Distribution and indicator species of zooplankton in the East Sea, Yellow Sea and Northern East China Sea in winter

Aim: Zooplankton are distributed by hydrographic factors such as temperature and salinity. The research aims to investigate the distribution patterns of zooplankton and indicator species of water bodies, and to understand the relationship between zooplankton distribution and water bodies in Korean waters in winter. Methodology: Zooplankton, samples were collected and temperatures and salinities were recorded at 130 stations around Korean peninsula in the Yellow Sea and the northern East China Sea (ECS), using a Bongo net and CTD in winter, 2016. Research areas using K-mean clustering based on temperatures and salinities were divided into six water bodies: the North Korea Cold Current (NKCC), the East Korea Warm Current (EKWC), the Jeju Warm Current (JWC), the Yellow Sea Warm Current (YSWC), the Yellow Sea (Y1), and mixed water. The indicator indices for water bodies were calculated using INSPAN (Indicator Species Analysis). Results: NKCC, YSWC and Y1 were represented by high proportions of cold water species of 81, 44 and 41 species, respectively, while EKWC and JWC were relatively dominated by warm water species of 99 and 102 species. The water bodies of Yellow Sea and the northern ECS were greatly similar, but the East/Japan Sea was significantly distinguished. With the Indicator value and distribution, indicator species for water bodies were identified: Scolecithricella minorin the NKCC, Candacia bipinnata, Clausocalanus furcatus, and Pleuromamma gracilisin the EKWC, Scolecithricella longispinosa and Euchaeta plana in the JWC, Centropages abdominalis in the Y1. Interpretation: Distributions of zooplanktons and the similarity of community structures were determined by the interaction of water bodies. Zooplankton species can be used as indicator of water bodies because of their dependence on ocean currents.