In situ detrimental impacts of Prorocentrum donghaiense blooms on zooplankton in the East China Sea

Large-scale algal blooms of the dinoflagellate Prorocentrum donghaiense have occurred frequently in the East China Sea (ECS) in recent decades. However, its impacts on the zooplankton in situ are still under not well understood. During a spring P. donghaiense bloom (April-May 2013) along the northern coast of Fujian Province (120°-121°30″E, 26°30″-28°N), we found that the bloom decreased the abundance of copepods and had no significant effect on chaetognaths and small jellyfish. However, the abundance of small jellyfish increased over the course of the study. The zooplankton community changed from being copepod and small jellyfish- to small jellyfish-dominated during the bloom. In the bloom areas, the copepod Calanus sinicus showed higher mortality and lower egg production rates (EPR) than those in the non-bloom areas. The results suggested that P. donghaiense blooms had detrimental effects on the structure of zooplankton community and the recruitments of C. sinicus.