbreak.Gyro InfectionThe esophagus.An infection of any of the monogenetic trematodes or,more specifically, of Gyrodactylus sp.HabitatThose plants, animals, and physical components of the environmentthat constitute the natural food, physical-chemical conditions,and cover requirements of an organism.Hagerman Redmouth Disease Sra Enteric Redmouth Disease.HaptorHardnessPosterior attachment organ of monogenetic trematodes.The power of water to neutralize soap, due to the presence ofcations such as calcium and magnesium; usually expressed as parts permillion equivalents of calcium carbonate. Refers to the calcium andmagnesium ion concentration in water on a scale of very soft (0-20ppm as CaCO3), soft (20 50 ppm), hard (50-500 ppm) and very hard(500* ppm).Hatchery Constant A single value derived by combining the factors inthe numerator of the feeding rate formula: Percent body weight feddaily : (3 x food conversion x daily length increase x 100) +length of fish. This value may be used to estimate feeding rates whenwater temperature, food conversion, and growth rate remain constant.Hematocrit Percent of total blood volume that consists of cells: packedcell volume.

484 FISH HA.TCHERY MANAGEMENTHematomaA tumor-like enlargement in the tissue caused by bloodescaping the vascular system.Hematopoiesis The formation of blood or blood cells in the livingbody. The major hematopoietic tissue in fish is located in the anteriorkidney. Synonym: hemapoiesis.Hematopoietic Kidney The anterior portion of the kidney ("head kidney")involved in the production of blood cells.HemoglobinThe respiratory pigment of red blood cells that takes upoxygen at the gills or lungs and releases it at the tissues.Hemorrhage An escape of blood from its vessels, through either intactor ruptured walls.Hepatic Pertaining to the liver.HepatitisHepatomaInflammation of the liver.A tumor with cells resembling those of liver; includes anytumor of the liver. Hepatoma is associated with mold toxins in feedeaten by cultured fishes. The toxin having the greatest affect on fishesis aflatoxin Br , from Aspergillus flaaus.Heterotrophic Bacteria Bacteria that oxidize organic material (carbohydrate,protein, fats) to CO2, NH{-N,source.HistologyMicroscopic study of cells, tissues, and organs.and water for their energyHistopathology The study of microscopically visible changes indiseased tissues.Homing Return of fish to their stream or lake of origin to sPawn.Ilormone A chemical product of living cells affecting organs that do notsecrete it.HRM See Enteric Redmouth Disease.Hyamine ,See Quaternary Ammonium Compounds.Hybrid Progeny resulting from a cross between parents that are geneticallyunlike.Hybrid Vigor Condition in which the offspring perform better than theparents. Synonym: heterosis.Hydrogen Ion Concentration (Activity) The cause of acidity in water.See pH.Hydrogen Sulfide An odorous, soluble gas, H2S, resulting liom anaerobicdecomposition of sulfur-containing compounds, especially proteins.Hyoid BonesBones in the floor of the mouth supporting the tongue.Hyper- A prefix denoting excessive, above normal, or situated above.Hyperemia Increased blood resulting in distension of the blood vessels.Hypo-A prefix denoting deficiency, lack, below, beneath.IchA protozoan disease caused by the ciliate lchthyophtherius multifilis;"white-spot disease."

G I,OSSARY4Tt5IHNImmuneImmunitystatus.Immunization,See Infectious Hematopoietic Necrosis.Unsusceptible to a disease.Lack of susceptibility; resistance. An inherited or acquiredProcess or procedure by which an individual is maderesistant to disease, specifically infectious disease.Imprintingexposure to stimuli.The imposition of a behavior pattern in a young animal byInbred Line A line produced by continued matings of brothers to sistersand progeny to parents over several generations.Incidence The number of new cases of a particular disease occurringwithin a specified period in a group of organisms.Incubation (Disease) Period of time between the exposure of an individualto a pathogen and the appearance of the disease it causes.Incubation (Eggs) Period from fertilization of the egg until it hatches.Incubator Device for artificial rearing of fertilized fish eggs and newlyhatched fry.Indispensable Amino Acid Sae Essential Amino Acids.Inert Gases Those gases in the atmosphere that are inert or nearlyinert; nitrogen, argon, helium, xenon, krypton, and others. Sae GasBubble Disease.Infection Contamination (external or internal) with a disease-causinsorganism or material, whether or not overt disease results.Infection, Focal A well circumscribed or localized infection in or on ahost.Infection, Secondary Infection of a host that already is infected by adifferent pathogen.Infection, Terminal An infection, often secondary, that leads to deathof the host.Infectious Catarrhal Enteritis See Infectious Pancreatic Necrosis.Infectious Disease A disease that can be transmitted between hosts.Infectious Hematopoietic Necrosis (IHN) A disease caused by infectioushematopoietic viruses of the Rabdouirus group. Synonyms: chinooksalmon virus disease, Oregon sockeye salmon virus, SacramentoRiver chinook disease.Infectious Pancreatic Necrosis (IpW) A disease caused by aninfectious pancreatic necrosis virus that presently has not been placedinto a group. Synonym: infectious catarrhal enteritis.Inferior Mouth Mouth on the under side of the head, openinq downward.Inflammation The reaction of the tissues to injury; characterized clinicallyby heat, swelling, redness, and pain.Ingest To eat or take into the body.

486 FISH HATcHERY MANAGEMENTInoculationThe introduction of an organism into the tissues of a livingorganism or into a culture medium.Instinct Inherited behavioral response.Intensive Culture Rearing of fish at densities greater than can be supportedin the natural environment; utilizes high water flow orexchange rates and requires the feeding of formulated feeds.InterspinalsIntestineBones to which the rays of the fins are attached.The lower part of the alimentary tract from the pyloric end ofthe stomach to the anus.Intragravel Water Water occupying interstitial sPaces within gravel.Intranuscular Injection Administration of a substance into the musclesof an animal.Intraperitoneal Injection Administration of a substance into the peritonealcavity (body cavity).In Vitro Used in reference to tests or experiments conducted in an artificialenvironment, including cell or tissue culture.In Viuo Used in reference to tests or experiments conducted in or onintact, living organisms.Ion Exchange A process of exchanging certain cations or anions inIPNIsotonicIsthmuswater for sodium, hydrogen, or hydroxyl (OH ) ions in a resinousmaterial.Saa Infectious Pancreatic Necrosis.No osmotic difference; one solution having the same osmoticpressure as another.The region just anterior to the breast of a fish where the gillmembranes converge; the fleshy interspace between gill openings.KidneyOne of the pair of glandular organs in the abdominal cavity thatproduces urine.Kidney Disease ,Saa Bacterial Kidney Disease.Kilogram Calorie The amount of heat required to raise the temperatureof one kilogram of water one degree centigrade, also called kilocalorie(kcal), or large calorie.Larva (plural: Larvae) An immature form, which must undergo changeof appearance or pass through a metamorphic stage to reach the adultstate.Lateral Band A horizontal pigmented band along the sides of a fish.LDVLateral Line A series of sensory pores, sensitive to low-frequency vibrations,located laterally along both sides of the body.Srr Lymphocystis Disease.

GLOSSARY 487Length May refer to the total length, fork length, or standard length(see under each item).Lesion Any visible alteration in the normal structure of organs, tissues,or cells.Leucocyte A white blood corpuscle.Lime (Calclum Oxide, Quicklime, Burnt Lime)CaO; used as a disinfectantfor fish-holdine facilities. Produces heat and extreme alkalineconditions.Line Breeding Mating individuals so that their descendants will bekept closely related to an ancestor that is regarded as unusually desirable.Linolenic Acid An l8-carbon fatty acid with two double bonds. CertainLipidmembers of the series are essential for health, growth, and survival ofsome, if not most, fishes.Any of a group of organic compounds consisting of the fats andother substances of similar properties. They are insoluble in water, butsoluble in fat solvents and alcohol.Long Bath A type of bath frequently used in ponds. Low concentrationsof chemical are applied and allowed to disperse by natural processes.Lymphocystis Disease A virus disease of the skin and fins affectingmany freshwater and marine fishes of the world. The disease is causedby the lymphocystis virus of the Iridovirus group.Malignant Progressive growth of certain tumors that may spread to distantsites or invade surrounding tissue and kill the host.MalnutritionMandibleMASMass SelectionFaulty or inadequate nutrition.Lower jaw.Srr Motile Aeromonas Septicemia.Selection of individuals from a general population foruse as parents in the next generation.Mating System Any of a number of schemes by which individuals areassorted in pairs leading to sexual reproduction.Maxilla or Maxillary The hindmost bone of the upper jaw.MeanThe arithmetic average of a series of observations.Mechanical Damage Extensive connective tisue proliferation, leadingMedianto impaired growth and reproductive processes, caused by parasitesmigrating through tissue.values.MelanophoreA value in a series halfway between the highest and lowestA black pigment cell; large numbers of these give fish adark color.Menadione A fat-soluble vitamin: a form of vitamin K.

488 FISH HAT(-IIF.R]' MANAGLMLN IMeristic Characters Body parts that can be counted (scales, gill rakers,vertebrae, etc.); useful in species identifications.Merthiolate, Sodium (Thimerosal) o-Carboxyphenyl-thioethylmercury,sodium salt; used as an external disinfectant, especially for living fisheggs.Metabolic Rate The amount of oxygen used for total metabolism perunit of time per unit of body weight.Metabolism Vital processes involved in the release of body energy, thebuilding and repair of body tissue, and the excretion of waste materials;combination of anabolism and catabolism.Methylene Blue 3, 7-Dis-Dimethylamino-phenazathionium chloride; aquinoneimine dye effective against external protozoans and superficialbacterial infections.tt":.J;. Microorganism, such as a virus, bacterium, fungus, or proto-MicropyleMigrationMiltMitosisMJBOpening in egg that allows entrance of the sperm.Movement of fish populations.Sperm-bearingfluid.The process by which the nucleus is divided into two daughternuclei with equivalent chromosome complements.Coffee can; essential measuring device used by some fish culturistsin lieu of a graduated cylinder.Monthly Temperature Unit (MTU) Equal to one degree FahrenheitMorbidabove freezing (SZ' F) based on the average monthly water remperature(30 days).MorbidityCaused by disease; unhealthy; diseased.The condition of being diseased.Morbidity Rate The proportion of individuals with a specific diseaseMoribundduring a given time in a population.Morphologyplants.MortalityObviously progressing towards death, nearly dead.The science of the form and structure of animals andThe ratio of dead to living individuals in a population.Mortality Rate The number of deaths per unit of population during aspecified period. Synonyms: death rate; crude mortality rate; fatalityrate.Motile Aeromonas Septicemia (MAS) An acute to chronic infectiousMottleddisease caused by any motile bacteria belonging to the genus Aeromonas,primarily Aeromonas hydrophila or Aeromonas pun(tate (: Aeromonasliq uifaciens) . Synonyms : bacterial hemorrhagic septicemia; pike pest.Blotched; color spots running together.Mouth Fungus Sae Columnaris Disease.

GLOSSARY 489Mucking (Egg) The addition of an inert substance such as clay or starchto adhesive eggs to prevent them from sticking together during spawntaking. Most commonly used with esocid and walleye eggs.Mucus A viscid or slimy substance secreted by the mucous glands of fish.MutationMycologyMycosisMyomereMyotomestruc ture.A sudden heritable variation in a qene or in a chromosomeThe study of fungi.Any disease caused by an infectious fungus.An embryonic muscular segment that later becomes a sectionof the side muscle of a fish.MyxobacteriosisMusclesegment.A disease caused by any member of the Myxobacteriagroup of bacteria. Sse Peduncle Disease, Cold Water Disease, Fin RotDisease, Columnaris Disease.NaresNecropsyNecrosisThe openings of the nasal cavity.A medical examination of the body after death to ascertainthe cause of death. Synonym for humans: autopsy.NematodaDying of cells or tissues within the living body.A diverse phylum of roundworms, many of which are plantor animal parasites.Nephrocalcinosis A condition of renal insufficiency due to the precipitationof calcium phosphate (CufOr) in the tubules of the kidney.Observed frequently in fish.Niacin One of the water-soluble B-complex vitamins, essential formaintenance of the health of skin and other epithelial tissues in fishes.Nicotinic Acid Saa Niacin.NitrificationA method through which ammonia is biologically oxidizedto nitrite and then nitrate.Nitrite The NOf ion.NitrogenAn odorless, gaseous element that makes up 78'lo of the earth'satmosphere and is a constituent of all living tissue. It is almost inert inits gaseous form.Nitrogenous Wastes Simple nitrogen compounds produced by themetabolism of proteins, such as urea and uric acid.NonpathogenicRefers to an organism that may infect but causes nodisease.Nostril See Nares.Nutrient A chemical used for growth and maintenance of an organism.NutritionThe sum of the processes in which an animal (or plant) takesin and utilizes food.Nutritional Gill Disease Gill hyperplasia caused by deficiency of pantothenicacid in the diet.

FISH HATCHERY MANAGEMENTOcean RanchingType of aquaculture involving the release of juvenileaquatic animals into marine waters to grow on natural foods to harvestablesize.Open-Formula Feed A diet in which all the ingredients and their proportionsare public (nonproprietary).OperculumOpticA bony flap-like protective gill covering.Referring to the eye.Osmoregulation The process by which organisms maintain stableosmotic pressures in their blood, tissues, and cells in the face of differingchemical properties among tissues and cells, and between theorganism and the external environments.Osmosis The diffusion of liquid that takes place through a semipermeablemembrane between solutions starting at different osmotic pressures,and that tends to equalize those pressures. Water always willmove toward the more concentrated solution, regardless of the substancesdissolved, untilequalized, regardless of electric charge.the concentration of dissolved particles isOsmotic Pressure The pressure needed to prevent water from flowingOutfallinto a more concentrated solution from a less concentrated one acrossa semipermeable membrane.Wastewater at its point of effluence or its entry into a river orother body of water.Ovarian Fluid Fluid surrounding eggs inside the female's body.Ovaries The female reproductive organs.Overt Disease A disease, not necessarily infectious, that is apparent orOviductobvious by gross inspection; a disease exhibiting clinical signs-The tube that carries eggs from the ovary to the exterior.Oviparous Producing eggs that are fertilized, develop, and hatch outsidethe female body.Ovoviviparous Producing eggs, usually with much yolk, that are fertilizedinternally. Little or no nourishment is furnished by the motherOvulateduring development; hatching may occur before or after expulsion.Process of producing mature eggs capable of being fertilized.Ovum (plural: Ova) Egg cell or single egg.Oxidation Combination with oxygen; removal of electrons to increasepositive charge.Oxytetracycline (Terramycin) One of the tetracycline antibiotics producedby Streptomyces rimosus and effective against a wide variety ofbacteria pathogenic to fishes.PancreasThe organ that functions as both an endocrine gland secretinginsulin and an exocrine gland secreting digestive enzymes.

GLOSSARY 489Mucking (Egg) The addition of an inert substance such as clay or starchto adhesive eggs to prevent them from sticking together during spawntaking. Most commonly used with esocid and walleye eggs.Mucus A viscid or slimy substance secreted by the mucous glands of fish.Mutation A sudden heritable variation in a sene or in a chromosomestruc ture.Mycology The study of fungi.Mycosis Any disease caused by an infectious fungus.Myomere An embryonic muscular segment that later becomes a sectionof the side muscle of a fish.Myotome Musclesegment.Myxobacteriosis A disease caused by any member of the Myxobacteriagroup of bacteria. ,See Peduncle Disease, Cold Water Disease, Fin RotDisease, Columnaris Disease.NaresNecropsyNecrosisThe openings of the nasal cavity.A medical examination of the body after death to ascertainthe cause of death. Synonym for humans: autopsy.NematodaDying of cells or tissues within the living body.A diverse phylum of roundworms, many of which are plantor animal parasites.Nephrocalcinosis A condition of renal insufficiency due to the precipitationof calcium phosphate (CufO*; in the tubules of the kidney.Observed frequently in fish.Niacin One of the water-soluble B-complex vitamins, essential formaintenance of the health of skin and other epithelial tissues in fishes.Nicotinic Acid Sre Niacin.NitrificationA method through which ammonia is biologically oxidizedto nitrite and then nitrate.Nitrite The NO2 ion.Nitrogen An odorless, gaseous element that makes up 78% of the earth'satmosphere and is a constituent of all living tissue. It is almost inert inits gaseous form.Nitrogenous Wastes Simple nitrogen compounds produced by themetabolism of proteins, such as urea and uric acid.Nonpathogenicdisease.Nostril Sae Nares.NutrientNutritionRefers to an organism that may infect but causes noA chemical used for growth and maintenance of.an organism.The sum of the processes in which an animal (or plant) takesin and utilizes food.Nutritional Gill Disease Gill hyperplasia caused by deficiency of Pantothenicacid in the diet.

GLOSSARY 491Pantothenic Acid One of the essential B-complex vitamins.Para-aminobenzoic Acid (PABA) A vitamin-like substance thought tobe essential in the diet for maintenance of health of certain fishes. Norequirement determined for fish.Parasite An organism that lives in or on another organism (the host)and that depends on the host for its food, has a higher reproductivepotential than the host, and may harm the host when present in largenumbers.Parasite, ObligateAn organism that cannot lead an independent, nonparasiticexistence.Parasiticide Antiparasite chemical (added to water) or drug (f"d otinjected).ParasitologyParrThe study of parasites.A life stage of salmonid fishes that extends from the time feedingbegins until the fish become sufficiently pigmented to obliterate theparr marks, usually ending during the first year.Parr Markcertain other fishes.Part Per Billion (ppb)One of the vertical color bars found on young salmonids andA concentration at which one unit is containedin a total of a billion units. Equivalent to one microgram per kilogram(t pglkg), or nanoliter per liter (t nl/lite.).Part Per Million (pp-) A concentration at which one unit is containedin a total of a million units. Equivalent to one milligram per kilogram(t t"t/t g) or one microliter per liter (t 4tltiter).Part Per Thousand (ppt or o/oo) A concentration at which one unit iscontained in a total of a thousand units. Equivalent to one gram perkilogram (t g/tg) or one milliliter per liter (l ml/liter). Normally, thisterm is used to specify the salinity of estuarine or sea waters.Pathogen, Opportunistic An organism capable of causing disease onlywhen the host's resistance is lowered. Compare withSecondary Invader.PathologyThe study of diseases and the structural and functionalchanges produced by them.Pectoral Fins The anterior and ventrally located fins whose principlefunction is locomotor maneuvering.Peduncle Disease A chronic, necrotic disease of the fins, primarily thecaudal fin, caused by invasion of a myxobacterium (commonly CTtophagapsychrofhilia) into fin and caudal peduncle tissue of an unhealthyfish. Synonyms: fin rot disease; cold water disease.Pelvic Fins Paired fins corresponding to the posterior limbs of thehigher vertebrates (sometimes called ventral fins), located below orbehind the pectoral fins.PeritoneumThe membrane liningPerivitelline Fluid Fluid lying(chorion) of an egg.the abdominal cavity.between the yolkand outer shell

492 FISH HATCHERY MANAGEMENTPerivitelline Space Area between yolk and chorion of an egg whereembryo expansion occurs.Permanganate, Potassium KMnOa; strong oxidizing agent used as adisinfectant and to control external parasites.Petechia A minute rounded spot of hemorrhage on a surface, usuallypHless than one millimeter in diameter.An expression of the acid-base relationship designated as the logarithmof the reciprocal of the hydrogen-ion activity; the value of 7.0expresses neutral solutions; values decreasing below 7.0 representincreasing acidity; those increasing above 7.0 represent increasinglybasic solutions.Pharynx The cavity between the mouth and esophagus.Phenotype Appearance of an individual as contrasted with its geneticmakeup or genotype. Also used to designate a group of individualswith similar appearance but not necessarily identical genotypes.Photoperiod The number of daylight hours best suited to the growthand maturation of an organism.Photosynthesis The formation of carbohydrates from carbon dioxideand water that takes place in the chlorophyll-containing tissues ofplants exposed to light; oxygen is produced as a by-product.PhytoplanktonMinute plants suspended in water with little or no capabilityfor controlling their position in the water mass; frequentlyreferred to as algae.Pig Trough Sra Von Bayer Trough.Pigmentation Disposition of coloring matter in an organ or tissue.Pituitary Small endocrine organ located near the brain.Planting of Fish The act of releasing fish from a hatchery into aspecific lake or river. Synonyms: distribution; stocking.Plasma The fluid fraction of the blood, as distinguished from corpuscles.Plasma contains dissolved salts and proteins. Compare riiiri Serum.PoikilothermicPollutantthe environment.Having a body temperature that fluctuates with that ofA term referring to a wide range of toxic chemicals andorganic materials introduced into waterways from industrial plants andsewage wastes.PollutionThe addition of any substance not normally found in oroccurring in a material or ecosystem.PopulationA coexisting and interbreeding group of individuals of thesame species in a particular locality.Population Density The number of individuals of one population in agiven area or volume.Portal of Entryhost.The pathway by which pathogens or parasites enter the

GLOSSARY 493Portal of ExitThe pathway by which pathogens or parasites leave orare shed by the host.Posttreatment Treatment of hatchery wastewater before it is dischargedinto the receiving water (pollution abatement).Pox A disease sign in which eruptive lesions are observed primarily onthe skin and mucous membranes.Pox Disease A common disease of freshwater fishes, primarily minnows,characterized by small, flat epithelial growths and caused by a virus asyet unidentified. Synonyms: carp pox; papilloma.Pretreatment Treatment of water before it enters the hatchery.Prevention, Disease Steps taken to stop a disease outbreak before itoccurs; may include environmental manipulation, immunization,administration of drugs, etc.Progeny Offspring.Progeny Test A test of the value of an individual based on the performanceof its offspring produced in some definite system of mating.Prophylactic Activity or agent that prevents the occurrence of disease.Protein Any of the numerous naturally occurring complex combinationsof amino acids that contain the elements carbon, hydrogen, nitrogen,oxygen and occasionally sulfur, phosphorus or other elements.Protozoa The phylum of mostly microscopic animals made up of a singlecell or a group of more or less identical cells and living chiefly inwater; includes many parasitic forms.Pseudobranch The remnant of the first gill arch that often does nothave a respiratory function and is thought to be involved in hormoneactivation or secretion.Pseudomonas Septicemia A hemorrhagic, septicemic disease of fishescaused by infection of a member of the genus Pseudomonas. This is astress-mediated disease that usually occurs as a generalized septicemia.Sea Bacterial Hemorrhagic Septicemia.Pyloric Cecum Sae Cecum.Pyridoxine (Vitamin 86;) One of the B-complex vitamins involved in fatmetabolism, but playing a more important role in Protein metabolism.As a result, carnivorous fish have stringent requirements for thisvitamin.Quaternary Ammonium Compounds Several of the cationic surfaceactiveagents and germicides, each with a quaternary ammoniumstructure. They are bactericidal but will not kill external parasites offish. Generally, they are used for controlling external bacterial pathogensand disinfecting hatching equipment.Radii of Scale Lines on the proximal part of a scale, radiating fromnear center to the edge.

494 trsH HATcHERY MANAGEMENTRandom Mating Matings without consideration of definable characteristicsof the broodfish; nonselective mating.Ration A fixed allowance of food for a day or other unit of time.RayA supporting rod for a fin. There are two kinds: hard (spines) andsoft rays.Rearing Unit Any facility in which fish are held during the rearingprocess, such as rectangular raceways, circular ponds, circulation raceways,and earth ponds.RecessiveCharacter possessed by one parent that is masked in theprogeny by the corresponding alternative or dominant characterderived from the other parent.Reciprocal Mating (Crosses) Paired crosses in which both males andfemales of one parental line are mated with the other parental line.Reconditioning Treatment Treatment of water to allow its reuse forfish rearing.Rectum Most distal part of the intestine; repository for the feces.Red Pest See Motile Aeromonas Disease.Red Sore Disease Sae Vibriosis.Redd Area of stream or lake bottom excavated by a female salmonidduring spawning.Redmouth DiseaseAn original name for bacterial hemorrhagic septicemiacaused by an infection of Aeromonas hydrophila specifically. Synonyms:motile aeromonas disease; bacterial hemorrhagic septicemia.Residue, Tissue Quantity of a drug or other chemical remaining inbody tissues after treatment or exposure is stopped.Resistance The natural ability of an organism to withstand the effectsof various physical, chemical, and biological agents that potentially areharmful to the organism.Resistant, Drug Said of a microorganism, usually a bacterium, that cannotbe controlled (inhibited) or killed by a drug.Reuse, Recycle The use of water more than one time for fish propagation.There may or may not be water treatment between uses and differentrearing units may be involved.Riboflavin An essential vitamin of the B-complex group (B2).RoccalRoeRoundwormSee Quaternary Ammonium Compounds.The eggs of fishes.SaeNematoda.Sac FryA fish with an external yolk sac.Safe Concentration The maximum concentration of a material thatproduces no adverse sublethal or chronic effect.SalinityConcentration of sodium, potassium, magnesium, calcium,

GLOSSARYbicarbonate, carbonate, sulfate, and halides (chloride, fluoride,bromide) in water. Sae Dissolved Solids.Sample A part, piece, item, or observation taken or shown as representativeof a total population.Sample Count A method of estimating fish population weight fromSanitizerindividual weights of a small portion of the population.A chemical that reduces microbial contamination on equipment.Saprolegniasis An infection by fungi of the genus Saprolegnia, usuallyon the external surfaces of a fish body or on dead or dying fish eggs'Saturation In solutions, the maximum amount of a substance that canbe dissolved in a liquid without it being precipitated or released intothe air.Scale Formula A conventional formula used in identifying fishes."Scales 7 + 65 + 12," for example, indicates 7 scales above the lateralline, 65 along the lateral line, and 12 below it.Scales Above the Lateral Line Usually, the number of scales countedalong an oblique row beginning with the first scale above the lateralline and running anteriorly to the base of the dorsal fin.Scales Below the Lateral Line The number of scales counted along arow beginning at the origin of the anal fin and running obliquely dorsallyeither forward or backward, to the lateral line. For certain speciesthis count is made from the base of the pelvic fin.Sea Water Water containing from 3.0 to 3.506 total salts.Secchi DiskA circular metal plate with the upper surface divided intofour quadrants, two painted white and two painted black. It is loweredinto the water on a graduated line, and the depth at which it disappearsis noted as the limit of visibility.Second Dorsal Fin The posterior of two dorsal fins, usually the softrayeddorsal fin of spiny-rayed fishes.Secondary InvaderSedimentAn opportunist pathogen that obtains entrance to ahost following breakdown of the first line of defense.Settleable solids that form bottom deposits.Sedimentation Pond (Settling Basin) A wastewater treatment facility inwhich settleable solids are removed from the hatchery effluent.Selective Breeding Selection of mates in a breeding program to produceoffspring possessing certain defined characteristics.Sensitive, Drug Said of a microorganism, usually a bacterium, that canbe controlled (inhibited) or killed by use of a drug. Sea Resistant,Drug.SepticemiaA clinical sign characterized by a severe bacteremic infection,generally involving the significant invasion of the blood streamby microorganisms.

496 FISH HATCHERY MANAGEMENTSerumThe fluid portion of blood that remains after the blood is allowedto clot and the cells are removed.Settleable SolidsThat fraction of the suspended solids that will settleout of suspension under quiescent conditions.Shocking (Eggs) Act of mechanically agitating eggs, which ruptures theperivitelline membranes and turns infertile eggs white.Short BathA type of bath most useful in facilities having a controllablerapid exchange of water. The water flow is stopped, and a relativelyhigh concentration of chemical is thoroughly mixed in and retainedfor about I hour.Side Effect An effect of a chemical or treatment other than thatSignSiltintended.Any manifestation of disease, such as an aberration in structure,physiology, or behavior, as interpreted by an observer. Note the term"symptom" is only appropriate for human medicine because itincludes the patient's feelings (sensations) about the disease.Soil particles carried or deposited by moving water.Single-pass System A system in which water is passed through fishSludgerearing units without being recycled and then discharged from thehatchery.The mixture of solids and water that is drawn off a settlingchamber.Smolt Juvenile salmonid at the time of physiological adaptation to lifein the marine environment.Snout The portion of the head in front of the eyes. The snout is measuredfrom its most anterior tip to the anterior margin of the eyesocket.Soft-egg DiseasePathological softening of fish eggs during incubation,the etiological agent(s) being unknown but possibly a bacterium.Soft Fins Fins with soft rays only, designated as soft dorsal, etc.Soft Rays Fin rays that are cross-striated or articulated, like a bamboofishing pole.Solubility The degree to which a substance can be dissolved in a liquid;usually expressed as milligrams per liter or percent.Spawning (Hatchery context) Act of obtaining eggs from female fishSpeciesand sperm from male fish.The largest group of similar individuals that actually or potentiallycan successfully interbreed with one another but not with othersuch groups; a systematic unit including geographic races andvarieties, and included in a genus.Specific DrugSpenton others.Spawned out.A drug that has therapeutic effect on one disease but not

GLOSSARY 497SpermatozoonA male reproductive cell, consisting usually of head,middle piece, and locomotory flagellum.Spinal CordSpinesThe cylindrical structure within the spinal canal, a part ofthe central nervous system.Spiny RaysSpleenUnsegmented rays, commonly hard and pointed.Stiff or noncross-striated fin rays.The site of red blood cell, thrombocyte, lymphocyte, and granulocyteproduction.Sporadic Diseasea single case.A disease that occurs only occasionally and usually asStabilization Pond A simple waste-water treatment facility in whichorganic matter is oxidized and stabilized (converted to inert residue).Standard Length The distance from the most anterior portion of thebody to the junction of the caudal peduncle and anal fin.Standard Metabolic Rate The metabolic rate of poikilothermic animalsunder conditions of minimum activity, measured per unit time andbody weight at a particular temperature. Close to basal metabolic rate,but animals rarely are at complete rest. ,Sae Basal Metabolism.Sterilant An agent that kills all microorganisms.SterilizeStockobject.StomachStrainsStressStressorSubacuteTo destroy all microorganisms and their spores in or about anGroup of fish that share a common environment and gene pool.The expansion of the alimentary tract between the esophagousand the pyloric valve.Group of fish with presumed common ancestry.A state manifested by a syndrome or bodily change caused by someforce, condition, or circumstance (i.e., by a stressor) in or on an organismor on one of its physiological or anatomical systems. Any condition thatforces an organism to expend more energy to maintain stability.Any stimulus, or succession of stimuli, that tends to disrupt thenormal stability of an animal.SulfadimethoxineNot lethal; between acute and chronic.pathogens of fishes.Sulfonamide drug effective against certain bacterialSulfaguanidine Sulfonamide drug used in combination with sulfamerazineto control certain bacterial pathogens of fishes.Sulfamerazinepathogens of fish.Sulfonamide drug effective against certain bacterialSulfamethazine (Sulmet) Sulfonamide drug effective against certainbacterial pathogens of fishes.Sulfate Any salt of sulfuric acid; any salt containing the radical SOf .Sulfisoxasole (Gantrisin) Sulfonamide drug effective against certainbacterial pathogens of fishes.

498 FISH HAI'CHERY MANAGEMENTSulfomerthiolate (Thimerfonate Sodium) Used as an external disinfectantof living fish eggs.Sulfonamides Antimicrobial compounds having the general formulaSuperiorH2NSOtand acting via competition with p-aminobenzoic acid in folicacid metabolism (for example, sulfamerazine, sulfamethazine).As applied to the mouth, opening in an upward direction.Supersaturation Greater-than-normal solubility of a chemical as aresult of unusual temperatures or pressures.Supplemental Diet A diet used to augment available natural foods.Generally used in extensive fish culture.Susceptible Having little resistance to disease or to injurious agents.Suspended SolidsSwim BladderSwim-upParticles retained in suspension in the water column.See A,ir Bladder.Term used to describe fry when they begin active swimmingin search of food.SyndromeA group of signs that together characterize a disease.Temperature Shock Physiological stress induced by sudden or rapidchanges in temperature, defined by some as any change greater than 3degrees per hour.Tender Stage Period of early development, from a few hours after fertilizationto the time pigmentation of the eyes becomes evident, duringwhich the embryo is highly sensitive to shock. Also called green-eggstage, sensitive stage.Terramycin SeeOxytetracycline.Testes The male reproductive organs.Therapeutic Serving to heal or cure.Thiamine An essential B-complex vitamin that maintains normal carbohydratemetabolism and is essential for certain other metabolicProcesses.Thiosulfate, Sodium (Sodi,r- Hyposulfite, Hypo, Antichlor) NarS2Ol;Titrationused to remove chlorine from solution or as a titrant for determinationof dissolved oxygen by the Winkler method.A method of determining the strength (concentration) of asolution by adding known amounts of a reacting chemical until a colorchange is detected.Tocopherol Vitamin E; an essential vitamin that acts as a biologicalantioxidant.Topical Local application of concentrated treatment directly onto alesion.Total Dissolved Solids (TDS),Saa Dissolved Solids.Total Length The distance from the most anterior point to the mostposterior tip of the fish tail.

GLOSSARY 499Total Solids All of the solids in the water, including dissolved,Toxicitysuspended, and settleable components.A relative measure of the ability of a chemical to be toxic.Usually refers to the ability of a substance to kill or cause an adverseeffect. High toxicity means that small amounts are capable of causingToxindeath or ill health.Toxicology The study of the interactions between organisms and a toxicant.A particular class of poisons, usually albuminous proteins of highmolecular weight produced by animals or plants, to which the bodymay respond by the production of antitoxins.Transmissionanother.The transfer of a disease aqent from one individual toTransmission, Horizontal Any transfer of a disease agent between individualsexcept for the special case of parent-to-progeny transfer viareproduc tive processes.Transmission, Vertical The parent-to-progeny transfer of diseaseagents via eggs or sperm.Trauma An injury caused by a mechanical or physical agent.TrematodaTumorThe flukes. Subclass Monogenea: ectoparasitic in general,one host; subclass Digenea: endoparasitic in general, two hosts ormore.An abnormal mass of tissue, the growth of which exceeds and isuncoordinated with that of the tissues and persists in the same excessivemanner after the disappearance of the stimuli that evoked thechange.TurbidityPresence of suspended or colloidal matter or planktonicorganisms that reduces light penetration of water.Turbulencestirring forces.Agitation of liquids by currents, jetting actions, winds, orUbiquitousUDNUlcerExisting everywhere at the same time.Saa Ulcerative Dermal Necrosis.A break in the skin or mucous membrane with loss of surface tissue;disintegration and necrosis of epithelial tissue.Ulcer Disease An infectious disease of eastern brook trout caused bvthe bacterium Hemophilus piscium.Ulcerative Dermal Necrosis (UOt{) A disease of unknown etiologyoccurring in older fishes, usually during spawning, and primarilyinvolving salmonids.United States Pharmacopeia (USp) An authoritative treatise ondrugs, products used in medicine, formulas for mixtures, and chemicaltests used for identity and purity of the above.

500 r'tsH HA'rcIIIrRy N,TANACEMEN r'Urea One of the compounds in which nitrogen is excreted from fish inthe urine. Most nitrogen is eliminated as ammonia through the gills.IJremia The condition caused by faulty renal function and resultins inexcessive nitrogenous compounds in the blood.Urinary Bladder The bladder attached caudally to the kidneys; thekidneys drain into it.Urogenital Pore External outlet for the urinary and genital ducts.VaccineA preparation of nonvirulent disease organisms (dead or alive)that retains the capacity to stimulate production of antibodies againstit. See Antigen.Vector A living organism that carries an infectious agent from aninfected individual to another, directly or indirectly.Vein A tubular vessel that carries blood to the heart.Vent The external posterior opening of the alimentary canal; the anus.Ventral Fins Pelvic fins.VHS See Yiral Hemorrhagic Septicemia.Viable Alive.Vibriosis An infectious disease caused by the bacterium Vibrio anguillarium.Synonyms: pike pest; eel pest; red sore.Viral Hemorrhagic Septicemia (VHS) A severe disease of troutcaused by a virus of the Rhabdovirus group. Synonyms: egtveddisease; infectious kidney swelling and liver degeneration (f NUI-) ;trout pest.Viremia The presence of virus in the blood stream.Virulence The relative capacity of a pathogen to produce disease.Vitamin An organic compound occurring in minute amounts in foodsand essential for numerous metabolic reactions.Vitarnin D A radiated form of ergosterol that has not been provedessential for fish.Vitamin K An essential, fat-soluble vitamin necessary for formation ofprothrombin; deficiency causes reduced blood clotting.Vitamin Premix A mixture of crystaline vitamins or concentrates usedto fortify a formulated feed.Viviparous Bringing forth living young; the mother contributes foodtoward the development of the embryos.Vomer Bone of the anterior part of the roof of the mouth, commonly triangularand often with teeth.Von Bayer Trough A l2-inch V-shaped trough used to count eggs.'WarmwaterSpecies Generally, fish that spawn at temperatures above60'F. The chief cultured warmwater species are basses, sunfish, catfish,and minnows. ,Sea Coldwater Species; Coolwater Species.

GLOSSARY 501Water HardeningProcess by which an egg absorbs water that accumulatesin the perivitelline space.Water Quality As it relates to fish nutrition, involves dissolved mineralneeds of fishes inhabiting that water (ionic strength).Water Treatment Primary: removal of a substantial amount ofsuspended matter, but little or no removal of colloidal and dissolvedmatter. Secondary: biological treatment methods (for example, bycontact stabilization, extended aeration). Tertiary (advanced):removal of chemicals and dissolved solids.Weir A structure for measuring water flow.W'estern Gill Disease See Nutritional Gill Disease.Whirling Disease A disease of trout caused by the sporozoan protozoanMyxosoma cerebralis.White Grub An infestation by the metacercarcial stage of Neodiplostomummulticellulata in the liver of many freshwater fishes.White Spot Disease A noninfectious malady of incubating eggs or onthe yolk sac of alevins. The cause of the disease is thought to bemechanical damage. Also see lch.Yellow Grub An infestation by the metacercarial stage of Clinostomummarginatum.Yolk The food part of an egg.Zooplankton Minute animals in water, chiefly rotifers and crustaceans,that depend upon water movement to carry them about, having onlyweak capabilities for movement. They are important prey for youngfish.Zoospores Motile spores of fungi.Zygote Cell formed by the union of two gametes, and the individualdeveloping from this cell.

IndexThe Table of Contents for this book also is intendedas a functional index.Acidity (pH)natural waters I l, 15rearing ponds I l0-l l2Antimycin A, fish control 93Ammoniaestimation, hatchery water 24-25ionization tables 378-382pond effluent 27production per pound feed 26removal: chlorine oxidation 23; ion exchange 22; biologicalnitrification 2l-22toxicity 20-21upper limit for fish l4Bass, largemouthbroodstock: acquisition 132; maturation 136carrying capacity, ponds 75-76diseases: bacterial gill disease 301; European gill rot 314-315;motile aeromonas septicemia (MnS) SOgeggs: disinfection 189; temperature units l9l50ll

504 FISH I{A'TCHERY MANACFT,MEN TBass, largem outh (continued)feeding: guides 253-254; habits 136-137rearing-pond management 102, 137, 151spawning 136-137, 151, 152, 192; hormone-induced 173temperature requirements 136-137, l7ltransportation: small containers 366; tank carrying capacity363treatment, formalin 276use of forage fish 136Bass, smallmouthanesthetics 359broodstock acquisition 132disease, European gill rot 314eggs, temperature units l9lfeeding guides 253-254spawning 136,152-154temperature requirements 136-137Bass, stripedbroodstock acquisition 132carrying capacity, ponds 77disease, European gill rot 314eggs: development 160-164; incubation 196; sampling159-160; temperature units l9lfeeding guide 254grading 83oxygen requirements 8rearing-pond management 102spawning 134-135, 156, 159, 164-165; hormone-induced 173temperature requirements I 34-135transportation: carrying capacity 363; stress 358-359treatment, formalin 276tolerance, pH I IBiological design criteria 5l-55Biological Oxygen Demand (nOn), production per pound feed 27Bluegillbroodstock acquisition 138carrying capacity, ponds 76culture 154diet 138disease, bacterial gill disease 301eggs, temperature units 191rearing-pond management 102, 138

I N I)F,X 505Bluegill \continued)spawning 136; natural 151temperature requirements 136transportation: small containers 366; tanks l')63treatment, formalin 276used as forage fish 140Box filter 93Branding 14tlCage culture 48-49Calciumfertilizer 100-l0lhatchery water l5Carbon dioxidehatchery water 15plant growth 97pond acidity 110-112tolerated, fish 9-10Carp, commondiseases: European gill rot 314; furunculosis 306; hemorrhagicsepticemia 266; Lernaea 3li4; spring viremia'267source, pituitary hormone 172spawning 136; hormone-induced 173stress, disease 267temperature requirements 136Carrying capacity 63-7{lCatfish, bluebroodstock selection 148disease, channel catfish virus disease 298tolerance, salinity l4Catfish, channelbroodstock selection 148capture 132carrying capacity: pond 138 (broodstock), 76-77 (fingerlings);raceways 77diet 13udiseases: Ambiphrya \Scyphidia) 323; bacterial gill disease 301;channel catfish virus disease 267, 298; Cleidodisrus 330;Epistltis 319-320; fungus disease ("ggs) st+; furunculosis306; Henneguya 32!t; Ich 316; Ichtyobodo (Costia) 316; motileaeromonas septicemia (MAS) 309; Trichophrla 323

I,' ISH HA'f CH E,IIY N'I ANAGI]M IiN'fCatfish, channel (continued)eggs: handling 154-155; hatching jars 196;195; temPerature units l9lfeeds and feeding: conversion 226, 227; energy226-227; fish flavor 224; floating and sinkinglated 217 , 400; frequen cy 257; guide 249-252;sizes 259availability235; formuinitial256;grading 84growth, temPerature- related 2l Ilight control 171,ri,.i,ior,, carbohydrates 218-220; diseases 390-393; lipids224; proteitts 217; vitamins 227-228selective breeding 147sex determination 138spawning 134-135; hormone-induced 173; pens and receptacles155stress 267temperature: control 171; requirements 134-135; StandardEnvironmental Temperature (SET) 211tolerance: ammonia 21; nitrite 22; pH 11; salinity 14; temperature134_137; total dissolved solids l2to*lcityt ammonia 21; nitrite 22; toxaphene' feeds 233transportation 362-363; small containers 367treatments: copPer sulfate 277; forrnalin 276; nitrofurans 281;potassrum Permanganate')78; salt 275; Terramycin 280Catfish, flatheadspawning 134-135temperature requirements 134-1 35Catfish, white' broodstock selection 148Char, Arctic, sPawning channels 150Chemical Oxygen Demand (COO), pond effluent 27Chemicals (ser Drugs and chemicals)Chlorineammonia removal, hatcherY water 23decontamination: equipment 283; hatchery 284fish control 93neutralization 283pond disinfection 90toxicitY 14,283Circular rearing units 40-43Clinoptilolite, ion-exchange ammonia removal 22Condition factor, calculation 6lincubation trough

Crayfish, problem in ponds 114Density lndex 7l-74Diseasesbacterial: columnaris 302-303; enteric redmouth (EnU)306-308; fin rot 304; furunculosis 304-306; bacterial kidneydisease 312-313; motile aeromona septicemia (MAS)307-310; peduncle disease 303-304; vibriosis 310-3llcertification 293control 263- 265environmental: blue sac 268; coagulated yolk (white-spot)268; gas bubble disease 9fungal 3 l4-3 l5immunization 286-288inspections 292-293leaflets 342-344nutritional 390-393parasitic: Ambiphrya \Sclphidia) 321, 323 Argulus 334; Ceratomlxa326-327; Chilodonella 319; Cleidodiscus 330, 332; Dactylogltrus330; Epistylis 319-322; Gyrodactylus 330-33 l; Hennegula324-326; Hexamita 323-324; Ichtyobodo \Costia)315-3 l6; Ichthlophthirrus 316-319; Lernaea 334; Ple*tophora328-329; Sanguinicola 332-333; Trichodina 320-321 ; Trichophrya322-323recognition 264-265regulations 289-292resistance 286-287treatment 266-270; constant-flow 272, 403; drug coating, pellets405; feeding, injection 273; flush 272; prolonged bath27t,402-403vaccination 288-289viral: channel catfish virus disease (CCV) 267,298; herpesvirusdisease of salmonids 298-299; infectious hematopoieticnecrosis (IgN) ZOZ, 296-297; infectious pancreaticnecrosis (IPN) 2S+; lymphocystis disease 299-300; viralhemorrhagic septicemia (VHS) 295-296Dissolved gas criteria 10Drugs and chemicalsdosages and characteristics: acriflavin 281-282; calciumhydroxide 282; copper sulfate 276-277; de-z-butyl tinoxide 282; formalin 275-276; iodophores 282; Masoten282-283; nitrofurans 280-281; potassium permanganate277-278; quaternary ammonium compounds 278-279; salt275; sulfonamides 281; Terramycin 279-280

508 !'tsH HA't cH[,Ry NIANAc;F]MltN lDrugs and chemicals (continued)registration 274-275storage 27 4Earthen ponds 47-4ttEel. American. infected with Ich 317Eggs (2see also individual species)disinfection 189, 275, 282, 285, 314transportation (shipping) 193English- metric conversions 375-37 7Feeds and feeding (see also individual species)application practices 238-239calculations 242 255conversion 239,242Daphnia, food source 248frequency 255-257guides: coolwater fishes 248-249; salmonids 239-248; warmwaterfishes 249-254fish meal 215formulated: antioxidants 232; closed 236; deficiencies 264,390-400; specifications 390-400; dust, particles 234, 236,238; energy levels 225-227; fat-soluble vitamins 227; fibercontent 231, 232, 236; floating 235, 251; mineral levels229-2311 moisture 234, 235,238; open 235-236; pigmentation232, 235; protein levels 215-217, 2J6; sinking 234;levels 227-229, 232; water-trace minerals 231; vitaminsoluble vitalr'ins 227habits, broodfish 132-134handling 236-238hatchery constant 245manufacturing: lipid rancidity 221, 222, 238; lipid toxicity222; organic toxicants 233, 390-400; pesticide contamination221; spray coating 235, 405; temperature 234,235natural foods 233packaging 236performance 238storage 235-238Fertilizerscombinations 101-102composition 97pond application 96

INDEX 509Flow Index 67-71Forage fishgoldfish 142-143herring 140minnow, fathead l4l-142shad 140shiner, golden 143-144sucker, white 140-141tilapia 140, 144Goldfishdiseases: Ambiphrya (scyphidia) 323; Chilodonella 319; furunculosis306; Lernaea 334; motile aeromonas septicemia (MAS)308rearing-pond management 102spawning 136; hormone-induced 172temperature requirements 136tolerance, nitrogen gas 9used as forage fish 140,142-143Growth projections 62-63Hatchery design standards 34-39Heavy-metal toxicity: cadmium, copper, lead, mercury, zinc 13, l4Hyamine, pond disinfection 90Hybrid vigor 148Hybridization (cross breeding) 144, 148 149Hydrogen cyanide 10Hydrogen sulfidehatchery water l5rearing ponds I 12toxicity 10, l4Interspecific hybrids 148-149Inventory methods 78-83Iron, hatchery water l5Lamprey, sea, furunculosis 306Length-weight relationships 60-61; tables 406-467Lime, pond disinfection 89-90

510 FISH HATcIIERY MANAGFIM!lN l'Magnesium, hatchery water 15Manganese, hatchery water l5Metric- English conversions 375-376Minerals, water enrichment l3Muskellungebroodstock acquisition 132eggs, temperature units 191, 192feeds and feeding: formulated248-249; initial 256forage fish for 140248-249, 399, 400; guideshybridization 14tinutrition: diseases 390-393; protein requirements 217spawning 134-135, 157transportation, carrying capacity 364Muskie, tiger (see also Pike, northern; muskellunge), hut.h"tyconstant 249Nets, seinesbroodfish capture 132inventory 82-83Nitratehatchery water l5fertilizer 98pond effluent 27production per pound feed 26Nitrite, toxicity 14, 22Osmoregulation 213Oxygenhatchery water 6-8, l5ponds 108-l l0saturation nomogram 5Ozonesterilant l8-19toxicity l4Pen rearing 50pH (see acidity)Phosphorus, phosphatehatchery water l5fertilizer 98-100pond effluent 27production per pound feed 26Pickerel, chain, protein requirements 217

INDEX5I IPike, northernbroodstock acquisition 132carrying capacity, ponds 77-78diseases: European gill rot 314; furunculosis 306eggs 159; temperature units 191feeds and feeding: formulated 248, 399, 400; frequency 256;guide 248-249forage fish for 140grading 83hybridization 148nutrition: diseases 390-393; protein requirements 217spawning 134-135, 156-159sperm storage 168transportation: small containers 367; tank carrying capacity364temperature requirements 134-l 35Polychlorinated biphenyls (PCB's), toxicity l4Potassium, fertilizer 100Rearing facilitiescharacteristics 52-53selection 50Record keepingfactors considered I l4-l l5hatchery codes 387-388lot history production charts I 17-122ponds 126production summaries 122-126rectangular rearing unitscirculation ponds 46-47tanks, raceways 43-46Roccal, pond disinfection 90Rotational line-crossing | 45-l 47Rotenone, fish control 93Salinity l3-14Salmonanesthetics 170, 359-360broodstock acquisition 132diseases: bacterial gill disease 300; bacterial kidney disease312-3 13; Ceratomlxa shasta 326; Chilodonella 319; columnarisdisease 302; enteric redmouth (EnU) 307; fungus314; furunculosis 304-306; Gyrodactylis 330, Henneguya 325;

512 FISH HATCHL,RY ISalmon lcontinued)herpesvirus disease 298-299; Hexamita salominis 323; Ich316; Ichtlobodo (Costia) 316; infectious hematopoieticnecrosis (IHN) 296-297; infectious pancreatic necrosis(f pru) 294; Mltxosoma cerebralis 327; peduncle disease303-304; Trichodina 320; vibriosis 311; viral hemorrhagicsepticemia (VHS) Zg0eggs: disinfection 189, 2ti2; incubation 193-200; storage 193;temperature units l9lfeeds and feeding: energy availability 226; formulated 209,235, 396-397, 400; frequency 255-257; guides 239-248;sizes 258; spawning activity 133; storage 236-238handling, loading 85, 358-359nutrition: carbohydrates 218-219; diseases 390-393; lipids222_223; proteins 215 (f.y), 216 (yearlings) ; vitamins227-228spawning 165-167sperm storage 193stress, disease 265-268temperature: requirements 134-135; Standard EnvironmentalTemperature (Srr) zt Itransportation: methods (sre Chapter 6); tank carrying capacity361treatments: acriflavin 281; copper sulfate 276-277; formalin275-276; nitrofurans 280-28 l; quaternary ammonium compounds278-279; salt 275; sulfonamides 281; Terramycin279-280Salmon, Atlantic (see also Salmon)broodstock acquisition 132diseases: bacterial kidney disease 312; Ceratomyxa shasta 326;enteric redmouth (EnU) 307; herpesvirus disease 299;vibriosis 3ll; viral hemorrhagic septicemia (VHS) 296egg development 191spawning 134-135, 165temperature requirements 134-135Salmon, chinook (see also Salmon)diseases: bacterial kidney disease 312; Ceratomyxa shasta 326;enteric redmouth (ERM) 307; Henneguya 325; infectioushematopoietic necrosis (IHN) 296egg development l9lfeeding frequency 257gamete storage 169nutrition, protein requirements 216spawning 134-135; channels 150temperature requirements I 34-1 35

INDEX513Salmon, chum (saa a/so Salmon), carbon dioxide tolerance 9Salmon, coho (saa a/so Salmon)carbon dioxide tolerance 10eggs, temperature units 191feeding guide 242nutrition, folic acid deficiency 223oxygen requirements 7-8spawning 134-135; channels 150temperature requirements 134-135Salmon, sockeye (see also Salmon)diseases: bacterial kidney disease 312;herpesvirus disease 298; infectious(rHN) 296Ceratomyxa shasta 326;hematopoietic necrosiseggs: sensitivity, artificial light 171; temperature unitsspawning 134-135, 150; photoperiod control 170sperm storage 169temperature requirements 134-135Saltwater fishflesh flavor 233protein utilization 214vitamin requirements 229Sauger, broodstock acquisition 132Screens, perforated aluminum 9lSea (ocean) ranching 50Sedimentation basins 27-30Selective breeding 144, 145Settleable solidspond effluent 27production per pound feed 27Shad, Americanspawning 136temperature requirements 136Shiner, goldenanesthetics, transportation 359disease, Pleistophora oaariae 328spawning 136temperature requirements 136used as forage 140, 143-144Shrimp, tadpole, pond nuisance 113-ll4Sock filter 93Solid waste disposal 30-31Spawning (see also individual species)air-spawning 165-166aquarium 156hand stripping 156-159191

!'lSII HA I CH!lRY MAr-r\GllN{lrN lSpawning (continued)natural 149-155open pond 154pen 154species summaries 134-137Specimen, disease diagnosiscollection, shiPPing 335-342preservation 341-342Standard disease diagnostic procedures 292Standard Environmental Temperatures (SET) 2l IState abbreviations 389Steelhead (see also Trout)broodstock acquisition 132diseases: Ceratomyxa shasta 3'26; enteric redmouth (nnU)eggs, incubation l9!)spawning 165survival, growth' hatchery-wild crosses 147S tre ssdiseases 265-268factors 265; 267 -')68handling 85, ll58Sunfish, redeardisease, bacterial gill disease 301eggs, temPerature units l9lformulated feed l3tJrearing-pond management 102Suspended solids 10-l ISwedish pond 433OZTemperature requirements lll4-137Total alkalinity, hatchery water 15Total hardness' hatcherY water l5Transportationairplane :148-349stress 358-359tanks: aeration 353-355; anesthetics 359-360; carrying capacity360-364; circulation systems 352-353; design 350-352;insulation (rf-fu.tot) 350-351 ; water quality 355-i158trucks 348-350Troutanesthetics 170, :159-360broodstock acquisition 132

'lrout (continued)diseases: bacterial gill disease 300; bacterial kidney disease312-3 13; Ceratomyxa shasta 326; Chilodonella 319; columnarisdisease lj02; copepod parasites 333-334; enteric redmouth(ERM) 306-308; EpisQlis 319-322; fin rot 304;fungus l'i14; furunculosis 300, 304-306; Gyrodacelus330-:l3l; herpesvirus disease 298-299; Hexamita salmonis323-324; Ich 316-319 ; Ichtlobodo (Costia) 315-317; infecti

ir l 6 I-tsH Il.,\'t ('Ht.ItY l\{,\N'\(;l.r.lllN I', | .. r\L roul \(onunuea Iused, forage fish 140Trout, brook (see a/sa Trout)hybridization l4tiinitial feeding 25(imineral absorption l3shipping, small containers 3(i(jspawning 13,1 135temperature requirements I 34-lilir'f rout, brown (see also Trout)initial feeding 25(ispawning l3't-13irtemperature requirements 134-135Trout, cutthroat (sre Iro.,t)Trout, lake (sae a/so Trout)hybridization 1'{tlspawning 134 13lrtemperature requirements l3't 135Trout, rainbow (see also Trout)anesthetic 170feeds and feeding: guide 240; initial 256nutritional diseases 230selective breeding 145spawning methods 134 135temperature requirements I 34-l l']5transportation, small containers 36(j'furbidity, ponds ll2V-trap tt(j- 87Vertebrates, ponds 114Volume-weight chemical calculations 402Walleyebroodstock acquisition li32carrying capacity, ponds 77-78disease, lymphocystis 299-300dissolved solids absorption l4eggs 159, 1!)2; temperature units 191feeds and feeding: formulated 24t], 399, 400; guide 248-249;initial 256forage fish for 140

Walleye \continued)nutrition: diseases 390-393; protein 217oxygen requrrements tirearing-pond management 102spawning l:i2, 134-135temperature requirements lll,t-135transportation: small containers li('i7; tank carrying capacityWater364loss, ponds 113quality criteria I'1, 15reconditioning 1{)supply structures 90Weed control, aquaticbiological 103 104chemical 104-105mechanical 103Weight-volume chemical calculations .102Weir operation, use 384-3U6n U.S. C;OVERNMEN'I PRIN'IINC OIUCE: lr)lt2-:]21) 150

Walleye (continued)nutrition: diseases 390-393; protein 217oxygen requirements tlrearing-pond management 102spawning ll'12, 134 135temperature requirements 134- 135transportation: small containers 367; tank carrying capacity364Waterloss, ponds 113quality criteria 14, l5reconditioning l9supply structures 1)0Weed control, aquaticbiological 103-104chemical 104-105mechanical l0llWeight-volume chemical calculations,t02Weir operation, use 384-386IND|X 517t Ll.S. (;OVIIRNMEN I PRIN TtNC ()FFTCE: 1118232r) l.;0