祟明东滩团结沙鱼类群落多样性与生长特性

研究了长江口祟明东滩团结沙5~8月间的鱼类多样性和生长特性。初步调查表明,祟明东滩团结沙共有鱼类9目19种,以鲤形目最多,鲻形目次之。这些鱼类分为4个主要生态类型,包括河口性鱼类4种、近海鱼类3种、江海洄游型鱼类4种和淡水鱼类8种。鱼类群落多样性较低,以个体数为单位计算的Shannon-Wiener多样性指数H′为2.790,Simpson优势度指数λ为0.198,Pielou种类均匀度指数J′为0.657。主要优势鱼类为窄体舌鳎、刀鲚、长蛇鮈、鲻、鲫、中国花鲈和中华鲟等7种,个体都较小。这7种鱼中窄体舌鳎、刀鲚、长蛇鮈、鲻、鲫和中华鲟呈等速生长,而中国花鲈为异速生长,肥满度最大的是鲫,最小的是刀鲚。5~8月间每个月渔获物的种类与数量组成有一定差异。为了更好地保护长江口祟明东滩的鱼类资源,应加强长江口渔业生态环境的综合治理,加大增殖和保护鱼类资源的力度,充分发挥长江口中华鲟自然保护区的保护功能。

Community diversity and growth characteristic of fish in Tuanjiesha along the eastern beach of Chongming Island

Community diversity and growth characteristic of the fish in Tuanjiesha along the eastern beach of Chongming Island were studied.The results showed that there were 19 species caught in this area which belongs to 9 orders.The species of Cypriniformes was the most and Mugiliformes came second among these orders.These fish could be categorized into four types,including 4 species of estuarine fishes,3 species of marine fishes,4 species of diadromous fishes and 8 species of freshwater fishes.Diversity of fish community in the catch was low.The diversity index(H′),dominance index(λ) and evenness index(J′) of fish community were 2.790,0.198 and 0.657,respectively.Cynoglossus gracilis,Coilia ectenes,Saurogobio dumerili,Mugil cephalus,Carassius auratus,Lateolabrax maculatus and Acipenser sinensis were the dominant species.The growth of Lateolabrax maculatus was allometric growth and the others were isometric growth among these 7 fishes.Relative fatness of Carassius auratus was biggest and Coilia ectenes was smallest.The species and individual number in the monthly catch were different from May to August.Effective measures should be taken to conserve fish resources along the eastern beach of Chongming Island,such as enhancing compositive management of the environment of Yangtze Estuary,strengthening multiplication of fish resources,and improving conservation function of Nature Reserve for Chinese Sturgeon at Yangtze Estuary.