东海赤潮高发区春季浮游动物生态特征的研究

根据2002年4～5月东海122°～123°30′E、29°～32°N水域海洋综合调查资料，对东海赤潮高发区浮游动物的数量分布、群落特征、种类组成及优势种等进行了分析．结果表明，在调查区共鉴定出饵料浮游动物128种[不含16种浮游幼虫(体)和仔鱼]，分5门12大类，以桡足类占优势(40种，31．25％)．浮游动物群落以广温广盐生态类群为主．中华哲水蚤(Calanus sinicus)为最主要优势种(142．10ind·m-3，68．09％)．总生物量均值为243．80mg-m3(55．53～773．92mg·m-3)，最高密集区(>500mg·m-3)位于长江口30°45′～31°15′N、122°45′～123°15′E水域．饵料生物量均值为195．96mg·m13(55．53～496．09mg·m。)，呈长江口(30°30′N以北)水域高于舟山岛东南水域、长江口外海(122°45′E以东)高于近海水域的分布趋势．多样性指数(H′)均值为2．12(1．09～3．73)．长江口水域多样度、均匀度和丰富度低，优势度大，反映出浮游动物群落结构不够稳定．采用逐步回归分析得知，影响本区春季浮游动物生态特征值分布的主要因子是水温、硅藻和甲藻．

Ecological characteristics of zooplankton in frequent HAB areas of the East China Sea in Spring

A comprehensive oceanographic survey was made in the East China Sea (122 degrees-123 degrees 30'E, 29 degrees-32 degrees N) during April to May, 2002, and the zooplankton samples were collected by zooplankton net (mesh size 0.567 mm). Analyses on the ecological characteristics of zooplankton such as its quantity, community characteristics, species composition and dominant species showed that 128 species of diet zooplankton were identified (16 pelagic larvae and fish juveniles were not involved). Among them, copepods occupied dominant position, including 40 species, composing 31.25% of diet zooplankton. The community was divided into 3 ecological types, in which, eurythermy and euryhalinity occupied dominant position. Key species, Calanus sinicus, was the first dominant species (142.10 ind.m-3, composing 68.09% of diet zooplankton abundance). The average biomass of zooplankton was 243.80 mg.m-3 (55.53-773.92 mg.m-3), and the highest density (> 500 mg.m-3) was found in the estuary area of the Yangtze River (30 degrees 45'-31 degrees 15'N, 122 degrees 45'-123 degrees 15'E). The average biomass of diet zooplankton was 195.96 mg.m-3 (55.53-496.09 mg.m-3). It was also showed that the biomass value of the estuary area of the Yangtze River (the north of 30 degrees 30'N) was higher than that of the southwest of Zhoushan waters, and that of the offshore of the estuary area of the Yangtze River (122 degrees 45'E) was higher than that of coastal waters. The mean value of diversity index (H') was 2.12 (1.09-3.73), and the stations having low H' (< 2) occupied 37.03%. The index of diversity, evenness and richness in the estuary area of the Yangtze River were low, but dominance was high. These results showed that the community structure of zooplankton in studied areas was not stable. Regression analysis results showed that main factors in relation to the characteristic distribution of zooplankton were temperature, diatom abundance, and dinoflagellate abundance.