Present status of Icthyofaunal diversity of Garhwal Himalayan river Bhilangna and its tributaries with reference to changing environment

Abstract

Fish as a group, from biodiversity view point has the highest species diversity among all vertebrate taxa. Present communication deals with the reassessment of ichthyofaunal diversity of the river Bhilangna and its two sub tributaries, the Balganga and the Nailchami of Bhagirathi river system in Garhwal Himalaya. The observation made during study showed the occurrence of 22 fish species belonging to 2 orders, 3 families and 9 genera from varying habitat of falls, cascades, rapids, riffles and pools in various sections of river Bhilangna and its tributaries. Schizothorax richardsonii, S. plagiostomus are dominate species in the riverine segment of river Bhilangna while Cyprinus carpio (common carp) is the dominate species in impoundment segment of river Bhilangana (reservoir area). The comparison of results of present study with earlier reports revealed that fish fauna has decreased with passage of time in the Bhilangana river system which may be due to degradation and fragmentation of riverine habitat caused by various developmental activities, changes in the natural flow pattern of river, indiscriminate fishing by the use of destructive and unscientific fishing methods, and other natural calamities.