Beluga whales are diving deeper and longer to find food
Beluga whales that spend summers feeding in the Arctic are now diving deeper and longer to find food than in earlier years, according to a new analysis from University of Washington.
The study said reductions in sea ice in the Arctic have a clear impact on animals such as polar bears that rely on frozen surfaces for feeding, mating and migrating. At the same time, sea ice loss is changing Arctic habitat and affecting other species in more indirect ways.
The study, published this month in the journal Diversity and Distributions, is one of the first to consider the indirect effects of sea ice loss on Arctic species that dwell near the ice, but don’t necessarily depend on it for survival.
The study said sea ice loss appears to affect how the Chukchi belugas dove for their food.
Based on their observation, during the period when there was less sea ice, the whales dove significantly longer and deeper than in the earlier period — presumably in search of prey as the animals, in turn, changed their habits because of different ocean conditions brought on by sea ice loss.
Specifically, during the earlier period belugas dove for 20 minutes or longer only once per day, compared to nearly three times a day during the later period. Similarly, their average daily dive depth increased from about 50 meters (164 feet) to 64 meters (210 feet) between the two periods.
It’s unclear whether diving changes are positive or negative for belugas, and studies on body condition and health are still needed to understand the implications of these changes.