Fishing ground hotspots reveal long-term variation in chub mackerel Scomber japonicus habitat in the East China Sea

The global warming trend has altered the ocean environment, but space-time changes in the oceanic distribution of small pelagic fishes have been difficult to identify due to their extensive ranges. Using detailed Japanese fishery logbooks, we reconstructed the main location of chub mackerel Scomber japonicus fishing grounds (hotspots) in the East China Sea over 328 consecutive months (27 yr). Our analyses revealed that the chub mackerel hotspots migrated seasonally over the continental shelf of the East China Sea, and demonstrated multi-year and decadal shifts in location, changing according to the spatial variation in the surface temperatures of the East China Sea. Spatial variation in sea surface temperatures was correlated with the volume transport of ocean currents, indicating that temperature and flow fields affected chub mackerel distribution both directly and indirectly. We also found that long-term fluctuations in climate were associated with chub mackerel hotspots, suggesting that atmosphere–ocean interactions may drive chub mackerel distribution variability. This empirical evidence regarding wide-ranging and long-term changes in chub mackerel distribution implies that future management measures need to enhance information sharing among relevant countries around the East China Sea.