First observation on the early embryonic and larval development of spiny oyster Saccostrea kegaki Torigoe & Inaba, 1981 (Bivalvial: Ostreoida) using scanning electron microscope on the north coast of Jeju, Korea

In the present study, we monitored the early development of Saccostrea kegakia subtropical oyster species distributing on rocky intertidal off the northern Jeju Island using scanning electron microscope (SEM). The female oyster collected in early August, 2012 were fully mature exhibiting relatively small eggs ($46.5{\pm}1.4{\mu}m$ in diameter) in the gonad, while testis of the mature male oysters were filled with fully developed sperms of 36.9 ${\mu}m$ in length. The fertilized eggs developed into 2-cell stage with polar body after 1 hr 20 min of fertilization, then followed by Morula stage (3 hr 20 min), Blastula stage (4 hr 50 min), Gastrula stage (7 hr), and trochophore larvae stage (9 hr 30 min). The observed early development of S. kegaki in this study was similar the early development of other oysters, although size of the fertilized eggs were somewhat smaller.

주사전자현미경 (Scanning Electron Microscope)을 이용한 제주 북부 연안에 서식하는 가시굴 (Saccostrea kegaki Torigoe & Inaba, 1981)의 초기 유생발달관찰