Evaluating intertidal molluscan assemblages along the Goa coast: Spatial trends in species richness and community structure

This study assesses the diversity and spatial distribution of intertidal molluscan assemblages along the Goa coast, based on surveys conducted from 2023 to 2024 across 17 sites. A total of 3,563 specimens were recorded, comprising 86 species from 60 genera, 36 families, and 14 orders within Gastropoda (42 species) and Bivalvia (44 species). Species richness varied considerably among sites, with Caranzalem Beach showing the highest diversity (52 species, 26 families) and Baga Beach the lowest (4 species, 3 families). Diversity indices reflected these patterns, indicating high evenness and low dominance at Caranzalem Beach. Rarefaction analyses confirmed sampling adequacy, with Caranzalem Beach exhibiting the highest observed and extrapolated richness, while Kakolem and Baga Beaches showed minimal increases. Habitat-wise, sandy substrates supported the highest species richness (54%), followed by rocky (29%) and muddy (17%) habitats. Bray–Curtis similarity revealed closer faunal affinity between rocky and muddy zones (∼55%) than with sandy areas (∼30%). Overall, the study highlights marked spatial variability in molluscan diversity along the Goa coast, driven by habitat heterogeneity, anthropogenic pressures, and environmental conditions. The findings provide essential baseline data for long-term monitoring and sustainable coastal biodiversity management.