Fish Hatchery Management - fisheries & aquaculture

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.