Mesozooplankton Community Structure in the Yellow Sea in Spring

We investigated mesozooplankton in the Yellow Sea in spring to understand its community structure and relationship with environmental factors. Total mesozooplankton density ranged from 1,542 to 7,367 ind. m and the biomass ranged from 3 to 42 mg C m. The total density and biomass had a positive relationship with chlorophyll-a (chl-a) concentration. The mesozooplankton community was divided into two groups at 125.5 E by cluster analysis: one was an inshore group and the other was an offshore group. The inshore group of mesozooplankton was of high density but low diversity, while the offshore group was of high diversity but low density. Copepod Acartia hongi and its copepodites were the most abundant species, comprising 27.8% of the total mesozooplankton density. A. hongi was especially abundant at the inshore, serving as the indicator species of the inshore group. Redundancy analysis found a positive relationship between the density of A. hongi and chl-a concentration. Oithona similis and Centropages abdominalis were 2 and 3 dominant species comprising 9 and 7% of the total density, respectively. The density of O. similis was positively related to water depth, but C. abdominalis was related to chl-a concentration. Chl-a concentration seems to influence significantly the mesozooplankton community structure in the Yellow Sea in spring, rather than water temperature or salinity.