BROODSTOCK, SPAWNING, AND EGG HANDLING 



155 



number of broodfish in the pond and the rate at which spawning is prog- 

 ressing. In checking a container, the culturist gently raises it to the surface. 

 If this is done quietly and carefully, the male usually is not disturbed. Cau- 

 tion should be used, because an attacking male can bite severely. If the wa- 

 ter is not clear, the container can be slowly tilted and partly emptied. 



Catfish eggs may be handled in different ways. The eggs may be re- 

 moved, or left in the spawning pond to hatch and the fry reared in the 

 ponds. Removal of the eggs has several advantages. It minimizes the 

 spread of diseases and parasites from adults to young, and provides for egg 

 disinfection. The eggs are protected from predation and the fry can be 

 stocked in the rearing ponds at known rates. 



The pen method of spawning catfish utilizes pens about 10 feet long and 

 5 feet wide located in a row in the spawning ponds (Figure 48). They are 

 constructed of wood, wire fencing, or concrete blocks. They should be en- 

 closed on all four sides but the bank of the pond may be used as one side. 

 The sides should be embedded in the pond bottom and extend at least 12 

 inches above the water surface to prevent fish from escaping. Water should 

 be 2-3 feet deep. 



Location of the spawning container in the pen is not critical, but gen- 

 erally it faces away from the pond bank. Broodfish are sexed and paired in 

 the pens. Usually the best results occur when the male is equal in size to, 

 or slightly larger than, the female. This discourages the female from eating 

 the eggs that are being guarded by the male. After spawning, eggs and 

 parent fish may be removed and another pair placed in the pen. Some- 

 times, the female is removed as soon as an egg mass is found, and the male 

 is then allowed to hatch the eggs. Usually, containers are checked daily 

 and the eggs removed to a hatching trough. A male may be used to spawn 

 several females. 



Figure 48. Channel catfish spawning pens. Note spawning receptacle (arrow). 

 (FWS photo.) 



