关键词: 长江, 环境DNA, 鱼类早期资源, 鱼类多样性

Abstract: The traditional fishery resources survey is difficult to implement under the ecological background of “the Yangtze River Protection”. Fishery environmental DNA (eDNA) technology has been widely used in fishery resources monitoring because of its advantages of non-invasiveness and high sensitivity. Fish larvae survey can reflect fisheries resource status and diversity. To assess the present situation of fish resources in the Nanjing section of the Yangtze River, we analyzed fish species composition and diversity using the traditional fish larvae survey method and eDNA technology from June to August 2023. The results showed that 39 fish species were detected in the Nanjing section of the Yangtze River with the two methods, which belong to 6 genera and 11 families. The traditional fish survey identified 6 orders, 9 families, 30 species, and the eDNA method identified 5 orders, 9 families, 30 species, among them, 21 fish species were both detected by the two methods. The common dominant species detected by the two methods are Coilia nasus, Hemiculter bleekeri, and Pseudolaubuca sinensis. Furthermore, the Shannon diversity index calculated by traditional fish larvae survey and eDNA method was 1.89±0.22 and 1.86±0.15, respectively, and the Pielou evenness index was 0.63±0.08 and 0.56±0.04, respectively. The fish diversity in the Nanjing section of the Yangtze River was at a high level and showed a recovery trend. This study revealed the feasibility and application prospects of fish larvae survey and eDNA technology in fishery resource monitoring, providing basic information and scientific basis for the protection and restoration of fish resources in the Nanjing section of the Yangtze River.

Key words: the Yangtze River, environmental DNA, fish larvae, fish diversity