Tag Archives: baffin bay

Sea ice breakup update: high ice coverage just about everywhere, even Hudson Bay

There is still a lot of sea ice in Hudson Bay, Foxe Basin, Davis Strait and Baffin Bay this week – more than average for this date – with slightly less than average in the Beaufort Sea. Past behaviour of Western and Southern Hudson Bay polar bears suggests the mean date that bears come ashore for the summer this year will be later than average due to the plentiful ice available, regardless of when polar bear biologists decide that “breakup” has occurred.

Hudson Bay breakup July 8 2015_CIS

Hudson Bay, with almost 50% of the bay still covered in ice, has the third highest coverage this week since 1992 (after 2009 and 2004); Davis Strait has the highest coverage since 1992; and Foxe Basin and Baffin Bay have the highest coverage since 1998. For this week, the Beaufort Sea has the second highest coverage since 2006 (after 2013), and more ice than was present in 1971, 1982, 1987, 1988 and 1998 – among others.

Published data shows that most polar bears of Western Hudson Bay traditionally come ashore in July, but this year it might be late July or even August. Have a look at the charts below.
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Supporting document for Canada’s polar bear status maps reveal surprises

My request to Environment Canada in early December 2014 for the documents supporting their polar bear status maps has finally generated results.

In an email dated 2 March 2015, I received the document produced by the EC Polar Bear Technical Committee (PBTC). I waited to see if it would be appended to the webpage where the maps were posted last year (reported here and here). However, as of today, that has not happened, so I am posting it here. There are some rather striking differences that may surprise you.

UPDATE 22 March 2015: A copy of the letter from the Director General of the Canadian Wildlife Service that accompanied the document below, which I forgot to include, is here. It states that the once a new status table has been compiled (provided below), “it is reviewed by the Polar Bear Administrative Committee and then becomes a public document.” The implication is that the reviewed document has not yet been produced.
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Polar bear habitat – more Arctic sea ice in Canada this week than in early 1970s

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.

Canada sea ice freeze-up_same week_Dec 25 1971_2014 standard average

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.

Sea ice extent 2014 Dec 25 NSIDC

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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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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Polar bear habitat update – ice coverage at the beginning of this year’s critical feeding period

Polar bears are all out on the sea ice at this time of year, feeding on new-born seal pups. Here’s a look at what the ice conditions are like at this critical time.

Polar_Bear_male on sea ice_Alaska Katovik Regehr photo_April 29, 2005_sm labeled

end April extent NSIDC May 4

The ice extent is still well within two standard deviations from the 1981-2010 average, which indicates no deviation from natural variation, as the graph (below) for May 1, 2014 from the US National Snow and Ice Data Center (NSIDC) shows.

Sea ice extent 2014 May 1_NSIDC_graph

Between the official spring maximum (according to the NSIDC ) on March 21, with a total extent of 14.8 million km2, the ice slowly retreated in some regions and increased in others, while most regions remained pretty much the same. This is an important reminder that the Arctic as a whole is not a homogeneous region but one with marked regional variation.

As has been noted elsewhere (Sunshine Hours), ice in the Greenland Sea (habitat of ‘East Greenland’ bears) and the Barents Sea both increased in extent over this period. Bering Sea ice (habitat of southern ‘Chukchi Sea’ bears) declined markedly but Baffin Bay/Gulf of St. Lawrence ice (habitat of ‘Davis Strait’ bears) declined much less, as NOAA’s MASIE maps copied below show very well.

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Baffin Bay polar bear population survey done, results due end 2014

From this story in today’s Alaska Dispatch (via CBC NewsEye on the Arctic), November 11, 2013, which adds a few more details regarding the progress of ongoing population surveys and the next PBSG meeting:

“The Nunavut government has wrapped up three years of fieldwork on Baffin Bay polar bears, and is preparing to release a new population estimate sometime next year….
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Lancaster Sound – a rarely-mentioned region with a large polar bear population

The polar bear subpopulation designated as Lancaster Sound lies at the eastern entrance to the Northwest Passage in the Canadian High Arctic (Fig.1). We rarely hear about it but this region has one of the largest polar bear populations anywhere in the Arctic – only the Barents Sea and Foxe Basin have higher estimated population sizes.

Figure 1. Lancaster Sound, magenta. Map courtesy Polar Bear Specialist Group, additional labels added.

Figure 1. Polar bear subpopulations with Lancaster Sound marked. Map courtesy IUCN Polar Bear Specialist Group, additional labels added.

Lancaster Sound includes the communities of Arctic Bay on northwestern Baffin Island and Resolute Bay on Cornwallis Island. Devon Island, which lies on the northern boundary, has no permanent communities, although two research stations are present (see here and here). A more detailed map showing the exact boundaries is available in Vongraven and Peacock (2011).

The eastern portion of Lancaster Sound is generally clear of ice by late summer (hence the Northwest Passage) but the western third of the region not only retains pack ice later in the season but some multiyear ice remains throughout the year.

The proximity of Lancaster Sound to Baffin Bay and the eastern Northwest Passage (Fig.2) undoubtedly exposed polar bears there to hunting by European whalers during the 1800s and early 1900s (see previous post here, especially Fig. 5), from which the population appears to have recovered.

On the other hand, the proximity of Lancaster Sound to oil and gas reserves further north in the High Arctic generated much-needed funds for polar bear biologists in the mid-to-late 1970s to collect essential baseline data for the entire region (Schweinsburg et al. 1982; Stirling et al. 1979, 1984; Stirling and Latour 1978).

Figure 2. The main Northwest Passage route starts at Lancaster Sound and runs east through Parry Channel because these waterways routinely clear of ice in late summer. The approximate boundary of the Lancaster Sound polar bear subpopulation (area ~490,000 km2) is marked in yellow; POW is Prince of Wales Island. Map from Wikipedia, labels added.

Figure 2. The main Northwest Passage route starts at Lancaster Sound and runs east through Parry Channel because these waterways routinely clear of ice in late summer. The approximate boundary of the Lancaster Sound polar bear subpopulation is marked in yellow; POW is Prince of Wales Island. Map from Wikipedia, labels added. Click to enlarge.

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Polar Bear Specialist Group meeting postponed until 2014

[Update October 14, 2013: correction regarding Davis Strait population estimate, noted below]

I heard via the grapevine that the IUCN Polar Bear Specialist Group (PBSG) meeting, tentatively slated to be held this July (Obbard et al. 2010), has been postponed until 2014. [That will be the 16th Working Meeting, as they are called]

Word has it that shifting the meeting forward will allow the group time to put together a new population estimate that will incorporate recent survey results.

So which subpopulations are slated to be updated?

Figure 1. Polar bear subpopulations defined by the Polar Bear Specialist Group (PBSG). Note that Baffin Bay, Davis Strait, Western Hudson Bay and Southern Hudson Bay are all similar in that they become ice-free by early fall (the September minimum) or before.

Polar bear subpopulations defined by the Polar Bear Specialist Group (PBSG). Courtesy the PBSG.

As far as I can determine, there are at least two that haven’t quite been finished: Baffin Bay and Southern Beaufort. The Baffin Bay survey was supposed to be completed this spring, so the numbers just need to be crunched. Southern Beaufort has a survey in progress, planned to continue through the fall of 2013.

Here are some comments on the 2012 Southern Beaufort field season (USFWS Newletter 2013:17):

“The number of polar bears observed in 2012 was high relative to similar surveys conducted over the past decade. During August and September surveys, the majority of bears were observed east of Prudhoe Bay, primarily near Kaktovik. Body condition appeared relatively normal for this time of year with most bears reported to be in average condition.” [my bold] [see previous post here re: Kaktovik bears]

There are new counts for Foxe Basin (estimated at ~2,580 bears, similar to the early 1990s estimate of ~2,200; Stapleton, Peacock and Garshelis 2012) and Western Hudson Bay (estimated at ~1,000 bears, similar to the 2004 estimate of ~935; Stapleton, Atkinson et al. 2012) based on aerial surveys. These numbers have not yet been incorporated into the global total, although the studies suggest both of those populations have been stable since the last survey.

CBC News (June 26, 2012):

“A study has found that the polar bear population in the Foxe Basin region of Nunavut is stable and the bears are in good health.

The territorial government did an aerial survey of the bear population in 2009 and 2010. The survey results show the population is about the same size as it was in 1990 – about 2,580 bears.” [my bold]

There is also the new population estimate for Davis Strait (Peacock et al. 2013) that needs to be incorporated into the global total – in this case, there has been an increase from the previous estimate (up from ~1,400 to ~2,158). [corrected Oct. 14 2013] The population increase for Davis Strait has already been incorporated into the current global estimate. The new numbers were available by 2009 (the time of the last PBSG meeting) but the peer-reviewed publications (with all of the pertinent details) were not produced until recently (2012-2013, discussed here and here).
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Baffin Bay polar bear status – waiting for the count

Here’s a quick summary of the status of Baffin Bay polar bears, a subpopulation I’ve not previously discussed in detail. Nothing especially earth-shattering here, except perhaps to wonder about the involvement of the World Wildlife Fund (WWF) in a new helicopter survey of the region.

Baffin Bay (Fig. 1) is north of Davis Strait. It lies between western Greenland and Baffin Island in the eastern Arctic.

Unlike the other north/south neighbour-pair of Western/Southern Hudson Bay   (which I discussed previously), the sea ice history for Baffin Bay/Davis Strait is not as similar: Davis Strait bears have a much longer on-shore fast than Baffin Bay bears (see last post here). However, all four of these subpopulations have ‘seasonal sea ice’ – that is, the ice melts completely in late mid-to-late summer, forcing bears onshore for varying lengths of time until fall freeze-up.

Figure 1. The Baffin Bay subpopulation region lies north of Davis Strait (map on the left from Vongraven and Peacock 2011: Fig. 3) and management is shared between Canada (Nunavut) and Greenland. In total area, it covers 1.08 million km2 and its “suitable ice habitat in spring” (according to Taylor and Lee 1995) is 413,500 km,2 somewhat less than Davis Strait. The map on the right shows the sea ice extent at the end of March 2010 (NSIDC), the winter maximum.

Figure 1. The Baffin Bay subpopulation region lies north of Davis Strait (map on the left from Vongraven and Peacock 2011: Fig. 3) and management is shared between Canada (Nunavut) and Greenland. In total area, it covers 1.08 million km2 and its “suitable ice habitat in spring” (according to Taylor and Lee 1995) is 413,500 km2, somewhat less than Davis Strait. The map on the right shows the sea ice extent at the end of March 2010 (NSIDC), the winter maximum.

A peer-reviewed paper published last year (Rode et al. 2012) compared body condition vs. sea ice changes in Davis Strait and Baffin Bay (discussed here). But while that research contributed to an updated population estimate for Davis Strait (Peacock et al. 2013, discussed here), it did not do the same for Baffin Bay. This is likely because the body condition work in Baffin Bay was split between spring and fall, and it has already been determined that many Baffin Bay bears are offshore in the spring and not available for counting using shore-based methods.

That’s a shame, because the last population estimate was completed back in 1997 (Taylor et al. 2005) and it is now seriously out of date.

However, it appears the Government of Nunavut is currently in the process of surveying this region by helicopter, so a new population estimate should be available soon.

But this aspect of the survey might surprise you — a press release issued February 11, 2013 by WWF contained the following statement:

Results from the above-noted surveys will be completed and shared beginning in April 2013.

WWF made contributions of $82,000 to the Government of the Northwest Territories and $111,000 to the Government of Nunavut via Environment Canada, towards the total costs of these surveys. These funds were raised through the Arctic Home campaign from engaged Canadians and matched by The Coca-Cola Company.”  [my bold]

So, of the hundreds of millions the WWF pulls in from donations, they passed along less than $100,000 [$96,500 plus an equal contribution by Coca-Cola) to offset “the total costs of the survey.

We are not told what those total costs are, but I expect they run well over a million dollars for a multiyear/multi-region project like this, perhaps over two million. Which makes $96,500 rather a drop in the bucket. That might have paid for some of the jet fuel for the helicopters used for the survey, but probably not all of it.

Status details below.
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Baffin Bay-Davis Strait ice concentration comparison – why use the “summer mean”?

I’ve been in the process of looking at the status of polar bears in the Baffin Bay region, which lies to the north of Davis Strait (Fig. 1), but a related issue caught my attention that I think deserves discussion.

Figure 1. Polar bear subpopulations defined by the Polar Bear Specialist Group (PBSG). Note that Baffin Bay, Davis Strait, Western Hudson Bay and Southern Hudson Bay are all similar in that they become ice-free by early fall (the September minimum) or before.

Figure 1. Polar bear subpopulations defined by the Polar Bear Specialist Group (PBSG). Note that Baffin Bay, Davis Strait, Western Hudson Bay and Southern Hudson Bay are all similar in that they become ice-free by early fall (the September minimum) or even before.

Recall that in a recent post on the Beaufort Sea ice extent comparison offered by the National Snow and Ice Data Center (NSIDC) here, I commented:

What puzzled me was why they featured only the last 7 years when satellite data go back to at least 1979. Is there something in that data they don’t want us to see?”

Something similar struck me about the analysis of sea ice in Baffin Bay and Davis Strait conducted by polar bear researchers Karyn Rode and colleagues (Rode et al. 2012). In their comparison of body condition (relative fatness) of bears in Davis Strait and Baffin Bay (see previous post here), they introduced an entirely new sea ice metric – “mean daily summer sea ice concentration,” defined as the mean of values between May 15 and October 15 each year based on ice charts provided by the Canadian Ice Service.

Why invent a metric that has never been used (as far as I know) for analysis of polar bear health, survival or success?

Why not use breakup dates, as has been done for decades for subpopulations in Hudson Bay (e.g. Cherry et al. 2013), where the ice also disappears in late summer?

Is there something in the ice data for Baffin Bay and Davis Strait that Rode and colleagues don’t want us to see?

Since I had already made a composite of Cryosphere Today ice maps at July 12 for my discussion of the Chukchi/Beaufort NSIDC analysis mentioned above, it was relatively easy to look at what was going on in Baffin Bay and Davis Strait on that date in mid-summer. Keep in mind that ice extent and concentration at July 12 records the state of polar bear habitat prior to the late summer decline in sea ice that occurs every year.

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