The Vembanad Lake and its connected backwater system around Cochin are well known as the nursery grounds for the commercially important fishery resources of this area. This account embodies the results of studies on the environmental parameters of the estuarine system around Cocb in extending over an area of 300 sq. km. Observations were made on the hydrography, primary and secondary productions. The relative influence of the environmental factors like, temperature, salinity, dissolved oxygen and nutrients on the plankton production is interpreted from the correlation coefficient
