Tag Archives: population size

Western Hudson Bay polar bear numbers are stable, no trend in ice breakup or freeze-up

This needs saying again: the latest study on Western Hudson Bay polar bears reveal the population has been stable since 2004 and there has been no significant trend in either breakup or freeze-up dates since 2001.

Triplets in Wapusk NP from McCall webpage 2013

Environment Canada and the IUCN Polar Bear Specialist Group concur that the current size of the WHB subpopulation is about 1030 bears. Documents found online indicate a new version of the 2013 WHB mark-recapture report (Lunn et al. 2013) is now available (Lunn et al. 2014) and that a new population survey is planned for 2016. A 2013 story based on false information produced by The Guardian that is still in circulation should be retracted.
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Sea ice is not a stable habitat for polar bears – summarized today in The Arctic Journal

In The Arctic Journal, 7 October 2015: Unstable thinking about polar bear habitat [not my title choice]

Unstable thinking about polar bear habitat_Oct 7 2015 title page

This is a previously unpublished summary, written exclusively for The Arctic Journal, of my peer-reviewed, fully referenced essay on this topic that was published earlier this year by the Global Warming Policy Foundation in their “Briefing Paper” series (#16, June 8, 2015: The Arctic Fallacy: Sea Ice Stability and the Polar Bear), which includes a foreword by Dr. Matthew Cronin, Professor of Animal Genetics at the University of Alaska Fairbanks. Pdf here.

Here are the essential points, one by one:
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Activist explorer blames more polar bear encounters since 1985 on reduced sea ice

Activist polar explorer Børge Ousland’s told National Geographic that more polar bear encounters on land are due to reduced sea ice –  without any reference to population changes over that time or revealing when or where these observations were made.

IceLegacy_NG video Sept 30 2015

More vague anecdotal observations and opinions posing as scientific evidence.
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Polar bear doom and gloom from USGS vs. biologist Mitch Taylor’s reasoned thoughts

A few days ago polar bear biologist Mitch Taylor and Nunavut’s Gabriel Niryungaluk talked to Toronto radio host Roy Green about the recent USGS dire model predictions for the future of polar bears.

Taylor interview_5 July 2015 Polar bear numbers_radio

There’s an audio podcast and, courtesy of the valuable efforts of fellow blogger Alex Cull, a transcript. Links below, plus some excerpts of Mitch Taylor’s commentary.
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My new Arctic Fallacy paper- Sea ice stability and the polar bear

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

Chukchi June 15 2014_USGS_Brian Battaile_after swim_sm

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.

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Walrus and sea ice, a summary

I’ve written a briefing paper for the GWPF refuting claims that huge herds of Pacific walruses hauled out on land are a sign of global warming.

Here’s the GWPF press release:

London, 20 October: A briefing paper published today by the Global Warming Policy Foundation refutes claims that Arctic walruses are in distress and danger due to global warming.

The paper, written by Canadian zoologist Dr Susan Crockford, assesses the recent mass haulouts of walrus females and calves on the beaches of Alaska and Russia bordering the Chukchi Sea. The events have been blamed by US government biologists and WWF activists on lack of summer sea ice, amplified into alarming scare stories by news media around the world.

Such claims ignore previous haulouts that suggest a different cause. Scientific reports about large walrus haulouts that have occurred repeatedly over the last 45 years show that they are not new phenomena for this region.

At least two documented incidents of similar magnitude have occurred in the recent past: one in 1978, on eastern St. Lawrence Island and the other in 1972, on the western end of Wrangel Island. The 1978 event involved an estimated total of almost 150,000 walrus hauled out within in a small geographic area.

Moreover, sea ice maps for the months when known mass haulouts occurred, compared to years when they did not, suggest no strong correlation with low sea ice levels.

“The WWF and American walrus biologists have categorically linked the Point Lay mass haulout event to global warming, but available evidence suggests that’s alarmist nonsense,” Dr Crockford said.

“Blaming lack of sea ice for recent events ignores the documented factor – large population size – that drove walruses onto beaches en masse in the past, when plenty of ice was available. Conservation measures have almost certainly led to a spectacular recovery of walrus numbers over the last few years. This suggests that recent mass haulouts are more an indicator that Chukchi walrus are nearing maximum capacity than a sign of impending global warming catastrophe,” Dr Crockford added.

Here’s the paper. [Link fixed, h/t HO]

Mass haulouts of female Pacific walrus as a sign of population health

Mass haulouts of female Pacific walrus and their calves in fall don’t happen all the time but they do occur. I recently pointed out (here and here) two instances of such incidents from the 1970s.

I said this provided evidence that the September 2014 incident reported in the media was not “a new phenomenon” for this region, as WWF spokepersons and Alaskan biologists have claimed (reiterated in this PBS interview).

Figure 1. Walrus females and calves hauled out on a beach in Svalbard, photo accompanying an October 6, 2014 news report in “Eye on the Arctic” of the rapidly increasing Atlantic walrus population there.   (Photo: Thomas Nilsen/Barents Observer).

Figure 1. Walrus females and calves hauled out on a beach in Svalbard, photo accompanying an October 6, 2014 news report in “Eye on the Arctic” of the rapidly increasing Atlantic walrus population there. (Photo: Thomas Nilsen, Barents Observer).

One aspect of the recent occurrence of a large herd on an Alaskan beach that apparently needs reiterating is that the population of walruses declined rather markedly after a 1970s peak and has rebounded since. This suggests that huge herds of females and calves hauling out on beaches in the fall to feed might only be seen when the population is very large.
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