*M.S. Johal, Yogesh K. Rawal and Anil K. Tyor
Fish and Fisheries laboratory, Department of Zoology, Panjab University, Chandigarh -160 014
*Correspondence Author : email@example.com
The Himalayas are the main watersheds in the Indo-Gangetic region, having numerous rivers, streams, lakes and reservoirs. The Western Himalayas face a serious water crisis on account of the low inflows, which are the least during the last fifteen years. This area may face a serious water crisis in the coming years. The presence of the dams like Tehri in the seismically active areas poses a great threat to the mankind. The dams, big or small, create a habitat unsuitable for the hillstream fishes leading to the decline in the endemic fish fauna. The classic example of habitat destruction leading to the decline in the fish fauna, being the Gobindsagar reservoir, where the catch of exotic silver carp, Hypophthalmichthys molitrix (Val.) has risen from a mere 2.00% in 1978 to 84.73% in the year 1997-98 at the expense of two indigenous carps namely Catla catla (Ham.) and Tor putitora (Ham.). This paper advocates the need for the provision of fish ladders in dams to facilitate auto stocking in the natural water bodies and also for upstream migration of the native fishes.
Key words:Hillstream, Dams, Fish, Anthropogenic activities.