Reproductive cycle of the sea urchin Anthocidaris crassispina [Echinoidea] from Hirado island, Nagasaki prefecture [Japan]
1993
Yamasaki, M. (Tohoku National Fisheries Research Inst., Shiogama, Miyagi (Japan)) | Kiyomoto, S.
Histological observations were made on the gonads of the sea urchin, Anthocidaris crassispina, from Hirado Island, Nagasaki Prefecture at various seasons of the year. On the basis of the cytological characteristic processes of the development of germ cells, the maturation processes in the gonads of both sexes were defined into the following five stages; (1) recovering, (2) developing, (3) premature, (4) mature, and (5) spent. Using the ratio of the number of individuals of each gonadal development stage to the total number, in conjunction with the gonad index (100 x gonad wet weight(g)/(test diameter: cm)2/test height(cm)), the annual reproductive cycle was evaluated for the females as: September to January as recovering period, February to March as developing period, April as premature period, May to June as mature period, and July to August as spawning period. The males exhibited a paralleled annual reproductive cycle to that of the females, i.e. September to January as recovering period, February to March as developing period, April as premature period, May to June as mature period, and July to August as sperm ejecting period
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