A comparative study of the lipid dynamics of the euphausiid, Euphausia pacifica, from Korean Seas (East/Japan Sea, South Sea, and Yellow Sea)

Abstract

The euphausiid, Euphausia pacifica, is a cosmopolitan species in the North Pacific Ocean and is also widely distributed in all Korean Seas including the East/Japan Sea, South Sea and Yellow Sea. It is assumed that they have different life strategies in order to live under various environmental/oceanographic conditions. Although they are one of the key species in marine ecosystems of Korean Seas, little information on their biology and ecology is available. Therefore, this study was conducted to understand and compare the ecological/physiological characters (i.e. food availability, reproduction and mechanism for energy storage) of E. pacifica from three geographically and environmentally different Korean Seas by examining lipid biomarkers including total lipids and lipid class composition. According to the preliminary results, E. pacifica from the East/Japan Sea have the same level of lipid content (about 10% of dry weight) and composition (phospholipids as a dominant lipid class – more than 50% of total lipids) found in E. pacifica from the eastern North Pacific Ocean (California Current System). These preliminary results suggest that the lipid dynamics (i.e. lipid contents and class composition) of E. pacifica may not be so different among regions in the North Pacific Ocean having similar environmental conditions (temperature, salinity, upwelling, etc.) to East/Japan Sea. However, currently we are investigating samples from the other Seas (South Sea and Yellow Sea) having distinctly different oceanographic conditions to determine if there are regional differences of lipid dynamics with regard to their living strategies and life cycle features.