fish, tost females required 6 milligrams 

 per pound (i.e., 3 injections at 2 milli- 

 grams per pound of body weight). 



6. The total number of injections 

 required for spavming varied from 1 to 28 

 with the average being 3. Five fish spawned 

 with 1 injection, 8 with 2, 35 with 3, 



6 with 4, 4 with 5, 3 with 6, and 13 

 with more than 6 injections. 



7. Fish spawned when injected with 



1 milligram of pituitary material per pound 

 of body weight each 12 hours, with 2 mil- 

 ligrams per pound each 24 hours, and with 

 increasing doses up to 8 milligrams per 

 pound each 96 hours. 



8. The period of time from the last 

 injection to spawning varied from 2 1/2 

 hours to 72 hours. Most fish began spawning 

 within 16 to 24 hours following the last 

 injection. 



LITERATURE CITED 



CLEMENS, HOWARD P., AND KERMIT E. SNEED. 



1957. The spawning behavior of the chan- 

 nel catfish, Ictalurus punctatus . 

 U. S. Fish and Wildlife Service, 

 Special Scientific Report — Fisheries 

 No. 219, 11 pp. 



HASLER, A. D., R. K. MEYER, AND W. J. WISBY. 

 1950. Hastening spawning in salmon with 

 pituitary hormones. Mimeographed 

 report submitted to U. S. Fish and 

 Wildlife Service. Reviewed by Pick- 

 ford and Atz, 1957, p. 264. 



MARZOLF, RICHARD C. 



1957. The reproduction of channel cat- 

 fish in Missouri ponds. Jour. 

 Wildlife Mgt., vol. 21, No. 1, pp. 

 22-28. 



PICKFORD, GRACE E. , AND JAMES W. ATZ. 



1957. The physiology of the pituitary 

 gland of fishes. New York Zoological 

 Society, pp. I-XIII;' 1-613. New York. 



12 



iNT.Dur.,p.c.eo- Tmo* 



