Ichthyofaunal diversity and conservation status of the Tsurang and Milak Rivers of Mokokchung District, Nagaland

Nagaland, located in northeast India, is rich in biodiversity and boasts numerous rivers that support a diverse array of fish species. However, the fish populations in the Tsurang and Milak rivers of the Mokokchung district remain largely unexplored. This study aimed to document the fish diversity in these rivers and assess their conservation status. Seasonal sampling was conducted from 2020 to 2023 using various fishing gear, and species identification was performed using standard taxonomic keys. A total of 37 fish species were recorded, belonging to 4 orders, 13 families, and 25 genera. The Milak river demonstrated greater species richness, with 32 species compared to 22 species in the Tsurang river. The families Cyprinidae and Danionidae were the most dominant, each comprising 10 species. The conservation assessment revealed that one species, Tor putitora, is listed as endangered, four species as vulnerable, and four as near threatened, according to the IUCN Red List. Significant anthropogenic threats, such as habitat degradation, open coal mining, and overfishing, pose serious risks to these freshwater ecosystems. The findings highlight the urgent need for sustainable management and conservation strategies to protect the ichthyofaunal diversity of the Tsurang and Milak rivers.