中文摘要：

于2011和2012年的5-6月，2010和2011年的10-11月对三峡库区大宁河江段的鱼类种类组成、物种多样性及其时空分布进行了调查。共监测129船次，统计渔获物393.8kg，生物学测定11569尾，共采集鱼类68种，隶属于5目13科。草鱼（Ctenopharyngodon idella）、鲢（Hypophthalmichthy smolitrix）、鳙（Aristichthys nobilis）、光泽黄颡鱼（Peltevbagrus nitidus）、瓦氏黄颡鱼（Peltevbagrus vachellii）、鲇（Silurus asotus）、齐口裂腹鱼（Schizothorax prenanti）、宽鳍鳅（Zacco platypus）为主要优势种。在对3个采样点的鱼类组成、相似度、优势种组成、生物多样性指数分析后，发现河流生境改变对大宁河下游江段鱼类群落结构影响明显；圆口铜鱼（Coreius guichenoti）和铜鱼（Coreius heterodon）作为库区最主要渔获对象，数量现已剧减；鲇、鲤（Cyprinus carpio）及黄颡鱼（Pseudobagrus fulvidraco）等在渔获物中比重相对上升；不同采样点的渔获物组成存在差异，渔获物中个体小型化较为严重。

英文摘要：

A survey aiming at the species composition, diversity and distribution of the fish was taken in the Daning River during May and June in 2011 and 2012, October and November in 2010 and 2011. A total of 129 boats were investigated, 393.8kg fish were captured and 11569 samples were measured. There were 68 species which belongs to 5 families and 13 genera. The main dominant species were Ctenopharyngodon idella, Hypophthalmichthys molitrix, Aristichthys nobilis, Peltevbagrus nitidus, Peltevbagrus vachellii, Silurus asotus, Schizothorax prencmti, Zacco platypus. Fish composition, community similarity, dominant species and biological diversity of three sample sites were analyzed. The results showed that the change of river habitat had obviously influenced the structure of community fish in the lower reaches of the Darling River. The abundance of Coreius heterodon and Coreius guichenoti, which ever were the main species in the Three Gorges reservoir, had been decreasing; The number of Silurus asotus, Cypprinus carpio and Pseudobagrus fulvidraco had been increasing; The catches in different sections of the river were different, and the number of small individual had been getting more.