HYDRO-BIOLOGICAL PROFILE OF RIVER SUTLEJ IN ITS MIDDLE STRETCH IN WESTERN HIMALAYAS

Among the water quality parameters of R. Sutlej in its middle stretch during 1983-85, the temperature (9.6-17.5°C) was found to be the factor having profound influences over the hydrobiological parameters including fish and other aquatic life. The phytoplankton population in the river was poor with an average of 170 units/1, being maximum (306 units/1) in January and minimum (53 units/1) in August, when the river was influxed with the floods. The dilution effect offloods not only reduced the plankton density but also lowered the organic carbon productivity, besides affecting the concentration of nutrients in the river. The fish habitat of the river included 21 species belonging to 12 genera and 4 families with predominance of schizothoracids (53.13%) by number followed by Laleo spp. (27.08%) and T.putitora (6.25%).