上海青草沙水库鱼类群落结构的年际变化

位于长江口的青草沙水库是2010年末建成投入使用的、目前世界上最大的河口江心避咸蓄淡型水库，为掌握青草沙水库建成后鱼类群落结构变动趋势，于2015年1月至2019年12月对青草沙水库按季度进行了为期5年的鱼类调查，结果表明：采集鱼类样本共5158尾，鉴定为51种鱼类，隶属于为9目、16科、41属；鲤形目鱼类占比最高，为87.1%；降海洄游型鱼类、溯河洄游型鱼类、河口型鱼类占比自2015到2019年逐年呈下降趋势，淡水定居型鱼类占比逐年上升；鲢、鳙、鲫3种鱼类在所有调查年份中均为优势种，鲫优势度在逐年增加；Cluster聚类分析结果表明2015、2016年群落结构相似，2017、2018、2019三年群落结构相似；结合Margalef、Pielou和Shannon-Wiener指数值的年际变化，目前群落结构比较稳定。青草沙水库目前淡水鱼类占优势，洄游型和河口型鱼类逐渐从水库中消失，鱼类组成越来越接近于淡水湖泊的鱼类特征，与其外围的长江口鱼类群落结构产生了差异。

Analysis of interannual variations for the fish community structure in Shanghai Qingcaosha Reservoir

Qingcaosha Reservoir, located in the Yangtze River, is the largest estuary reservoir built and put into use at the end of 2010. In order to grasp the trend of fish community structure changes after the completion of Qingcaosha Reservoir, a five-year fish survey was conducted quarterly from January 2015 to December 2019. The results show that 5158 fish samples were collected and 51 species were identified Fish, belonging to 9 orders, 16 families and 41 genera; Cyprinids account for the highest proportion, 87.1%; the proportion of migratory fish, ana dromous migratory fish, estuarine fish decreased year by year from 2015 to 2019, and the proportion of freshwater settled fish increased year by year; silver carp, bighead carp and crucian carp are dominant species in all survey years, and the dominance of crucian carp is increasing year by year; cluster clustering The results show that the community structure is similar in 2015 and 2016, and similar in 2017, 2018 and 2019. Combined with the annual changes of Margalef, Pielou and Shannon Wiener index values, it shows that the disturbance degree of the community structure of Qingcaosha Reservoir is on the rise. At present, fresh water fish are dominant in Qingcaosha Reservoir, and migratory and estuarine fish gradually disappear from the reservoir. The fish composition is more and more close to the characteristics of fresh water in the lower reaches of the Yangtze River, which is different from the fish community structure in the peripheral Yangtze River Estuary.