Fish community diversity assessment of protected Saraiyaman wetland in the Ganga River basin, India

'Saraiyaman' along Gandak River in the Ganges basin is a protected natural oxbow lake. In spite of the protection mechanism, it has been unrecognised for its habitat services to the fish community by resource managers and local dwellers. To investigate fish diversity and habitat status of Saraiyaman, exploratory surveys were conducted from April 2017 to March 2021. The analysis resulted in distribution of 58 fish species belonging to 7 orders, 20 families and 40 genera. Cypriniformes was found as the most dominant order. Out of 58 species, 7 were evaluated under Near Threatened (NT) category. The high value of Shannon diversity index (H' = 3.50) highlighted significance of habitat offered by Saraiyaman for diverse fish species and its potential to serve as a gene pool for conservation of endemic and threatened fish species of the Ganga basin. The loss of Saraiyaman's connection from River Gandak, increasing encroachment by cropland and climate change have resulted in water level reduction, water area shrinkage, eutrophication, infestation of aquatic weeds, degradation in habitat condition for fish community, decline in fish population, especially vulnerable catfish Wallago attu, and lack of quality fish brooders. Hence, under influence of multiple stressors, Saraiyaman is leading towards marsh and land afterwards. The baseline information generated on habitat and fish diversity status and management measures suggested in the present study will help in restoration of the function and services of Saraiyaman through existing protection mechanism by ensuring the conservation and sustainable resource utilisation for achieving the wetland-associated CBD-Sustainable Development Goals.