Fish Hatchery Management - fisheries & aquaculture

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