A New Record of Bivalve Species, Gari elongata (Lamark, 1818) (Family: Psammobiidae) in Puttlam Estuary, North Western Province, Sri Lanka

Abstract

The Puttlam estuary located in North Western Province Sri Lanka is well known for its marine diversity of different bivalve species. During recent surveys a species not recorded from the estuary previously was encountered and it was important to identify and report the species for conservation and management purposes. Although this species has been reported from Koggala and Trincomalee estuaries, it had not been recorded from this part of the country (North western region) The objective of this paper is to report the finding of this species from the Puttalam estuary. During a lagoon survey some shells of a species not seen previously was observed from two areas of the Puttalam lagoon. Therefore, a survey in the using a 1 m2 quadrate was carried out in around lagoon shore areas. 5 samples along a 50 m transect was taken at each sampling point. Sampling in locations closer to human habitats did not provide any specimens. Live specimens of the species were collected from two areas visited only by seasonal fishermen, and identified using identification guides and available information as well as from experts on the distribution of the species. With these results occurrence of bivalve, Gari elongata (Lamark, 1818), is reported from the Puttalam estuary for the first time. The study indicated a population density of 20±2 individuals in the upper layers of sediment in one location while it was 8±1 individual in the other location. The species inhabited undisturbed areas with a water depth less than 50 cm. Both locations Kumburawa and Mohotthuwarama, were away from human habitats and were used only for fishing by seasonal lagoon fisher folk. The Shell characteristics were used to identify the species as G. elongata (Lamark, 1818) using identification guides. The distribution records within Sri Lanka were accessed with help of mollusc expert and it was found that the species was not known to occur in this part of the country previously. These shells were not among the edible varieties collected from the lagoon. Occurrence of this species will be important in future lagoon management activities of the Puttalam estuary.
Keywords: Bivalve, Gari elongata, Puttlam estuary