SPECIES COMPOSITION AND QUANTITATIVE DISTRIBUTION OF ZOOPLANKTON IN SANYA BAY, HAINAN PROVINCE, CHINA

Based on the data obtained from the four cruises carried out in October 1998, January, April and August of 1999, the species composition, quantitative distribution and seasonal variation of zooplankton in the Sanya Bay were analyzed. Totally 118 species of holoplankton and 11 groups of planktonic larvae were identified. Copepods were of the largest species richness, followed by medusae. Zooplankton in the Sanya Bay could be divided into the following four ecological groups according to their ecological habits and distribution characters, i. e. estuarine group, warm-temperate neritic group, warm water nearshore group and widely-distributed warm water pelagic group, and the last two were dominant groups in the Sanya Bay. No obvious seasonal succession was observed for dominant species. Sagitta enflata was the most dominant species of zooplankton in the studied area. Seasonal variations of zooplankton biomass were obvious. It showed a monocycle, with the peak in autumn and the rock bottom in spring. The annual mean biomass was 129 mg·m~(-3) and distributed evenly in the surveyed areas except for autumn. Chaetognaths were the most abundant. The seasonal variation of zooplankton biomass was in agreement with that of phytoplankton density.