A Systematic Study on the Ascidians from Cheju Island, Korea

Abstract

In order to carry out a systematic study of ascidians in Cheju Island, the authors identified and classified specimens collected from 11 sites around Cheju Island from December 1 1969 to January 1989. Using the information gathered from this study as well as previous s studies, the authors prepared a detailed list of the ascidians of Cheju Island. A As a result of this study, the ascidians of Cheju Island are 50 species in 10 families. Among them, 3 species (Dideηmum apersum, Didemnum translucidum, Botrylloides perspicuum) had not previously been known to exist in Korean waters. Description and drawings of these three species are presented in this report. It was also discovered that ten of the fifty species are found only in the Cheju Island area. The fifty species recorded in the Cheju Island area account for 68% of the seventy three species recorded from all Korea. Classifying them by t the temperature of the water where they are found, the authors found the following: one cold water species (2% of the total), seven cold-temperate water species (14%), thirty eight warm-temperate water species (76%) and four tropical water species (8%)