Polar cod (Boreogadus saida) is the dominant forage fish in Arctic seas and the main prey of the ringed seal (Pusa hispida), the beluga (Delphinapterus leucas) and several seabird species. Changes in the abundance of polar cod will have cascading effects on arctic marine ecosystems. We tested the hypothesis that an earlier sea ice breakup and warmer sea surface temperatures (SST) in spring-summer ...