长江口沿岸碎波带浮游动物种类组成及季节性变化

Composition and seasonal fluctuation of zooplankton in the surf zones of Yangtze River estuary

为探明长江口碎波带浮游动物的种类组成及分布,2006年7月至2007年6月每月大潮期间在长江口沿岸碎波带设置13个站位点,用浮游Ⅰ型生物网(口径30 cm,网目0.2mm)共拖网156次,采集到浮游动物74种,浮游幼虫10类;浮游动物中甲壳动物共63种(桡足类43种,枝角类15种,其他5种),水生昆虫5种,轮虫3种,水母类2种,毛颚动物1种。最优势种为中华华哲水蚤(Sinocalanus sinensis),优势度Y=0.52;其次为火腿许水蚤(Schmackeria poplesia),Y=0.22。研究结果表明,长江口碎波带浮游动物以河口半咸水性浮游动物为主,受长江径流量、外海水团、温度和盐度等环境因素影响,淡水性种类和近岸低盐性种类平均密度呈季节性变化,不同区域浮游动物群落结构相差较大。

To clarify the species composition and distribution of zooplankton in the surf zones of Yangtze River estuary,zooplankton was collected monthly along the 13 stations by a zooplankton net（diameter： 30 cm,0.2 mm mesh-aperture） from April 2006 to June 2007,respectively.Totally 156 seine hauls were made,74 species and 10 kind of planktonic larvae were observed during the study period.It included 63 crustacean species（43 copepod species,15 cladoceran species and other 5 species）,5 insect species,3 rotifers,2 medusa species,1 chaetognath species.Sinocalanus sinensis was the most dominant species with 0.52 dominance index;Schmackeria poplesia was the second dominant species with 0.22 dominance index.The results indicate that the zooplankton community in the surf zone of Yangtze River estuary was mainly composed of brackish estuarine species during the investigation.Influenced by environmental factors such as river runoff,ocean current,temperature and salinity,the abundance of fresh and coastal species displays seasonal variations.And the community structure of zooplankton varied widely in different sites.