eng Science and Education Publishing Applied Ecology and Environmental Sciences 2328-3920 2022-03-20 10 3 126 130 10.12691/aees-10-3-8 AEES20221038 article Suraj Sk pu14bot@gmail.com 1 Monojit Ray 2 Botany, Barrackpore Rastraguru Surendranath College, Kolkata Chemistry, Barrackpore Rastraguru Surendranath College, Kolkata This study is on seasonal algal composition in River Rupnarayan between June and December 2021 (monsoon and winter seasons). It is also studied the availability of algae present in the river Rupnarayan as a source of food for fishes specially Tenualosa ilisha. To study the water quality in relation with algal growth in the River Rupnarayan, some physicochemical parameters like pH, Conductance (µS/cm), Hardness (ppm), TDS (ppm), Dissolve Oxygen (ppm), Salinity(ppm), Turbidity (NTU), total Alkalinity (ppm), Biological Oxygen Demand (mg/l) were evaluated. Result showed a clear relation between physicochemical parameters and algal growth during monsoon and winter periods. Major group of algae recorded during observation were Chlorophyceae, Cyanophyceae and Bacilariophyceae. Species of Anabaena, Nostoc, Spirogyra, Chlorella,Chlorococcum, Oscillatoria were dominant in the rainy season and Diatoms in the winter season. The river water is slightly alkaline, have low salinity and low TDS. The river water contained adequate sodium, potassium and nitrate in monsoon and winter periods. http://pubs.sciepub.com/aees/10/3/8/aees-10-3-8.pdf Rupnarayan monsoon winter season algae physicochemical parameters