S.G. Das, T.S. Dalvi and K.M. Pariya
Abstract
Marine bivalves occupy the intertidal zones and play a pivotal role in the transient tidal ecosystems. Apart from that they are known for their bioaccumulation potential. Konkan coastline is approximately 720 km long. Anjarle coast near Dapoli covers approximately 6.9 km area encompassing of four beaches such as Anjarle, Savne, Padale and Aade beach. These were the study area for a period ranging from January to December 2024. Twenty-one species of bivalves belonging to nine different families were recorded. Each sampling site on the Anjarle coast was visited three times a year, during the pre-monsoon, monsoon, and post-monsoon seasons. Surveys were carried out during low tide conditions to ensure consistency in sampling effort. During each visit, an intertidal stretch of about 100-150 meters was assessed using opportunistic handpicking. The same sites and survey extent were maintained across all seasons to ensure comparability of diversity estimates. Further, anthropogenic activities were also observed on these beaches which affects the diversity of bivalves. Bivalves being filter-feeders, with resistance to variable environmental conditions and the ability to accumulate multiple types of substances from the environment are bio-indicators for environmental pollutants. The Simpsonâs dominance index (D = 0.234) indicates that no single family dominates the assemblage, with Veneridae being the most prominent family in terms of genus richness. The Simpsonâs diversity index (1 - D = 0.766) implies a diversified and evenly distributed bivalve community. Richness indexes back up this tendency, with Margalefâs index (2.63) and Menhinickâs index (1.96) indicating considerable richness when corrected for the sample size. Overall, the bivalve assemblage at Anjarle has a balanced community structure, with moderate dominance and appreciable variety, indicating a rather stable intertidal ecology.