Ichthyofaunal diversity, ecological significance and conservation assessment of the Tisi (Tuisi) River, Mizoram, Northeast India

The Indo-Myanmar region, recognized as a global biodiversity hotspot, hosts a rich diversity of freshwater fish species, many of which are endemic. Situated within this ecologically critical hotspot zone, the Tisi River in Siaha District, Mizoram, plays a vital role in sustaining aquatic biodiversity and supporting local livelihoods. The present study, conducted in 2024, aims to document and assess the fish diversity of the Tisi River, an area previously underexplored in ichthyological surveys. A total of 29 fish species belonging to 19 genera were recorded during seasonal field surveys using cast nets, gill nets, and electrofishing. Species were identified using standard taxonomic references, and their conservation status was evaluated based on the IUCN Red List (2024). The genus Garra was found to be the most dominant, with six species including the endemic Garra khawbungi. The study found that 34.48% of species were categorized as Least Concern, while others were listed as Vulnerable, Near Threatened, Data Deficient, or Not Evaluated. This distribution highlights the river's ecological complexity and its conservation significance. The findings underscore the need for targeted conservation and further taxonomic assessments to protect the river’s unique fish fauna and ecological integrity.