Freshwater Fish Species of Vietnam: Species Richness, Endemism and IUCN's One Plan Approach to Conservation

Abstract

Vietnam is among the top countries in terms of biodiversity. Despite continuous new discoveries, its freshwater ichthyofauna remains understudied, with persistent taxonomic challenges, including new species descriptions, taxonomic reclassifications, the presence of non-native species and the need of topical threat analyses. Vietnam's waterbodies are estimated to host more than 1000 fish species, and yet only 730 and 498 freshwater fish species are listed in Fishbase and Eschmeyer's Catalog of Fishes, respectively (including synonyms, diadromous and non-native species). To provide an up-to-date status of Vietnam's ichthyofauna, this study aims to evaluate its species richness and conservation concerns. In line with the IUCN's One Plan Approach and given the topical conservation campaign ‘Vietnamazing’, we also assessed the involvement of zoos and aquaria in maintaining and breeding Vietnamese freshwater fish species. As a result, a total of 647 native freshwater fish species were identified in Vietnam with 270 non-threatened, 44 threatened and 333 not evaluated or data-deficient species according to the IUCN Red List, as well as 219 endemic taxa. Two major species richness hotspots were found in the Mekong and Red River Deltas. The third but less rich hotspot was found in the Truong Son Mountain Range. Protected areas (PAs) in these hotspot regions covered a maximum of 166 species per PA. In total, 87 Vietnamese freshwater fish species were kept in 287 zoos worldwide, of which 15 were threatened. The results underscore the importance of Vietnam's PAs and the pivotal role of zoos in supporting One Plan Approach conservation efforts for threatened and endemic species. We recommend the establishment of new PAs in the Mekong and Red River deltas. Furthermore, increased funding for rangers and public awareness campaigns as well as stronger legislation for fishery are needed to protect Vietnam's ichthyofauna effectively.