Abstract: According to an example, artificial ovulation and spawning of freshwater eels may be induced to promote artificial ovulation without employing intraperitoneal injection, by feeding a feminization-inducing material (e.g., 17?-estradiol) for inducing feminization during a predetermined period into a raising bath in which broodfish are raised and, when an ovulation induction period arrives, adding pituitary extracts of catadromous fish as an artificial ovulation-promoting substance to the bath. Raising water of the raising bath may be prepared by selectively setting fresh water, brackish water and seawater conditions, a feminization-inducing material for inducing complete feminization of broodfish of the freshwater eels is fed to the raising bath, including the raising water under a fresh water condition, and pre-treatment for feminization is performed.

Abstract: According to an example, artificial ovulation and spawning of freshwater eels may be induced to promote artificial ovulation without employing intraperitoneal injection, by feeding a feminization-inducing material (e.g., 17?-estradiol) for inducing feminization during a predetermined period into a raising bath in which broodfish are raised and, when an ovulation induction period arrives, adding pituitary extracts of catadromous fish as an artificial ovulation-promoting substance to the bath. Raising water of the raising bath may be prepared by selectively setting fresh water, brackish water and seawater conditions, a feminization-inducing material for inducing complete feminization of broodfish of the freshwater eels is fed to the raising bath, including the raising water under a fresh water condition, and pre-treatment for feminization is performed.