여름철 북부 동중국해의 중형동물플랑크톤 분포와 요각류 Calanus sinicus의 개체군 동태

Abstract

Mesozooplankton community in the northern East China Sea was investigated at 15 stations in July 2006 with total biomass and size fractionated biomass of mesozooplankton and also biomass and somatic production of copepod Calanus sinicus. A total of 187 mesozooplankton taxa were identified. The most abundant taxa identified were small sized copepods, mainly Paracalanus parvus, Oithona similis and Oithona copepodite. The average carbon biomass of total mesozooplankton varied from 3.8 to 65.7 mgC m^(-3) (mean 16.5 mgC m^(-3)), and the maximum value of total biomass was observed in the northwestern part and the minimum value in the southeastern part of the study area. The mesozooplankton biomass in the 1-2mm size fraction was the highest in the four size fractionated groups (0.2-0.5mm, 0.5-1mm, 1-2mm and 2-5mm). The copepodites and adults of C. sinicus occurred in the most of stations and the biomass of C. sinicus ranged from 0.24 to 11.41 mgC m^(-3) (mean 4.34 mgC m^(-3)), with higher in the western part of the study area. The estimated somatic production of C. sinicus was 0.03～1.40 mgC m^(-3) day^(-1) (mean 0.50 mgC m^(-3) day^(-1)). The water mass of the northern East China Sea can be divided into four type: the Changjiang diluted water, the Yellow Sea Cold Bottom Water, the Tsushima Warm Current, and the maxed water containing the Changjiang diluted water, the Yellow Sea Cold Bottom Water and the Tsushima Warm Current. Variations in zooplankton composition and abundance might be used as proxies to observe long term changes in marine ecosystems. The future plan is to continually monitor this ecosystem to understand seasonal and inter-annual variations in relation to the climate and environmental changes.