Impacts of Interannual Environmental Forcing and Climate Change on the Distribution of Atlantic Mackerel on the US Northeast Continental Shelf

The Northwest Atlantic stock of Atlantic mackerel Scomber scombrus is distributed from Cape Hatteras to New-foundland and migrates great distances on a seasonal basis. Atlanticmackerel are sensitive to changes in temperature, preferring water greater than 5 degrees C. Annual changes in the winter and early-spring distributions of Atlantic mackerel were investigated using satellite imagery, research trawl surveys, geographical information systems, and spatial and standard statistical analyses. During the past 40-plus years (1968-2008), the distribution of the stock has shifted about 250 km to the north and east. Also, a change has occurred in the depth distribution of the stock, from deeper off-shelf locations to shallower on-shelf ones. Areal and bathymetric changes in distribution are correlated with interannual temperature variability and gradual warming. These results have implications for U. S. commercial and recreational mackerel fisheries because, despite the current high abundance of the stock, the changes in distribution will probably make it more difficult to find and catch Atlantic mackerel in certain areas in the future.