• Journal of Aquaculture
• /
• v.9 no.4
• /
• pp.419-427
• /
• 1996

In order to obtain the basic information for seedling production of surf clam, Spisula sachalinensis, spawning induction and egg development were investigated. $NH_4OH$ addition and serotonin injection could induce the spawning in surf clam. Water temperature rising, sperm suspension immersion, UV-ray irradiated seawater and $H_2O_2$ addition less affected on induction of spawning than $NH_4OH$ and serotonin did. On the other hand, males were more sensitive to the treatments than females. The response time to initial spawning in the case of $NH_4OH$ addition was $3\~4$ hours. However in the case of serotonin injection, it was within 5 minutes. The number of eggs released by $NH_4OH$ addition were significantly more than those released by serotonin injection. The serotonin injection induced higher rates of germinal vesicle breakdown than the $NH_4OH$ addition. Fertilizing and hatching rates of the eggs also were the similar results. Eggs of surf clam were demersal isolated eggs and averaging $65.2{\pm}±1.8\;{\mu}m$ in diameter after spawning. Optimum range of water temperature for the development of egg was $15\~20^{\circ}C$, The required time for development of D-shaped larvae was 42 hours at $15^{\circ}C$ and 27 hours at $20^{\circ}C$, respectively.