Tag Archives: Hudson Bay

My new Arctic Fallacy paper- Sea ice stability and the polar bear

Posted on June 8, 2015 | Comments Off

I have a new paper out that explains a fundamental problem with polar bear conservation.

I’m convinced that a flawed and out-dated ecological concept — that sea ice, under natural conditions, provides a stable, predictable habitat — is what has allowed the present doom and gloom attitude of most polar bear specialists to develop.

Sea ice changes, of course, from season to season. However, the concept that sea ice is a stable habitat assumes that these seasonal changes are predictable and virtually the same from one year to the next – at least, similar enough that the differences are not responsible for causing marked declines in population size.

The assumption is that under natural, stable conditions populations of Arctic animals will either stay the same over time or increase. Biologists were taught at university that sea ice should be a stable habitat and as a result, they’ve glossed over evidence they collected to the contrary. [see recent posts here and here, for example]

Negative effects on populations of short-term natural variations in spring sea ice or spring snow cover on sea ice have been entirely ignored in modeled predictions of future conditions. The focus has been on summer ice extent.

I have summarized this evidence in a fully referenced, peer-reviewed essay that explores how the acceptance of this fallacy (“sea ice is a stable habitat”) has so skewed the conservation biology of polar bears that to outsiders it may look like a scientific integrity issue.

The summary and the essay are below (with embedded links and references). The Global Warming Policy Foundation (GWPF) has published the essay in their “Briefing Paper” series (#16, The Arctic Fallacy: Sea Ice Stability and the Polar Bear), which includes a must-read foreword by Dr. Matthew Cronin, Professor of Animal Genetics at the University of Alaska Fairbanks. Press release here, pdf here.

I think you’ll find it timely and thought-provoking.

Comments Off on My new Arctic Fallacy paper- Sea ice stability and the polar bear

Posted in Conservation Status, Sea ice habitat

Tagged Beaufort Sea, climate change, Cronin, ecology, global warming, GWPF, habitat, Hudson Bay, IUCN Polar Bear Specialist Group, K-selection, model, PBSG, polar bear, Polar Bears International, polarbearscience, population size, predictions, ringed seal, sea ice, snow depth, stable, summer, thick spring ice, variability

Hudson Bay sea ice coverage is atypical this year but what does that mean for polar bears?

Posted on May 26, 2015 | Comments Off

There is a rather large patch of open water in the northwest sector but what’s also unusual about breakup this year is the virtual lack of open water in eastern Hudson Bay – that almost never happens (compare to 2013 here). In addition, there’s still very little open water in Hudson Strait, which connects Hudson Bay to Davis Strait in the east – that’s also unusual.

Figure 1. Sea ice extent over Hudson Bay and Hudson Strait at 26 May 2015. Canadian Ice Service. Click to enlarge.

The question is: does the somewhat unusual pattern of ice cover at this date – which developed rapidly over the last few weeks – suggest we can predict whether polar bears will have a shorter-than-average hunting season?

To answer that, you have to look at maps generated by the same source over several years. The result, in my opinion, is inconclusive – while so far, this year looks a bit more like 2009 (which was a very late sea ice breakup year) than it does 2011 (which was an early breakup year), it’s really too early to tell.

I suggest we simply won’t know for another month or so which pattern will prevail. However, that hasn’t stopped IUCN Polar Bear Specialist Group member Andrew Derocher (via Twitter, e.g., here and here, among many others) from suggesting that this year’s pattern is likely a portend of doom for Hudson Bay polar bears. See what you think.
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Comments Off on Hudson Bay sea ice coverage is atypical this year but what does that mean for polar bears?

Posted in Life History, Sea ice habitat

Tagged advocacy, breakup, Davis Strait, Derocher, Hudson Bay, Hudson Strait, open water, polar bear, polynyas, sea ice, shore leads

Arctic polynyas and sea ice extent in Canada at 20 May 2015

Posted on May 21, 2015 | Comments Off

The map of sea ice extent in Canada at 20 May 2015 is an almost-perfect example of the placement of recurring patches of open water polynyas that were present in the Canadian Arctic at this time of year in 1975-1979. Notes from field work on shore leads in Hudson Bay ice at May, 1948 offer further insight into the current pattern of sea ice cover on the bay.

May is traditionally the time when recurring polynyas in the Canadian Arctic become more prominent and persistent shore leads (cracks in the ice near shore, also called “flaw leads”) become wider. Polar bears hunt around these polynyas because ringed and bearded seals congregate around them in the spring (Stirling et al. 1981; Stirling 1997). These polynyas are often not truly “open water” but covered by thin ice that’s easy for seals to break through.

Slight differences in location and size of polynyas and shore leads from year to year (especially in spring) are governed primarily by prevailing winds (Dunbar 1981:29) and to a lesser extent, currents. See my previous discussion on Beaufort Sea polynyas, with references: Beaufort Sea polynyas open two weeks before 1975 – open water is good news for polar bears.

This suggests that while sea ice cover over Hudson Bay and the Beaufort Sea is now a bit below average for this time of year (as the maps for this week show), it does not necessarily portend an earlier breakup or longer open-water period later in the year.

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Posted in Life History, Sea ice habitat

Tagged Beaufort Sea, breakup, Hudson Bay, open water, polynyas, sea ice, spring, wind

Polar bear habitat update: Hudson Bay sea ice breakup on track

Posted on May 18, 2015 | Comments Off

Hudson Bay sea ice coverage is only slightly below average for this time of year (week of 14 May, below) but well above levels for 2006, when Western Hudson Bay breakup was relatively early).

Figure 1. Sea ice coverage over Hudson Bay for the week of 14 May, 1971-2015. Canadian Ice Service. Click to enlarge.

Even at its highest extent in April, Hudson Bay is only 97-98% ice covered (due to persistent shoreleads and polynyas), which means ice levels are currently only 10% or so below maximum. In other words, there is still lots of polar bear hunting habitat over the bay.

That’s a bit lower than ice coverage was for the last two years at this date (2013-2014), which had average or above average ice cover. However, there is currently a bit more ice on Hudson Bay than there was in 2011 and 2012 – and much more than there was in 2010 and 2006.
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Posted in Sea ice habitat

Tagged breakup, habitat, Hudson Bay, open water, polar bear, polynya, sea ice, spring, western hudson bay

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

Posted on April 14, 2015 | Comments Off

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.

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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Posted in Sea ice habitat

Tagged average breakup date, breakup, Canadian Ice Service, concentration, eastern Hudson Bay, habitat, Hudson Bay, Mt. Pinatubo, sea ice, spring ice conditions, western hudson bay

Superb sea ice conditions for polar bears worldwide during their critical feeding period

Posted on April 3, 2015 | Comments Off

Prognosis, excellent. The sea ice hunting platform that polar bears require is everywhere and Davis Strait ice extent is the fourth-highest it’s ever been at this time of year.

The spring feeding period is a messy, brutal business – many cute baby seals will die as polar bears consume 2/3rds of their yearly food supply over the next few months (April – June/early July), while sea ice is abundant.

That leaves the remaining 1/3 of their energetic needs to be met over the following 9 months (most of it in late fall (late November/December) and hardly any during the summer months, regardless of whether the bears are on land or out on the sea ice) or over the winter. Continue reading

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Posted in Life History, Sea ice habitat

Tagged breakup, Davis Strait, habitat, harp seals, Hudson Bay, hunting platform, polar bears, ringed seals, sea ice, sea ice extent, seals, spring ice maximum

Polar bear habitat – more Arctic sea ice in Canada this week than in early 1970s

Posted on December 26, 2014 | Comments Off

This week, Arctic sea ice in Canada, where 2/3 of the world’s polar bears live, had more sea ice than was present in the early 1970s. Globally, the ice is spitting-distance close to the 1981-2010 average calculated by the NSIDC for this date – which means lots of winter/spring hunting habitat for polar bears.

This is the peak of the polar bear birthing season (both in the wild and in zoos.) Newborns will be snug in maternity dens built by their mothers onshore or on the sea ice; the rest of the population will be out on the ice.

Regional ice charts going back to the late 1960s and early 1970s for this week show even more surprises — have a look.

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Posted in Sea ice habitat

Tagged baffin bay, Davis Strait, Eastern Beaufort, Eastern Canada, Hudson Bay, ice extent, polar bear, polar bear habitat, polar bears in winter, sea ice, Southern Beaufort, Western Arctic

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

Posted on December 11, 2014 | Comments Off

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):

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

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Posted in Sea ice habitat

Tagged Canadian Ice Service, Churchill, Davis Strait, December, Hudson Bay, National Snow and Ice Data Center, polar bear habitat, polar bears, polar bears in winter, problem bears, sea ice, western hudson bay

Polar bear habitat update – November 2014 average sea ice levels higher than 2003

Posted on December 3, 2014 | Comments Off

Average polar bear habitat for November 2014 was well within two standard deviations¹ and higher than 2003, according to the November report from the National Snow and Ice Data Center (line and labels added, below).

Notice that the lowest average November level occurred in 2006 — not 2007 (after the second lowest September extent since 1978) and not 2012 (after the lowest September extent since 1978). Take note that the scale on the graph above does not go to zero but to a whopping ~9.5 million square km!

Quotes from the NSIDC monthy report and sea ice maps for November 2014 and 2 December 2014 below.

UPDATE 3 December 2014: CIS has issued a new ice map corrected for ice level on Hudson Bay – new map below.
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Posted in Sea ice habitat

Tagged arctic sea ice, Chukchi Sea, CIS, Davis Strait, Hudson Bay, NSIDC, polar bear, polar bear habit, sea ice extent, September ice minimum, standard deviation

Hudson Bay freeze-up: way more ice for this day than in 2013

Posted on November 20, 2014 | Comments Off

On this day (20 November 2014), there is way more sea ice over Hudson Bay and Foxe Basin than 2013, with ice starting to form in Hudson Strait.

The polar bears of Hudson Bay are on the ice (except pregnant females, who will be in their dens); Churchill polar bear season is over (see previous discussions here and here).

Ice maps and graph courtesy Canadian Ice Service.