BIOLOGICAL STUDIES ON OYSTER CULTURE(III) Oyster Growth Comparison between 4 Farms in Hansan - Geoje Bay and Density-dependent Relative Shell Growth

Growth rates of oysters at four oyster farms in Hansan-Geoje Bay, near Chungmu, southern Korea, and density-dependent relative shell growth were investigated from November 1979 to May 1980 with the following results: The oysters at Sorang farm showed the best growth, the shell height in May 1980 attaining 10.10 cm, at Hwado 8.69cm and Songdo 8.57cm, all of which started growing in June 1979. At Chubong the oysters which started growing in July attained 8.6cm. The best grown oysters at Sorang shelved relatively slow growth in meat weight until February 1980, and then showed rapid growth upto May. At Hwado and Songdo they grew fast from December 1979 to February 1950, and from April to May 1980. Those at Chubong gradually increased growth rate from December 1979, and in April and May they showed rapid growth but still being smaller than the others. The ratio of meat weight to shell weight increased at Whado, Songdo and Chuhong after December 1979, but at Sorang it increased rapidly after February 1980. The ratio of shell length to shell height was 0.60 and up when the individual number of oysters attached to each cultch-disc(oyster shell) was less than 13, 0.56 to 0.60 when 14 to 25, and 0.51 or less when over 28, respectively.