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ABSTRACT

We investigated the growth performance of oysters (initial shell height 57.5 ± 8.5 mm) under differing conditions of tidal exposure time and culture rack height in an experiment that commenced in April, 2011. Significant differences were observed in shell height from June 2011, in total weight from August, and in meat weight from September. Fatness tended to decrease during the experimental period, but was not significantly different at the end of the experiment. Significant differences in survival rates were mainly observed from June to August. After September, further changes were not observed in any experimental treatment group. The greatest growth potential (L ∞ ) and survival rate were observed at a sea level of approximately 116 cm. The results indicate that in the study area the use of oyster culture conditions involving 1 or 2 h of tidal exposure and 60 -70 cm rack height could result in oysters reaching the favored commercial half shell size within 14 months, with > 80% survival.

In order to improve oyster farming condition, estimation of food availability (CC) was carried out in Garorim Bay, Seosan, Korea. The primary production of the waters were ranged from 0.07 to 0.26 gC/m 2 /day. A strong tendency was observed that the inner side of the bay was higher at primary production. Estimated food availability was ranged from 0.0424 to 1.655. Temporal shortage in food supply was observed at April with about 15% less than the oysters' requirement, which may be causative of spat mortality after introducing into the farms. Food availability was met the food demand during summer but significant shortage was also observed at after August, which may main causative of retarded oyster fattening in the waters. This study suggested that adjustment of cultural density may be necessary for the improved harvesting of the oyster.