In general for acquiring fertilized fish eggs, if mature female and
male fish spawn in captivity with or without hormonal administration
to induce ovulation, spawning behavior and consequent fertilization
usually occur at an appropriate timing after ovulation. On the other
hand, if females are stripped and the collected eggs are inseminated
with sperm, the time interval between ovulation and fertilization causes
aging of the ovulated eggs in the ovary or the coelomic cavity defined as
‘over-ripening’, which results in the deterioration of egg quality