Seasonal variation in copepod abundance and community structure in the Laoshan Bay, China

Abstract

Copepods are preferred prey of many fish and the variability in copepod community is an important driver of fish survival during their larval stage. Seasonal variation in the copepod community structure in the Laoshan Bay, Yellow Sea, China was investigated from May to November 2014. A total of 25 copepod species were identified and the copepod community was numerically dominated by Acartia spp. (53%), followed by Paracalanus sp (28%), Oithona similis (11%), Corycaeus affinis (3%), Parvocalanus crassirostris (2%) and Calanus sinicus (1%). Acartia hongi was most numerous in spring and it was rapidly declining towards winter. Paracalanus sp. densities peaked in August accounting for highest proportion of the total copepod abundance. The abundances of O. similis and C. affinis were relatively stable during the study period and contributed the most to total copepod abundance in November and September. Copepod community was similar between June and July and between September and November. BIO-ENV analysis showed that seawater temperature was most important among environmental factors in explaining the seasonal similarities and between season dissimilarities of copepod communities. Copepods had high abundance from May to August in the Laoshan Bay, Yellow Sea potentially suggesting sufficient prey availability for fish larvae, while autumn-spawned fish may experience a food limitation due to low copepod densities.