Tag Archives: body condition

Problem polar bears of Churchill: first report of the season similar to 2016

The first activity report of the Churchill Polar Bear Alert Program has been released for 2017. It comes on the same week as last year’s (so about the same dates for first bears ashore both years), and reports pretty much the same activity.

Churchill PB reports_week 1_ July 10-16_July 2017

Odd that this year’s report contains no mention whatsoever of the condition of the bears as did last year’s (see below), which may have brought criticism for spoiling the media ‘message’ that WHB bears are suffering because of reduced sea ice. Better no comment at all than good news, eh?

Sea ice for the week of 10 July off Western Hudson Bay this year consisted of a broad strip of thick first year ice (>1.2m thick) just off shore.

Hudson Bay weekly ice stage of development 2017 July 10

The ice charted above looked like this on a standard ice map:

Sea ice Canada 2017 July 11

There are no other reports that I could find of polar bears ashore along the coast of Western Hudson Bay, so these bears must be the first wave.

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Much more sea ice in NW Hudson Bay this year than 2016 or 2015 at 27 May

In recent years, sea ice loss over Hudson Bay has begun with open water in the NW corner (which is just as likely due to prevailing offshore winds as ice melt) rather than along the east coast but this year that patch of ice is smaller than its been for the last two years. In addition, despite two patches of open water at either end of the Beaufort Sea, most of the coast of Alaska is still covered in thick ice — much more than existed last year, yet masses of polar bears did not die as far as I know (actually, WHB bears came ashore in excellent condition last year).

Sea ice Canada 2017 May 27

Compare to previous years:

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Polar bear mating season winds down with lots of sea ice habitat available

Habitat for polar bears is abundant worldwide as the prime feeding season passes its peak and mating season for sexually mature bears winds down.

JR1_1266.tif

Battle among polar bear males for the right to mate, from this 2011 DailyMail story here.

There is much more ice than usual around Svalbard in the Barents Sea and off Newfoundland and southern Labrador, home to ‘Davis Strait’ bears. There have been no media reports of polar bears onshore anywhere (since the third week of April in Newfoundland and late January in Svalbard).

Sea ice map below for 12 May 2017:

Svalbard ice extent 2017 May 12_NIS

Compare the extent and concentration of ice around Svalbard above (at 12 May 2017) to conditions that prevailed on the same date in 2015 (below), considered a “good ice” year for local polar bears (and the year of the last population size count which registered an increase over the 2004 count):

Svalbard ice extent 2015 May 12_NIS

There hasn’t been this much ice in the area at this point in the season for many years, especially to the north of Svalbard, and levels since late April have been above even the long-term average (disregard the huge downward blip, which is clearly a sensor malfunction of some kind):

Svalbard ice extent 2017 May 12 graph_NIS

In fact, ice is pretty solid throughout the Barents Sea and East Greenland at this time:

Barents Sea ice extent 2017 May 12_NIS

Across the Atlantic, the situation is similar, with unseasonably heavy sea ice off eastern North America and the Southern Beaufort Sea.

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IUCN PBSG insists the 2015 Barents Sea polar bear count was not an increase

Similar to the spin on the 2013 Baffin Bay/Kane Basin polar bear population survey, the IUCN Polar Bear Specialist Group now insists the latest count of the Barents Sea subpopulation is not evidence of an increase in numbers since 2004, as the leader of the study announced in 2015.

Svalbard polar bear_Aars August 2015-NP058930_press release

This is Part 2 of the big surprises in the latest version of the polar bear status table published by the IUCN Polar Bear Specialist Group (PBSG) on 30 March 2017. See last post here regarding the PBSG population size estimates that no longer concur with the 2015 Red List assessment, including the global total — even though PBSG members wrote the report (Wiig et al. 2015, and its Supplement).

Here I want to focus on the results of subpopulation surveys that were made public after the 2015 Red List assessment was published, particularly the Barents Sea estimate.

While the 2013 Baffin Bay and Kane Basin estimates (SWG 2016) have been added to the new PBSG table, any suggestion that these might indicate population increases are strong discounted. Similarly, contrary to initial reports by the principal investigators of the survey, the PBSG insist that the Barents Sea population has not actually increased since 2004, which you may or many not find convincing.

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Ice formation in W Hudson Bay slower than 2015 but not likely as slow as 1983

After a great start this year for Churchill-area polar bears of Western Hudson Bay – who came off the ice in better than usual condition after what must have been a good spring hunting season – ice maps suggest that freeze-up will be later than last year, an impression confirmed by on-the-ground observers.

Ice coverage this year at 7 November (2016):

sea-ice-extent-canada-2016-nov-7_cis

Ice coverage last year at this date (7 November 2015), see this post for details:
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Recent studies show Sept ice of 3-5 mkm2 did not kill polar bears off as predicted

The annual Arctic sea ice minimum for 2016 is imminent and the hand-wringing about polar bear survival has already begun. While this year is shaping up to be another very low sea ice minimum in the Arctic – not as low as 2012 but lower than as low as 2007 (previously the 2nd lowest since 1979) – contrary to predictions, several recent studies show that such low sea ice coverage in summer has had no (or very limited) negative effects on polar bear health and survival. In fact, for polar bears in some areas low summer sea ice has been quite beneficial (although these are not the populations that polar bear specialists predicted would do better).

polar_thin_ice Jessica Robertson_USGS

Since low summer extents of recent magnitude (3.0 – 5.0 mkm2) are clearly not any sort of threat to polar bears, it seems improbable that even an ice-free (≤ 1.0 mkm2) summer (e.g. Wang and Overland 2015) would be devastating to the species [don’t forget Cronin and Cronin 2016: they’ve survived such conditions before] – as long as conditions in spring allow for the necessary concentrated feeding on young seals.

sea-ice-mins_2007_2012_2015_polarbearscienceAbove: Top, minimum at 2012 (16 Sept, 3.41 mkm2, lowest since 1979); Center, 2007 (18 Sept, 4.17 mkm2); Bottom, 2015 (9 Sept, 4.50 mkm2), from NSIDC. Below: sea ice at 10 Sept 2016, 4.137 mkm2 – minimum not yet called).

sea-ice-extent-2016-sept-10_nsidc

Recall that in 2006, the IUCN Polar Bear Specialist Group based their conservation status of ‘vulnerable’ (likely to become threatened within the next 45 years due to reduced habitat) on the predictions of sea ice specialists (see 2008 update here).

Sea ice experts in 2005 predicted such low summer sea ice extents as polar bears have endured since 2007 (3.0 – 5.0 mkm2) would not happen until 2040-2070, at which time PBSG biologists said that >30% of the world’s bears would be gone.

Evidence to the contrary comes from polar bear specialists working in the Chukchi, Beaufort, and Barents Seas – and in Southern Hudson Bay – since 2007. Overall, the latest IUCN Red Book assessment (2015) put the global population size at 22,000-31,000 (or about 26,500).

All of this means that those polar bear experts were wrong: polar bears are more resilient to low summer sea ice conditions than they assumed.

UPDATE 2 January 2017: I’ve added some quotes from the original USGS reports that explicitly state their dire predictions for 2050 that differ from the predictions made by the IUCN Polar Bear Specialist Group.
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Add human graves to the list of things that attract polar bears to communities

A report last week that a polar bear dug a human cadaver out of a coffin buried in the cemetery on the west coast of Hudson Bay did not get the media attention it perhaps deserved: it takes the term ‘grisly’ to a new level.

Early arrival of polar bears at Nunavut hamlet prompts early monitoring: One bear digs into burial plot at Arviat cemetery (NunatsiaqOnline, 29 August 2016).

mother-and-cub-on-beach_Stirling

Quotes from the story, a map, and comments on problem bears below.
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