Tag Archives: litter size

Churchill problem polar bear report for week 3 and a triplet litter of cubs spotted

Courtesy the Town of Churchill:

Also, note that a mother with a litter of triplets spotted along the coast of Wapusk National Park (just east and south of Churchill) in good condition, 15 September 2020 (see photo below). Biologist Nick Lunn falsely claimed in 2018 that no triplet litters had been born in Western Hudson Bay since 1996 – a correction made later claimed Lunn meant there hasn’t been any triplet litters seen in the fall, which was also not true in 2017 or in 2020:

Compare weekly stats above for this year to a few previous years at the second week in September:

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New paper says Baffin Bay polar bears may have been affected by less summer sea ice

A new paper on Baffin Bay polar bears reports data on body condition and litter sizes collected as part of a major study of the region completed in 2013 compared to sea ice declines since the 1990s; based on a computer model, the authors predict that in 37 years time (if sea ice declines continuously), the incidence of twin litters could “largely disappear.” However, no decline in population numbers was predicted and a critical caveat acknowledges that factors other than changes in sea ice could have affected the body condition and litter size data the authors analyzed, which means the conclusions are scientifically inconclusive.


Fat polar bear, summer 2012 near Thule, NW Greenland (Baffin Bay subpopulation). Robin Davies photo.

The last (2013) polar bear population survey of Baffin Bay (SWG 2016) generated an estimate of almost 3,000 (2,826; range 2,059-3,593), which means that regardless of some slight changes in body condition and litter size over the last two decades (which may or may not have been caused by loss of sea ice), there are currently a lot of bears in Baffin Bay.

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Norwegian polar bears continue to thrive in 2019: Svalbard spring study results are in

Results from spring Norwegian fieldwork in the Svalbard region of the Barents Sea are in and they show that despite having to deal with the most extreme loss of summer sea ice in the Arctic, polar bears in this region continue to thrive.

Svalbard polarbear-helicopter-npolar-framcentre

Svalbard polar bear territory (managed by Norway) includes sea ice to the Russian boarder to the east as well as the area around the Svalbard archipelago: the map below is from Aars et al. 2017.

Aars et a. 2017 Figure 1

Observations were collected around Svalbard by a team lead by Jon Aars and Magnus Andersen of the Norwegian Polar Institute between March and May this year, and posted online 4 June 2019. Kudos to them for making their on-going observations and analysis available, in a timely manner for all to see.

Note that Svalbard is the western half of the ‘Barents Sea’ polar bear subpopulation: in recent years, most of the region’s polar bears have been living around Franz Josef Land in the eastern (Russian) sector where Norwegian researchers are not permitted to work.

Barents Sea with Franz Josef Land

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Svalbard polar bear data 2016 through 2018 shows no impact of low ice years

Last week, the Norwegian Polar Institute updated their online data collected for the Svalbard area to include 2017 and 2018 — fall sea ice data and spring polar bear data. Older data for comparison go back to 1993 for polar bears and 1979 for sea ice, showing little to no impact of the reduced ice present since 2016 in late spring through fall.

Svalbard polar bear_NP015991-isbjorn-JA

Here’s what the introduction says, in part [my bold]:

“…The polar bear habitat is changing rapidly, and the Polar Basin could be ice-free in summer within a few years. Gaining access to preferred denning areas and their favourite prey, ringed seals, depends on good sea ice conditions at the right time and place. The population probably increased considerably during the years after hunting was banned in 1973, and new knowledge indicates that the population hasn’t been reduced the last 10-15 years, in spite of a large reduction in available sea ice in the same period.”

See Aars et al. 2017 for details on the 2015 Svalbard polar bear population count, keeping in mind that the subpopulation region is called “Barents Sea” for a reason: only a few hundred individuals currently stick close to Svalbard year round while most Barents Sea bears inhabit the pack ice around Franz Josef Land to the east (Aars et al. 2009; Crockford 2017, 2018).
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Polar bear biologists doing mark-recapture work in Hudson Bay may have misled the world

What exactly are Western Hudson Bay (WHB) polar bear researchers hiding? Since 2004, research on the body condition and cub production of Western Hudson Bay (WHB) polar bears has been carried out but none of the results of these mark-recapture studies have been made public.

U Alberta student Mislan bio photos_PolarBearScience

The researchers all claim that WHB polar bears are struggling to survive because of recent sea ice changes but won’t release the 10 years worth of updated information they possess on the bears or the sea ice.

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Barents Sea polar bear status and sea ice declines

So far, I’ve not discussed the Barents Sea subpopulation in very much detail, except in comparison to other groups. For example, the Barents is considered to be the same type of sea ice “ecoregion” as the Chukchi Sea and the Southern Beaufort (discussed here). Previous studies on the Barents Sea polar bear population (Derocher 2005) indicate it may have recovered from extreme levels of overhunting (discussed here) and had stabilized, or was increasing very slowly, as early as 2002 (discussed here) — similar to what has happened in Davis Strait (discussed here).

Figure 1. Polar bear subpopulations, with the Barents Sea region highlighted; map courtesy the IUCN Polar Bear Specialist Group (PBSG), extra labels added.

Figure 1. Polar bear subpopulations, with the Barents Sea region highlighted; map courtesy the IUCN Polar Bear Specialist Group (PBSG), extra labels added.

The most recent Barents Sea population estimate was done in 2004 (2,650; range ~1900-3600), based on an aerial survey (Aars et al. 2009). Aerial surveys are the only practical method of establishing population counts in regions like this where many bears never set foot on land. The previous estimate for the Barents (1982) was “2,000-5,000” but its accuracy was considered “poor” (discussed here).

The IUCN Polar Bear Specialist Group (PBSG), in their most recent report, lists the Barents Sea population as “data deficient” for status, current trend and estimated risk of decline within 10 years (Obbard et al. 2010:62, Table 1) and the “notes” for this entry say:

Population estimate is based on a new aerial survey. There was likely an increase in the subpopulation size after 1973 until recently. Current growth trend is unknown.

This 2004 estimate is now almost a decade old and potentially no longer an accurate representation of what’s happening in the Barents Sea. The most up-to-date information has not yet been published but it is available online. It’s eye-opening to say the least, if only that it appears to be yet another example of a polar bear population that is so far not showing signs of being harmed by sea ice declines, as I’ve discussed before (here).

[Update October 15, 2013: I’ve simplified the text discussion and figure regarding the Aars and Andersen denning study from the original posted]

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Record sea ice loss in 2007 had no effect on polar bears, Chukchi study confirms

One aspect of the recently published study on Chukchi Sea polar bears (Rode et al.2014 [now in print] 2013; see here and here) has not been stressed enough: their finding that the differences in overall condition between bears in the Chukchi and Southern Beaufort Seas came down to disparities in spring feeding opportunities and therefore, the condition of spring sea ice.

The fact that spring — not summer — is the most critical period for polar bears is something I’ve pointed out before (see here and here, for example) but it’s worth repeating at this time of year, when all eyes are on the annual ice minimum. It is often treated as a given that the decline in extent of summer sea ice in the Arctic since 1979 has been detrimental to polar bears. However, this is an assumption that we can now say is not supported by scientific evidence (see summary of that evidence here).

The results published by Rode et al. (2014 2013) not only add further support to the conclusion that declines in summer sea ice have not harmed polar bears, but should put the matter to rest – unless new evidence to the contrary is produced.

Chukchi bears, the report tells us, had more food available in the spring than Southern Beaufort bears (see map below) and this was the primary reason that bears were doing very well in the Chukchi and not quite as well in the Southern Beaufort. And because the polar bears for this study were captured and measured in mid-March to early May, from 2008 to 2011, they reflect spring-time conditions for 2008-2011 as well as year-round conditions from 2007 through 2010.

This means that the annual low ice extent for 2007 (record-breaking at the time), in the fall before this study began, had no discernible negative effect on either Chukchi or Southern Beaufort polar bears – and neither did similarly low annual minimums in two of the three remaining years of the study (Fig 1).

Figure 1. Sea ice extent at August 27, 2007 – the lowest extent that year (downloaded September 15, 2013 from IARC-JAXA, Arctic Sea-ice Monitor). At the time, it was the lowest extent recorded since 1979 (2012 broke that record). This (2007) was the fall before the Rode & Regehr study on Chukchi/Southern Beaufort polar bears began (2008-2011). The ice was almost as low in September 2008 and 2010, while 2009 was more like 2013.

Figure 1. Sea ice extent at August 27, 2007 – the lowest extent that year (downloaded September 15, 2013 from IARC-JAXA, Arctic Sea-ice Monitor). At the time, it was the lowest extent recorded since 1979 (2012 broke that record). This (2007) was the fall before the Rode & Regehr study on Chukchi/Southern Beaufort polar bears began (2008-2011). The ice was almost as low in 2008 and 2010, while 2009 was more like 2013.

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How and why great news about Chukchi polar bears has been suppressed

A new peer-reviewed report (Rode et al. 2014 [in print] 2013, accepted), released last month (announced here), documents the fact that polar bears in the Chukchi Sea are doing better than virtually any other population studied, despite significant losses in summer sea ice over the last two decades – even though the Polar Bear Specialist Group (PBSG) said this population was declining (Obbard et al. 2010).

Rode and Regehr 2010_Chukchi_report2010_Fig1_triplets_labelled

Rather than this good news being shouted far and wide, what we’ve seen so far is a mere whisper. The strategy for suppressing the information appears to have several parts: make it hard to find; don’t actively publicize it; down-play the spectacularly good nature of the news; minimize how wrong they were; keep the focus on the future.

Something similar happened with the newly-published paper on Davis Strait bears (Peacock et al. 2013, discussed here and here) but the news there wasn’t quite so shockingly different from expected. The suppression of good news stands in marked contrast to anything with a hint of bad news, which gets reported around the world — for example, Andrew Derocher and colleagues and their prepare now to save polar bears” policy paper in February, 2013.

US Fish & Wildlife biologist Eric Regehr, co-investigator of the Chukchi study and co-author of the newly-published report, wrote an announcement about the paper. It wasn’t a real press release, since it was not actually sent to media outlets. It was a statement, with a brief summary of the paper, posted on a regional US Fish & Wildlife website, with no mention of lead author Karyn Rode. Not surprisingly, lack of active promotion = no media coverage.

The posted announcement also down-played how well the Chukchi bears are doing. In fact, the news documented in the paper is much better than any of them let on: Chukchi polar bears are doing better than virtually all other populations studied.

But Regehr also had to do some damage control to counter the evidence this paper contains of how wrong they had all been — not only about the Chukchi population today but about their predictions for polar bears in the future.

After all, the computer models used to predict a dire future for polar bears combined the Chukchi Sea with the Southern Beaufort, as having similar ice habitats (“ice ecoregions”). The published paper and Regehr’s statement now say these two regions are very different and that polar bear response to loss of sea ice is “complex” rather than a simple matter of less summer ice = harm to polar bears. Regehr goes on to say that polar bear scientists expected this would happen. I call total BS on this one, which I explain in full later (with a map).

Finally, Regehr’s statement emphasizes that good news for 1 subpopulation out of 19 today should not be celebrated because the overall future for polar bears — prophesied by computerized crystal balls — is bleak. Focus on the future, they say. Did they forget that for years they’ve been telling us that polar bears are already being harmed and that this foreshadows what’s to come? Now we have the results of yet another peer-reviewed study showing bears not being harmed by declines in summer ice (see the full list here).

So, in the end, all of this double-talk and contradiction is not just about suppressing this particular paper. There’s much more at stake.

The Rode et al. Chukchi paper is strong evidence that their predictions of a grim future for polar bears – based on theoretical responses to summer sea ice declines that should already be apparent – have been refuted by their own studies. It’s no wonder they want to keep the media away from this story.

Details below.  [Update September 11, 2013: another news outlet picks up the story, see Point 2 below]

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Good news about Chukchi Sea polar bears whispered by US Fish & Wildlife Service

Just out: the “accepted” version of the Rode et al. paper discussed here last month — detailing just how well polar bears in the Chukchi Sea subpopulation are doing, despite recent declines in sea ice.

However, what was decidedly odd was how I found out about it.

Yesterday (Aug 28), while looking for something else, I found a “press release” tweeted by World Wildlife Fund (WWF) employee Geoff York, who is now also a full voting member of the Polar Bear Specialist Group (PBSG).

Chukchi bears press release tweet_Geoff York Aug 28 2013

The announcement that York tweeted is listed as “alaska.fws.gov/external/newsroom/pdf/cs_polar_bear_article.pdf” and I found a stand-alone copy of the pdf with that title on Google.

However, FWS has so far (Aug. 29, 7:00 am PT) not mentioned this item on their [central] website, their twitter account, or their Facebook page (pdf here, with its original title). The “press release” has no date and is not on FWS letterhead but is authored by “Eric V. Regehr, U.S. Fish & Wildlife Service.” [I guess FWS employees can issue their own press releases?] UPDATE: Found it finally in the “FWS Alaska region” (Alaska FWS, posted Aug. 22, 2013, which included the Eric Regehr summary tweeted by York), via a news report at SitNews dated Aug. 27. Mystery solved]

Also odd that so far, no one except Geoff York himself seems to have picked it up (nothing so far on WWF website or Facebook page, Polar Bears International pages, or at ScienceDaily. [Update: see news report at SitNews dated Aug. 27. Still odd that the FWS report has been sitting there quietly since the 22nd (Thursday of last week)]

Not exactly how I’d choose to spread good news, but perhaps that’s the point.

Nevertheless, not too much new in the paper itself [contact me if you’d like a copy] – no population size estimate, for example – other than what I included in the summary provided last month (based on a March presentation by lead author Karyn Rode), except this: spring litter sizes [1.90 in 2007 and 2.17 in 2009 on Wrangel Island] were “are among the highest reported for 18 of 19 polar bear populations” and were similar to litter sizes 20 years earlier.

I guess the picture of the Chukchi female with a litter of triplet yearling cubs included without mention in the 2010 Rode and Regehr report (pdf here, copied below, discussed previously here) was significant after all.

Rode and Regehr 2010_Chukchi_report2010_Fig1_triplets_labelled

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