The variation in zooplankton abundance related to sea water temperature changes in Incheon coastal water, Gyeonggi Bay from 2000 to 2007

초록

The main objective of this study was to understand the dynamic variation of the abundance of zooplankton in Incheon coastal waters from 2000 to 2007. Incheon coastal waters are influenced by substantial exchange because of tidal action. Zooplankton sampling was conducted bimonthly at 6 stations located in Incheon coastal waters with a conical-type net from 2000 to 2007. Thirty-nine taxa of zooplankton were identified in Incheon waters, which consisted of 1 Dinoflagellate, 2 Chaetognatha, 3 Cladocera, 24 Copepods, 1 Appendicularia and 11 other kinds of zooplankton including meroplankton. Total abundances of zooplankton were highly variable, ranging from 588 inds./m3 to 61,658 inds./m3. The maximum value of total abundance appeared in June from 2000 to 2002. After 2003, the maximum value of total abundance appeared in April. During the study period, the copepod Acartia hongi was the most abundant species overall. However, during summer, the dinoflagellate Noctiluca scintillans was the dominant species and abundance of the genera Oithona and Paracalanus increased with water temperature. The proportion of meroplankton increased during the warm season throughout study period. We suggest that the seasonal succession and the variation of zooplankton communities were influenced by seasonal variations in water temperature and by the variation of phytoplankton abundance in the study area.