Estimation of the Effect of Flushing Time on Oyster Aquaculture Potential in Jaran Bay

Abstract

Flushing time is a concept to show the characteristics of water exchange in the sea, and a longer flushing time generally translates as delayed water exchange and thus a higher likeliness of water pollution in the sea. In oyster growing regions, flushing time determines the filter-feeding performance and growth of oysters as well as food availability and fecal dispersion. This study was carried out to estimate the effect of flushing time on oyster aquaculture potential in Jaran Bay on the southern coast of Korea by calculating clearance efficiency using flushing time calculated by the particle tracking model and clearance time estimated during field observations. Clearance efficiency refers to the ratio of flushing time to clearance time of oysters with decreasing values of clearance efficiency representing higher growth potential of oyster. Flushing time in Jaran Bay was calculated as ranging between 6.9–12.8 days depending on tidal cycle with the average being 8.4 days and as ranging between 26.4–197 days depending on the growing phase of oysters with the average being 50.6 days. Hence, clearance efficiency was calculated as ranging between 0.035–0.485 with the average being 0.166. These results indicate that a higher rate of water exchange increases food availability for oysters and facilitates fecal spread, thus enhancing the aquaculture potential of oysters. It can be concluded that both flushing time and clearance time is affected by tidal cycles and seasons and based on calculated values of clearance efficiency, this study successfully quantified the effect of flushing time of seawater on the oyster aquaculture potential.