1Department of Marine Bioscience, Fukui Prefectural University, Obama, Fukui 917-0003, 2Fukui Inland General Center, Fukui 910-0816, Japan
The present study investigates indicators of egg quality and characteristics of abnormal oocytes collected from cultured fourspine sculpins. Stripped ova in the artificial eggs collected from cultured broodstocks of fourspine sculpin were classified into four types according to the characteristics of the egg stripping and oil droplets, and diameter of ova. These parameters of stripped eggs could be used as indicators for identification of egg quality based on an eyed-egg rate from each type of stripped eggs. A negative correlation was found between the rate of over-ripened egg with fewer than three oil droplets and the eyed-egg rate and hatching rate. This result suggests that the over-ripened egg rate may serve as an efficient and reliable indicator for estimating the eyed-egg rate and hatching rate in seed production. In abnormal collected eggs from which no fertilized eggs were obtained, stripped ovarian tissues included un-ovulated oocytes and over-ripened oocytes in ovarian follicles from both cultured wild and reared broodstocks.