Abstract
Spawning induction and early growth of the sea urchin, Strongylocentrotus intermedius were studied with the purpose of artificial seedling production. Gonadosomatic index(GSI) of the sea urchin showed the highest value in October, and rapidly decreased in December. It means that October and November is the peak of spawning season of the sea urchin in the latitude. Spawning induction by injection of potassium chloride solution in October has showed 44.0~100.0% reaction rate, and were produced 6,300$\times$10$^4$ eggs. Spawned eggs have shown the fertilization rate of 92.3~98.2% and the hatching rate of 78.2~87.0%. The metamorphosis of larvae after hatching in the seawater temperature of 13.7~17.1$^{\circ}C$ resulted in early eight-armed larvae in 13 days and late eight-armed larvae in 20 days. The collection of progenies was possible in 24~25 days after hatching and collection rate was 18.5~26.1% (mean 22.3%). Test diameter immediately after collection had a mean 350 ${\mu}{\textrm}{m}$. Survival rate and test diameter of juvenile sea urchin after collection were 58.5%, 1.32 mm in 30 days, 27.7%, 3.82 mm in 92 days and 15.6%, 11.70 mm in 181 days, respectively.
북쪽말똥성게의 인공종묘생산을 목적으로 산란유발과 초기성장에 관한 조사 결과를 요약하면 다음과 같다. 생식소숙도지수(GSI)는 암수 모두 10월에 최고치를 보인 후 12월에 급격히 감소하여, 주 산란기는 10-11월로 나타났다. KCI 자극에 의한 산란유발은 10월에 44.0~100.0%의 반응을 보여 6,300만개의 알을 얻었으며, 수정률은 92.3~98.2%, 부화율은 78.2~87.0%였다. 사육수온 13.4~17.1$^{\circ}C$에서 부유유생은 부화 13일째에 8완 전기유생, 부화 20일째에는 8완후기유생으로 변태하였다. 채묘는 부화 24~25일째 가능하였으며, 채묘율은 18.5~26.1%(평균 22.3%)이었고 채묘직후 새끼성게는 평균각경 350 $\mu\textrm{m}$이었다. 채묘 후 새끼성게의 생존율과 평균각경은 30일째 58.5%와 1.32mm, 92일째 27.7%와 3.82mm 및 사육 최종 일인 181일째에 15.6%와 11.70mm였다.
