长江下游狼山沙和新开沙水域渔业资源群落结构特征分析

为了解中华绒螯蟹Eriocheir sinensis幼蟹主要栖息地渔业资源群落结构特征,于2016年6月—2017年1月在长江下游的狼山沙和新开沙水域放置定制网具,对两沙洲渔获物的种类组成、生态类型、优势种、多样性指数和群落结构特征等进行了分析。结果表明:两沙洲捕获物种共37种,隶属于8目16科,各物种以底层杂食性鱼类为主;优势种为中华绒螯蟹、日本沼虾Macrobrachium nipponense和无齿螳臂相手蟹Chiromantes dehaani等;有水生植物站点的Shannon-Wiener指数、Margalef指数、Wilhm改进指数和Pielou指数均低于无水生植物站点,有水生植物站点的Mc Naughton指数高于无水生植物站点;根据聚类和非参数多维尺度分析(NMDS)可将渔业资源群落分为3类,Ⅰ类渔业生物种类少、物种丰富度指数低,Ⅱ类中华绒螯蟹和无齿螳臂相手蟹的捕捞数量及质量占绝对优势,Ⅲ类渔业生物种类多、物种丰富度指数高。研究表明,狼山沙和新开沙渔业生物种类较少,渔业资源群落结构不稳定,有必要加强对两沙洲及邻近水域渔业资源群落结构的修复。

Characteristics of community structure of fishery resources in waters of Langshansha and Xinkaisha in lower reaches of the Yangtze River

The species composition, ecological type, dominant species, diversity index, and community structure characteristics were analyzed in catches of Chinese mitten handed crab Eriocheir sinensis collected by traps disposed in Landshansha and Xinkaisha in lower reaches of the Yangtze River from June of 2016 to January of 2017 in order to study the characteristics of community structure of fishery resources in the major habitats of Chinese mitten hand-ed crab. The results showed that 37 species of fishes(belonging to 8 orders and 16 families) were found in the two waters,with dominant bottom omnivorous fishes including Chinese mitten handed crab,freshwater prawn Macrobra-chium nipponense,crab Chiromantes dehaani and others. There were lower Shannon- Wiener index, Margalef in-dex,Wilhm improvement index and Pielou index in the site with aquatic plants than in the sites without aquatic plants,but it was the opposite case in McNaughton index. According to clustering and nonparametric multidimen-sional scale analysis (NMDS),the fishery resource community was classified into three types. There were few fish species and low Shannon-Wiener index in Type Ⅰ. The Type Ⅱ was dominated by Chinese mitten handed crab and Chiromantes dehaani. The most fish species and maximal Shannon-Wiener index were observed in Type Ⅲ. The findings indicated that there were few fish species and the relatively unstable community structure of fishery re-sources in Langshansha and Xinkaisha,and thus that it is necessary to repair the community structure of fishery re-sources in these areas.