Category Archives: Sea ice habitat

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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Breakup date average for W. Hudson Bay is July 1 – this year, it’s late again

In the last few days, ice coverage on Western Hudson Bay finally dropped below the 30% level that now defines ‘breakup’ for polar bears: a few bears near Churchill started to come ashore late last week but most will stay on the ice until the end of July. That means breakup this year was unofficially July 8th, a week later than average (July 1) for the third year in a row.
Sea ice extent Canada 2014 July 7 CIS

Don’t’ tell that to the folks at Polar Bears International, though, because they’re busy telling people that the ice-free season for Western Hudson Bay bears is now longer than it was before the 1990s. What they mean is that the overall trend is toward early breakup dates.

But what they don’t admit is that over the last 44 years, breakup was a full two weeks earlier than average for Western Hudson Bay only six times and only three of those early breakups occurred within the last 13 years. See the calculations below and see what you think.

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Tracking polar bears in the Beaufort Sea: June 2014 map

Here is the June 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 June 2004 is copied below (Fig. 1).

Compare this to May’s map (Fig. 2) – the 20 bears from last month are down to 14, and all seven of the bears outfitted with glue-on satellite transmitters in April [either males or subadult animals] have either moved out of the area or their tags have fallen off or stopped transmitting. This means that all of the bears shown on the June map below are females with satellite radio collars.
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Swimming bear video used for propaganda was not shot with bear-mounted cameras

I just went back to Andy Revkin’s blog post on the swimming polar bear video story that I wrote about on Wednesday to see what kind of feedback it was getting. I found that it pays to check up.

pbear_swimming_USGS

A reader from Oregon questioned the filming techniques used for this video.

Revkin followed up.

And it turned out, the reader from Oregon was correct — the film used in this video was shot with “an assortment of traditional methods,not with the strapped on cameras that the USGS were using on the bears.

Revkin assumed from the background provided to him that this was leading-edge technology, bear-generated video. And even though he’d interviewed the filmmaker, the truth hadn’t come out.

Update June 29, 2014 – another damning comment made, added below.

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Swimming bear video used to promote climate change threat to polar bears

A video being hyped around the internet – “Witness a polar bear’s heartbreaking swim for ice in the Arctic” said one headline – is simply shameless propaganda, facilitated by the US Geological Survey and its polar bear biologists. USGS scientists involved in this work should be ashamed of themselves.

The caption for the Youtube video (published Jun 21, 2014) says this:

Take a swim with a polar bear family as they traverse the Arctic Ocean in search of sea ice.

This is a load of nonsense and a total misrepresentation of the facts.

In addition, the text added to the video is pure propaganda: it is being used to promote the US government position that sea ice loss due to climate change is a massive threat to polar bears. Unfortunately, recent studies contradict the contention that polar bears have already been harmed by declines in summer sea ice.

Here are some background to the video you should be aware of:

1) The bears were swimming away from the USGS researchers and film crew who had shot them full of sedatives and attached a camera to one of their necks — they were not swimming toward sea ice 100 miles away.

2) The video was shot in the Bering Sea, in April 2014, when sea ice was about its maximum extent of the year — there was lots of ice around when this video was filmed.

3) The company doing the filming is using this video as a fundraiser.

Details below, including a sea ice map for April 2014.

UPDATE June 27, 2014 – see follow-up post here.

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Spring/summer sea ice bonanza for polar bears – conditions excellent again for 2014

Again this year – contrary to predictions – there has been no early breakup of the sea ice on Hudson Bay and even though it’s the height of summer, there is plenty of ice throughout the Arctic to act as a feeding platform for polar bears. This makes it unlikely there will be a longer-than-average summer fast for polar bears again this year.

Figure 1. NSIDC MASIE map for June 21, 2014.

Figure 1. NSIDC MASIE map for June 21, 2014.

Sea ice maps around the Arctic for June 21 (and June 24, for Hudson Bay) reviewed and discussed below in relation to polar bear habitat — have a look.

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Tracking polar bears in the Beaufort Sea – May 2014 map and USGS video footage

Here is the May 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 May 2014 is copied below (Fig. 1).

Compare this to April’s map (Fig. 2) – the 24 bears from April are down to 20 and the bears are spreading out a bit from the area on the central Alaskan coast where they were originally tagged. Fifteen of these bears have satellite collar transmitters [and therefore are females] and 5 of these bears have glue-on satellite transmitters [either males or subadult animals].

Some comments on the polar bear video cam footage released June 6 by USGS and stories on it run by the media follow.

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Activists pressure tactics to force Canada to list polar bears as ‘threatened’ have failed

The Center for Biological Diversity has failed in its bid to use NAFTA (North American Free Trade Agreement) to pressure Canada to list polar bears as a species ‘threatened’ with extinction — wrapping up a story I wrote about twice last year (here and here).

Chukchi male 1240 lbs labeled Durner 2008

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Barents Sea polar bear cubs – new data for 2014 made to sound ominous

Last week, Damian Carrington (May 28, 2014) at The Guardian offered a scary-sounding polar bear story, based on the work of Jon Aars and colleagues from the Norwegian Polar Institute (Fewer polar bear cubs are being born in the Arctic islands, survey finds). As often is the case however, once you see the scientific data, you will sleep better.

[Dr Aars also gave a radio interview with CBC Canada (May 29): "Is climate change the cause of lower polar bear birth rates in Norway?"; audio available]

[Update June 24, 2014 — see below]

Female polar bear with cubs. (U.S. Fish & Wildlife Service/AP)

Female polar bear with cubs. (U.S. Fish & Wildlife Service)

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Tracking polar bears in the Beaufort Sea – more bears added to the April 2014 map

Polar bears were tagged in 2013 and 2014 on the spring-time sea ice of the southern Beaufort Sea. Seventeen of these bears have satellite collar transmitters and 7 of these bears have glue-on satellite transmitters” say the folks at the USGS Alaska Science Center.

I guess that’s why the April map was late getting posted.

Polar bear ear tag_USFWS_PolarBearNews2010

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