FISHERV BLXLETIN: VOL. 69, NO. 2 



Haydock (1971), 2.5, 5.0, and 10.0 mg of com- 

 mercial carp pituitary,* 1.0, 2.5, and 5.0 mg of 

 deoxycorticosterone acetate (DOC A),' 1.0 mg of 

 luteinizing hormone (PLH) ," and 25, 50, and 100 

 international units (lU) of human chorionic 

 gonadotropin (HCG)." The ti-eatments were 

 given in single 0.1-ml injections using a carrier 

 of Holtfreter's solution (Emmel and Cowdry, 

 1964) in all cases except for DOCA where se- 

 same oil was used. The suspensions of pituitary 

 were prepared by triturating a weighed quantity 

 in a small tissue grinder with enough liquid to 

 form the proper concentration. The suspension 

 was then pipetted into a small serum bottle 

 where it could be withdrawn with an injection 

 syringe. The injections were administered in- 

 traperitoneally with a 24-gauge needle between 

 the pelvic fin and vent. Prior to injection the 

 fish were anesthetized in 50 liters of water 

 with 7 ppm quinaldine (Vrooman and Paloma, 

 1966). 



Under each treatment 12 to 15 fish were in- 

 jected. The sex and level of ripeness of living 

 anchovies are difficult to distinguish and a por- 

 tion of the fish in these trials were immature. 

 Therefore it was necessary to inject this rel- 

 atively large number of fish to increase the 

 probability that some would be sufficiently de- 

 veloped to respond to hormone injections. In- 

 jected fish were placed in small holding tanks 

 1.2 X 1-2 m with 0.9 m of water. These tanks 

 had running seawater and the temperature was 

 also maintained at 15° C. Nets with 202-fj. mesh 

 were placed at the outflows of these tanks to 

 collect eggs in the event of spawning. If no 

 spawning occurred after 48 hr, the fish were 

 stripped and fertilization attempted by the dry 

 method (Davis, 1961). In this method the eggs 

 and sperm are expressed, mixed, and left to 

 stand in a dry container for 5 to 10 min before 

 being placed in water. It was noticed in all 

 trials that at least some males produced motile 

 sperm. 



The fish were killed after stripping and 



' Purchased from StoUer Fisheries, Spirit Lake, Iowa. 



" DOCA and HCG purchased from Sigma Chemical 

 Co., St. Louis, Mo. 



* PLH and PMS purchased from Calbiochem, Los 

 Angeles, Calif. 



ovaries were removed from the females. Each 

 ovary was teased apart and the major dia- 

 meters of the most advanced eggs measured. 

 The maximum diameters of injected fish were 

 compared with the diameters of more than 500 

 captive uninjected females sampled during the 

 previous 16 months to determine which of the 

 treatments were efl^'ective in producing growth. 



The eff'ect of two injections of different hor- 

 mones were examined in the second series of 

 trials. The first injection was 50 lU of HCG 

 and the second, given 48 hr later, was one of the 

 following: 2.5 mg of salmon pituitary, 10.0 

 mg of carp pituitary, 5.0 mg of DOCA, 1.0 mg 

 of PLH and 250 lU of gonadotropin from preg- 

 nant mare serum (PMS).° The methods of 

 anesthetizing, injecting, and holding of fish were 

 the same. If spawning did not occur within 

 48 hr after the second injection, the fish were 

 stripped and fertilization attempted. In this 

 and the final series of trials the fish were not 

 killed after stripping and measurements of egg 

 diameters were not made. Here the only cri- 

 terion for success was spawning or production 

 of viable eggs through stripping. 



The eff'ect of three injections of the same 

 hormone was tested in the third and final series 

 of trials. One group of fish was given three 

 injections of 2.5 mg of salmon pituitary and 

 another group three injections of 50 lU of HCG. 

 The injections were spaced a day apart and the 

 procedures were the same as described earlier. 

 If no spawning occurred within 24 hr after the 

 third injection, the fish were stripped and fertil- 

 ization attempted. 



RESULTS 



None of the fish that were given a single 

 injection spawned or produced viable eggs 

 through stripping. Most of the stripped eggs 

 were clumped, opaque, and apparently had not 

 ovulated. Some of the treatment, however, pro- 

 duced noticeable increases in egg diameters. 

 Table 1 shows the number of females under 

 the various single-injection treatments and the 

 number with and without eggs larger than 1.0 

 mm. The number of females was small in some 



358 



