Diversity and Conservation Status of Ichthyofauna in the River Rapti, Uttar Pradesh, India

The present investigation was undertaken to assess the diversity, threats, and conservation status of ichthyofauna in the River Rapti flowing through the Shravasti, Balrampur, and Siddharthnagar districts of Uttar Pradesh, India. A systematic survey was conducted at six sampling sites along the river, with sampling carried out monthly over a one-year period from July 2024 to June 2025. A total of 61 fish species belonging to 39 genera, 22 families, and 9 orders were recorded during the study. Among these, the order Cypriniformes was the most dominant, comprising 24 species (39.34%), followed by Siluriformes with 18 species (29.50%), Perciformes with 7 species (11.48%), Ophiocephaliformes with 4 species (6.56%), Synbranchiformes with 3 species (4.92%), Osteoglossiformes with 2 species (3.28%), and Clupeiformes, Beloniformes, and Tetraodontiformes, each represented by a single species (1.64%). According to the International Union for Conservation of Nature (IUCN) Red List categories, the majority of the recorded species (54) fall under the Least Concern (LC) category. Five species—Notopterus chitala, Ompok bimaculatus, Ompok pabda, Hypophthalmichthys molitrix, and Ailia coila—were identified as belonging to the Near Threatened (NT) category, while two species—Wallago attu and Bagarius bagarius—were classified as Vulnerable (VU). The findings of the present study indicate that the River Rapti and its ichthyofaunal diversity are experiencing considerable ecological degradation. Major threats include aquatic pollution, siltation, anthropogenic disturbances, illegal fishing practices, and the introduction of exotic fish species as well as invasive aquatic plants. These factors collectively pose serious risks to the sustainability of the river ecosystem. Therefore, immediate and effective conservation measures are required to protect this ecologically valuable river system and its associated aquatic biodiversity. The present study provides baseline information on the ichthyofaunal diversity of the River Rapti and serves as a preliminary reference for future ecological and conservation-oriented research in this river ecosystem. The author strongly recommends the formulation and implementation of a comprehensive conservation action plan to prevent further decline and potential extinction of fish species inhabiting the river.