Figure 7 (a) shows the variations in abundance of crab species with respect to the distance from the estuary. The variations in soil moisture content,soil organic carbons content, soil pH and soil salinity in the relation to the distance from the estuary are given in Figure 7 b . Table 2 indicates the significance of environmental factors on the abundance of six crab species in the Negombo Lagoon.As shown in the table 2,E. versicolor, M.thukuhar, and S. smithii did not show significant correlations with the environmental factors tasted. M. messor showed significant positive correlations with soil moisture and soil pH ehile S. guttatum showed a significant negative correlation with soil salinity and signification positive correlation with the soil temperature. Juvenile crabs of unidentified species showed a significant positive correlation with soil moisture.