Predicting how climate change threatens the prey base of Arctic marine predators

Arctic sea ice loss has direct consequences for predators. Climate-driven
distribution shifts of native and invasive prey species may exacerbate
these consequences. We assessed potential changes by modelling the prey
base of a widely distributed Arctic predator (ringed seal; Pusa hispida)
in a sentinel area for change (Hudson Bay) under high- and low-greenhouse
gas emissions scenarios from 1950 to 2100. All changes were relatively
negligible under the low-emission scenario, but under the high-emission
scenario, we projected a 50% decline in the abundance of the
well-distributed, ice-adapted, and energy-rich Arctic cod (Boreogadus
saida) and an increase in the abundance of smaller temperate-associated
fish in southern and coastal areas. Further, our model predicted that all
fish species declined in mean body size, but a 29% increase in total prey
biomass. Declines in energy-rich prey and restrictions in their spatial
range are likely to have cascading effects on Arctic predators.