To develop new products for aquaculture, which fishermen at South Sea can get high income, after bay scallop was transplanted from Sandong province in China from October 17, 1996 to March 18, 1997 at Duekrang Bay in Janghung gun and Kamak Bay in Y대녀 City on Chollanam province, Sumjin river estuary in Hadong gun and Gejae Bay in Keoje city on Kyongsangnam proince. Temperature was decreased from 20.5$^{circ}C$ to 5.1$^{circ}C$ in February and then it was increased to 12.0 in March. Ranges of salinity, DO and Chlorophyll-a were 22.40-34.70 psu, 5.24-9.77 mg/l and 1.27-22.28 $mu extrm{g}$/l, respectively, and low temperature, sudden changes of salinity and low concentration of chlorophyll-a influenced the growth of bay scallop. bay scallop in the rearing period showed the fastest growth from October 17 to November 18 through the every size rages, while it grew slowly or stopped growing from December 18 to March 18. Among 4 transplanted areas, young scallop at Duekrang Bay showed the fastest growth and then Kamak Bay, Gejae Bay, Sumjin estuary in order. The daily growth rate of young scallop in the middle size range (5.70%) was higher than those in large (2.07%) and small (5.49%) size range. The meat weight index showed the highest in December. Survival rates from October to December were high, not related to the size ranges, but survival rate of the small young scallop from January to March was higher than Those of the rest. As the Result, transplanted bay scallop at South Sea was shown to grow by the middle of December (around 1$0^{circ}C$ temperature).