Abstract

Chilka is the largest brackish water lake in Asia and also the second largest lake in the world. It is situated between 19°28' and 19°54' North latitude and 85°05' and 85° 38' East longitude. A mix of estuarine, marine and freshwater ecosystem is observed here and the lagoon has a long history of sustainable fishing. In September 2000 as a part of its management endeavour, the local authority had opened a new mouth at Satpada to facilitate efficient tidal mixing between the lake and the sea. Prior to this (1996 to 1997) salinity in the lake was low, which favoured intense growth of (invasive) macrophytic vegetation (e.g. Potamogeton, Halophila, Gracilaria, Ruppia etc.) and the effect is the greatest in the northern most part of the lake with intense (freshwater) weeds mainly Eichornia, Hydrilla, Chara, etc. Aquatic macrophytes are important in the functioning of the water body. They offer food and shelter for many organisms and promote habitat diversity. The paper seeks to isolate and describe weedy and non weedy zones inside the lake using grid sampling by Gramin® GPS.

Key words: Chilka Lake, macrophyte, weeded and nonweeded, global positioning system (GPS), salinity