Impact of hydroelectric projects on finfish diversity in the Sharavathi River estuary of Uttara Kannada District, central west coast of India

Estuarine areas, associated with high biological productivity and rich fishery, are also often densely settled by humans. Seldom was any comprehensive study ever made in India on the impact on estuarine fin fish diversity due to execution of hydroelectric projects in the upstream of rivers. The study here in the Sharavathi River estuary in central west coast of India illustrates how too low salinity conditions, resultant of incessant fresh water releases form upstream hydroelectric projects, created in the estuary conditions unfavorable for many high and medium stenohaline fishes retaining only euryhaline ones tolerant of wide ranges of salinity and perhaps adding few species characteristic of low salinity to fresh water conditions. Scope of EIA on dam projects should be expanded to include even estuaries and immediate marine areas.