Biological Studies of Gorgonian Coral Calicogorgia granulosa (Anthozoa: Gorgonacea: Plexauridae)

Abstract

Calicogorgia granulosa (Kukenthal and Gorzawsky, 1908) is a dominant gorgonian in Jejudo Island. There are the unique soft coral communities with tropical and subtropical elements. We surveyed on four areas which is containing 38 sites used by SCUBA diving. This species are inhabited nine dominant sites around Seogwipo area. Also, ecological characters and branching patterns were examined using statistical analysis. There were three branching patterns and it had correlation with topographical features of substrate. The sexual reproduction and larval development of C. granulosa were examined in the southern most part of Jejudo Island, Korea, from August 2003 to March 2007. The reproductive mode, gametogenic cycle, fecundity and spawning time of reproduction on the species were assessed by using histological preparation and field surveys. Early developmental processes from gametes, embryos to planulae have been observed under the light and stereo microscopes. C. granulosa was found to be a gonochoric broadcaster. The ratio of females to males was 1.5 : 1. Gametes were found all year round. Gametogenesis took place three times a year and the spawning of gametes occurred at new moon in March, August and November. Spawned eggs ranging from 650 to 750 ㎛ in diameter were spherical and dark blue. Fertilized eggs developed into mature planulae over 4-6 days after spawning. The mature planulae were settled on substrata on 25 days post-spawning. Especially, they preferred to settle on the lower part of substrata. And the planulae developed into the primary polyps with 8 tentacles and oral part within five days after settlement. The survival rate of planulae was recorded approximately 30 % in the laboratory.;2006년에서 2007년에 보강 조사를 했다. 조직해부학적 연구를 통하여 성별, 성비, 생식방법, 생식력, 생식선의 형태적 특징 및 발달주기를 규명하였고 현장조사를 통하여 생식선의 방출시기와 초기발생을 연구하였다. 둥근컵산호는 자웅이체이며 암컷과 수컷은 1.5 : 1의 비율로 조사되었다. 둥근컵산호는 1년 내내 생식선이 지속적으로 발달해 있으며 총 3차례의 성숙시기를 통해 수정을 한다. 수정 시기는 8월, 11월, 3월에 일어나며 신월에 맞추어 정자와 난자가 방출 된다. 방출된 정자와 난자가 수정을 한 후 상실배에 이르기 까지 12시간가량 소요된다. 유생시기에는 자유유영을 하였으며 10일 안에 기질에 부착하게 된다. 유생은 기질의 아랫부분 혹은 바닥을 선호하는 것으로 나타났다. 유생은 2달 안에 촉수가 모두 발달한 초기 폴립 단계로 성장하였다.