基于环境DNA技术的乌江干流梯级水电站库区的鱼类多样性

Fish diversity of the cascade hydropower reservoir area of the Wujiang River based on environmental DNA technology

摘要:

目的 为调查乌江干流梯级水电站库区间的鱼类多样性差异，探索水电站开发对鱼类多样性的影响。方法 于2021年7月在乌江干流12个江段 (11个梯级水电站库区和涪陵入江段)共采集36个环境DNA样本，并以 COⅠ基因作为分子标记，利用环境DNA宏条形码技术对各江段的鱼类多样性和种类结构组成进行分析。结果 环境DNA宏条形码共获得83 864条有效 COⅠ序列，按序列相似性≥97%聚类后得到423个OTUs，基于本地参考数据库的比对注释分析后，整个乌江干流共检测到32种淡水鱼类，隶属于5目9科25属，其中鲤形目鱼类最多，占比约为56.25%。结论 物种多样性和种类组成结构差异分析结果显示，乌江干流梯级水电站库区间的鱼类物种多样性和种类组成结构总体上存在一定差异，表明梯级水电站的长期阻隔作用对鱼类多样性和种类结构组成产生了一定影响。本研究利用环境DNA宏条形码技术对乌江鱼类多样性和种类结构组成开展调查，有助于了解乌江干流鱼类资源现状，同时为乌江流域鱼类多样性保护提供科技支持。

Abstract:

A total of 36 environmental DNA samples were collected in 12 sections of the mainstream of the Wujiang River (11 cascade hydropower reservoir areas and the Fuling section entering the Yangtze River) in July 2021 to investigate the differences in fish diversity among the reservoir areas of Wujiang’s cascade hydropower stations, and explore the impact of hydropower development on fish diversity. Meanwhile, the fish diversity and species composition structure of each river section were analyzed using environmental DNA metabarcoding technology based on CO Ⅰgene sequence. A total of 83 864 valid CO Ⅰ sequences were obtained from environmental DNA metabarcoding, and 423 OTUs were obtained after clustering by sequence similarity ≥97%, based on the alignment and annotation analysis of the self-built database, a total of 32 species of freshwater fish were detected in the entire Wujiang River, which belongs to 5 orders, 9 families and 25 genera, among which the Cypriniformes was the most species of all fish, accounting for about 56.25%. The results showed that the fish species diversity and species composition structure were some differences in the cascade hydropower reservoir area of the Wujiang River, indicating that the long-term barrier effect of cascade hydropower partially affected fish diversity and species composition structure. This study uses environmental DNA metabarcoding technology to investigate the fish diversity and species composition structure of the Wujiang River, which is helpful in understanding the current status of fish resources in the mainstream of the Wujiang River and provides certain scientific and technical support for the protection of fish diversity in the Wujiang River Basin.