长江河口潮间带鱼类群落的时空变化

根据2006年3—11月每月在长江口4个潮间带站点的36网次鱼类采样数据，分析了该水域鱼类群落组成的时空变化特征.结果表明：本次调查采获鱼类55种，隶属20科，其中，鲤科鱼类最多，有18种，占总种数的32.7%，虾虎鱼科其次，有8种，占14.5%，石首鱼科4种，占7.3%；调查水域潮间带鱼类群落可分为口内淡水区鱼类群落和河口咸淡水区鱼类群落2组，河口咸淡水区鱼类的物种多样性比口内淡水区略低，其中，口内淡水区以油似鳊和鳊等淡水鱼类为优势种，河口咸水区以斑尾刺虾虎鱼、鲻和棘头梅童等咸淡水鱼类为优势种；二组间鱼类种类组成的平均相异性为80.75%，23种鱼类对平均相异性的累积贡献率>90%，主要贡献来自油鲻、斑尾刺虾虎鱼、棘头梅童鱼、似鳊、红狼牙虾虎鱼、鲫、鳊和长蛇鮈等；春季的研究区鱼类群落丰度与夏、秋两季均存在一定程度的差异，而夏、秋两季间的差异相对较小.就单组鱼类群落丰度而言，水温对其季节变化的影响较盐度大，而盐度对整个河口鱼类群落的影响较水温大.

Spatiotemporal changes of fish community in Yangtze estuary intertidal zone

Based on the 36 fish samplings at 4 stations in the intertidal zone of Yangtze estuary from March to November 2006,the spatial and temporal changes of the fish community were analyzed.A total of 55 fish species belonging to 20 families were collected.Cyprinid had the largest species number(18 species),followed by Gobiidae(8 species),and Sciaenidae(4 species).The intertidal fish community was classified into brackish water and freshwater groups.Brackish water group had somewhat lower diversity than freshwater group.In the estuary mouth,the dominant species were of brackish-water fishes,including Acanthogobius ommaturus,Mugil cephalus and Collichthys lucidus,etc.; in the inner estuary,freshwater fishes were dominant,including Hemiculter bleeleri,Pseudobrama simony,and Parabramis pekinensis.The average dissimilarity between the two groups reached 80.75%,and the accumulative contribution of 23 fish species was more than 90%,mainly coming from Hemiculter bleeleri,Acanthogobius ommaturus,Mugil cephahts,Collichthys lucidus,Pseudobrama simony,Parabramis pekinensis,Saurogobio dumerili,and Odontamblyopus rubicundus.The abundance of fish assemblages in spring differed from that in summer and autumn to certain extent,but the abundance in summer and autumn had little differences.For each of the two groups,the abundance was more affected by water temperature than by water salinity; for the whole fish community,opposite situation was observed.