三峡库区小江鱼类群落特征及其历史变化

为了解三峡库区蓄水后小江流域鱼类群落现状及其历史变化,于2016年春季(5月)、秋季(9月)和冬季(12月)开展了小江鱼类调查。共调查到鱼类37种,隶属于6目11科;种类组成以鲤形目为主,占总数的64.86%,其中黑尾■Hemiculer tchangi和岩原鲤Procypris rabaudi为长江上游特有种类;草鱼Ctenopharyngodon idellus、赤眼鳟Squaliobarbus curriculus、■Elopichthys bambusa、鲫Carassius auratus、鲤Cyprinus carpio、鲢Hypophthalmichthys molitrix、鳙Aristichthys nobilis和黑尾■构成小江主要经济鱼类。对比历史资料分析显示:两次调查结果相似性指数为0.45(为中等不相似);特有种鱼类退化明显:主要经济鱼类组成发生了改变;土著鱼类物种多样性和资源量均呈明显下降趋势,而适应于静水或缓流水环境的鱼类呈上升趋势。推测水坝建设、过度捕捞及不合理的采砂活动等因素是导致变化的主要原因。结果建议,合理设置水坝(汉丰湖)调水机制,对于保护该水域土著鱼类资源具有重要意义。

ASSEMBLAGE CHARACTERISTICS AND HISTORICAL CHANGES OF FISH IN THE XIAOJIANG RIVER OF THE THREE GORGE RESERVOIR

To explore the status of fish assemblage characteristics and historical changes,investigations on fish assemblage were carried out in the Xiaojiang River of Three Gorges Reservoir in spring (May),autumn (September) and winter (December) of 2016.A total of 37 fish species were collected,belonging to 6 formes and 11 families,among which 2 species were endemic to the upper reaches of the Yangtze River,such as Hemiculer tchangi and Procypris rabaudi.Cypriniformes were dominant,accounting for 64.86％ of the total species captured.The main commercial fish species were from the Cypriniformes,including Ctenopharyngodon idellus,Squaliobarbus curriculus,Elopichthys bambusa,Carassius auratus Cyprinus carpio,Hypophthalmichthys molitrix,and Aristichthys nobilis in the Xiaojiang River.Compared with the historical data,the similarity index is low (0.45),and the composition of the main commercial fishes were changed.At the same time,species diversity and resources of indigenous fish showed a declining trend and the endemic species had significant degradation,while the fish adapting to the hydrostatic or slow-flowing water environment was on the rise in the Xiaojiang River.Over exploitation,artificial drainage system construction,illegal dredging are potential underlying reasons for observed shifts in the fish assemblages.The results suggest that the reasonable drainage patterns (Hanfeng Lake) is of great significance to protect the indigenous fish resources in the Xiaojiang River.