Comparison of Growth and Survival Rate in Shortnecked Clams, Ruditapes philippinarum from Different Seedling Production Areas

산지별 바지락, Ruditapes philippinarum의 성장과 생존율 비교

Growth and survival rate in shortnecked clam, Ruditapes philippinarum were studied from different seedling production areas, Hadong, Ulsan and Kochang to Kwangyang Bay, Korea, and three stocking densities (1,000, 1,500 and 3,000 individuals/$m^2$) of clam from Ulsan seedling production area were examined. During the experimental period, water temperature and specific gravity were ranged from 4.5 to $26.0^{\circ}C$ and from 1.0216 to 1.0248, respectively. Shell length was grown from $2.30{\pm}0.05\;to\;3,29{\pm}0.02$ cm in Hadong, $1.32{\pm}0.02\;to\;3.15{\pm}2.02$ cm in Ulsan, $1.24{\pm}0.03\;to\;3.18{\pm}0.02$ cm in Kochang. Kochang's seed was displayed fast growth rate than others. In different rearing densities, the lower density group was showed a rapid growth rate. Shell length from the 1,000 individuals per $m^2$ group grew longer than that from the 2,000 individuals group. Total weight from the 1,000 individuals group was higher than that from the 1,5()0 individual and the 2,000 individual groups. Survival rate by seedling production areas, Hadong, Ulsan and Kochang showed $69.4\%,\;63.8\%\;and\;41.7\%$, respectively. Survival rate by rearing density, 1,000, 1,500 and 2,000 individual groups showed $70.8\%,\;67.8\%\;and\;59.0\%$, respectively.

산지가 다른 3지역의 바지락, Ruditapes philippinarum 종패를 재료로 전남 승주군 해룡면 신성포의 바지락 양식장에서 산지별 및 방양밀도별로 성장과 생존에 관하여 조사하였다. 실험기간 동안의 수온은 4.5 (1월)${\~}26.0^{\circ}C$ (8월) 범위로 나타났으며, 비중은 1.0216 (8월)${\~}1.0248$ (2월) 범위였다. 산지별 바지락의 양성결과, 각장 성장은 하동산이 $2.30{\pm}0.05$ cm에서 $3.29{\pm}0.02$ cm, 울산산이 $1.32{\pm}0.02$ cm에서 $3.15{\pm}0.02$ cm, 고창산이 $1.24{\pm}0.03$ cm에서 $3.18{\pm}0.02$ cm로 성장하여, 고창산의 성장이 하동산과 울산산에 비해 빠르게 나타났다. 밀도별 양성실험에서 개시시 각장 $1.32{\pm}0.02$ cm 내외였던 것이 실험 종료시 $m^2$당 1,000개체 실험구가 $3.21{\pm}0.02$ cm로 2,000개체 실험구 $2.61{\pm}0.02$ cm 보다 성장이 빨랐으며, 전중도 1,000, 1,500 및 2,000 개체구에서 각각 $5.47{\pm}0.22\;g,\;5.12{\pm}0.788\;g,\;4.62{\pm}1.62\;g$로 나타나 밀도가 낮은 실험구에서 성장이 좋았다. 산지별 바지락의 생존율은 실험 종료시 하동산, 울산산, 고창산이 각각 $69.4\%,\;63.8\%,\;41.7\%$로 고창산이 가장 낮았으며, 밀도별 생존율은 1,000개체, 1,500개체, 2,000개체 실험구가 각각 $70.8\%,\;67.8\%,\;59.0\%$로 밀도가 높을 수록 낮아지는 경향을 보였다.