Posted onOctober 26, 2021|Comments Off on Caught on film: polar bear stalks, kills and eats a Svalbard reindeer but climate change is hardly to blame
The possibility that a polar bear somewhere in the Arctic might occassionally be successful at stalking and killing a reindeer (aka caribou) shouldn’t surprise anyone, let alone a biologist on Svalbard. But having video footage of the event makes it immediately newsworthy, especially when the researchers vaguely suggest that global warming might be to blame.
The title of the scientific paper that has generated the latest polar bear hype is called ‘Yes, they can: polar bears Ursus maritimus successfully hunt Svalbard reindeer Rangifer tarandus platyrhynchus’ (Stempnlewicz et al. 2021).
Would any serious scientist really think they couldn’t?
Posted onOctober 20, 2021|Comments Off on Most Chukchi Sea ice in 20 years means no walrus feasts for polar bears at famous Russian cliffs
After years of hype, including documentary over-reach by David Attenborough and his collaborators at WWF and Netflix, there has been relatively abundant ice in the Chukchi Sea this summer, particulary along the Russian coast and around Wrangel Island, which in recent years have been important summer refuge areas for polar bears and Pacific walrus.
Walrus carcasses at the base of the cliff at Cape Schmidt, September 2017. Credit: Y. Basov.
This year, there has been nothing like the complete retreat of ice into the Arctic Basin as happened in 2007, 2012, and 2020. The chart below shows the ice extent at 11 October 2021:
Wrangel Island was surrounded by ice in 2000 and 2001, which made access to walrus haulouts on the island impossible (Kochnev 2004). Most of the walrus haulouts along the Chukotka coast were also ice-covered in September in those years, as were all of the western locations in 2021 – as the ice charts below show. The extra ice will have drastically affected the distribution of walrus this year, which in turn will have meant no walrus carcasses for polar bears to feast on as they have done for many years now.
Posted onOctober 15, 2021|Comments Off on No signs of a climate emergency for W. Hudson Bay polar bears this year ahead of UN climate meeting
I’ve been told that another complete aerial survey of the Western Hudson Bay polar bear subpopulation (from the Nunavut to Ontario boundaries) was conducted in August this year and that the bears have been hanging out further south than usual. It will be years before the results of the population count are published, of course (especially if it’s good news) but my contacts also say virtually all of the bears are in great condition again this year.
Posted onOctober 8, 2021|Comments Off on Churchill problem polar bear reports finally completed and posted online
Although since 2015 at least the Polar Bear Alert Program in Churchill Manitoba usually issued and published its problem bear reports weekly during the ice-free season, this year has been an odd exception. Two reports in early July, then nothing. Yesterday, there was a dump of reports that had been compiled on 1 September and 7 October, according to their metadata.
There are still a few weeks missing, including the two most recent weeks but at least now we have a more complete picture of what’s been going on with problem bears in The Polar Bear Capital of the World that can be compared to previous years. Such reports in various forms go back to the late 1960s, although only those from recent years have been publicly available (Kearney 1989; Towns et al. 2009).
Posted onOctober 7, 2021|Comments Off on Alaska polar bear researchers claim poor sea ice limited spring field work in 2021 more than 2019
According to an Inside Climate Newsreport, polar bear researchers at the US Geological Survey had trouble darting bears in the Southern Beaufort Sea in March-May of 2019 and 2021. They claim their research program was hampered by thinner-than-necessary ice for safely landing the nearly 4,000 lb. outfitted helicopter (with crew and gear) in 2019 but that conditions in 2021 were even worse (it is implied work proceeded in 2020 despite pandemic restrictions but no data for that year are discussed).
However, this claim of worse conditions in 2021 is not corroborated by reports from sea ice experts and ice charts for the Southern Beaufort this spring, where thick first year and multiyear ice was present from March through June. Ice didn’t begin to pull away from landfast ice to form patches of open water near the Canadian border until late April 2021 compared to early May in 2019 (as it did in 2016), as shown in the video and charts below. Moreover, the researchers oddly fail to mention that the presence of thin ice and open water in spring is essential for polar bear survival in the Southern Beaufort, a fact which has been documented and discussed in the scientific literature by their colleagues.
Posted onSeptember 30, 2021|Comments Off on Sea ice growth after the summer minimum begins in the Canadian Arctic Archipelago
The Arctic sea ice minimum was declared to have been reached on 16 September this year (4.72 mkm2), breaking no records.
Ice extent can only go up from this point forward but at this time of year, it happens slowly and isn’t noticeable in the Arctic Basin as much as it is in the Canadian Arctic Archipelago. As I wrote about last year, new ice development in the fall next to shore creates upwelling conditions that attract fish and seals, and therefore provides feeding opportunities for polar bears.
The same process likely happens when new ice forms next to old ice. These few weeks of developing sea ice, wherever they occur, are the last chance polar bears have to replace weight lost over the summer before the cold and darkness of winter reduces hunting opportunities to virtually nil.
Posted onSeptember 27, 2021|Comments Off on Fat polar bear of late summer in Arctic Canada
Retired Mountie and bird photographer Clare Kines captured on film one of those ‘canaries of in the coal mine’ of the Canadian Arctic we hear so much about. Kines is from Arctic Bay and took the photo a few weeks ago, on 9 September, on the north end of Baffin Island (just east of where the famous National Geographic‘starving’ bear was filmed in 2017). His photo was published 14 September by Nunatsiaq News.
Posted onSeptember 21, 2021|Comments Off on Wrangel Island research team counted a record number of Chukchi Sea polar bears in 2020
Many Chukchi Sea polar bears spend the summer on Wrangel Island and a survey there conducted by Russian researchers in 2020 reportedly collected data on a record 747 bears, well up from the 589 reportedly counted in 2017 by the same team (photo below is from 2015).
Note the latest survey of the Chukchi Sea estimated about 3,000 bears inhabit the region (AC SWG 2018; Regehr et al. 2018), at least 1,000 more that the figure of 2,000 used in recent IUCN assessments and survival predictions (Amstrup et al. 2007; Regehr et al. 2016; Wiig et al. 2015). Wrangel Island is the primary terrestrial denning area in the Chukchi Sea (Garner et al. 1984; Rode et al. 2014) and a recently published study showed that the body condition (i.e. fatness) and litter size of Chukchi Sea polar bears has not been negatively affected by low summer sea ice (Rode et al. 2021).
Posted onSeptember 15, 2021|Comments Off on Still waiting for two thirds of polar bears worldwide to disappear due to lack of summer sea ice
It’s hard to believe that a polar bear specialist would claim that their predictions have come true, given the facts of the matter: that polar bears arguably number over 30,000 worldwide and regions with the most dramatic sea ice declines have not documented reduced polar bear health or survival. But in mid-July this year, Andrew Derocher – one of the field’s most vocal promoters – did just that: proclaimed on twitter that “virtually all of our predictions are coming true.” Except, none of them did, especially the most widely-promoted one, which failed spectacularly.
Posted onSeptember 8, 2021|Comments Off on Svalbard polar bear paper falsely assumes that loss of genetic diversity has negative consequences
A new paper published today deals with an animal conservation issue I’ve addressed twice before: the theoretical assumption that loss of genetic diversity must be detrimental to species survival despite there being little evidence that this has been the case in real life. For this new study, the authors carried out some complicated measuring of genetic diversity loss and inbreeding amongst and between Svalbard region polar bear populations between 1995 and 2016 (see map below), and then modelled what this could lead to in 100 generations (1210 years), with the over-anxious hand-wringing we’ve all come to expect from such prophesies. As far as I can see, it’s all meaningless number-crunching without relevance to the real world of polar bears.
To support their claim of harm from loss of genetic diversity, the authors of this paper (Maduna et al. 2021) cite four theoretical papers that assume as fact that loss of genetic diversity is harmful but not the evidence to back up the claim. They apparently never bothered to look at species that have actually suffered dramatic loss of genetic diversity. Northern elephant seals, for example, reduced to 20-30 animals more than 100 years ago, have rebounded to a population of about 170,000 with extremely low genetic diversity but no apparent health or survival repercussions. Similar genetic bottlenecks and recoveries have been documented in Guadalupe fur seals, San Nicolas Island foxes, mouflon sheep, and North Atlantic right whales (among others), which I discussed in detail here (with references). I discussed the issue again in regards to a similar polar bear ‘genetic diversity’ paper in 2016.
Conspicuous by its absence in this new publication is a citation of the recent paper that revealed the body condition of female Svalbard polar bears had increasedsignificantlybetween 2004 and 2017 despite a pronounced decline in summer and winter sea ice extent (Lippold et al. 2019: 988). Nor did the paper cite data collected by the Norwegian Polar Institute that show the body condition of adult males in Svalbard has not changed since 1993 or that population numbers have not declined. Instead, the authors mention only that reduced numbers of pregnant females have reached traditional denning areas due to lack of ice and that bears have spent less time feeding at glacier fronts than they used to do (Maduna et al. 2021: 2), as if the only polar bear data available in relation to sea ice decline was negative.
Figure 1 from Maduna et al. 2021
Population bottlenecks during the Last Glacial Maximum when suitable habitat was scarce and another in the late 1800s/early 1900s due to wanton overhunting left polar bears with remarkably low genetic diversity but no apparent ill-effects to their overall heath. Oddly, this recent work by Maduna and colleagues assumes without evidence that a bit less genetic diversity could be devastating to Svalbard bears more than 1000 years from now. While the media expectedly promote this as scary new evidence of what climate change has wrought (here and here), I am not impressed.
This is conservation biology done WWF-style: loss of genetic diversity sounds bad to people who don’t know better, but real-world evidence shows it isn’t.
References
Lippold, A., Bourgeon, S., Aars, J., Andersen, M., Polder, A., Lyche, J.L., Bytingsvik, J., Jenssen, B.M., Derocher, A.E., Welker, J.M. and Routti, H. 2019. Temporal trends of persistent organic pollutants in Barents Sea polar bears (Ursus maritimus) in relation to changes in feeding habits and body condition. Environmental Science and Technology 53(2):984-995. https://pubs.acs.org/doi/10.1021/acs.est.8b05416
Maduna, S. N., Aars, J., Fløystad, I., Klütsch, C. F. C., Zeyl Fiskebeck, E. M. L., Wiig, Ø. et al. 2021. Sea ice reduction drives genetic differentiation among Barents Sea polar bears. Proceedings of the Royals Society B 288 (1958): 20211741. https://doi.org/10.1098/rspb.2021.1741 OPEN ACCESS
Comments Off on Svalbard polar bear paper falsely assumes that loss of genetic diversity has negative consequences
Watch polar bear habitat reform in the Canadian Arctic: “last 10 days” Canadian Ice Service animation (works anytime) HERE.
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