완도 군외면 연안에 입식한 갯벌 굴의 먹이선택성에 관한 연구

Abstract

As one of optimal condition for establishment of criteria of tidal flat oyster farm, we investigated food selectivity between phytoplankton composition in seawater and gut content of oyster reared at 4 × 3 different condition in exposure duration and rack height on the eastern coast of Wando island, Korea. The seawater temperature ranged from 8.9℃ to 28.0℃, which was characterized as lower ranged temperature difference because of strong tidal front around Jindo and indirect influence of off sea waters. Salinity was ordinarily maintained in the range of 30-33 psu, because a hydrodynamic feature prevents the magnitude land-driven freshwater input from Doam tidal gate in Gangjin-gun. A total of 58 phytoplankton species (37 genera) were identified with 58 species of Bacilariophyceae (35 genera) and 5 species of Dinophyceae (2 genera) in seawater but 50 species (50 genera) with 47 species of Bacilariophyceae (31 genera) and 3 species of Dinophyceae (2 genera). The gut content was highly correlated with the standing stock of phytoplankton in seawater. The common dominant species were Paralia sulcata, Navicula sp., Chaetoceros sp. and so on. A Bacillaria paxillifer showed a complementary selectivity to that of Cheatoceros genus with strong positive electivity in the blooming season. In exposure duration experiment, gut content of 1 hr level was significantly higher than that of 2-4 hr level, which can be a feasible criteria for a facility of oyster rack farm in tidal flat.