Abstract
Observation on mollusk on five estuary of Lamong Bay waters was conducted on June and October 2005. The aim of this study was to determine condition and community structure of molluscs living in those areas. Samples were collected using Eckmann grab and sieved through 0.5 mm mesh-sized. The number of mollusk species was 21 species, consist of 8 species class of Gastropoda and 13 species class of Bivalvia. A diversity index (H) ranged 0.802 to 1.028, an evenness index (J) was 0.923 to 1 and a richness index (D) was 15.126 to 20.959. In which Tellina palatum (Tellinidae) and Placemen calophyla (Veneridae) class of Bivalvia relatively wide distributed. In generally, this result showed that five estuary of Lamong Bay waters has a relatively low molluscs diversity.