Relationship between post-ovulation time and fertilization rate of eggs in artificial insemination of yellowtail, Seriola quinqueradiata

This study examined the relationship between post-ovulation time and fertilization rates of artificially inseminated eggs of yellowtail, Seriola quinqueradiata. Ovulation was induced by a single injection of HCG (500 IU/kg) and occurred between 36 and 54 hours. The fertilization rates of the eggs collected from eleven fish decreased with time after ovulation from 92.5% (0 hour) to 16.7% (48 hours). The hatching rates of the eggs collected from the eleven fish also decreased, and were 50.3% (peak), 10.6% and finally 0% at 0, 12 and 24 hours after ovulation, respectively. These results suggest that artificial insemination of yellowtail must be carried out immediately after ovulation in order to obtain eggs of good quality.