ICHTHYOPLANKTON COMMUNITY ASSOCIATED WITH OCEANIC FRONTS IN EARLY WINTER ON THE CONTINENTAL SHELF OF THE SOUTHERN EAST CHINA SEA

Abstract

The study of ichthyoplankton community associated with oceanic features on the continental shelf of southern East China Sea (ECS) was conducted in early winter from 2006 to 2009. The species composition of the ichthyoplankton and its spatial distribution was classified and compared with oceanic front. A total number of 1,809 fish larvae individuals were sampled from 5 field surveys, and represented 76 families and 137 species. Using the Bray-Curtis dissimilarity, the abundance of species found to exceed 0.5% of the total sample from 36 stations were classified into four groups: China Coastal Group, Mixed Shelf Group, Taiwan Strait Group, and Kuroshio Group. The shallow water species Sebastiscus marmoratus dominated the China Coastal Group, while the Mixed Shelf Group was dominated by Saurida spp., Trichiurus lepturus, and Bregmaceros spp. The Taiwan Strait Group was dominated by Engraulis japonicus and Benthosema pterotum. The dominant species in the Kuroshio Group was found to include Sigmops gracile and unidentified Myctophid larvae. The spatial distribution of the ichthyoplankton community groups was superimposed on a thermal front map of the study area. This clearly revealed that the China Coastal Front could be the boundary which separated the China Coastal Group on the west and the Mixed Shelf Group on the east. In addition, ichthyoplankton were found to increase in abundance and diversity in the region close to the Kuroshio Front.