UTTAR PRADESH JOURNAL OF ZOOLOGY

The present investigation was conducted to assess the ichthyofaunal diversity of the Ghaghara River, a tributary of the Ganga River, at three sites in Ambedkar Nagar District, Uttar Pradesh: (Site I Ausan Pur 26°38'03.3"N 82°30'31.3"E); (Site II Kewtala 26°26'34.8"N 83°02'01.4"E); and (Site III Kamariya Ghat 26°24'03.8"N 83°04'31.8"E) from September 2025 to May 2026. A total of 39 fish species belonging to 16 families and 8 orders in the class Actinopterygii were recorded. Among the orders, Siluriformes 13 (30%) were dominant, followed by   Cypriniformes 11 species (28.21%), while the family Cyprinidae showed the highest representation (23.08%), followed by Bagridae with five species. Conservation status analysis revealed that 33 species (84.62%) were classified as Least Concern, indicating relatively stable populations with a low risk of extinction. 4 species, (10.26%) namely Hypophthalmichthys molitrix, Ompok bimaculatus, Chitala chitala, and Ompok pabda, were categorized as Near Threatened (NT), suggesting the need for regular monitoring and habitat protection. 2 species, (5.13%) Wallago attu and Bagarius bagarius, were classified as Vulnerable (VU). Seasonal variation in fish diversity was evident, with the highest species richness recorded during the monsoon season (38 species), followed by the post-monsoon (30 species) and pre-monsoon seasons (25 species). The Shannon–Wiener diversity index ranged from 2.89 to 3.43, while Simpson’s diversity index varied from 0.9269 to 0.9602, indicating a diverse and relatively stable fish community structure. Bray–Curtis similarity analysis revealed clear seasonal grouping of fish assemblages, with the highest similarity observed between December 2025 and January 2026 (90.27%). The low stress value (0.01) associated with the multidimensional scaling (MDS) plot indicated excellent ordination of the samples. Seasonal variations significantly influenced fish diversity, abundance, and community structure, with the monsoon season supporting the highest species richness and abundance due to favourable habitat and breeding conditions. The occurrence of Near Threatened and Vulnerable species highlights the conservation significance of the Ghaghara River ecosystem and emphasises the need for effective management strategies for the sustainable conservation of riverine fish biodiversity in eastern Uttar Pradesh.