When sea ice melts in the summer, beluga whales that hang out in the Bering Sea during winter traverse up north. This is typically when they eat really good, but climate change may be messing with their summertime fish buffets.
With the increased loss of sea ice and the shift in prey habits, beluga whales have been diving deeper and longer, according to a paper published in Diversity and Distributions earlier this month. Researchers with the University of Washington came to that conclusion by tracking two beluga populations from July to October over two extensive periods: from 1993-2002, and from 2004-2012.
Between 2007 and 2012, in particular, the team noticed that whale dives became dramatically longer and deeper. In earlier years, a 20-minute or longer dive would occur just once a day, but during this later period, those same dives happened nearly three times a day. The depths to which beluga whales were diving increased over time, too.
The paper couldn’t conclude whether these changes were helping or hurting belugas, but researchers do hypothesize that the changes in the ocean as the Arctic warms are leading to more opportunities to find prey, more prey hiding deeper, or a combination of the two.
“Reduced sea ice cover over a longer period of time over the summer could mean improved foraging for belugas,” said lead author Donna Hauser, a researcher at the university’s Polar Science Center, in a press release. “But it’s also important to recognize these changes in diving behavior are energetically costly.”
Overall, the majestic creatures fared pretty well during both time periods. For the most part, they returned to the same areas even if those areas were covered by less ice. Beluga whales might be one of the animals that actually survive the major ecological shifts climate change is causing. After all, they’re adaptable and resilient, said Hauser.
“Belugas feed on a lot of different prey and use many different habitats, across open water and dense sea ice and everything in between,” Hauser said, in the release. “Because they are such generalists, that could buffer them under climate change.”
That’s not exactly true for other creatures who dwell on this sea ice—like polar bears. A loss of sea ice is making it harder for bears to hunt, which can create rippling effects throughout the ecosystem. Studies need to take a closer look at these effects to have a fuller picture of the Arctic’s future.
