Climate change forces Arctic animals to shift feeding habits

Photgraphs taken in Churchill, Manitoba, of a polar bear amongst the fireweed waiting for the Hudson Bay to freeze over. In the words of the photographer, “The polar bear was all by himself as they are very solitary animals anyway, but this one looked particularly sad as it wandered around, almost as though it didn’t understand where the snow had gone.” 

Churchill is said to have the largest and most southerly concentration of polar bears on earth. In late summer and early fall, the bears make their way to Hudson Bay to hunt for seals on the ice. Each year, however, the ice is forming later and later, forcing the animals to go hungry for longer.

Andrew Derocher, Professor of Biological Sciences at the University of Albert, has spent decades studying polar bears and states, “We probably won’t have polar bears in Churchill once we get out to midcentury — they could be gone in a couple of years. If we had a very early melt, and a very late freeze, we could see up to 50 percent mortality in a single year.”

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written by Sarah Hussein PHYS photography by Michael Poliza and Viktor Lyagushkin edited by O Society Mar 8, 2019

Tokyo – Seals and whales in the Arctic shift their feeding patterns as climate change alters their habitats, and the way they do so may determine whether or not they survive.

Researchers harnessed datasets spanning two decades to examine how two species of Arctic wildlife — beluga whales, also known as white whales, and ringed seals — adapt to their changing habitat.

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Svalbard, Norway, with place names and ocean currents. Glaciers (white) and tidal glacier fronts (red) in 2015 are shown. The West Spitsbergen Current (dark-red arrows) transports warm Atlantic water, while the East Spitsbergen Current (blue arrows) transports cold Arctic water.

The research focuses on the area around Svalbard — northwest of Norway — which is experiencing rapid impacts from climate change, specifically a “large collapse in sea-ice conditions in 2006, which continues to the present day,” says lead researcher, Charmain Hamilton.

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“Both white whales and ringed seals were tagged in Svalbard before this collapse occurred to study their basic ecology. Repeat sampling after the sea-ice collapse occurred thus offered the opportunity for a natural experiment,” added Hamilton, who works with the Norwegian Polar Institute.

Both species traditionally hunt for food in areas with sea ice and particularly at so-called tidal glacier fronts, where glaciers meet the ocean.

But with climate change melting sea ice and prompting glaciers to retreat, researchers in Norway decided to look at whether — and how — animals in the affected areas are adapting.

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“The Arctic is the bellwether of climate change,” the researchers write in the study published Wednesday in the Royal Society Biology Letters journal.

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“With the rapid pace of change rendering genetic adaptation unfeasible,” they reasoned that behavioural and dietary changes “will likely be the first observable responses within ecosystems.”

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They compared datasets produced by trackers attached to seals and whales over two sets of time periods.

For the seals, they compared tracker data from 28 individuals between 1996-2003 and then 2010-2016, and for the whales they looked at data from 18 animals between 1995-2001 and 16 animals from 2013-2016.

The data show two decades ago, both species spent around half their time foraging at glacier fronts and eating a diet dominated by polar cod.

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But ringed seals now spend “significantly higher proportions of time near tidal glacier fronts” while the white whales had the opposite response and had moved elsewhere to look for food.

“Tidal glacier fronts appear to be serving as Arctic ‘refugia’ for RS (ringed seals), explaining why this species has increased the amount of time spent near glaciers,” the study said.

White whales meanwhile now “have larger home ranges and spent less time near glacier fronts and more time in the centre of fjords.”

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The researchers, from the Norwegian Polar Institute and the University of Tromso, speculated that whales have shifted their diet, taking advantage of the fact that climate change is allowing new fish species to move further north as waters warm.

Seals in contrast stuck with their old diet, but appeared to spend more time searching for the food at the glacier fronts.

“What was most surprising about the results were the limited changes we found in the ringed seals’ behaviour,” Hamilton told AFP.

“It is not clear why this species is becoming more tightly associated with tidal glacier front refugia and not also foraging on Atlantic fish and invertebrates in other areas of the fjords.”

The study points out that beluga whales tend to be dietary generalists compared to ringed seals, and said the “flexible” response of whales would improve their chances of adapting to warming climes.

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By contrast, the apparent doubling down by the ringed seals on their traditional hunting grounds “reflects limited adaptability and resilience.”

And that could be bad news for the seals in a changing world.

“Species and subpopulations that are not able to make such changes are almost certain to decline, perhaps to extinction where refugial areas become too limiting for species survival,” the study said.

Beluga whales are protected, so studies examining their stomach contents for clues on diet are not possible, but research on how the ringed seal’s diet has changed will be completed later this year, Hamilton said.

And further research on both species is planned, including into how sea-ice collapse is affecting reproduction among ringed seals.

Meet Natalia, The Crazy Russian Arctic Oceanographer Who Polar Bear Plunges to Swim With Beluga Whales

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Natalia Avseenko swims with beluga whales in the White Sea off the coast of northern Russia. A skinny dipping Russian researcher took a ten meter sub-zero plunge in a bid to get up close and personal with two beautiful 15-foot-long beluga whales. Scientists believe that the whales could be more friendly with humans if they swim naked. As these pictures show, the clever-looking marine mammals called Matrena and Nilma seem happy to swim with her.

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Champion free diver, Natalia Avseenko, 36, from Moscow gamely jumped into an ice hole in the White Sea off the coast of northern Russia. She was able to hold her breath and swim underwater for an incredible 11 minutes. These pictures show her swimming in the minus one degree Centigrade waters, which is cold enough to kill a normal person in 15 minutes. Beluga whales generally shy away from conventional scuba divers because they seem to dislike the gas bubbles their tanks produce. It is thought the synthetic materials used to make wet suits may smell bad to belugas.

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