Significance, Threats, Conservation, and Management of Indigenous Small Fish (ISF) of Gandak River (Bihar), India

Gandak is a transboundary Himalayan tributary of the Ganga River system. The fish diversity of this important Gangetic River was studied during 2014–2016. A total of 75 fish species were recorded during the survey, of which 52 species were indigenous small fishes (ISFs) belonging to 18 families, and the rest 23 species were non-ISFs. Family-wise species richness in the Gandak River was highest in the Cyprinidae family. The catch composition of ISFs and non-SIFs is 69% and 31%, respectively. ISFs of the Gandak River were categorized as food fish (25%), aquarium (4%), and food and aquarium fishes (71%). In Gandak River, siltation, sand mining, flow modification, and obstruction, use of small mesh-sized gears and illegal fishing methods, pollution (municipal discharge), and agricultural runoff were major observed threats to ISFs. Therefore, a multifaceted approach involving fishers, civil society, government, and researchers is urgently needed to conserve ISFs in the river to sustain the fisheries and livelihoods of dependent communities. This chapter reviewed the fish diversity (particularly ISFs) of the Ganga-Brahmaputra River and Mekong River basin. Furthermore, it will provide a survey observance of fish diversity and ISFs in particular with their economic importance, threats, and conservation and management strategies in the Gandak River.