大渡河金川至丹巴河段干、支流鱼类资源及其多样性分布

Fish Resources and Diversity in the Mainstem and Tributaries of Dadu River from Jinchuan to Danba

为进一步了解大渡河金川至丹巴河段干、支流鱼类群落结构及其多样性分布特征,2020年5和9月及2021年7月,对大渡河上游金川电站坝址至猴子岩电站库尾111.5 km干流及区间主要支流进行了系统的鱼类资源调查。结果显示,研究河段共分布鱼类18种,隶属2目6科10属;鲤形目有15种,占总种数的83.33%;鲇形目3种,占16.66%。土著鱼类主要为裂腹鱼亚科、高原鳅属和爬鮡属等适应高山峡谷流水生境、特化程度较高的鱼类;大渡软刺裸裂尻鱼(Schizopygopsis malacanthus chengi)、细尾高原鳅(Triplophysa stenura)和齐口裂腹鱼(Schizothorax prenanti)为研究河段的优势种。渔获物统计及多样性分析表明,小金川、革什扎河、东谷河及勒乌沟等支流与干流土著鱼类组成较为相似,但干流与支流以及各支流间鱼类资源及其多样性差异明显。研究表明,金川至丹巴河段鱼类群落组成简单,生态脆弱性较高,且大部分土著鱼类为珍稀濒危和特有鱼类,种群资源一旦遭到破坏将很难恢复。大渡河上游鱼类正面临严重的外来鱼类入侵威胁,需引起高度关注。

The section from Jinchuan to Danba is in the upper reaches of Dadu River,with a length of 111.5 km.In this study,fish resource surveys were conducted at 22 sampling sites in the mainstem and tributaries of the section in May and September of 2020,and July of 2021.Fish community structure and diversity were then characterized based on survey results.The aim of the study was to provide reference for developing and implementing a targeted conservation strategy for fish resources and alleviate the adverse impacts of cascaded hydropower development.A total of 18 fish species from 10 genera,6 families and 2 orders were identified during the 3 surveys,consisting of 15 Cypriniformes species and 3 Caturiformes species,accounting for 83.33%and 16.66%of the total species.Among the 18 identified species,13 species were indigenous,highly specialized and adapted to alpine valley type running water habitats that include Schizothoracinae,Triplophysa and Euchiloglanis species.Schizopygopsis malacanthus chengi,Triplophysa stenura and Schizothorax prenanti were the dominant species in the investigated river section,with relative importance indices of 8846.5,2948.9 and 2542.8,respectively.Statistics of the fish catches and analysis of the fish community diversity show that indigenous fish composition of the mainstem was similar with that for the tributaries such as Xiaojinchuan River,Geshiza River,Donggu River and Lewugou River,but there were significant differences in fish resources and diversity between the mainstem and tributaries,as well as among the tributaries.In conclusion,the fish community structure in the mainstem and tributaries of Dadu River,from Jinchuan to Danba,was simple,with high ecological vulnerability.Once destroyed,the fish resources would be difficult to restore,as most of the indigenous fishes are endemic,rare and endangered.Further,close attention should be given to invasive fish species that also pose a serious threat to the fish community in the upper reaches of Dadu River.