Mahseer (Tor spp.) fishes of the world: status, challenges and opportunities for conservation

The mahseer fishes (Tor spp.) represent an iconic genus of large-bodied species of the Cyprinidae family. Across the 16 recognised species in the genus, individual fish can attain weights over 50 kg, resulting in some species being considered as premier sport fishes. Tor species also generally have high religious and cultural significance throughout South and Southeast Asia. Despite their economic and cultural importance, the status of Tor fishes has been increasingly imperilled through their riverine habitats being impacted by anthropogenic activities, such as hydropower dam construction and exploitation. Moreover, conservation efforts have been constrained by knowledge on the genus being heavily skewed towards aquaculture, with considerable knowledge gaps on their taxonomy, autecology, distribution and population status. Whilst taxonomic ambiguity has been a major constraint on conservation efforts, this has been partially overcome by recent, robust taxonomic revisions. This has enabled revision of the IUCN Red List status of Tor fishes; three species are now assessed as ‘Near Threatened’, one ‘Vulnerable’, three ‘Endangered’ and one ‘Critically Endangered’. However, eight species remain ‘Data deficient’. Here, i