Checklist on the ichthyofaunal resources and conservation status of Dikhu River, Nagaland, India

Dikhu River constitutes one of the major perennial rivers of Nagaland and due to its pristine beauty aids as a tourism spot. From the present study, ichthyofaunal diversity accounted for a total of 28 fish species belonging to 6 orders, 13 families, and 3 subfamilies. From the investigation, order Cypriniformes (67.9%) was found to be the most dominant, followed by Siluriformes (14.3%) and Anabantiformes (7.1%) while order Beloniformes, Synbranchiformes and Anguilliformes was found to be the least common with 10.7% in total. The IUCN red list of threatened species shows 71.4% are Least Concern, 7.1% Near Threatened, 3.6% Vulnerable, 3.6% Endangered, 10.7% Not Accessed and 3.6% Data Deficient. IUCN population status data shows that 57.1% are unknown, 10.7% stable, 10.7% not accessed, and 21.4% with decreasing population trends. Diversity indices (Shannon, Simpson, and Evenness) indices ranged 2.497–2.912, 0.892–0.936, and 0.820–0.908, respectively. Relative abundance determinations ranged from a high of 15.55% for Devario aequipinnatus to the lowest values for Tariqilabeo latius and Botia rostrata at 0.08%. Anthropogenic pressure on the Dikhu River has resulted in habitat modification and fragmentation, posing a hazard to fish diversity. Fish abundance was found to be highest in the post-monsoon season and lowest in winter. These findings are significant for academic purposes and support conservation strategies for local fish resources.