Abstract:In order to discuss the temporal and spatial variations of zooplankton community in coastal East China Sea and based on the data obtained from 3 cruises of zooplankton surveys conducted in the coastal waters of East China Sea in May, August and December of 2013, the species composition, biomass and abundance, dominant species and ecological groups were investigated. The results showed that a total of 108 species belonged to 15 groups in 7 phyla, including undefined species, together with 14 classes of pelagic larvae. The 7 phyla including Cnidaria, Ctenophora, Annelina, Mollusca, Arthropoda, Chaetognatha and Urochordata. Copepoda and Medusae were the most dominant groups in numbers of species and abundance. The most dominant group of zooplankton was Copepoda, including 47 species accounting for 43.52%. Medusae ranks second with a total of 19 species, accounting for 17.59%. There was a considerable seasonal variation in species of zooplankton in the coastal waters of East China Sea. In summer, the species richness was significantly higher than spring and winter. The linear relationship of species and latitude was negative correlated in May, August and December, which reached an extremely significant level. The whole area average abundance and biomass of zooplankton of coastal waters in East China Sea changed seasonally. Both the average abundance and biomass in winter were the lowest, the average biomass was the highest in summer, and the average abundance was the highest in spring. The community can be divided into 6 ecological groups according to the tolerance of zooplankton in hydrological environment and the differences of living areas, which were coastal species of low salinity, wide temperature and salinity species, high temperature and salinity species, warm coastal species, warm water species and cosmopolitan species. In spring and winter the coastal species of low salinity, wide temperature and salinity species accounted for absolute advantage in the southern Yellow Sea coastal waters, but warm water species were in higher proportion in summer. However, in Yangtze River estuary and adjacent waters, the warm water species were the dominant community in spring, summer and winter. What's more, in the central and southern coastal waters, warm water species play a dominant role in spring and winter. But the high temperature and salinity species, cosmopolitan species community was obviously dominant in summer. Calanus sinicus was the only common dominant species in these seasons. Dominant species changed more obviously, and the dominant species turnover rate was 90.9% from spring to summer, which was 50% from summer to autumn.