Fish Hatchery Management - fisheries & aquaculture

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.