Kadolkele, a mangrove area belonging to the National Aquatic Resources Research and Development Agency,which is situated adjacacent to the Negombo estuary in the Gampaha District,Sri Lanka,was selected as the study site. The area is about 10 ha in extent (Figure1).Three blet transects each with a width of 10 m and a length of 50 m were laid perpendicular to the shoreline and were subdivided into 10 M X 10 M plots.Each sampling plot had three systematic sampling units of 1 m x 1 m in size,which ran diagonally(Figure 2 ).Sampling was carried out in alternate 10 m X 10 m plot starting from lagoon shore as shown in Figure 2.