부남호 저층수 및 수온과 염분에 대한 바지락 영향 평가

Abstract

This study was conducted to measured the survival rate (or mortality) of Ruditapes philippinarum according to the change of salinity when the water temperature is high. In laboratory, the mortality test was performed on the R. philippinarum, we conducted experiments at water temperature 20, 25, and 30℃, salinity was tested at intervals 5 psu from 0 to 35 psu. As a result of exposure for bottom water of Bunam lake, the mortality was 20% in 100% bottom water, and it was found that there was no effect at concentrations below 50% in bottom water in Bunam lake. The LC50 by water temperature was 4.816 psu at 20℃, 14,645 psu at 25℃, and 20.063 psu at 30℃. The death of the clam was observed only at a concentration of 15 psu or less at 20℃. But the dead R. philippinarum observed at all concentrations of salinity at 30℃. The filtration rate was 0 ml min-1 at only 0 and 5 psu at 20℃, but the feeding activity started from 20 psu or higher at 30℃. As such, exposure to low-salinity water during the high-temperature period has an effect on the filtration rate and mortality of R. philippinarum.