有明海産重要二枚貝の産卵期-II

スミノエガキ及びマガキについて

抄録

1. The spawning seasons of Ostrea rivularis and O. gigas were determined by examining their body weight, maturation of gonads and discharge of the reproductive substances.
2. The spawning seasons of these two oysters do not cover well one another.
3. The spawning season of O. rivularis ranges from late May to early September. There are 3 major spawning periods during this season, (a) early June, (b) from late June to early July and (c) from the beginning to the middle of August.
4. O. gigas spawns from early May to early November. During this season there are 4 major periods of spawning; (a) from late May to early June, (b) middle of July, (c) from late August to early September and (d) late September.