Ichthyofaunal Assemblage and Species Diversity of Lakhandei River at Aurai, Muzaffarpur: A Field Study Perspective

The Lakhandei River is a significant tributary of the Bagmati-Ganga River system. Aurai is a small town and Block under district Muzaffarpur, Bihar. The river sustains a rich ichthyofaunal diversity essential for the local food security and ecological stability at Aurai. This study, synthesized from regional aquatic surveys and our Field work, identifies the composition and conservation status of fish species within this riverine stretch. A total of 43 fish species belonging to 15 families under 8 orders have been recorded. The order Cypriniformes remains dominant with 18 species under 12 genera and 2 families, followed by Siluriformes. In terms of percentage, it stands respectively as 41.86%, 31.10% and 13.33%. Its one family Cyprinidae alone contains 15 species. Bagridae, with 4 species, is the second most diverse family. In terms of family diversity, Siluriformes stood first with 5 families. Clupeiformes, Cypriniformes and Perciformes jointly stand at second position, each with two families. Other orders reported from the site are Beloniformes, Channiformes, Mastacembeliformes and Tetraodontiformes; each with one family. The Red List Conservation Status (IUCN 2024-25) of fish diversity in this region shows a prevalence of species categorized as Least Concern (LC), but several key species are under threat. Clarias magur (State fish of Bihar) is Endangered (EN), Notopterus notopterus, Hypophthalmichthys molitrix, Labeo pangusia, Ompok bimaculatus, and Ailia coila are Near Threatened (NT), while Wallago attu and Cyprinus carpio is Vulnerable (VU). Three species, Cyprinus carpio, Ctenopharyngodon idella and Hypophthalmichthys molitrix are introduced (exotic) species, rest were native one. Cyprinus carpio is also an Invasive Species. Anthropogenic stressors, including habitat fragmentation and seasonal eutrophication, pose significant threats to native populations.