The molluscan resources and ecology of Kakinada Bay

Abstract

In the Kakinada Bay several species of bivalves and gastropods are regularly fished and the annual production has been estimated to be about 6,000 t. Among them the window-pane oyster Placenta placenta (Linnaeus) and the blood-clam Anadara granosa (Linnaeus) are of particular interest. With these objectives a survey of the Kakinada Bay was conducted in March- April 1983. Environmental data which may have bearing on the distribution and abundance of the molluscs were also collected. In the present study A. granosa and P. placenta were generally abundant in areas where more than 50% of the sediment particles were < 0.125 mm. It is well known that the pediveliger larvae of bivalves delay metamorphosis until the conditions are suitable for settlement. The availability of substratum with finer particles which is rich in organic carbon seems to be an important factor limiting the distribution of these two species. On the other hand P. textile and M. meretrix occurred in considerable numbers in areas where the particle size of the sediment was coarse (>0.125 mm). The present study indicates considerably wider area and also overlapping in the distribution of these two species.