Diversity of Ichthyofauna and their Abundance in Ghaghara River, Siwan District, Bihar, India

The Ghaghara River, a significant tributary of the holy River Ganga, travels across northern India., providing essential water resources for agriculture, communities and biodiversity. The river's fish diversity is vital for maintaining local ecological balance and supporting livelihoods. Fish biodiversity and different diversity indices were evaluated in the study area from August 2021 to July 2022. Data was collected from four locations namely Darauli (S-1), Rakauli (S-2), Phulwariya (S-3) and Semariya (S-4) of the Ghaghara River and we found 61 species belongs to 47 genera, 21 families and 07 orders. Cypriniformes were the most common order, accounting for 42% of fish species, followed by Siluriformes (31%), and Perciformes (18%). The most prevalent family is Cyprinidae, which accounts for 39.3% of the fish fauna (24 species), followed by Bagridae (06 species) and Sisoridae (4 species). Total number of individuals, relative abundance (percentage catch), minimum and maximum size of each species were calculated. However, the river’s aquatic ecosystems, particularly its fish populations are increasingly under threat due to human activities, including habitat degradation, pollution, overfishing and the construction of hydropower projects. This study aims to assess the fish diversity of the Ghaghara River and explore the current conservation challenges and opportunities.