FISHERY BULLETIN: VOL. 73, NO. 2 



was provided. Very few females fed actively. 

 However the males, a majority of which were 

 running ripe, fed throughout the experiments. 



Hormone injections were carried out with 0-2 cc 

 syringes fitted with 20 gauge, 3.85 cm (1.5 inch) 

 needles. All injections were intramuscular. In- 

 traperitoneal injections were ruled out for fear of 

 injuring or killing the experimental fish. Injec- 

 tions were made into the back muscle below the 

 dorsal fin. Inserting and withdrawing the needle 

 slowly aided in retaining most of the fluid in the 

 fish (Figure 1). After injection, the flesh of the fish 

 was massaged to diffuse the fluid into the muscles. 

 A saline solution of isotonic sodium chloride was 

 used as a carrier for all hormone injections except 

 with deoxycorticosterone, which was mixed with 

 sesame oil and injected as a slurry. Hormones 

 tested in the various studies were: human 

 chorionic gonadotropin (HCG), oxytocin. 



k 



Figure l.-Winter flounder receiving hormone injection. 



deoxycorticosterone (DOCA), pregnant mare 

 serum gonadotropin (PMSG) and carp pituitary 

 (freeze-dried powder). The criteria chosen to test 

 the effectiveness of the hormones were gonad in- 

 dex, spawning, fertilization of eggs, and hatching 

 success. Hormones were prepared on the day of 

 injection, and dosages were established by the 

 weight of each individual fish. 



Running ripe fish were stripped by hand. Winter 

 flounder spawn adhesive demersal eggs which 

 form clumps under experimental conditions. 

 Spawned and fertilized eggs were handled and 

 treated according to the separation techniques of 

 Smigielski and Arnold (1972). 



Human chorionic gonadotropin was the first 

 hormone selected for evaluation. Stevens (1966) 

 reported successful spawnings of striped bass with 

 dosage levels of this hormone ranging from 31 

 through 403 lU /pound fish. Two hormone dosage 

 levels and two time sequences of injecting were 

 administered to three groups of test fish number- 

 ing five per group at dosage levels of 150 IU/454 g 

 fish injected daily, 300 IU/454 g fish injected daily, 

 and 300 IU/454 g fish injected every other day. A 

 fourth group served as controls. Water tempera- 

 tures during the first testing trial ranged between 

 5° and 7°C with a mean of 6.2° C. 



A second series of experiments was initiated 

 when the water temperature fell to 4°C. Water 

 temperatures during these trials ranged between 

 3° and 5°C with a mean of 3.2°C. A test group 

 numbering 15 fish was established and held in 

 three 1,890-liter aquaria. Dosage levels of 150 

 IU/454 g fish were dispensed daily and adminis- 

 tered over a time period of 12 days. 



Further experiments were initiated to evaluate 

 oxytocin, DOCA, and PMSG at the two water 

 temperature ranges of 6°-7.5°C and 3°-5°C. Mean 

 water temperatures during the trials were 7.2° 

 and 3.2°C. Because of variable results obtained 

 with the hormone HCG in prior experiments, HCG 

 was included in these trials for further testing. 

 Three dosage levels of each hormone were 

 evaluated and a total of five injections adminis- 

 tered over a period of 10 days. The dosage levels 

 were: oxytocin at 10, 20, and 40 IU/454 g fish; 

 DOCA at 5, 10, and 20 mg/454 g fish; PMSG at 55, 

 110, and 220 IU/454 g fish; and HCG at 100, 200, 

 and 400 IU/454 g fish. Female test fish were 

 measured, weighed, tagged, and placed into four 

 1,890-liter circular tanks supplied with a continual 

 supply of seawater. Each tank contained a total of 



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