DIVERSITY AND IMPACT OF SEASONAL VARIATION IN THE DISTRIBUTION OF MOLLUSCS IN MANAPADU COASTAL AREA, THOOTHUKUDI DISTRICT, TAMIL NADU, INDIA

Molluscs are economically and ecologically important components of aquatic ecosystems. In addition to supporting valuable aquaculture and wild-harvest industries, their populations determine the structure of benthic communities, cycling nutrients and they serve as prey resources for higher trophic levels. This study aims at identifying the diversity of Molluscs in the coastal area of Manapadu, Thoothukudi District, Tamil Nadu. The result of the study shows that a total of 61 species of molluscs belonging to 35 families were identified. Maximum numbers of species were identified during the post-monsoon season. Minimum species were identified during the summer season. ANOVA was carried out to test the level of significance. Significant results were observed only during the monsoon season. Biodiversity indices were calculated in which maximum species diversity of Shannon(H) Weiner index was noted as 4.107ng during the monsoon season, and minimum species diversity was recorded as 4.037 ng during the post-monsoon season. Alpha index and Margalf’s index were also used in the study which showed varied diversity throughout different seasons. The study shows that molluscan species fluctuated seasonally throughout the year. Suggestions to update the checklist and distribution of Molluscs from the Manapadu region located on the southeast coast of India were presented in this study.