Tag Archives: swimming

Scientific study finds polar bears excel at diving, contradicting previous expert opinion

A recent study by Norwegian biologist Karen Lone and colleagues, who tagged 57 polar bear females with sensors around Svalbard, discovered that polar bears can dive to a maximum depth of 13.9m and can swim long distances across open water without rest. Contrary to previous claims, polar bears are excellent divers and their breath-holding ability did not seem to limit how deep they could dive.

chukchi-bear-swimming-june-15-2014-brian-battaile-dsc_4036_lg.jpg

From the abstract of the new paper by Lone and colleagues (Lone et al. 2018):

“Some bears undertook notable long-distance-swims. Dive depths up to 13.9 m were recorded, with dives ≥5 m being common. The considerable swimming and diving capacities of polar bears might provide them with tools to exploit aquatic environments previously not utilized.”

Compare the above statement to one made by Stirling and van Meurs (2015), after describing a 3 minute dive video-taped during an aquatic stalk of a bearded seal, also in the Svalbard area:

“…increased diving ability cannot evolve rapidly enough to compensate for the increasing difficulty of hunting seals because of the rapidly declining availability of sea ice during the open-water period resulting from climate warming.” [my bold]

These two papers really show the difference between using anecdotal accounts as if they were evidence of species-wide physical abilities and doing a scientific study on the physical ability of interest.

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Dead polar bear washed ashore in NE Newfoundland, cause of death unknown

A dead polar bear was found on the shore of northeastern Newfoundland yesterday but the cause of death has not yet been determined.

From the local Telegram (5 June 2017):

“[Ann] Peddle of Bristol’s Hope was out for her morning walk when she came across the carcass of a polar bear that had washed ashore. The carcass had drifted between the rocks near the wharf in Bristol’s Hope, according to Peddle.

Peddle took some quick photos of the bear to post to social media before contacting the wildlife department at around 8:30 a.m.”

Ann Peddle took the photo below, which was printed with the above story:

Bristols Hope Nfld dead bear Telegraph June 5 2017_Ann Peddle

 

See the map below for the location of Bristol’s Hope in NE Newfoundland, along the west shore of Conception Bay  (see map at end of post for the names of the bays):
Bristols Hope Newfoundland location June 6 2017

Was this a death by drowning or some other, more likely cause?
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Most polar bears easily deterred this time of year, lucky Labrador boaters discover

A polar bear female accompanied by a cub recently attempted to board a small sailboat anchored in a remote harbour off central Labrador – giving the two American boaters below deck a mighty big surprise.

Labrador polar bear encounter Torngat boat_CBC 30 Aug 2016

‘He said ‘it’s a bear, it’s right on the boat, make some noise.'” – Nancy Zydler

The encounter occurred south of the same national park where a much-publicized attack occurred in July 2013 (see previous posts here and here) but had a happier ending. See more below from a CBC report released this morning (based on a radio interview) and some ecological context for the sighting not mentioned by the reporter.
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Longest-swimming polar bear lost less weight than if she had stayed onshore

Recent media hype over swimming polar bears in the Southern Beaufort has been quite spectacular (still going strong today at the Washington Post here) but a close look at relevant data shows the message is bogus. Researchers admit (in their methods section) they couldn’t tell if bears said to have swum “non-stop” actually hauled out for half a day or more to rest on small ice flows invisible to satellites and astonishingly, the bear getting all the media attention – who swam the longest of any bear – lost less weight than a bear would have done simply sitting on shore for the same length of time.

Washington Post_swimming polar bears_snapshot 21 April 2016

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RCMP shot fearless polar bear that came ashore on Fogo Island, Newfoundland

Just look at the polar bear on the cover of my new novel (right sidebar) and image that bear coming towards you with no intention of stopping. That’s what a Newfoundland RCMP officer faced yesterday – and he did what he had to do.

Fogo polar bear shot_CTV May 2 2016

This is the usual time for polar bear visits to northern Newfoundland but this one had a sad ending. The bear that came ashore at Deep Cove (where some of the action in my novel EATEN takes place, near the artist studio pictured in the photo shown above) on Fogo Island (map below) was killed by RCMP due to fears for public safety when it kept approaching officers even after warning shots were fired.

Maps and quotes from the 2 May CTV report below:

UPDATE 4 May 2016: more detailed (and accurate) information added below from a new CBC report – apparently, the bear was a large juvenile male, not an adult as originally reported, and was larger than initial reports indicated.

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No evidence that long-distance swimming contributed to Beaufort Sea polar bear population crash of 2004-2006

The air is thick with desperation on the polar bear front:

“[Andrew] Derocher said the polar bear population in the Beaufort Sea has fallen more than 50 per cent in the past 10 years.

“So it is a concern that this is probably one of the factors associated with the population decline,” he said.

Derocher_CBC news 19 April 2016

As the CBC report in which this quote appears states immediately afterwards, there is no evidence for such a thing in the paper under discussion:

“The study found no direct evidence of that – all polar bears appeared to survive the swims recorded in the study.”

There is no truth to Derocher’s first statement either. Desperation – you don’t have to be a scientist to sense it. And the media wonder why people don’t trust them…

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Most Beaufort polar bears swim from ice floe to floe during breakup, study shows

swimming3_USGS

You may have seen the headlines in Canadian news outlets over the last 2 days.
“Polar bears swimming farther as sea ice recedes, study shows”

“Melting sea ice forces polar bears to swim longer, farther: study”  [“Bear biologist Andrew Derocher says the forced swims are particularly hard on mothers with young cubs”]

“Polar bears swimming longer, farther because of melting sea ice, study finds”

Oddly, none of the above news reports said where the paper was published or mentioned the name of the lead author – only University of Alberta co-author Andrew Derocher was interviewed (see the only press release I could find here, issued by the San Diego Zoo where the lead author is now employed).[update: CBC ran another story a day later that corrected these omissions]

But what did the study actually say?

Significantly, no bears died while swimming during the two lowest sea ice extent summers since 1979 and no evidence was presented that swims were “particularly hard on mothers with young cubs.” The quotes from the paper below sum it up for Beaufort Sea (BS) bears (the inclusion of Hudson Bay (HB) bears in this study seems gratuitous and potentially misleading, since only a few swam anyway – only 15 out of 59):

“….91% (91/100) of the swims in the BS occurred before the annual September minimum sea ice extent had been reached.  In the BS, 81% (29/36) of swims started and ended in pack ice…

So, despite what may be implied during media moments, Beaufort Sea polar bears were  not frantically trying to reach the sea ice from land so that they could attempt to keep feeding over the summer – most of their swimming was done during breakup in July and August from one bit of pack ice to another and they showed no evidence of harm from doing so. Map from the study and more quotes below.
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Beaufort Sea swimming polar bears far from land but not very far from sea ice

Recent accounts of an encounter with a curious polar bear female and her two older cubs in the Beaufort Sea on 16 September give contradictory details about the position of sea ice at the time. The same researcher told one reporter that the ship was 240 km from land, another that it was 240 km from the sea ice, and in another account (that he wrote himself), said the ship had been far from land and sea ice.

Beaufort swimming polar bears_Sept 30 2015_Global news

University of Victoria (Canada) chemical oceanographer Jay Cullen said on the expedition web site:

“After arriving on station and beginning work the crew noticed three polar bears in the water together which swam around to the ship when our water sampling system was nearly 3500 meters below the surface. The ship was located far from sea ice and land. Indeed, Arctic sea ice extent was the fourth lowest on record this year and there has been speculation that this imposes stress on polar bears which rely on the ice to hunt.”  [my bold]

But the maps below show that at the time of the incident (taken from the expedition web site) and the NSIDC Masie sea ice map for 16 September 2015, the ship [the CCGS Amundsen, acting as a research vessel] was actually quite close to an isolated large patch of sea ice, although further from the edge of the main pack. A patch of sea ice plenty big enough for a polar bear to rest upon – no wonder the bears did not appear stressed.

And the polar bear biologist Cullen consulted (Dr. Andrew Derocher) implied by his response that the bear was indeed far from sea ice. Reminds me of the swimming polar bear off the Hibernia oil platform off Newfoundland March 2015, which turned out to be not far from ice at all. See what you think.
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Tracking polar bears – two S. Beaufort bears spent August 2015 on ice that doesn’t exist

Two out of seven polar bears with collars in the Southern Beaufort Sea either spent the month of August on ice that satellites couldn’t see – or they spent the entire month swimming around the Beaufort. Which seems most likely?

Thin ice Lisa Robbins Sept 15 USGS_04

See previous discussions here and here regarding the problem satellites have in accurately detecting melting ice. The presence of these two bears is evidence that there is more polar bear habitat than satellites record as officially present. This was also an issue for Hudson Bay bears earlier this year.

Five out of the seven visible females were on the ice in August – but are the other six bears that were visible last month spending the summer in the Arctic Basin like the one I reported last week? Or have their collars actually failed or dropped off? USGS isn’t saying.

See the August track map below, from the USGS Tracking Polar Bears website1 and a sea ice map.
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Polar bear season for Newfoundland residents still going strong, recent sightings confirm

Two recent sightings of polar bears along the north shore of Newfoundland are a reminder that sea ice is still a prominent feature of the Davis Strait polar bear subpopulation landscape at this time of year.

LaScie_Newfoundland_April 27 2015_ColleenGray label

A polar bear was sighted in the community of La Scie, northern Newfoundland Monday, 27 April (pictured above, swimming in the harbour), while another landed in the town of Fogo, on Fogo Island, last week (see maps below).
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