雅鲁藏布江是我国最长的十大河流之一, 流域纵贯古北界和东洋界两大动物地理区, 孕育了丰富的生物多样性, 但缺乏从全流域尺度认识鱼类组成和多样性格局及其变化过程的研究。本研究依据近20年实地调查数据, 综合雅鲁藏布江鱼类多样性研究文献, 特别是藏南鱼类分类学和多样性研究, 整理形成雅鲁藏布江流域鱼类多样性名录及分布, 并分析了多样性现状与面临的主要威胁。截至2023年, 雅鲁藏布江流域共分布土著鱼类10目25科70属155种(亚种), 包括特有鱼类29种, 特有属1个; 国家重点保护水生野生动物(II级) 5种; 受威胁物种26种。鱼类区系组成以青藏高原鱼类和南亚鱼类为主, 雅鲁藏布江大峡谷加热萨-帮辛段可能是两大动物区的分界线; 雅鲁藏布江流域自然水体记录有外来鱼类8目16科24属30种, 其中3种为雅鲁藏布江流域内不同地区间引入。近年来, 外来鱼类呈现出从高原内部水系之间引入以及北方冷水性鱼类快速增加的趋势。雅鲁藏布江鱼类多样性正面临外来鱼类入侵等威胁。本文也对当前研究不足和未来关注的重点进行了讨论。

Aims: The Yarlung Tsangpo River, one of the ten longest rivers in China, spans two major zoogeographic regions of the world: The Palearctic and the Oriental realms. While previous papers have focused on small portions of the river, a basin-wide-scale study to catalog its fish composition, diversity patterns, and species fluctuation is lacking. This study synthesized empirical data from field studies over the past two decades on fish diversity in the Yarlung Tsangpo River, compiled a list of fish diversity in the Yarlung Tsangpo River Basin in China, and analyzed the status of the fish diversity and the main threats to its diversity. The findings provide a scientific foundation for management and conservation of fish diversity in the Yarlung Tsangpo River Basin.

Methods: In total, 66 sections were included in this study. Of them, 58 were actually surveyed in the field, and 8 were collected from literatures; two in the upper reaches, 40 in the middle reaches, and 24 in the lower reaches; 24 in the main stream, 33 in the tributaries, 2 in the lakes, 3 in the tributary reservoirs, and 4 wetlands. These sampling sections (locations) were selected according to their geomorphological characteristics, as well as the accessibility of each location for sampling. The fish investgations were conducted from 2004 to 2023. Methods for collecting fishes included gillnets, shrimp coops, and battery-powered backpack electrofisher. After compiling the data from all of the sites, the degree of endemicity was calculated using the corrected weighted endemism index.

Results: There are 155 native species in 10 orders, 25 families, and 70 genera in the Yarlung Tsangpo River Basin. Out of all of the detected species, 29 species and one genus are endemic to the river. Five species were on China’s Key Protected Species List (Grade II); and 26 species were categorised as threatened (i.e. endangered, vulnerable, or near threatened) on the IUCN Red List of Threatened Species and China’s Biodiversity Red List. The sections with high species richness are located in the middle and lower reaches of the Yarlung Tsangpo River, while the lowest species richness is found in the Great Canyon sections. Fish fauna of the river is dominated by Qinghai-Tibetan Plateau, and South Asian fishes. The Jiaresa-Bangxin section of the Yarlung Tsangpo River Grand Canyon may be the boundary between the two major zoogeographical regions of freshwater fish. By the end of 2023, 30 species of non-native fish in 8 orders, 16 families, and 24 genera had been recorded in the natural water bodies of the Yarlung Tsangpo River Basin. Of these non-native fish species, three species were introduced to different regions within the Yarlung Tsangpo River Basin. In recent years, there has been a rapid increase in the introduction of both native fishes and non-native cold-adapted fishes through the plateau’s drainage systems.

Conclusion: Through cataloging the fish diversity in the Yarlung Tsangpo River Basin, we found that invasion of non-native fishes is the main threat to fish diversity. In the future, we should focus on fish surveys of lakes and tributaries in the lower reaches of the river, strengthen the resources for data integration, and establish a basin-level data management platform. Further, taxonomic research should be strengthened through international cooperation. Additionally, long-term monitoring of fish resources should be implemented as soon as possible to monitor fish diversity and promote conservation in the Yarlung Tsangpo River.