The Variations of the Abundance and Distribution Pattern of <i>Calanus sinicus</i> Brodsky in the Western South Yellow Sea in Spring and Summer

Abstract

Multidisciplinary comprehensive investigations were conducted in the western South Yellow Sea in the summer, 2006 and spring, 2007. The abundance and distribution pattern of a dominant zooplankton species, Calanus sinicus, and its relationship with the environmental conditions are analyzed. The data of C. sinicus and hydrological parameter in the spring and summer of 1959 are used to compare the variations of C. sinicus and hydrographical conditions in the past 50 years. Results show that the abundance of C. sinicus was significantly higher in 2006 and 2007 than that in 1959 which may be correlate with both the bottom-up and top-down effects; the distribution pattern in the spring of the two years was similar, on the contrary, However, the hydrographical characteristics were conspicuously different between the two springs, for example, the coverage and strength of the Qingdao Cold Water Mass, the penetrating pathway of Yellow Sea Warm Current and the distribution pattern of the oceanic front. Correspondingly, the distribution pattern of C. sinicus in the summer of the two years showed great differences. Thus, it is suggested that the distribution pattern of C. sinicus in summer might be influenced by the hydrographical characteristics in spring, which probably further affects the present of some economically important fishes which fed on C. sinicus.