polarbearscience

Both sides now: New paper critiques Canadian polar bear population status

Posted on March 24, 2016 | Comments Off

Demographic and traditional knowledge perspectives on the current status of Canadian polar bear subpopulations. 2016 (in press). Jordan York, Martha Dowsley, Adam Cornwell, Miroslaw Kuc and Mitchell Taylor. Ecology and Evolution 6(9):2897-2924. DOI: 10.1002/ece3.2030

York et al 2016 fig 1_numbers 2013

Take home quote:

“We see reason for concern, but find no reliable evidence to support the contention that polar bears are currently experiencing a climate crisis. We suggest that the qualitative projections for dramatic reductions in population numbers and range are overly pessimistic given the response of polar bears, climate, and sea ice to the present.”

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Posted in Conservation Status, Population, Sea ice habitat

Tagged Canada, climate change, facts, Mitch Taylor, polar bear, population status, predictions, projections, sea ice

Condition of S Hudson Bay polar bears varies with freeze-up only says new study

Posted on March 23, 2016 | Comments Off

Despite the fact that the polar bears of Southern Hudson Bay (SHB) live further south year round than any others, a recent study found their average body weight has declined relatively little since the 1980s. There has been no decline in the size of the population over that time either. Perhaps that’s why there was neither a press release nor a massive media blitz when this paper came out earlier this month.

James Bay female and cub_Ontaro Govt

Remarkably – despite what we are told about how critical breakup dates are to polar bear health and survival in Hudson Bay – this study found that for SHB bears, the small decline in body condition index correlated only with freeze-up dates, not breakup dates or length of the ice-free season. They also found that regional breakup and freeze-up dates relevant to polar bears in this area was the day when ice cover reached 5% (not 50%).

In other words, SHB polar bears left the ice (or returned to it) when the average ice cover near the coast was about 5%. This finding is yet more evidence that the meteorological definition of “breakup” (date of 50% ice cover) used by many researchers (see discussion here) is not appropriate for describing the seasonal movements of polar bears on and off shore.

Continue reading

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Posted in Life History, Sea ice habitat

Tagged body condition, breakup, defining breakup, facts, freeze-up, Obbard, polar bear, sea ice, Southern Hudson Bay

Polar bears onshore in winter – will more bears mean more deadly attacks?

Posted on March 19, 2016 | Comments Off

Incidents of polar bears causing problems onshore this winter (January & February) – including one that killed a horse in Greenland and another that threatened a resident in western Hudson Bay (only weeks after several incidents in southern Labrador) may be the tip of a very scary iceberg. I’ve taken a look at what records exist of this phenomenon, which in the past often involved deadly attacks. The large number of reports this winter appears to be a real increase, which is a rather terrifying prospect indeed.

Doug Clark photo polar bears onshore in Feb 2013 Wapusk NP

In winter, all polar bears except females in dens nursing newborn cubs are presumed by biologists to be on the sea ice hunting but it turns out that is not quite true. Although relatively rare over the last twenty years or so, it appears that in some areas, bears are now coming ashore in winter.

The photo above shows a polar bear photographed by a remote camera installed at Broad River Camp, Wapusk National Park, western Hudson Bay on 7 February 2013. It was visible to the camera for 40 minutes but apparently caused no trouble (camera installed and maintained by associate professor Doug Clark from the University of Saskatchewan and colleagues).

Given the fact that there are now many more polar bears than there were in the 1970s as well as more people living in many coastal Arctic communities, problems with bears in winter are likely to increase, as this winter’s events show. More bears out on the ice in winter (January-March) will almost certainly create more competition for the little bit of food that’s available (seals are hard to catch in winter), which means some bears might increasingly be looking for alternate sources of food onshore.

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Posted in Life History, Polar bear attacks, Population

Tagged attacks, conflicts, consequences of conservation, hungry, killing, onshore, polar bear, population increases, problem bears

Challenging Alaska polar bear research sound bites and bewildering ESA status

Posted on March 15, 2016 | Comments Off

Beaufort Sea male polar bear USGS_2005 Amstrup photo

It’s easy to take polar bear research papers at face value but it’s not very scientific. The snappy sound bites provided for the benefit of the media – whether they’re embedded in press releases or in published abstracts – don’t cut it with trained scientists. Trained scientists read the whole report, critically examine the evidence it contains and assess that evidence within the context of previous knowledge. That’s what they are trained to do.

I challenge the superficial summary on the status of Alaskan polar bear populations provided by FactCheck.org journalist Vanessa Schipani. Schipani disputed a comment made by Alaska Senator Lisa Murkowski that, according to the latest research Alaskan polar bear population numbers are strong and healthy. I’m not especially interested in the political context of the statement, only Schipani’s bald claim that Murkowski’s declaration is false.

I’ve read all the relevant papers in full and I contend that the evidence supports Murkowski’s statement. Schipani is confusing the issue by regurgitating ‘facts’ that don’t tell the truth of the matter. By the sum of accounts, Alaskan polar bear populations are indeed healthy and strong – whether or not this status will continue is an entirely different question. Continue reading

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Posted in Conservation Status, Population

Tagged Alaska, Beaufort, Chukchi, conservation, ESA, facts, IUCN, polar bear, population size, Red list, ringed seals, sea ice, status

A new count planned for Southern Beaufort polar bears

Posted on March 13, 2016 | Comments Off

I know I was not the only one that thought the last polar bear count conducted by the US Geological Survey (USGS) in the Southern Beaufort generated an untenable result but it appears that some of those challengers are in a position to demand a recount.

polar_bear_usfws_no date_sm

CBC News ran a story late last week announcing a plan is in the works to do an aerial survey of Southern Beaufort Sea polar bears across their entire range over two years starting in 2017 (11 March 2016, “Joint U.S.-Canada Beaufort Sea polar bear survey planned“).

With luck, this period will not include another bout of the same thick spring ice conditions that decimated the population in the mid-2000s (which many reporters concluded was due to reduced summer sea ice because that’s what leading biologists implied). Even if it does, lucky timing will not negate the fact that this population is routinely subjected to devastating population declines caused by natural changes to spring sea ice conditions from which they have recovered on numerous occasions. Continue reading

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Posted in Conservation Status, Population, Sea ice habitat

Tagged aerial survey, Alaska, Arctic, Beaufort Sea, facts, hunters, Invuialuit, mark-recapture, Northwest Territories, polar bear, population estimate, sea ice, traditional knowledge

Worrywart biologists fuel media fearmongering over winter sea ice levels

Posted on March 8, 2016 | Comments Off

Have you heard the old adage, “Don’t buy trouble”? I’m thinking we could use a lot more of that attitude from polar bear and Arctic seal biologists these days.

Gulf St Lawrence ice conc 7 March 2016_CIS

In an interview with CBC News yesterday, Department of Fisheries and Oceans Canada (DFO) seal specialist Mike Hammill fed the fear the media wanted to hear while admitting this year’s low ice levels in the Gulf of St. Lawrence will not affect harp seal numbers significantly (7 March 2016, “Lack of ice means fewer seal pups off the Magdalen Islands this year: Researcher says impact on overall herd limited, but ice patterns over time could be concern”).

Harp sea newborn_wikipedia

And University of Alberta’s Andrew Derocher has been busy tweeting his heart out that slightly lower than average sea ice levels this winter could mean a “challenging” spring for some polar bears – as if spring isn’t always challenging for some bears (especially young bears that are inexperienced hunters and low in the social hierarchy – meaning bigger, older bears often steal their kills – and old bears that are running out of steam).
Continue reading

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Posted in Advocacy, Life History, Sea ice habitat

Tagged buying trouble, Derocher, facts, Gulf of St. Lawrence, Hammill, harp seals, Labrador Sea, Newfoundland, polar bear, sea ice, spring ice conditions, winter maximum

More Churchill polar bear captures due to increased vigilance not global warming

Posted on February 29, 2016 | Comments Off

Polar bear specialists just don’t get it: virtually no one except the ever-gullible media believes their exaggerated stories of doom. Yet they keep trying and with every lie and misrepresentation of fact, they erode the confidence of the public. Unfortunately, it’s not just trust in polar bear specialists that’s being eaten away, it’s trust in science generally.

Churchill polar bear encounters up in 2015_CBC headline Feb 28 2016

This time, it’s a head-line grabbing piece about the number of problem polar bears in Churchill, Manitoba (written by Chinta Puxley) that made the usual media rounds yesterday (CBC News, CTV News, Global News, Huffington Post, Winnipeg Sun, The Globe and Mail). The main culprits are Daryll Hedman, regional wildlife manager for Manitoba Conservation, and polar bear biologist Andrew Derocher.

However, it’s hard not to see that the increased number of bears captured by Manitoba Conservation officers around Churchill can be best explained as a natural reaction by officials to a particularly frightening polar bear attack in 2013. Continue reading

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Posted in Advocacy, Polar bear attacks, Sea ice habitat

Tagged attack, attacks, Churchill, Dercoher, facts, Hedman, misinformation, polar bear, polar bear patrol, problem bears, science, sea ice, trust, western hudson bay

Biggest threat to polar bears reconsidered

Posted on February 27, 2016 | Comments Off

What presents a bigger risk to current polar bear populations: natural hazards that have already proven deadly or potential, yet-to-be-realized threats prophesied to occur due to human activities? That’s a perfect question for International Polar Bear Day.

Natural ice_snow variation and polar bears_model_PolarBearScienceFeb 20 2016

Dag Vongraven, chair of the IUCN Polar Bear Specialist Group, remarked last year that “until 2001, everything was fine.”

Polar bear researchers thus assume that 2001 was the year climate change became the new over-hunting – but is it true? What are the relative harms presented by proven natural causes, potential human-caused threats, and predicted threats due to sea ice declines blamed on global warming? Considered objectively, is climate change really the single biggest threat to polar bear health and survival right now?
Continue reading

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Posted in Advocacy, Conservation Status, Population, Summary

Tagged climate change, Derocher, endangered, extinction, facts, forecast, global warming, hazards, International Polar Bear Day, IUCN, natural causes, natural variability, over-hunting, poaching, polar bear, prediction, sea ice, snow, Stirling, threatened, threats, Vongraven

W. Hudson Bay polar bear numbers declined then stabilized, says new paper

Posted on February 26, 2016 | Comments Off

Western Hudson Bay bear, Wakusp National Park, August 2011.

In the just-published version of their Western Hudson Bay (WHB) population survey conducted in 2011, Nick Lunn and colleagues highlighted in the abstract:

“Our analysis suggested a long-term decline in the number of bears from 1,185 (993-1411) in 1987 to 806 (653-984) in 2011…”

But they didn’t mention that the 806 estimate for 2011 was based on only a portion of the WHB region (Fig. 1) and has not been accepted by their peers as a valid estimate of the population size. They also failed to mention that the decline occurred due to thick spring ice and/or unsuitable snow conditions for ringed seals between 1989 and 1992 (Fig. 2), which resulted in reduced availability of polar bear prey (as I discussed in detail in Crockford 2015).

They know the “long-term” population decline is what the media will grab onto and run with – rather than the next sentence, which says “In the last 10 years of the study, the number of bears appeared stable due to temporary stability in sea ice conditions.”

In other words, their study shows there has been no decline in the population since 2004, which had been predicted to occur (see previous post, Prediction #1), and there has been no trend in either breakup or freeze-up dates between 2001 and 2010 (or since). See previous post on the government report on which this paper is based here.

The bottom line is this: no one is buying this population estimate of 806 bears for the Western Hudson Bay population – both the IUCN Polar Bear Specialist Group and Environment Canada are using Seth Stapleton and colleagues (2014) estimate from their aerial survey done the same year and that official population size number is 1030 bears. Continue reading →

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Posted in Advocacy, Population

Tagged declining, Derocher, ecl, facts, fewer bears, ice thickness, Lunn, polar bear, ringed seals, snow depth, stable, western hudson bay

Polar bear habitat update: Labrador sea ice highest in 20 years

Posted on February 26, 2016 | Comments Off

Sea ice off the southern Labrador coast hasn’t been this high for this date in 20 years: that’s great news for the harp and hooded seals that will give birth at the Front in another few weeks – for a while anyway, because a bumper crop of baby seals is also good news for the polar bears who gather there to eat them.

Sea_ice_near_coast_of_Labrador_-a_wikipedia sm