Author Archives: susanjcrockford

Tracking polar bears in the Beaufort Sea – September 2014 map

Posted on October 6, 2014 | Comments Off

Here is the September 2014 follow-up to my post on the July 2013 track map for female polar bears being followed by satellite in the Beaufort Sea by the US Geological Survey (USGS) – “Ten out of ten polar bears being tracked this summer in the Beaufort Sea are on the ice.”

See that post for methods and other background on this topic, and some track maps from 2012 (also available at the USGS website here).

The USGS track map for September 2014 is copied below (Fig. 1).

At the end of September, with sea ice starting to rebuild, it appears there were 8 bears on the ice and three on land.

The situation for September was not very much different from August, except that two of the 11 bears (up from one) were on the ice in the Chukchi Sea in September, a phenomenon that was recently acknowledged to have affected the last population estimate for the Southern Beaufort subpopulation.

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Posted in Population, Sea ice habitat

Tagged Alaska, Beaufort Sea, Chukchi Sea, Kaktovik, polar bear movements, polar bears, population estimate, Prudhoe Bay, satellite collars, sea ice, Southern Beaufort, tracking polar bears, USGS

High walrus numbers may explain why females and calves are hauling out in droves

Posted on October 4, 2014 | Comments Off

Are the recent mass gatherings of females and calves on the beaches of western Alaska and the Russian Far East a sign that population are again close to the limit the habitat can support, as they were in the 1970s?

At the risk of belabouring the point that lack of sea ice does not seem to be a reasonable explanation for this phenomenon (see my last two posts, here and here, and Andrew Montford’s excellent additions here), I think this is a possibility that needs to be considered.

Walruses at Point Lay Sept 27 2014 NOAA CMDA0007_sm

2014 Point Lay, NOAA photo

Walrus are well protected in the US and Russia, and population numbers have risen again since the 1990s, after significant declines in the early 1900s and again in the 1980s.

A paper from the late 1980s suggests that a return to high population numbers may be a more plausible cause for mass gatherings of females and calves that lead to stampede deaths than does reduced sea ice due to global warming.

Have a look and see what you think. It may not be the only reason but it may be a major contributing factor.

Comments Off on High walrus numbers may explain why females and calves are hauling out in droves

Posted in Advocacy, Sea ice habitat, walrus

Tagged carrying capacity, Chukchi Sea, climate change, females and calves, global warming, haulouts, mass gatherings, mass mortality, polar bear prey, sea ice declines, stampede, walrus

Mass gatherings of walrus follow-up – sea ice maps for 1978 and 1972

Posted on October 2, 2014 | Comments Off

Walruses as polar bear prey and sea ice were on my mind last night and I remembered that we DO have detailed sea ice information for 1978 and 1972 – from the sea ice atlas put together by University of Alaska Fairbanks (UAF), which has ice concentration maps for Alaska going back to 1850 — and for every year up to 2013 (reported previously here).

Chukchi Sea walrus, June 2014. US Fish and Wildlife Service.

I’ve copied some of the ice maps below.

It is clear that ice was available close to Wrangel Island in 1972 when walruses chose to haul out on the island in huge numbers. And in 1978, there was ice present to the north of the walrus herd, but they had moved away from the ice to get to St. Lawrence Island, where they hauled out in large numbers.

This means it is more likely that food resources were the issue, not sea ice.
UPDATE OCTOBER 3 2014:

See another interesting follow-up elsewhere: Walrus inconsistencies
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Comments Off on Mass gatherings of walrus follow-up – sea ice maps for 1978 and 1972

Posted in Life History, Sea ice habitat, walrus

Tagged Chukchi Sea, climate change, Fay, global warming, ice levels, Kelly, mass mortality, Point Lay, sea ice atlas, sea ice declines, sea ice maps, St. Lawrence Island, stampede, UAF, walus, Wrangel Island, WWF

Mass haulouts of Pacific walrus and stampede deaths are not new, not due to low ice cover

Posted on October 1, 2014 | Comments Off

Large haulouts of walruses — such as the one making news at Point Lay, Alaska on the Chukchi Sea (and which happened before back in 2009) — are not a new phenomenon for this region over the last 45 years and thus cannot be due to low sea ice levels. Nor are deaths by stampede within these herds (composed primarily of females and their young) unusual, as a brief search of the literature reveals.

The attempts by WWF and others to link this event to global warming is self-serving nonsense that has nothing to do with science.

UPDATE October 3, 2014: See below. Also, do see follow-up posts here, here, and especially, here.

UPDATE October 23, 2014: A briefing paper summary is here and a video version of that paper (“The Walrus Fuss” — 3 1/2 minutes long) here.

There is also a follow-up post on the situation here.

Comments Off on Mass haulouts of Pacific walrus and stampede deaths are not new, not due to low ice cover

Posted in Advocacy, Sea ice habitat, walrus

Tagged Chukchi Sea, climate change, Fay, global warming, ice levels, Kelly, mass mortality, Point Lay, sea ice declines, St. Lawrence Island, stampede, walus, WWF

Natural selection helps polar bears adapt to sea ice variability – which means some bears die

Posted on September 30, 2014 | Comments Off

Evolution is not just for the long-term – natural selection also goes on over short time periods. In the case of polar bears, this adaptation is almost certainly critical for its long-term survival.

Hudson Bay female with cub_Wapusk_Thorsten Milse_Gov CA

Hudson Bay female with cub Wapusk National Park, Thorsten Milse, Government of Canada

Not all polar bears are identical — that is the reality that allows natural selection to operate.

I will argue that early breakup years in Western Hudson Bay weed out individual polar bears that do not have the physiological or behavioral characteristics necessary to be useful members of the population – and that this is a good thing for the entire population.

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Posted in Evolution, Population, Sea ice habitat

Tagged adaptation, declining sea ice, early breakup, evolution, historical sea ice record, indivdual variation, late freeze-up, natural selection, NSIDC, polar bear, resilience, sea ice minimum, sea ice variability, Stirling, Stroeve, survival, western hudson bay

About the time I asked a challenging question at a global warming workshop

Posted on September 24, 2014 | Comments Off

When you really want to challenge a speaker at a scientific meeting or public lecture, deciding what’s the best question to ask is often difficult. Here’s an example that might inspire you.

In 2009, I asked polar bear biologist Lily Peacock what appeared to be an innocuous question about Foxe Basin sea ice¹ at a scientific workshop that got everyone’s attention.

The question — and the reaction — might surprise you.

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Posted in Advocacy, Conservation Status, Sea ice habitat

Tagged Arctic marine mammals, breakup, Foxe Basin, global warming, Hudson Bay, International Polar Year, late breakup, Peacock, polar bear ecology, polar bears, public lectures, scientific meetings, sea ice, Society for Marine Mammalogy, spring sea ice, Stirling, workshop

Journalists still pushing the “polar bears eat snow geese story,” as if it matters

Posted on September 23, 2014 | Comments Off

I wrote about this issue in January (January – and journalists are still pushing it).

Figure 1. Courtesy NY Times, Sept. 22 2014. Click to enlarge.

This month, the New York Times (September 22, 2014 James Gorman, “For Polar Bears, a Climate Change Twist”) is pushing it big-time (and so it’s been picked up elsewhere, like by the Anchorage Daily News).

Myths and misinformation about this phenomenon dispelled below.
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Comments Off on Journalists still pushing the “polar bears eat snow geese story,” as if it matters

Posted in Conservation Status, Life History

Tagged Churchill, climate change, consumption of eggs, Foxe Basin, goose eggs, Gormezano, Hudson Strait, nutritional stress, polar bear, polar bear diet, prolonged ice-free season, Rockwell, Russell, sea bird eggs, sea ice decline, snow goose, starving polar bears, terrestrial foods, western hudson bay

Polar bears are not in peril due to recent sea ice changes

Posted on September 21, 2014 | Comments Off

To counter the misleading ploy used by the Sunday Times — of implying polar bears are in peril because of recent changes in Arctic sea ice (Sunday Times & The Australian, 21/22 Sept. 2014 Arctic ice cap in a ‘death spiral’) — I’ll go over again why the polar bear as a species is not threatened by declines in summer sea ice or even winter ice that is predominantly “thin” (first year) ice.

Graphic above from the Sunday Times, September 21, 2014
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Comments Off on Polar bears are not in peril due to recent sea ice changes

Posted in Conservation Status, Sea ice habitat, Summary

Tagged Arctic ice cap, arctic sea ice, Chukchi Sea, death spiral, denning females, evidence, first year ice, ice thickness, ice-free Arctic, Mark Serreze, North Pole, Peter Wadhams, polar bear, sea ice extent, thin sea ice

Ian Stirling now says the polar bear that “died of climate change” last year was “in his prime”

Posted on September 18, 2014 | Comments Off

With Barents Sea ice way above average this summer, Polar Bear Specialist Group biologist Ian Stirling now claims the old polar bear that he said died of climate change last year on Svalbard was “in his prime” and still blames the bear’s death on lack of sea ice — despite all evidence to the contrary.

UPDATE Sept. 19, 2014 typo fixed in Fig. 1 caption [sea ice low for 2012 was 3.41 m2km, not 4.1, see here.]

Figure 1. The National Snow and Ice Data Center (NSIDC) says the September minimum for 2014 is “imminent” and suggests the low may come in at 5.1 million square kilometers (far short of the ~~4.1~~ 3.41 m2km low reached in 2012. About the much larger than average amount of ice around Svalbard and Franz Josef Land, they said only: “As was the case for the beginning of the month, extent remains below average in all sectors of the Arctic except for a region in the Barents Sea, east of Svalbard.”

Comments Off on Ian Stirling now says the polar bear that “died of climate change” last year was “in his prime”

Posted in Advocacy, Life History, Sea ice habitat

Tagged AMO, annual summer minimum, Atlantic Multidecadal Oscillation, Barents Sea, Franz Josef Land, Hopen Island, minimum ice extent, Mult, NSIDC, polar bear that died of climate change, Polar Bears International, sea ice extent, starving polar bear, Stirling, Svalbard

Polar bear attacks on humans – an evolutionary perspective

Posted on September 16, 2014 | Comments Off

What with polar bear populations higher than they were 50 years ago and with many bears onshore during the ice-free season, a few polar bear attacks are to be expected – but how does the behaviour that drives those attacks compare with their closest evolutionary cousin, the grizzly?