Abstract
This study was carried out to find out the effects of delay between ovulation and hand-stripping, with special reference to changes in several characteristics of eggs retained in the body cavity following the induction of ovulation in the ayu with HCG. The processes after ovulation were divided into 4 stages using macroscopical and microscopical techniques. The eggs in stage I were normal while those in stage IV were completely over-ripened eggs which were observed 8 days following ovulation, The eggs in stage II were observed during the whole period of the experiment and seemed to show various qualities. The percentages of eyed eggs and hatched larvae showed their peaks one day after ovulation, followed by rapid decrease. Suggestion has been made that in the ayu the eggs remain in good condition for about 48 hr. Furthermore, the changes in body weight, GSI, water content in the eggs and concentrations of sodium, chloride and potassium in the eggs were discussed in relation to the processes of over-ripening in the ayu.
