As the climate warms, boreal fish species are expected to expand into the Arctic domain. Though water temperature is an important factor driving expansion of aquatic species, other variables may play a critical role in restricting those movements. Continuous darkness during the Arctic polar night has been suggested to impair foraging in visually searching boreal fish and may thus limit their northward ...

Species with a broad and flexible diet may be at an advantage in a rapidly changing environment such as in today's Arctic ecosystems. Polar cod (<i>Boreogadus saida</i>), an abundant and ecologically important circumpolar Arctic fish, is often described as a zooplankton generalist feeder, which suggests that it may cope successfully with changes in prey composition. This description is justified ...