SIGNIFICANT OUTCOMES

1. Six species of edible clam bivalves viz. Anadara granosa, Meretrix casta, M. meretrix, Paphia malabarica, Polymesoda erosa, Villorita cyprinoides, and oysters are present in the Uttara Kannada estuaries.
2. According to historical data, five species of edible clam bivalves viz. Meretrix meretrix, M. casta, Anadara granosa, Polymesoda erosa, Villorita cyprinoides and oysters were present in the Sharavathi estuary. Out of them only P. erosa and oysters remain in the estuary; the rest are not traceable today.
3. In Kali estuary, the edible bivalves were distributed for about 27 km from river-mouth in 1978 whereas now it is distributed only for about 12 km from river-mouth, and the population of Paphia malabarica declined drastically.
4. The major reason for the low bivalve diversity in Sharavathi estuary and reduced distribution zones in Kali estuary could be attributed to the construction of hydel projects causing continuous release of fresh water into the estuary, after power generation, even during the summer months, resulting in very low salinity that is unable to sustain most bivalves.
5. The collection of edible bivalves is a major activity of fisher-folks and even others which contributes to the livelihood of many estuarine villages, but faded away in Sharavathi due to the disappearance of bivalves.
6. The hydel projects have adverse impact on estuarine biodiversity, not only on bivalves but most of high salinity tolerant mangroves of Sharavathi also are not to be found, except in fringes very close to the river mouth.