Seasonal variation in the population structure and production of the copepod Calanus sinicus in the Yellow Sea

Abstract

We estimated the total production of Calanus sinicus over four seasons by measuring somatic and egg production rates in the Yellow Sea. In the process of measuring somatic production, the length–weight relationship and growth rates of C. sinicus in this region were also derived. The population abundance and biomass of C. sinicus were especially high in spring. All copepodite stages had similar proportions in spring, whereas the late stages and adults were most common in summer. The mean total production of the C. sinicus population was 107.6–259.7 μg C m−3 day−1, ranging from higher values in spring to lower values in summer. The annual total production of C. sinicus in the Yellow Sea was 64.3 mg C m−3 year−1 (4032 mg C m−2 year−1). The production of C. sinicus was positively correlated with chlorophyll a concentration, rather than water temperature or salinity. This study is the first to quantify the secondary production of C. sinicus in the Yellow Sea. These findings will broaden our understanding of the ecology of C. sinicus and its contribution to the Yellow Sea food web.