The Erhai Lake is an extant production base of Yunnan province for aquatic products. Due to the environment and fishery pattern change, the fish fauna of the Erhai Lake are varied. How about the status? How about the fish community structure and its distribution? There are less typical reports till now. This study investigated species composition and abundance of fish at 21 sites in the Erhai Lake for two times in August and November 2009, respectively. The fish nets for each station at about 5:00 pm on the first day and harvested at 5:00 am on the second day. Three samples were conducted at each site for each sampling. Species composition and number of individuals, sampling time, environment factor, latitude and longitude of the sampling site, types of nets were recorded. The fishes were identified and classified. The data were analyzed and interpreted with diversity index (Shannon-Wiener index; Pielou index), similarity coefficient (Sorenson index; Bray-Curtis index) and various multivariate statistical methods (CLUSTER; MDS; ANOSIM; SIMPER). The results showed there were 23 species, belonging to 5 orders and 9 families. The fish community of Erhai Lake could be divided into three groups: alongshore community (C Ⅰ ), open water community (CⅡ) and upstream community (CⅢ). Analysis of similarity (ANOSIM) and similarity of percentage (SIMPER) showed the differences among these groups were significant (R=0.735, P＜0.01). The indicator species of C I were Hemiculter leucisculus, Carassius auratus, Pseudorasbora parva, etc., and their contribution of similarity in C I was 80.71%. The indicator species of CⅡ were Aristichthys nobilis, Hypophthalmichthys molitrix, Megalobrama amblycephala, etc., and their contribution of similarity in CⅡ was 98.2%. The indicator species of CⅢ were C. auratus, P. parva, Acheilognathus elongates, etc., and their contribution of similarity in CⅢ was 94.94%. The average contribution of dissimilarity between C Ⅰ and CⅡ was 76.8%, the discriminating species were H. leucisculus, A. nobilis, P. parva, etc., and their contribution of dissimilarity was 88.63%. The average contribution of dissimilarity between C I and CⅢ was 54.94%, the discriminating species were H. leucisculus, A. elongates, Abbottina rivularis, etc., and their contribution of dissimilarity was 78.99%. The average contribution of dissimilarity between CⅡ and CⅢ was 91.62%, the discriminating species were P. parva, H. molitrix, A. nobilis, etc., and their contribution of dissimilarity was 85.82%. The C I and CⅢ were mainly composed of small sized fishes, and CⅡ was larger ones. In conclusion, the diversity in spatial structure of fish community reflected the environmental heterogeneity in Erhai Lake.%根据2009年8-11月对洱海鱼类调查获得的有关资料,研究了洱海鱼类群落的空间分布格局,旨在为洱海鱼类资源的保护和利用提供有价值的资料.研究结果表明:洱海鱼类群落可分为3种群落类型,分别为洱海西岸与南北端湖滨带群落类型(群落Ⅰ)、东岸与湖心区群落类型(群落Ⅱ)和上游小型湖泊群落类型(群落Ⅲ).群落Ⅰ的主要特征种为(鳖)(Hemiculter leucisculus)、鲫(Carassius auratus)、麦穗鱼(Pseudorasbora parva)、黄(鱼幼)(Hypseleotris swinhonis)、子陵栉(鍜)虎鱼(Ctenogobius giurinus),对群落内平均相似性贡献率为80.71％.群落Ⅱ的主要特征种为鳙(Aristichthys nobilis)、鲢(Hypophthalmichthys molitrix)、团头鲂(Megalobrama amblycephala)、草鱼(Ctenopharyngodon idella)、鲤(Cyprinus carpio),对群落内平均相似性贡献率为98.20％.群落Ⅲ的主要特征种为鲫、麦穗鱼、长身(鐍)(Acheilognathuselongatus)、棒花鱼(Abbottina rivularis)、中华鳑鲏(Oryzias latipes sinensis)、子陵栉(鍜)虎鱼等,对群落内平均相似性贡献率为94.94％.群落Ⅰ和群落Ⅲ在种类和数量组成上以小型鱼类为主,群落Ⅱ则以大中型鱼类为主,鱼类群落在空间分布上的环境差异明显.
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