Study on the Monthly Variation in Hydro biological Condition and Its Relation to Fish Production of a Sewage Fed Bheri System at Suburban Kolkata

Abstract

The concept of resource recovery systems and waste recycling involving the wetlands of Kolkata are gradually loosing interest due to unplanned urban expansion without understanding the ecological, environmental and economic benefit of the century old sewage fed systems. The water quality parameters, noted during the study, exhibited marked seasonal variation and some were indicative of productivity. The BOD was optimum but DOM (Dissolved Organic Matter) was significantly lower. Among the nutrients, the values of phosphorous were higher and the values of all other nutrients found to increase with temperature. Overall production decreased in the successive years. Total plankton production, nitrate-nitrogen, and DOM and BOD showed negative co-relation with total fish production.