Spatio-temporal distribution of chub mackerel Scomber japonicus in the East China Sea during 2005-2016 and its relationship with sea surface temperature

Abstract:

Chub mackerel (Scomber japonicus) is a pelagic economically important species and an important fishing target for Chinese coastal fisheries. The distribution of S. japonicus is significantly affected by climatic and environmental conditions at different scales. Based on the fisheries data of S. japonicus from July to September during 2005-2016 provided by National Data Center of Distant-water Fisheries of China, combined with the key environmental factor sea surface temperature (SST) data, this study quantified the temporal and spatial changes of fishing ground of S. japonicus on the analysis of determining the longitudinal and latitudinal gravity centers of fishing effort. Additionally, the distribution of the fishing ground in relation to longitude, latitude and SST was analyzed. Furthermore, the representative years were selected by cluster analysis to evaluate the impacts of abnormal climate events on the spatial and temporal distribution of SST and gravity centers of fishing ground for S. japonicus in the East China Sea. The results showed that there was significant interannual and monthly variation in gravity centers of fishing ground for S. japonicus in the East China Sea. The fishing ground gradually moved northeastward from July to September, which mainly occurred in the SST ranging from 25 to 28℃. Cluster analysis suggested that gravity centers of fishing ground in each month were divided into four categories, and significant difference was found between 2007 and 2015 in each month. Moreover, a statistically significant positive correlation was found between SST anomaly on the fishing ground of S. japonicus and oceanic Niño index. A La Niña event occurred in 2007 and an El Niño event occurred in 2015. When the La Niña event occurred, the SST on the fishing ground increased, and the gravity center of the fishing ground gradually moved northward; while if the El Niño event occurred, the SST on the fishing ground largely decreased, and the gravity centers of the fishing ground were mostly located in its southern waters. Our findings indicated that spatio-temporal distribution of S. japonicus in the East China Sea was strongly regulated by the impacts of the El Niño and La Niña-driven SST changes on the fishing ground.