Increased macrobenthic density and diversity: Indicator of recovery of Chilika Lake from environmental degradation

Abstract

Chilika lake, Orissa, India is the largest brackish water lagoon in Asia. Ecologically, it is boasted with a wealth of flora and fauna. The rich demersal fishery (especially of prawn, crabs and mollusks) of Chilika supports over 80,000 fishermen from 122 villages. However, Chilika has been facing with some natural and manmade problems, particularly frequent shifting of the mouth region reduced seawater inflow, siltation and encroachment. Impacts of the developmental activities, on the lake environment were evaluated by a detailed monitoring study conducted during September 1999 to February 2001. Results of the present investigation are part of the monitoring program and describe the effect of dredging activity on the macrobenthic assemblages. Data on the abundance of macrobenthic fauna (density and biomass) were collected from 30 different locations from across the entire stretch of Chilika. A spatially replicated before-after design was used. Sampling was conducted during three occasions (before dredging, during dredging and after dredging). The increased values of species diversity in post dredging phase suggest that opening of new lake mouth in November 2000 has not only enhanced the quantity of incoming seawater and facilitated an immediate recovery of macrobenthic communities.