In Nam-myeon coastal area of southern sea, Korea, the following hydrobiological conditions prevailed during 1997: water temperature: 12.6 ~24.5 $^{circ}C$ ; Salinity: 27.32 ~33.$10 extperthousand$, Dissolved oxygen: 7.05 $ml/L$ and Chlorophyll a: 1.69 ~ 7.40 $mu $/L. Phytoplankton, dominated by Ceratium sp, peaked during June-July. Mean growth rates of the bay scallop of selected and non-selected groups cultured for 185 days in this area from July to December, 1997 were 0.17 and 0.19 mm/day for shell height, and 0.17 and 0.16 g/day for total weight, respectively. Maximum predicted values of shell height, calculated by von Bertalanffy growth model, were 54.98 mm for the selected and 52.62 mm for the non-selected groups. Survival of the selected and non-selected groups was 80.0 and 87.0%, respectively.