author(s)
Dinesh Kumar, Ashish Kumar Maurya, Laxmi Prasad, CP Singh, KV Radhakrishnan and SR Somasekara

abstract
The fish biodiversity and diversity indices were studied in the Himalayan River Ghaghara, a principal tributary of the mighty River Ganga for a period of one year (August 2016 to July 2017) based on data collected from three locations representing the upper, middle and lower reaches of the river. A total of 71 fish species belonging to 25 families and 49 genera were recorded and the catch composition showed predominance of fishes of the family Cyprinidae contributing 35% followed by Bagridae (10%) and Channidae (6%). The IUCN status of the fishes showed the golden mahseer (Tor putitora) as endangered (EN) while 2 species are vulnerable (VU) and 5 are nearly threatened (NT). The Shannon-Weiner Index (H) and the Simpson’s index of diversity (D) were found to have highest values for the site A-2 (values 3.786 and 0.974 respectively). The Evenness index varied from 0.754 to 0.847 and calculated maximum also for site A-2 while Margalef index was calculated maximum for Site A-1 as 8.198. The major threats to fishes in this river is attributed to overexploitation of fishery resources, invasion of exotic species in the aquatic ecosystem and pollution. Stringent management measures should be adopted for sustainable exploitation and conservation of fish resources of River Ghaghara.