Tag Archives: Southern Hudson Bay

It’s the middle of July – do researchers know where their Hudson Bay polar bears are?

If so, they’re not saying. This year, with higher-than-average sea ice, we’ve heard much less than usual about the location of tagged Hudson Bay polar bears. Odd, isn’t it?

Hudson Bay breakup 2015_2014_14 July

By this time last year, Polar Bears International rep Alysa McCall had published two reports on the location WHB polar bears tagged by the University of Alberta research team led by Andrew Derocher (Fig. 1 below).

Figure 1. Sea ice coverage and locations of female polar bears with tracking collars for 30 June 2014 and 8 July 2014 (black, Western Hudson Bay bears; blue, Southern Hudson Bay bears), courtesy Alysa McCall, Polar Bears International. Click to enlarge.

Figure 1. Sea ice coverage and locations of female polar bears with tracking collars for 30 June 2014 and 8 July 2014 (black, Western Hudson Bay bears; blue, Southern Hudson Bay bears), courtesy Alysa McCall, Polar Bears International. Click to enlarge.

This year, there’s been nothing: not a single PBI mention of WHB breakup. Derocher tweeted a track map on 6 July (2/9 bears ashore), with no updates since, but PBI’s “Bear Tracker” has not been updated since 2 July. Compare this year’s ice cover on Hudson Bay (and elsewhere in Canada) to last year on this date (14 July): quite a difference.
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Hudson Bay breakup later than average, longer hunting season for polar bears

Due to the atypical pattern of sea ice melt on Hudson Bay this year, 2015 will definitely be a later than average breakup year – perhaps not as late as 1992 but maybe almost as late as 2009. Easing into the first days of Arctic summer, there is still a lot of polar bear habitat left on Hudson Bay, especially in the east.

Hudson Bay breakup 2015 vs 2009 at 29 June_MASIE

Although official breakup in 2009 was only a little later than usual (9 July), bears came ashore about the same time (after mid-August) as they did in 1992, when breakup was very late (30 July). With the pattern this year being so unusual (and the melt so slow over the last few weeks), who knows how late it could be before the last bears leave the ice in 2015?

There is definitely more sea ice this year on the bay than there was last year, when breakup was about average for the last 24 years.

UPDATE 2 July 2015: CIS weekly ice coverage graphs added to the end of this post. Hudson Bay ice highest since 2009 and Davis Strait highest since 1994! Have a look.
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Hudson Bay breakup progressing slowly, still lots of polar bear habitat

Not much change in sea ice coverage since last week – most of Hudson Bay is still covered with concentrated ice, which is good news for Western and Southern Hudson Bay polar bears. They are still free to roam and hunt over most of the ice-covered bay.

Hudson Bay breakup 8 June 2015 vs 1 June_PolarBearScience

There may be slightly less ice than average for this time of year (Fig. 1, below) but coverage is still >70% with concentrated ice and does not appear to be melting quickly (see charts above and Fig. 2, below).

The dates for three previous earliest breakups according to Lunn and colleagues (Fig. 3) have come and gone, as all were in the first week of June (more on that in an upcoming post) – no records broken. More graphs and maps below, see previous posts here and here.
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Hudson Bay sea ice above average for this date – more good news for polar bears

It’s only the 4th of December and Hudson Bay ice formation is way up over late 2000s coverage for this date — and higher than 2012, which had the lowest overall September ice extent for the Arctic since 1978.

Hudson Bay freeze-up same week_Dec 4 1971_2014 w average

This means boom times for Western and Southern Hudson Bay polar bears as sea ice formation is several days to a week ahead of last year. And as I mentioned in my last post, average November ice coverage across the Arctic this year was higher than 2003. Don’t forget that 2/3’s of the world’s polar bears live in Canada (see recent status update here; map below).

Figure 4. The Davis Strait (DS) subpopulation region runs from just below the Arctic Circle at the north end to at least 470N in the south. About half of DS lays at the same latitude as Western Hudson Bay (WH). Courtesy Environment Canada.

Polar bear population status in Canada. Courtesy Environment Canada.

More maps and charts below.
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Hudson Bay freeze-up 2014 – average again this year, not late

Freeze-up of Hudson Bay sea ice is well underway now, virtually the same time as it was the last three years, and in 2008. Bears in the north will be able to move out, while near Churchill and in Southern Hudson Bay, some bears will be able to successfully hunt for seals on the newly-formed ice close to shore.

Over the next week or so, all the bears onshore will gradually move out onto the ice as freeze-up progresses. By the time there is ~10% ice coverage on the bay, most bears will have moved onto the ice (except pregnant females that have made dens onshore).

The Arctic outbreak underway in over North America may hasten this process along (see 7-day and 14-day weather forecasts for Churchill). Ice maps below courtesy Canadian Ice Service.

Sea ice extent Canada 2014 Nov 13 CIS

It seems pretty clear now that time of freeze-up on Hudson Bay is not correlated with the extent of sea ice at the September minimum. Have a look at the maps and graphs below.  UPDATE: more recent maps added below (ice concentration 15 November; ice development 14 November).
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W Hudson Bay mark-recapture studies of polar bears were invalid, says peer-reviewed study

“Our results suggest that mark–recapture estimates may have been negatively biased due to limited spatial sampling. We observed large numbers of bears summering in southeastern WH, an area not regularly sampled by mark–recapture.” Stapleton et al. 2014.

Polar bear at Wapusk National Park (just south of Churchill) in August 2011. Courtesy Parks Canada.

Polar bear at Wapusk National Park in August 2011. Courtesy Parks Canada.

We’ve seen the results of this 2011 study before, in government report format. But now it’s been revamped, peer-reviewed and published in a respected scientific journal – it actually came out in February, without fanfare, but I’ve only just come across it.

Some excerpts below, with conclusions that should raise some eyebrows.

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Are Polar Bears Really Endangered?

Christina Wu at the Urban Times (July 3, 2014) recently asked this question. She came up with a surprisingly balanced argument but some predictable responses from IUCN Polar Bear Specialist Group (PBSG) biologists. As a consequence, she overlooked some critical facts that make a big difference to the answer.

Figure 1. Are polar bears really endangered? The US Fish and Wildlife Service thinks so, but only because Steven Amstrup, based on a computer model projecting sea ice out to 2050, said so (Amstrup et al. 2007). This information has been used by the Center for Biological Diversity and other NGOs, like WWF and Polar Bears International (where Amstrup is now employed), to solicit donations.

Figure 1. Predictions of polar bear population declines by 2050 are being used by the Center for Biological Diversity, WWF and Polar Bears International to solicit donations.

UPDATED 18 May 2015 – see below.

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The scientific abomination that is the “Circumpolar Monitoring Framework for Polar Bears”

I keep coming across mentions of a grandiose plan for future polar bear research and conservation called the “Circumpolar Monitoring Framework for Polar Bears.”

This “framework” plan was referred to extensively at the recent International Polar Bear Forum (aka the “Meeting of the Parties” that signed the 1973 conservation treaty) held in Moscow, December 3-6, 2013 (see posts about the meeting here, here, and here). In fact, government representatives of all Arctic nations present at that meeting agreed in principle to support the proposed plan.

No media reports that I’ve come across after the Moscow polar bear meeting explained what the “monitoring framework” involved, so I’ve composed a brief summary and commentary, aided by some images from Dag Vongraven’s presentation in Moscow (Vongraven 2013; pdf here).

In short, Arctic government representatives at the Moscow forum agreed that all future polar bear research should be constrained by the premise that increases in global temperatures over the next century will occur exactly as predicted by climate models and will negatively affect polar bears precisely as predicted by models devised by polar bear biologists. Under the plan, subpopulations that are already showing predicted effects of global warming will get the bulk of research funds, while regions that are paradoxically not responding as predicted will get much less money for research and survey efforts. 

This strategy proposes a coordinated research plan that is blatantly agenda-driven: implementing it would seriously compromise the usefulness of all research results generated for decades to come. I don’t think it’s anything close to being a scientifically valid plan, but decide for yourself. 

Figure 1. Vongraven 2013, Slide 1.

Figure 1. Vongraven 2013, Title slide.

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Polar bear habitat update, end of November 2013

Freeze-up in the Arctic (~October-November) is important to polar bears because for those animals that have spent the ice-free period on shore (not all do), it marks the end of their summer fast — they can finally resume seal hunting.

Polar bears in the most southern regions, like Southern Hudson Bay, Western Hudson Bay, and Davis Strait (see Fig. 1), routinely experience the longest ice-free period. As these bears all spend the summer on shore, they appreciate a timely return of the ice.

 Figure 1. Polar bear subpopulations defined by the IUCN Polar Bear Specialist Group (PBSG), with a few extra labels added. I’ve rotated the original map 90 degrees (right) to make it easier to relate to the ice maps below. WH is Western Hudson Bay. Courtesy PBSG.  Click to enlarge.


Figure 1. Polar bear subpopulations defined by the IUCN Polar Bear Specialist Group (PBSG), with a few extra labels added. I’ve rotated the original map 90 degrees (right) to make it easier to relate to the ice maps below. WH is Western Hudson Bay; SB is Southern Beaufort. Courtesy PBSG. Click to enlarge.

Southern Hudson Bay bear populations routinely experience an ice-free season that is just as long as it is for Western Hudson Bay bears. However, Southern Hudson Bay polar bears numbers have remained stable over the last 30 years. Some folks insist that Western Hudson Bay bear numbers are shrinking to a worrisome degree, despite indications that the recent decline could be nothing more than a return to sustainable levels after a rapid population increase in the late 20th century (similar to changes documented for the Davis Strait and Barents Sea subpopulations).

Have a look at how sea ice – essential polar bear hunting habitat – has developed within these regions over the last 10 days or so (end of November 2013) and how November 2013 compares to November 1979. The ice maps tell the freeze-up story.
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Polar bear habitat virtually everywhere now

What did I tell you, back in mid-September?

Have a look at all the polar bear habit, ten days shy of the end of November!

Figure 1. MASIE sea ice extent for November 18, 2013 (using US National Ice Center data). You have to look closely but there is indeed ice forming around Svalbard (just above the tip of Greenland) and in James Bay (southern Hudson Bay). Click to enlarge. High resolution map here.

Figure 1. MASIE sea ice extent for November 18, 2013 (using US National Ice Center data). You have to look closely but there is indeed ice forming around Svalbard (just above the tip of Greenland) and in James Bay (southern Hudson Bay). Click to enlarge. High resolution map here.

Figure 2. Canadian Ice Service map. Good amounts of ice developing in northern Hudson Bay, Foxe Basin and Davis Strait (between southern Greenland and Baffin Island), with ice forming along the shore in James Bay (the southern-most region where polar bears are on-shore at the moment). Click to enlarge.

Figure 2. Canadian Ice Service map. Ice developing rapidly in northern Hudson Bay, Foxe Basin and Davis Strait (between southern Greenland and Baffin Island), with ice also forming along the shore in James Bay (the southern-most region where polar bears are onshore at the moment). Click to enlarge.