
The diversity and distribution of molluscs have been studied in different stretches of Subarnarekha River-Estuary (upstream, middle stream and downstream) during the period of July 2012 to June, 2014. A total of 23 species of molluscs belonging to 16 genera under 13 families were recorded. Out of all recorded species, 9 species were found to inhabit in freshwater habitats, 14 species preferred to reside in saline environment while 4 species were encountered both in freshwater and brackish water zones. Binary distribution and similarity index have revealed the relationships not only among different molluscan species but also on their mode of preference of habitats, especially against environmental stresses vis-a-vis their power of tolerance and sensitivity as indicator species.