Tag Archives: western hudson bay

Snow depth over spring sea ice affects polar bear feeding success and ringed seal survival

Snow depth over sea ice in spring affects the hunting success of polar bears on ringed seal (Phoca hispida) pups, but the relationship is more complicated than you might think and there is less data on this phenomenon than you would believe.

Ringed seal lair_snow and ice thickness_PolarBearScience_sm

Regional snow depth in spring (April-May) varies naturally from year to year due to weather patterns driven in part by long-term climate cycles (like the Atlantic Multidecadal Oscillation, Pacific Decadal Oscillation, and the Arctic Oscillation).

This year, it was very cold in Eastern North America, with record-breaking snow fall in some areas. Snow depth was apparently greater than average over Hudson Bay sea ice this spring but was it deep enough to have impaired polar bear hunting success?

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Polar bear habitat update: highly concentrated ice in eastern Hudson Bay this spring

Sea ice in eastern Hudson Bay (bright white in the map below) is more concentrated than at this time last year and similar to the ice found in the Central Canadian Arctic.

Sea ice extent Canada 2015 April 11 CIS

There is more concentrated ice (10/10 concentration) in the east side of the Bay than there was in 1992, a heavy ice year blamed in part on the eruption of Mt. Pinatubo (Chambellant et al. 2012) that resulted in the latest breakup date for Western Hudson Bay since 1991.

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Polar bear habitat update – more spring sea ice around Svalbard than 2014 & 2012

Polar bear habitat for the last week of March is well above average in eastern Canada for the second year in a row. The very low extent of ice in the Sea of Okhotsk – which has contributed strongly to the low maximum extent this year – is irrelevant to our discussion, since no polar bears live there.

Polar_Bear_male_Regehr photo_March 21 2010_labeled

There is a bit more concentrated ice around Svalbard than last year (or in 2012), although ice in the Barents Sea in general is still below average due to the state of the Atlantic Multidecadal Oscillation (AMO). The state of the AMO and its effects on Barents Sea polar bear sea ice habitat has nothing to do with global warming: it’s a cycle that has been documented for centuries (Miles et al. 2014).

Still, there is plenty enough sea ice for polar bear hunting: this is the beginning of the critical feeding time for all polar bears (see here and here), but especially for the survival of new cubs-of-the-year, so I have a few words about Western Hudson Bay cubs below.

Have a look for yourself.
Update: Added 20 March 2015, comparison maps from Cryosphere Today for 2006 vs. 2015.
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IUCN Specialist Group quietly adds “sea ice changes” to their polar bear status table

In late January, the IUCN PBSG made significant changes to its polar bear status table but did not think it was worth bringing to the public’s attention via a tweet, press release or note on their web site’s home page.

Hudson Bay female with cub_Wapusk_Thorsten Milse_Gov CA

What changes? Well, while the group did not see fit to agree with all of Environment Canada’s assessments (e.g. listing Davis Strait bears as “likely increasing” compared to the PBSG’s “stable”, see full list here), it did upgrade their status of Western Hudson Bay bears to ‘stable’ (which EC did back in June 2014).

More significantly, however, they also added two metrics of sea ice change to their assessment table, presumably because alongside ‘human-caused removals’ (which they also track in their tables)1, sea ice changes are supposedly critical ‘threats’ to polar bear health and survival.

So critical, in fact, that they’ve only just now gotten around to measuring it consistently across polar bear territory. Funny thing is, they cite no document that shows the sea ice change calculations for each subpopulation region, nor who generated them.

Let me be clear: no one has ever generated such a sea ice metric before – it is a unique PBSG construct that you will find nowhere else. By providing no documentation that lays out the calculations for inspection, the PBSG are simply insisting the public accept their unpublished, non-peer-reviewed work on faith. Details below.
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Western Hudson Bay polar bears will still be around in 20 years

This is not a bet or prophesy based on models, it’s my conviction as an experienced zoologist, based on history demonstrating the resilience of the species.

Send_Nico_to_Churchill_PolarBearScience

I’m so sure about Western Hudson Bay polar bears that I’ve started a spare-change jar marked “Send Nico to Churchill.” Nico is my new grandson, just two months old now. This will be our first Christmas with a baby in a long time.

Nico_sm

Nico’s special savings account will assure that in 20 years (given wise investments), he’ll be able to see Churchill polar bears in their own element.

Warmest wishes to all my readers and thanks for your support, it is much appreciated.

Susan

Challenging NOAA’s “Arctic Report Card 2014” on polar bears

NOAA’s list of purported evidence for harm being caused to polar bears by Arctic warming is short and weak. It puts the gloomiest spin possible on the current well-being of an animal with all the earmarks of a healthy, well-distributed species.

Arctic report card 2014 screencap_Dec 18 2014

This year, polar bears are virtually the only species that NOAA mentions in their Arctic Report Card – they’ve put all their icon-eggs in one leaky basket [what happened to walrus??]. But polar bears are doing so well that to make an alarming case for polar bears as victims of Arctic warming, many important caveats had to be left out or misrepresented. Some details given are simply wrong.

This year’s polar bear chapter was penned by IUCN Polar Bear Specialist Group chairman Dag Vongraven (you might recall his email to me earlier this year) and a polar bear conservation activist from Polar Bears International (whose battle cry for donations is Save Our Sea Ice!”), Geoff York.

I challenge their four weak talking points one by one below.

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Hudson Bay sea ice well above average – excellent early December polar bear habitat

Sea ice development for this date is well above average on Hudson Bay – even more so than last week – making three years in a row of average-to-above average ice habitat available to polar bears in early December (see last week’s ice summary here). Coverage for the week of 11 December from 1971 to 2104 below (from Canadian Ice Service):

Hudson Bay freeze-up same week_Dec 11 1971_2014 w average

More maps below (from CIS and NSIDC), see others here.

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W Hudson Bay polar bear mark-recapture study report 2013 – at last

I have finally secured a copy of the 2013 Western Hudson Bay mark-recapture study produced by Environment Canada.

The pertinent figure is below: as you can see, there was no declining trend in Western Hudson Bay polar bears between 2000 and 2011. Click to enlarge.

WH EC Polar Bear Demography report Lunn 26 Nov 2013 Final _Fig 8

I have relatives visiting so I don’t have time to do an in-depth summary but the report’s opening “Summary” is copied below and a pdf provided. More later when I have had time to look at it more closely. Background on the issue here.

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Public misled about W Hudson Bay bears since November 2013

Leading polar bear biologists knew by November 2013 that mark-recapture studies showed the Western Hudson Bay subpopulation had not changed appreciably since 2004 but none said so. This includes Steven Amstrup and Ian Stirling at Polar Bears International, Andrew Derocher (University of Alberta), and Nick Lunn (Canadian Wildlife Service), all of whom are (or have been) extensively involved in Western Hudson Bay polar bear research and have made recent statements to the media on this topic.

Polar_Bear_2004-11-15_Wapusk Nat Park_Wikipedia

More details have emerged about the status of Western Hudson Bay (WHB) polar bears (reported a few days ago here), reported this morning in NunatsiaqOnline, excerpts below.

The story reveals that there are two Canadian Wildlife Service (Environment Canada) reports containing population estimates of Western Hudson Bay polar bears – one produced in 2011 and another in November 2013 (reversing the 2011 conclusion) – that have not been made public.

[In contrast, Nunavut Government reports on their 2011 population estimate, based on aerial surveys, were made public in both draft and final report formats (and have since been peer-reviewed and published)]

The conclusion of the 2013 report, quoted in this mornings article, suggests that some of our most vocal polar bear specialists have been misleading the public about the status of the Western Hudson Bay population for the last year.
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Western Hudson Bay polar bear population is stable: press release

Slowly but surely, word is leaking out: the Western Hudson Bay polar bear population is stable at ~1000 bears, confirming the good news contained in maps posted on the Environment Canada website a few months ago (discussed by me here and here). Environment Canada has apparently been giving presentations in local Western Hudson Bay communities relaying their decision.

Courtesy IUCN PBSG

Courtesy IUCN PBSG

Yesterday, a press release was issued by one of the official Inuit organizations in Nunavut announcing the new official status of the Western Hudson Bay polar bear population.
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