Journal of the Marine Biological Association of India

The shrinking backwaters of Kerala.

Volume 25 Issue 1&2

U. K. Gopalan, Doyilt Vengayil, P. Udayavarma and M. Krishnankutty

Abstract

The most serious anthropogenic environmental alteration taken place in the estuaries of Kerala in the living memory, is it's alarming rate of reduction in extent. Vembanad Kayal, the largest backwater system on the west coast of India, had an area of 36,500 ha in the last century. It has undergone man-made shrinkage at an alarming rate by bunding and reclamation for agriculture, aquaculture, harbour and urban development and other uses. As a result, only about 35 % of its area remains as open brackish waters at present, about half of which has been identified as suitable for developing into aquaculture farms in the coming decade. This shows that only about 17% of Vembanad system will be left as open brackish waters by the dawn of 21st century, provided it is not further encroached for other purposes. The mean depth of the backwaters has also been decreased to 65.67 % during the past fifty years as a result of siltation. The resultant reduction in volume together with other environmental alterations have adversely affected the fishery resources in this region. The carrying capacity of the system has been further threatened by the growing inflow of effluents from domestic, agricultural and industrial sources. The situation warrents multidisciplinary approach to understand the system in depth and to evolve effective management techniques.

Date : 30-12-1983