抄録
Life cycle in adult stage of the Sakhalin surf clam Spisula sachalinensis in Sendai Bay was studied based on the interrelation between reproductive and feeding cycles. The reproductive cycle is inversely related to the water temperature. Reproduction (gonad growth and spawning) occurs primarily under the low temperature regime and the reproductive activity stops after spawn-ing for about six months during summer-autumn. Seasonal change in weight of the digestive organs is caused by the active feeding in winter-spring.
The life cycle of surf clam may comprise of two phases: phase of high activity (Dec.-May) and that of low activity (June-Nov.). The synchronism between gonad growth and active feeding is the essential trait of life cycle of the surf clam, suggesting that resources from outside is directly used for the gonad growth without temporary reservation. The surf clam in Sendai Bay seems to concentrate its activity in winter through the process of adaptation to the environment.
