Resource-driven colonization by cod in a high Arctic food web

Climate change is commonly associated with many species redistributions and the influence of other factors may be marginalized, especially in the rapidly warming Arctic. The Barents Sea, a high latitude large marine ecosystem in the Northeast Atlantic has experienced above average temperatures since the mid 2000’s with divergent bottom temperature trends at sub-regional scales. Concurrently, the Barents Sea stock of Atlantic cod Gadus morhua, one of the most important commercial fish stocks in the world, increased following a large reduction in fishing pressure and expanded north of 80°N. We examined the influence of food availability and temperature on cod expansion using a comprehensive data set on cod stomach fullness stratified by sub-regions characterized by divergent temperature trends. We then tested whether food availability, as indexed by cod stomach fullness, played a role in cod expansion in sub-regions that were warming, cooling or showed no trend. The greatest increase in c...