Abstract
This study was undertaken to determine the effects of HCG and salmon gonadotropin on ovulation in the Japanese flounder, Limanda yokohamae. Ovulation was observed in the fish treated with 2000+1000 IU HCG or 3 mg salmon gonadotropin within 3-6 days following injections. Total ovary weight and GSI were significantly greater in the hormone-treated fish than in the control fish. Furthermore, in the hormone-treated fish body weight increased by 5-15 percent. The water content of the ovulated eggs was also greater than that in countrols, but ovarian hydration did not occur with ion movement as described in the case of ayu. In this seawater teleost, the hormone treatment may not induce the same sequence of events at ovulation with regard to water and ion movements as it does in the case of the freshwater teleost.