USGS biologists were clearly busy this spring putting more satellite radio collars and glue-on tags on Southern Beaufort Sea polar bears but there’s some surprising information in their April 2015 tracking map about current sea ice conditions.
From the 2013-2014 issue of “Polar Bear News” (USFWS).
What’s interesting is that the sea ice maps they use show less dark spots that might be open water this year than were present last year in late April. Oddly, this phenomenon has one prominent biologist worried about “challenging” polar bear habitat developing this year – without mentioning last year at all.
The USGS track map for April 2015 is copied below.1
Posted in Life History, Sea ice habitat
Tagged Beaufort Sea, Chukchi Sea, Eastern Beaufort, habitat, ice maps, melt ponds, polar bear movements, polar bears, satellite collars, satellite images, sea ice, Southern Beaufort, tracking polar bears, USGS
The trouble is, sea ice researchers and atmospheric scientists have not drawn that conclusion, despite what a new paper by Pilfold and colleagues imply. It shows just what lengths desperate IUCN Polar Bear Specialist Group (PBSG) biologists will go to in order to link the recent decline of Southern Beaufort bear numbers to global warming while ignoring similar past declines.
Posted in Advocacy, Life History, Sea ice habitat
Tagged Beaufort Sea, climate change, Derocher, Eastern Beaufort, extinction, feeding, future, global warming, IUCN Polar Bear Specialist Group, models, Pilfold, polar bear, population, predation, predictions, Red list, ringed seals, Southern Beaufort, Stirling, thick spring ice, threatened
This week, Arctic sea ice in Canada, where 2/3 of the world’s polar bears live, had more sea ice than was present in the early 1970s. Globally, the ice is spitting-distance close to the 1981-2010 average calculated by the NSIDC for this date – which means lots of winter/spring hunting habitat for polar bears.
This is the peak of the polar bear birthing season (both in the wild and in zoos.) Newborns will be snug in maternity dens built by their mothers onshore or on the sea ice; the rest of the population will be out on the ice.
Regional ice charts going back to the late 1960s and early 1970s for this week show even more surprises — have a look.
Posted in Sea ice habitat
Tagged baffin bay, Davis Strait, Eastern Beaufort, Eastern Canada, Hudson Bay, ice extent, polar bear, polar bear habitat, polar bears in winter, sea ice, Southern Beaufort, Western Arctic
Poor polar bear researchers: there are few full time jobs worldwide and research is underfunded.
This is not my opinion but the facts according to Andrew Derocher and Ian Stirling (2011) — see Fig. 1 and 2 below. I do not dispute them.
Figure 1. The distribution of full-time polar bear researchers worldwide. From Derocher and Stirling 2011, invited speaker presentation to the 2011 Polar Bear Meeting in Nunavut, Oct 24-26.
Since Derocher and Stirling have raised the issue, I contend it’s perfectly valid to ask: are polar bear biologists who proclaim their heartfelt fear for the future of polar bears at every opportunity behaving as advocates for polar bears or protecting their own careers?
Posted in Advocacy, Conservation Status
Tagged 2011 polar bear meeting Nunavut, Circumpolar Action Plan for Polar Bear Conservation, conflict of interest, conservation, COSEWIC, Derocher, Eastern Beaufort, expert testimony, government jobs, grant funding, helicopter survey, jobs, oil money, polar bear research, Southern Beaufort, Stirling, western hudson bay
Here’s the ground-truth follow-up to my suggestion of what polar bear habitat would likely look like 6 weeks after the minimum extent was reached this year – which was looking then like it would mirror 2009.
You’ll find my discussion, posted on September 22, here. At that point (September 13), ice extent was 5.1 million square kilometers; now it is 9.1 million square kilometers (Fig.1).
Have a look at the maps below: Fig. 2 to see how ice extent at October 31st compares to ice extent at the end of October 2009, and Fig. 3 to see what ice concentrations looked like in the Canadian Arctic.
Posted in Life History, Sea ice habitat
Tagged Beaufort, Canadian Ice Service, Chukchi, Eastern Beaufort, Ferguson, grey-white ice, Hudson Bay, polar bear, sea ice extent, summer ice minimum, young ice
Here is the follow-up to my post on the July track map for 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 track map for September was posted on the USGS website on October 17 (delayed due to the US government shutdown) and is copied here below (Figure 1). The ice rebounded during the second half of the month (after the annual minimum was reached on September 13). The ten bears from July were down to eight – their collars might have stopped working or fallen off (most likely), they might have left the area entirely (also possible) or they might have died (the researchers don’t say which).
Figure 1. Original caption: “Movements of 8 satellite-tagged polar bears for the month of September, 2013. Polar bears were tagged in 2013 on the spring-time sea ice of the southern Beaufort Sea. All 8 of these bears have satellite collar transmitters [i.e., all are females]. Polar bear satellite telemetry data are shown with Ice Analysis charts from 26 August, 2013. Ice Analysis charts are made available by the National Ice Center. The land cover is made available by Natural Earth. Click on the above image to enlarge.” [Note that the dots with the polar bear icons are the end points (end September), while the other end of the string is their position in early September, indicating that the ice is now moving towards the shore. The pink dot present in August is almost entirely obscured by the purple dot, which is overlapping the yellow dot on shore in Alaska; also, the light brown dot is on Banks Island, far right.]
It appears that of the eight polar bears still being followed by USGS researchers in September, four are on shore and four are still on the ice.
Only time will tell if the four females on shore are pregnant and preparing maternity dens for the winter, but this seems the likely reason they are not on the ice with the others.
One very interesting point worth noting:
the one bear (light brown) captured onshore in the Southern Beaufort
subpopulation region in the spring of 2013
, has moved into the Northern Beaufort
subpopulation region, on Banks Island (see map here
), and may be denning there. This inter-subpopulation movement is relatively uncommon.
The map for July 2013 is below, for comparison: Continue reading
Posted in Life History, Sea ice habitat
Tagged Beaufort Sea, denning females, Eastern Beaufort, females with radio collars, habitat, Northern Beaufort, polar bears, sea ice extent, Southern Beaufort, summer ice minimum, summer sea ice, tracking polar bears, tracking polar bears by satellite, USGS
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).
Posted in Conservation Status, Life History, Sea ice habitat
Tagged annual summer minimum, arctic sea ice, Beaufort Sea, body condition, Cherry, Chukchi, declining sea ice, Eastern Beaufort, good news, heavy sea ice, Hudson Bay, ice-free Arctic, litter size, loss of summer ice, Pilfold, polar bear, record low, Regehr, ringed seals, Rode, sea ice extent, Southern Beaufort, Stirling, summer ice minimum, summer sea ice, thick spring ice