The growth and mortality of Crassosfrea madrasensis were monitored at three stations along the Tuticorin coast over a 16-month period. Three categories of station-related growth (high, medium and low) were defined by comparisons of growth curves for different body variables. The mortality of the oyster was comparatively very low (5%), moderate (25.6%) and very high (50.7%) at stations 1,2 and 3 respectively. The results of the principal component analysis and analysis of variance applied to the hydrological parameters of the three experimental stations revealed a significant difference in the levels of turbidity, total suspended micro-matter and chlorophyll-a concentrations. The variations in growth and mortality between the stations are discussed in terms of difference in the levels of the above parameters. The results of the study indicated that food availability and turbidity may be the principal factors determining the growth and survival of this oyster in its natural environment