Molluscan diversity on Miramar Beach, Goa, India

Abstract

The mollsucs compose the large phylum of invertebrate, has around 85000 extant species comprises about 23 percent of all the named marine organisms. They live in marine waters, freshwater and also terrestrial habitats. They are highly diverse with regards to their size, structure, behaviour and in habitat. The phylum is typically dividied into 10 taxonomic classes, of which two are entirely extinct. Like any other groups, several molluscs are being discovered every year and the list of molluscs increases on regular basis. In India malacologists have contributed in discovering 'new species' every now and then. Despite the above, as Goa was liberated much later than Indian independence, there is a lacunae on the knowledge about the molluscan diversity in this part of our country. So to understand the molluscan diversity, an opportunistic survey was conducted from June to January, at Goa's famous, Miramar beach, a beach in the middle of the city. In the present survey, transect and quadrate method was followed. The results showed the presence of 47 species of mollusc under 23 different families on the beach, proving rich molluscan diversity in the study site. Appearance of the species varies during monsoon and winter seasons of the year. Highest number of species was recorded during the monsoon season which gradually declines with the onset of autumn and winter season. It has been speculated that appearance of molluscan species depend upon the temperature and food of the beach. Maximum number of the species during monsoon is due to the availability of food and optimum temperature for breeding.