환경변화가 제주도 문섬에 서식하는 태생굴, Ostrea circumpicta의 번식생리에 미치는 영향

Abstract

Ostrea circumpicta is a brooding oyster, which is widely distributed in southern Japan, China and Korea. Despite its abundance, studies on the reproductive biology of O. circumpicta are extremely rare. To date, only a few studies have investigated the ecology and reproductive biology of other brooding oysters. This study investigated the annual reproductive cycle and larval period of O. circumpicta in relation to environmental conditions. Oysters were collected from Munseom, Seogwipo, Korea from September 2003 to September 2004. Surface water temperature and salinity varied from 14 to 24°C and from 24.2 to 32.0‰, respectively during the study period. Histology and SEM were applied to investigate seasonal variation in gametogenesis and larvae. Gonad development of the male and female was synchronous. Early-late active oysters were observed from September 2003 to April 2004. Ripe gametes appeared when water temperature was elevated from 14 to 17°C. Fully mature eggs averaged 104 μmin diameter. Spawning was initiated in May and lasted until July 2004 when water temperature increased from 17°C to above 20°C. O. circumpicta larvae in the infrabranchial chambers were observed under light microscope and SEM in June and July. Finally, this study indicates that gametogenesis of O. circumpicta in Munseom, Jeju, Korea is associated with seasonal changes in water temperature and with plankton blooms in spring and autumn.