Groundwork for conservation: an updated checklist of Chondrichthyes of Taiwan

Abstract

Taiwan is recognized as an Important Shark and Ray Area by the International Union for Conservation of Nature (IUCN) owing to its remarkable chondrichthyan diversity, including many endangered species. Given ongoing nomenclatural changes and recent species discoveries, an updated, evidence-based checklist of Chondrichthyes in Taiwanese waters is needed urgently. Here, we present a comprehensive checklist based on literature reviews, voucher specimen examinations, data from recent (2021-2023) fish environmental DNA surveys, photographic assessments, and fish market/port observations. A total of 187 species are listed, representing 14 orders, 58 families, and 105 genera, with 176 species confirmed by voucher specimens. Northern Taiwan exhibits the highest species richness (129 species), followed by the southern, eastern, and western regions, and the northern South China Sea. Fifty-seven species exhibit restricted geographical distribution, being recorded in only one of these regions. One hundred and twenty-nine species are classified as 'Near Threatened' or worse on the IUCN Red List. In comparison to earlier records, we add 21 newly documented species and remove 15 owing to misidentifications or lack of evidence. Notably, no hemigaleid sharks and five other species have been recorded since the 1960s, suggesting possible regional extirpations. This updated checklist provides a crucial foundation for taxonomic research, conservation, and sustainable fisheries management in Taiwan.