Farming freshwater prawns

More documents

Recommendations

Info

FIGURE29The water distribution and treatment system is site specific;this is one exampleACBDNOTES: PUMPS 1 AND 2 MUST BE PERMANENT;PUMPS 3, 5, AND 6 CAN BE THE SAMESUBMERSIBLE PUMP; PUMP 4 COULD ALSOBE A SEPARATE SUBMERSIBLE (NEVER USE THESAME SUBMERSIBLE FOR TREATED WATER ANDUNTREATED WATER); SOME PUMPS CAN BEELIMINATED IF YOU DESIGN YOUR HATCHERYSO THAT THE TREATMENT AND MIXING TANKSARE ELEVATED SO THAT WATER CAN BEDRAWN FROM THEM BY GRAVITYAseawater intakeEFBCfreshwater intakepump 1HDEFGpump 2 (could bereplaced by gravity)treatment tank(s)settling tanks(s)pump 3GEHpump 4Ipump 5IJKLMmixing tank(s)postlarval holding tankspump 6hatchery tanksJKNOArtemia tanksdischarge by gravityLMNOOSOURCE: EMANUELA D’ANTONIFRESHWATER PRAWNS48
Water dischargeYou should take care to see that water discharged from your hatchery does not contaminatethe incoming sources of hatchery freshwater and seawater. This is particularly importantwhere surface sources of water are utilized. In a coastal hatchery using surface seawater,tidal and current characteristics should be taken into account in determining thelocations of the intake in relation to the farm effluent discharge. Where surface freshwateris taken from a river the farm effluent should be discharged well below the water intakepoint. Do not discharge water containing chemicals, such as heavy loads of chlorine forequipment disinfection, into open waters.LightThe ‘greenwater’ larval rearing system, which has generally fallen out of favour in commercialhatcheries in the past decade, obviously required light. The phytoplankton bloomin those systems provided shade for the larvae and helped to maintain good water quality.Nowadays, almost all freshwater prawn hatcheries operate a ‘clearwater’ system. Youshould not expose larvae to direct sunlight, which appears to be harmful. It is therefore recommendedthat 90% of the surface of ‘clearwater’ flow-through tanks kept outdoors shouldbe covered. The material used to cover the tank can be whatever is locally and cheaplyavailable, provided it does not disintegrate when exposed to sunlight, heavy rain or strongwinds. This prevents the growth of phytoplankton and reduces the incidence of whatTakuji Fujimura referred to as ‘skin cancer’.Some outdoor backyard hatcheries completely cover their hatchery tanks with blacktarpaulin to prevent the spray generated by the aeration in neighbouring tanks transferringdisease organisms. Most hatchery managers insist that some light, especially naturallight, is essential for good larval survival; they therefore provide transparent roofs to theirhatcheries but partially cover their tanks with asbestos or plastic sheeting to keep light toa minimum (see Figure 18). Natural light can be replaced by artificial sources (tungsten orspecial blue-black fluorescent tubes) which contain the near-blue (non-toxic) ultravioletwavelength. Successful rearing has been reported at light intensities varying between 250and 6 500 lux. However, a level of 250-800 lux is recommended for commercial hatcheries.Natural light is preferable but you can use artificial light to increase the intensity oncloudy days and to extend the day length. Excessive growth of algae tends to foul the biofiltersin recirculation systems and you should shade these filters, while providing indirectlight to the culture tanks themselves.FiltersTwo types of filtration equipment are used in hatcheries, physical and biological. Physicalfilters remove the solid wastes, mainly faeces, uneaten feed and bacterial debris. Biologicalfilters, sometimes called biofilters, are essential components of recirculation systems forfreshwater prawn hatcheries. They remove the ammonia excreted by the larvae and livefeeds, as well as that formed by the decomposition of organic matter. In these filters,ammonia is converted first to nitrites and then to nitrates. Some physical filtration occurswithin biofilters. Solid wastes are also removed during daily tank siphoning.Physical filters include sand filters, drum screen filters, and expanded media filters(e.g. bead filters). They can be either up-flowing (Figure 30) or down-flowing but need to beeasy to clean and should be designed to minimize water losses in the system. Sand or beadfilters may be adequate for freshwater prawn hatcheries. However, drum screen filters donot clog so much and have an automatic backwash. In sand filters a particle size of 850 µmCHAPTER 449
Page 1 and 2:
Farming freshwater prawnsA manual f
Page 3 and 4:
The designations employed and the p
Page 5 and 6:
abstractTHE ORIGINAL MANUAL on fres
Page 7 and 8:
table of contentsABSTRACTPREFACEINT
Page 9 and 10:
Feed type 114Measuring feed efficie
Page 11 and 12: 17. Measuring soil pH 10618. Reason
Page 13 and 14: 87. Keeping market-sized prawns ali
Page 15 and 16: major subject of cultivation becaus
Page 17 and 18: has little relevance, especially be
Page 19 and 20: (zoeae) are just under 2 mm long (f
Page 21 and 22: TABLE1Body segments (somites) in Ma
Page 23 and 24: Figure 5The major malemorphotypes o
Page 25 and 26: tions, where a breeding stock of bo
Page 27 and 28: most hatcheries operated on flow-th
Page 29 and 30: BOX 1Removal of iron and manganeseW
Page 31 and 32: TABLE 3Artificial brackishwater (12
Page 33 and 34: TABLE 4Diluting seawater and brine
Page 35 and 36: mentally cultured at up to 10 ppt;
Page 37 and 38: cal quality and its lack of predato
Page 39 and 40: CHOOSING YOUR SITE: SOIL CHARACTERI
Page 41 and 42: such as fertilizers and equipment.
Page 43 and 44: perate (usually originating from st
Page 45 and 46: 3.2 Holding your broodstock in temp
Page 47 and 48: ing system that consists of a 300 L
Page 49 and 50: 4CHAPTERHatchery phaseALL FRESHWATE
Page 51 and 52: SOURCE: HASSANAI KONGKEOand dust. T
Page 53 and 54: FIGURE17This shows the water flow t
Page 55 and 56: Figure 21The water inthese larvalta
Page 57 and 58: FIGURE24Turn-down drains are the be
Page 59 and 60: FIGURE26Installing a ring main air
Page 61: Figure 28Power supplies arenot alwa
Page 65 and 66: is recommended. The volume of these
Page 67 and 68: then multiply to cope with the nitr
Page 69 and 70: Regular monitoringof larval waterqu
Page 71 and 72: initial stocking rates shown inBox
Page 73 and 74: Recommendations forgood larval wate
Page 75 and 76: FIGURE35Many of the larvae that go
Page 77 and 78: TABLE 8Hatchery feeding scheduleLAR
Page 79 and 80: ing to avoid BSN leaving the tank.
Page 81 and 82: TABLE10The major diseases known to
Page 83 and 84: Notes on potential disease problems
Page 85 and 86: FIGURE36aA method of evaluating the
Page 87 and 88: occurred). You are therefore recomm
Page 89 and 90: 5CHAPTERPostlarval holdingand nurse
Page 91 and 92: Figure 39Substrates can beused in n
Page 93 and 94: FIGURE41Postlarvae in plastic bags
Page 95 and 96: pH and temperature of the rearing f
Page 97 and 98: It is difficult to recommend exact
Page 99 and 100: 6CHAPTERGrow-out phaseFRESHWATER PR
Page 101 and 102: FIGURE44ponds may become low enough
Page 103 and 104: FIGURE46Pond banks should have the
Page 105 and 106: FIGURE50The dissolved oxygen levels
Page 107 and 108: Figure 53Where thetopography of the
Page 109 and 110: Figure 56The outletstructure,someti
Page 111 and 112: Figure 58This freshwaterprawn pondh
Page 113 and 114:
FIGURE59 cont.CROSS SECTIONSOURCE:
Page 115 and 116:
Figure 64Long-shaftaeratorin action
Page 117 and 118:
there is only a single stocking), t
Page 119 and 120:
TABLE16Lime requirements for treati
Page 121 and 122:
semi-intensive stocking rates vary
Page 123 and 124:
Keeping rootedplants out ofyour pon
Page 125 and 126:
advantages obtained in temperate cu
Page 127 and 128:
Polyculture of freshwater prawnswit
Page 129 and 130:
only increases the availability of
Page 131 and 132:
Using water-stable feeds provides y
Page 133 and 134:
MEASURING FEED EFFICIENCYYou should
Page 135 and 136:
Example of feeding ratefor freshwat
Page 137 and 138:
allowed to become too low and there
Page 139 and 140:
found to be hosts for the bopyrid i
Page 141 and 142:
Figure 81A large BCMacrobrachiumros
Page 143 and 144:
7CHAPTERHarvesting andpost-harvest
Page 145 and 146:
FIGURE83You can cull-harvest your p
Page 147 and 148:
FIGURE85Larger ponds may also be cu
Page 149 and 150:
Figure 91HarvestingMacrobrachiumros
Page 151 and 152:
(Figure 95). To kill a batch of 50
Page 153 and 154:
described earlier in this manual) a
Page 155 and 156:
Once the prawns arrive at the point
Page 157 and 158:
properly. They should also be displ
Page 159 and 160:
ANNEX 1, Figures 1-12Macrobrachium
Page 161 and 162:
4ANNEXSource, hatching andenrichmen
Page 163 and 164:
The nutritional quality and physica
Page 165 and 166:
decapsulation improves the energy c
Page 167 and 168:
starved versus enriched BSN. Lavens
Page 169 and 170:
1ANNEX 4TABLEDetermining hatching p
Page 171 and 172:
4ANNEX 4TABLE Hydrating and decapsu
Page 173 and 174:
7ANNEX 4TABLE1. Set up the hatching
Page 175 and 176:
grades the particles and washes the
Page 177 and 178:
2. Stock estimation when postlarvae
Page 179 and 180:
animal, particularly within the gil
Page 181 and 182:
ANNEX 7 FIGURE1The size of the mesh
Page 183 and 184:
8ANNEXSize managementAS MENTIONED I
Page 185 and 186:
2. BehaviourThe behavioural charact
Page 187 and 188:
ANNEX 8 FIGURE3Changing the stockin
Page 189 and 190:
ANNEX 8 FIGURE4Orange claw (OC) and
Page 191 and 192:
9ANNEXFarm-made pond feedsTHIS ANNE
Page 193 and 194:
ANNEX 9, Figure 3Farm-made feedsnee
Page 195 and 196:
4ANNEX 9TABLEFarm-made grow-outfeed
Page 197 and 198:
which the requirements are applied.
Page 199 and 200:
Carapace:Caridean:Cephalon:Chela:Ch
Page 201 and 202:
Genital pores:Gill chamber:Greenwat
Page 203 and 204:
Puddling:Rostrum:Salinity:Sequester
Page 205 and 206:
ConversionsTHIS SECTION OF THE ANNE
Page 207 and 208:
Financial considerationsSOME COMMEN
Page 209 and 210:
ReferencesAlston, D.E. & Sampaio, C
Page 211 and 212:
Fujimura, T. & Okamoto, H. 1972. No
Page 213 and 214:
New, M.B., Singholka, S. & Vorasaya
Page 215:
This new manual, which replaces an
show all

Farming freshwater prawns

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?