Category Archives: Life History

W Hudson Bay polar bears now on the ice hunting but killer whales could be trapped

According to reports from folks on the ground in Western Hudson Bay, most polar bears were out on the ice resuming seal hunting by the 20th or 21st November at the latest (some got started quite a bit earlier). That’s less than 2 weeks later than the average date in the 1980s (which was November 8).

Sea ice Canada 25 Nov 2015_with Churchill

However, the rather odd pattern of freeze-up this year may not be good news for any killer whales still remaining in Hudson Bay – their access to the open ocean is already virtually blocked by ice.

UPDATE 26 November 2015: What a difference a day makes! Look at the spectacular ice development overnight along the west coast of Hudson Bay and in the central portion of the bay since yesterday (below).

Canadian Arctic Nov 26 2015_CIS

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Polar bear habitat update – Arctic sea ice today covers same area as it did on June 30

Arctic refreeze is well underway. Less than half way through the Arctic autumn (Oct-Dec), polar bear habitat on 11 November 2015 covered the same total area as it did on the last day of Arctic spring (April-June); it’s just distributed differently.

polar_bear_usfws_no date_sm

Yesterday, courtesy NSIDC Masie

masie_all_zoom_4km_2015 Nov 11

Here is what 30 June 2015 ice extent looked like, with the same amount of ice coverage:


For the week of 12 November, Hudson Bay sea ice development is well underway, with more ice in the north than there has been in many years; Davis Strait ice is the highest this week since 1999 and Baffin Bay ice coverage is above average. Foxe Basin and the Beaufort Sea are both approaching maximum coverage, which means bears there will be back out on the ice hunting. Chukchi Sea ice has finally surrounded Wrangel Island but the Svalbard Archipelago in the Barents Sea is still ice-free. More ice maps and charts below.
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Who tagged the Beaufort Sea polar bear with the tight collar?

I’ve updated my post from last week to reflect that an inquiry to USGS has generated a statement that the Beaufort Sea polar bear reported by CBC last week is NOT one of their bears. Apparently University of Alberta researchers were also tagging polar bears in the region.

polar-bear-radio-collar_CBC Oct 28 2015

See details in the updated post here.

Kaktovik, where the bear was photographed, is not too far from the Canadian border of the Southern Beaufort Sea subpopulation, see USGS tracking map below.

Original caption: "Movements of 3 satellite-tagged polar bears for the month of October, 2015. Polar bears were tagged in 2014 and 2015 on the spring-time sea ice of the southern Beaufort Sea. All 3 of these bears have satellite collar transmitters. Polar bear satellite telemetry data are shown with AMSR2 remotely-sensed ice coverage for 31 October, 2015." Click to enlarge.

Original caption: “Movements of 3 satellite-tagged polar bears for the month of October, 2015. Polar bears were tagged in 2014 and 2015 on the spring-time sea ice of the southern Beaufort Sea. All 3 of these bears have satellite collar transmitters. Polar bear satellite telemetry data are shown with AMSR2 remotely-sensed ice coverage for 31 October, 2015.” Click to enlarge.

How long is it going to take for the people responsible to own up to this situation – and more importantly, remove the tight collar from the bear?

Tracking polar bears in the Beaufort Sea – all three bears on the ice during October 2015

All three of the females with radio collars installed by USGS last spring (see footnote below) spent October out on the sea ice – which suggests the Kaktovik female with the tight collar that made the news last week was either wearing a failed collar, USGS removed her icon from the map, or she was not wearing a USGS collar.

polar-bear-radio-collar_CBC Oct 28 2015

It is possible that the poor bear was the one represented by the purple icon from last month (see map below), the only USGS collared bear that was on shore during September and still sending signals. The bear in the above photo was photographed in Kaktovik, easy walking distance for a bear, near the end of October.  The purple icon on shore in the September USGS map is no longer present this month.

As far as I know, there has been no follow-up information on the fate of this bear: we still don’t know whether the collar has yet been successfully removed.
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2015 may be the earliest in many years that W. Hudson Bay polar bears head for the sea ice

Great news for Western Hudson Bay polar bears! Following up from sea ice conditions last week, CIS maps show ice forming all along western Hudson Bay – not a huge amount, but the beginning of the end of the ice-free season, which recently has not occurred until mid-November (Cherry et al. 2013).

Canadian Arctic Oct 29 2015_CIS

There is above-average sea ice coverage in Foxe Basin and Davis Strait, and only slightly below average coverage in the Beaufort Sea (see graphs below). Polar bear habitat is shaping up very nicely indeed across Canada and the US this year.
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Tracking polar bears – 3 out of 4 S. Beaufort bears on the ice during September 2015

The shore of Alaska is not very important to Southern Beaufort polar bears – most of them stay on the sea ice during the summer and early fall, where they may or may not continue eating. These results of on-going satellite tracking studies by USGS1 confirm results of previous studies.

Tranquilized_pb570_S Beaufort March 2014_USGS

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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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