Fish community structure in relation to habitat variables in a seasonally open floodplain wetland of the Yamuna River basin of India

The study was carried out in Alwara wetland, a seasonally open floodplain wetland connected to the Yamuna River in the Kaushambi District of Uttar Pradesh, - to estimate the fish community structure in relation to habitat variables across three seasons. Altogether, 62 fish species comprising 9 orders, 23 families and 50 genera were recorded, including 5 exotic species. As per IUCN categorisation, 5 species viz., Wallago attu, Ompok bimaculatus, O. pabda, Chitala chitala and Ailia coila are near threatened and Clarias magur is endangered. Cypriniformes (40.32%) were the most dominant order, followed by Siluriformes (22.58%), Perciformes (19.35%), Synbranchiformes (4.84%), Clupeiformes and Mugiliformes (3.23%), Tetraodontiformes and Beloniformes (1.61%). The Shannon-Wiener diversity index (H’) ranged from 3.421 (post-monsoon) to 3.877 (monsoon) with an uneven abundance of fishes as indicated by the evenness index (post-monsoon = 0.6951 to monsoon = 0.8186). Water quality parameters were significantly (p<0.05) different across the seasons except specific conductivity, silicate-Si, phosphate-P, and dissolved organic matter (DOM). Certain sediment quality parameters differed significantly (p<0.05) across the seasons. Canonical correspondence analysis (CCA) was used to study the association of 27 commercially important fish species with 6 important water quality parameters and provided the baseline information on fish community structure. We observed growth and recruitment overfishing, which may affect fish diversity and its sustainable utilisation to support fishers’ livelihoods. Keywords: Alwara wetland, Diversity indices, Fish community, Endangered, Overfishing