Structure of the macroplankton-pelagic fish-cod trophic complex in a warmer Barents Sea

Long-term data indicate that climatic fluctuations in the Barents Sea can have significant impacts on populations of euphausiids, capelin and cod, but it is unclear how the current warming period in the area has altered trophic interactions among these taxa. The species composition and distribution of euphausiids; the abundance, distribution and feeding habits of capelin; and the feeding of cod on capelin and euphausiids were analysed. Data from the last decade suggest a shift in the spatial patterns and intensity of the euphausiid-capelin link, and a reduction in the volatility of population sizes of these species. Meanwhile, cod feeding has expanded farther to the north in the Barents Sea and may benefit from reduced fluctuations in prey availability. The reliability of advection of euphausiids into the region and the potential interactions with boreal species expanding into the Barents Sea, both of which are tightly coupled to climatic conditions, will determine how the pelagic ecosystem functions in the future.