乐清湾2009年夏季浮游动物种类组成和数量分布

2009-08对乐清湾进行了生物调查。共鉴定浮游动物66种,浮游幼虫15类,分为半咸水河口类群、近海暖温带类群、近海暖水类群和大洋广布类群,其中近海暖水类群占主导地位。Ⅰ型网主要优势种有针刺拟哲水蚤、汤氏长足水蚤、太平洋纺锤水蚤、刺尾纺锤水蚤等;Ⅱ型网主要优势种有针刺拟哲水蚤、强额拟哲水蚤、太平洋纺锤水蚤、刺尾纺锤水蚤、短角长腹剑水蚤、简长腹剑水蚤、小长腹剑水蚤等。浮游动物优势种分布有明显差别,太平洋纺锤水蚤分布仅限于湾顶海区,小长腹剑水蚤密集区也在此区域,其它优势种则分布于乐清湾中部和湾口海区。浮游动物平均生物量为125.05mg/m3,平均丰度为234.00个/m3,数量分布呈现出从湾顶向湾口逐渐降低的趋势。

Species Composition and Quantitative Distribution of Zooplankton in Yueqing Bay During the Summer of 2009

A comprehensive investigation on the marine environment of Yueqing Bay was carried out in August 2009.A total of 66 species of zooplankton and 15 groups of pelagic larvae were indentified.All these zooplankton could be divided into four ecotypes which were estuarine low salinity group,offshore warm water group,offshore warm temperate group,eurytopic group,respectively,and the offshore warm water group was the principal ecological group.The dominant species in plankton netⅠ were Paracalanus aculeatus,Calanopia thompsoni,Acartia pacifica,A.spinicauda,etc.And the dominant species in plankton net Ⅱ were P.aculeatus,P.crassirostris,A.pacifica,A.spinicauda,Oithona brevicornis,O.simplex,O.nana,etc.Distribution of those dominant species was dissimilar in different area of Yueqing Bay obviously,A.pacifica was distributed only in the upper area of the Yueqing Bay as well as O.nana did,but other dominant species appeared in the middle and mouth area of the bay.The average biomass and abundance of zooplankton were 125.05 mg/m3 and 234.00 ind./m3 respectively,which decreased from the upper to the lower area in the Yueqing Bay.