Fish Hatchery Management - fisheries & aquaculture

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.