The Effect of Water Temperature and Salinity on Settlement of Pacific Oyster, Crassostrea gigas Pediveliger Larvae

Abstract

채묘시험은 4구간의 수온구 20.0, 23.0, 26.0, <TEX>$29.0^{\circ}C$</TEX>에 염분을 20.0, 30.0, 40.0으로 조절하여 온도와 염분의 혼합구에 대한 참굴 부착기 유생의 채묘시험을 실시한 결과, 수온 <TEX>$29.0^{\circ}C$</TEX>에서 염분 20.0과 30.0으로 조절된 채묘구에서 평균 <TEX>$43.1{\pm}0.19%$</TEX>와 <TEX>$42.1{\pm}0.1%$</TEX>로 유의적으로 가장 높은 채묘율을 보였고, 수온 <TEX>$23.0^{\circ}C$</TEX>염분 40.0에서 <TEX>$34.9{\pm}0.6%$</TEX> 가장 낮은 부착률을 보였다 (P < 0.05). 부착밀도는 수온 <TEX>$29.0^{\circ}C$</TEX>에서 유의적으로 높았고, 염분 40.0의 고염분에서 유의적으로 낮았다(P < 0.05). 그러나 수온과 염분의 혼합효과는 유의적인 차이가 없었다 (P > 0.05). 수온에 따른 염분별 채묘구의 부착 빈도를 조사한 결과 가장 많은 부착빈도는 1.2-2.3 마리/<TEX>$cm^2$</TEX>을 보였고, 평균 부착밀도는 1.9-2.4마리/<TEX>$cm^2$</TEX>였다. 전체적으로 채묘율과 평균 부착밀도 그리고 부착빈도를 감안하면 본 실험 결과 효과적인 채묘관리를 위한 수온과 염분조건은 수온 <TEX>$29.0^{\circ}C$</TEX>, 염분 20.0-30.0으로 조절하는 것이 좋을 것으로 판단된다. The combined effects of water temperature and salinity on the settlement rate and density (spats/<TEX>$cm^2$</TEX>) of Crassostrea gigas pediveliger larvae were studied under the hatchery conditions. Four water temperatures (20.0, 23.0, 26.0 and <TEX>$29.0^{\circ}C$</TEX>) were tested at three salinities (20.0, 30.0 and 40.0). The optimum water temperature by salinity conditions were <TEX>$29.0^{\circ}C$</TEX> and 20.0, 30.0 which significantly (P < 0.05) the highest mean (<TEX>${\pm}S.D$</TEX>) larval settlement rate of <TEX>$43.1{\pm}0.1%$</TEX>, <TEX>$42.1{\pm}0.1%$</TEX>, respectively. But the combination of water temperatures and salinities for settlement density was not effected, but each factor as water temperature (<TEX>$29.0^{\circ}C$</TEX>), salinity (40.0) was shown significantly high and low settlement density, respectively (P < 0.05). The statistics result of settlement density frequency was appeared: mode (<TEX>$1.2-2.3spats/cm^2$</TEX>), Mean (<TEX>$1.9-2.4spats/cm^2$</TEX>), Range (<TEX>$3.0-5.8spats/cm^2$</TEX>) and the lowest variance was obtained 0.4 at water temperature <TEX>$20.0^{\circ}C$</TEX> by salinity 30.0, but <TEX>$29.0^{\circ}C$</TEX> by 20.0 was the highest (1.1). The best condition at this results for the larvae setting under the artificial seed collection of C. gigas was <TEX>$29.0^{\circ}C$</TEX> and 20.0-30.0.