What drastically increases the energy expenditure when sea ice retreats far from feeding grounds?

Swimming 300 miles round trip for foraging

The relationship between walruses and sea ice is fundamental to their feeding efficiency, as the ice edge serves as a crucial mobile resting platform for launching dives. When ice melts or retreats significantly far from the productive, shallow benthic feeding zones—sometimes up to 150 miles away—the logistical demands change dramatically. Instead of short dives from a nearby ice floe, the walrus is forced to haul out on land or remain on a distant floe, necessitating an extremely long round trip swim, potentially 300 miles, just to reach the feeding area before any calories can actually be gathered. This translates feeding efforts into long-distance travel punctuated by brief foraging, severely stressing the animal's overall energy balance.