南洞庭湖沅江段鱼类资源调查

Investigation of Fish Resources in Yuanjiang Section of South Dongting Lake

南洞庭湖沅江段为我国重要通江湖泊洞庭湖的重要组成部分,为了解其鱼类资源现状,于2013年8月—2015年12月期间对南洞庭湖沅江段鱼类资源进行调查。共采集鱼类标本12 962尾,经鉴定共计66种,隶属于7目13科44属,鲤形目占调查区域鱼类种类的69.70%,鲇形目和鲈形目次之。区系分布主体以地理位置所处的华东区为主,兼有华南区、华西区、北方区和宁蒙区的区系组成部分,华东区特有种占总种数的24.24%。栖息习性以湖泊定居型为主,占总种数的80.30%;食性以杂食性为主;栖息水层以底层为主;鱼类多样性指数(H′)为2.32,均匀度指数(J)为0.55,相较洞庭湖其他湖区处中等水平。调查结果相较历史调查记录出现种类数大幅减少、经济鱼类小型化、洄游型鱼类减少的现象,呈现衰退趋势。

The Yuanjiang section of South Dongting Lake is an important part of Dongting Lake in China.In order to understand the current status of its fish resources,an investigation was conducted in the Yuanjiang section of South Dongting Lake from August 2013 to December 2015.A total of 12 962 fish specimens were collected.Sixty-six species were identified in these specimens,belonging to 44 genera,13 families and 7 orders.Among these species,69.70%were Cypriniformes,followed by Siluriformes and Perciformes.The geographical distribution of the regional system is mainly in East China,where endemic species account for 24.24%of the total species,and is composed of the South China,West China,North China and Ning Meng regions.In addition,80.30%of the fish species tend to inhabit in lakes.Most of them are omnivorous and live in the bottom layer of water.The fish diversity index(H′)and evenness index(J)in the lakes of this section were 2.32 and 0.55,respectively,which were at a moderate level compared with those of other lake regions in Dongting Lake.The investigation showed the reduced number of species,the miniaturization of economic fish stocks and the decline of migratory fish stocks as compared with the previous survey records,indicating the recession of fish resources in the Yuanjiang section of South Dongting Lake.