season, the bites were often serious enough 

 to produce death. Identical behavior 

 occurs in channel catfish that spawn in 

 lakes, creeks, and hatchery ponds; and even 

 here sometimes the male bites are severe 

 enough to cause the death of the female. 



RECOMMENDED PROCEDURES 



To induce spawning in channel catfish 

 the following principles and precautions 

 should be observed: 



a. Brood stocks, particularly the 

 females, should receive good care and food 

 from one spawning season to the next. If it 

 is necessary to obtain new brood stock from 

 wild waters, it is best to do so immediately 

 before or during the natural spawning 

 season. 



g. If the male severely bites the 

 female, it is probably best to remove him 

 immediately and keep the pair separated 

 until after the female has received one or 

 two injections, when he can be placed with 

 the female again. 



h. Aquaria with at least 2 glass 

 sides appear to be in the most satisfactory 

 spawning containers. No sjind or other sub- 

 strate is necessary, although a tJir-paper 

 or plastic mat may be used if the eggs are 

 to be moved to a mechanical hatching device. 



i. The male may be left to attend 

 the eggs in the aquarium; or, if spawning 

 facilities are scarce, the eggs can be 

 hatched in a mechanical hatching trough. 



SUmARY 



b. Only well-developed females 

 nearly ready to spawn should be used. Hold 

 poorly developed or "hard" females in earth- 

 en ponds until later in" the season. Optimum 

 feeding must be continued in the ponds, but 

 no food is necessary while fish are spawning 

 in aquaria, even though the male will often 

 accept food until the beginning of the 

 spawning act. 



c. Acetone-dried pituitaries from 

 carp, flathead and channel catfish, gar, 

 and buffalofish are satisfactory. River 

 carpsucker and fresh-water drum are not re- 

 commended, but other fish pituitaries which 

 we have not tested may also be satisfactory. 



d. The pituitaries should be fine- 

 ly ground and mixed with 1 cc. of distilled 

 water and 10,000 units of penicillin per 

 dose. 



e. The dosage recommended is 2 

 milligrams of pituitaries per pound of body 

 weight each 24 hours. Dosages may be in- 

 creased or decreased according to the condi- 

 tion of the fish; i.e., soft, ripe females 

 require less pituitjiry m aterial. Ripe 

 females will usually respond to the third 

 injection, but ought not to be abandoned as 

 hopeless until after 10 or more injections, 

 Euid only then if the spawning facilities 

 are needed for more desirable females. 



f . Males selected need not be 

 injected, but are approximately the size of 

 the females with which they will be paired. 



1. Seventy-four pairs of channel cat- 

 fish were induced to spawn in glass aquaria 

 with fish pituitary injections. The first 

 injected female spawned when the water 

 temperature was 65° P., 3 weeks before the 

 first spawning in conventional outdoor pens 

 when the temperature was 72° F. The first 

 induced spawning was on May 12 and the last 

 on July 25. 



2. Ten-gallon glass aquaria were the 

 most satisfactory containers for spawning 

 fish up to 2 1/2 pounds in weight. Larger 

 fish, of course, required proportionally 

 larger containers. 



3. Peritoneal lesions, infections, 

 and adhesions which often accompany intra- 

 peritoneal injections were controlled by 

 including 10,000 units of crystal line peni- 

 cillin-G with each injection. Before the 

 routine use of penicillin, more than 30 

 percent of the deaths of injected females 

 were attributed to body-cavity infections. 



4. Spawning was induced in channel 

 catfish by injecting pituitary material 

 from carp, buffalofish, flathead and channel 

 catfish, and gar into the female. Little 

 difference was apparent in the potency of 

 the pituitaries from these different spe- 

 cies, regardless of month of collection. 



5. The total amount of acetone-dried 

 pituitary material required to induce spawn- 

 ing in channel catfish varied from 3 to 32 

 milligraims per pound of body weight of the 



11 



