HATCHERY REQUIREMENTS 49 



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Figure 22. A pond catch basin should have a supply line (arrow) to 

 provide fresh water to the fish when they are collected in the basin. 

 This pond outlet also has a valve to open the pond drain. 



away wastes and provide fresh water. Cage culture is readily adapted to 

 areas that cannot be drained or from which fish cannot be readily har- 

 vested. However, good water circulation must be assured, as an oxygen 

 depletion in water around cages can cause catastrophic fish losses. Disease 

 control is very difficult in cage culture and labor requirements are high. 

 Feeding and treatment for disease must be done by hand. 



Largemouth bass fingerlings have been experimentally grown in cages. 

 Cylindrical instead of rectangular containers were used to prevent crowd- 

 ing in corners, which might cause skin damage to active fish such as bass. 

 Moist trout pellets were fed to the fish; a retaining ring kept the food in- 

 side the cage until it could be eaten. 



Figure 23. Cage culture of catfish. IFWS photo.) 



