水电开发对大渡河上游鱼类资源的影响与保护对策

Impact of Hydropower Development on Fish Resources in the Upper Dadu River and Countermeasures for Conservation

分析大渡河上游水电开发建设运行过程中鱼类种类组成的演变趋势及存在的问题,为制定适宜的保护措施、减缓工程建设运行给水生生态带来的影响提供参考数据。2019-2021年对大渡河上游干流及支流鱼类资源状况进行了调查,将数据按照双江口以上河源区、双江口至丹巴河段、丹巴至泸定河段分段,通过计算相对重要性指数和种类相似性指数进行了对比分析。结果表明,大渡河上游共调查到鱼类3目8科22属36种,其中,鲤形目鱼类27种,占总种数的75.00%,鲤科12种,占鲤形目鱼类的44.44%;土著鱼类24种,占总种数的66.67%。其中,珍稀保护及特有鱼类12种,占土著鱼类总种数的50.00%,包括2种国家级保护鱼类、3种省级保护鱼类和11种长江上游特有鱼类;外来种12种,占总种数的33.33%,主要为鲤科、鳅科和鮰科等鱼类,其中,鲤科种类居多,占50.00%。大渡河裸裂尻鱼(Schizopygopsis chengi)、齐口裂腹鱼(Schizothorax prenanti)、重口裂腹鱼(S.davidi)是大渡河上游优势种,不同河段优势种有所不同,丹巴以上河段比较近似。受水电开发等活动影响,大渡河上游土著鱼类资源呈衰减趋势,而外来种增加。为切实保护好大渡河上游鱼类资源,建议尽快开展鱼类栖息地保护区划分、重要支流的生境修复、外来种控制,并开展电站的联合生态调度研究。

In this study,we explored species succession and its impacts on fish community structure in the upper reaches of Dadu River during the periods of hydropower development and operation,aiming to provide reference data to formulate conservation measures for fishery resources and mitigate the impact of dam construction and operation on aquatic ecology.The study was based on a fishery resource inves-tigation conducted in upper Dadu River from 2019 to 2021.A total of 36 sampling sites were set in the study area,and the data were analyzed by segments of source area(Shuangjiangkou,the Shuangjiangk-ou to Danba section,and the Danba to Luding River section).Comparative analysis of the fish community composition among the three segments was conducted by calculating the index of relative importance(IRI)and species similarity index.A total of 36 fish species belonging to 22 genera,8 families and 3 orders were identified,with the dominance by family Cyprinidae(12 species)and order Cypriniformes(27 species),accounting for 44.44%of Cypriniformes species and 75.00%of the total species.There were 24 indigenous species recorded during the survey,accounting for 66.67%of the total species.Among them,12 species are rare and endemic,accounting for 50.00%of the total indigenous species,and including 2 national protected species,3 provincial protected species and 11 species endemic to the upper Yangtze River.There were 12 exotic species,accounting for 33.33%of the total species,primarily consisting of Cyprinidae,loach and catfish,and dominated by Cyprinidae(50.00%).Fish caught in the source area above Shuangjiangkou were primarily Schizopygopsis chengi,Schizothorax prenanti,S.malacanthus and S.davidi,accounting for 91.16%of the total collected,with IRI of 4844.39,3803.33,2683.09,2662.73,respectively.Fish caught in the Shuangjiangkou to Danba section were primarily S.chengi,Triplophysa stenura,S.prenanti and S.davidi,accounting for 62.05%of the total collected,with IRI of 4560.33,2584.44,1400.89,1091.71,respectively.Fish caught in the Danba to Luding River section were primarily S.prenanti,T.leptosoma,Liobagrus marginatus,S.davidi,Cyprinus carpio specularis and Silurus asotus,accounting for 91.27%of the total collected,with IRI of 2518.96,2160.73,1781.35,1150.22,785.23,727.04,respectively.S.chengi,S.prenanti and S.davidi were the dominant species in the upper reaches of Dadu River,and the dominant species varied with river section,while the dominant species in the reaches above the Danba section was more similar.Impacted by hydropower development and other human activities,the fish resources in the upper reaches of Dadu River are declining and trending toward miniaturization.To effectively conserve fish resources in the upper Dadu River,we recommend promptly implementing fish habitat protection zones,restoring fish habitat in the major tributaries,controlling exotic species,and conducting research on ecological operation of hydropower stations.