In the news today: “Nunavut Draft Plan Says There Are Actually Too Many Polar Bears In Territory” (CTV News via The Canadian Press, Bob Weber, 12 November 2018).

From the Canadian Press story:

“There are too many polar bears in parts of Nunavut and climate change hasn’t yet affected any of them, says a draft management plan from the territorial government that contradicts much of conventional scientific thinking. The proposed plan — which is to go to public hearings in Iqaluit on Tuesday — says that growing bear numbers are increasingly jeopardizing public safety and it’s time Inuit knowledge drove management policy. “Inuit believe there are now so many bears that public safety has become a major concern,” says the document, the result of four years of study and public consultation.”

I’ve noted previously that there were two fatal polar bear attacks in Hudson Bay this summer. Both of them happened outside local communities and both happened early during the ice-free period (when bears would have been onshore for only a few weeks). Neither incident can be reasonably blamed on lack of sea ice, an extended ice-free period, or lack of management of problem polar bears within or near communities. The bears involved in the August attack were described as being in good condition.

Update 13 November 2018: See The Guardian‘s take on this story, by a different writer. Despite potential to talk to other polar bear specialists about this issue, only Derocher is quoted. Is no one else talking? “Polar bear numbers in Canadian Arctic pose threat to Inuit, controversial report says” (The Guardian, 13 November 2018).

Update 14 November 2018: See a new CBC story on Inuit perspectives on this issue. “Nunavut community says Inuit lives need to be protected over polar bear population” (CBC News, 14 November 2018).

“Although there is growing scientific evidence linking the impacts of climate change to reduced body condition of bears and projections of population declines, no declines have currently been attributed to climate change,” it says. “(Inuit knowledge) acknowledges that polar bears are exposed to the effects of climate change, but suggests that they are adaptable.” Environment Canada’s response says that’s “not in alignment with scientific evidence.” It cites two studies suggesting the opposite. Andrew Derocher, a University of Alberta polar bear expert, is blunter.

“That’s just plain wrong,” he said. “That’s been documented in many places now — not just linked to body condition but reproductive rates and survival.”

“Just plain wrong.” Bold statement not supported by evidence.

In fact, Derocher and his colleagues document a correlation between some sea ice changes and body condition declines but that does not prove that the sea ice changes are to blame (Crockford 2017, 2018). And in other areas, such as the Svalbard region of the Barents Sea, there is no correlation between the massive sea ice declines and body condition, reproductive rates or population declines (Aars et al. 2017). See data up to 2018 for condition of adult male polar bear captured around Svalbard:

In the Chukchi Sea, bears are in great condition and reproducing well despite very low summer sea ice levels since 2007 (Crawford et al. 2015; Crawford and Quackenbush 2013; Rode and Regehr 2010; Regehr et al. 2010, Rode et al. 2014, 2015, 2018), and a recent count (2016) indicates a thriving population.

That’s not what the predictions said would happen, which means the evidence Derocher refers to is not only circumstantial, it’s also contradictory (not all bears show the same response to low summer ice). In addition, much of the evidence Derocher claims exist for Western Hudson Bay bears has been collected by him but not published and he has never explained why he has not done so.

The news piece continues with more commentary from Derocher regarding attacks on people and other bear-human problems:

The management plan doesn’t propose to increase hunting quotas immediately. It contains provisions for increased education and programs on bear safety for hunters and communities. It does say hunting bans would no longer be automatically applied to shrinking populations and that “management objectives … could include managing polar bears for a decrease.” Derocher doesn’t dispute potentially dangerous bear-human encounters are becoming more frequent. But he, and other southern scientists, insist that’s happening as climate change reduces sea ice and drives bears inland. “They will move into communities seeking food. There’s lots of attractants around northern communities.” Places where attacks have occurred are not areas with the highest bear densities, he said. The plan reflects Nunavut’s desire to control its own wildlife resources, Derocher suggested. “They don’t ask for input from southern scientists. The less input from the south is where it seems to be moving.” Derocher said the Inuit’s ability to export polar bear hides — or the ability of their hunter clients to take such items home with them — depends on whether the rest of the world trusts the animals are being well-managed. “If the stated goal is to have fewer polar bears, that may be the tripping point whereby polar bear management in Canada comes under renewed scrutiny.”

Read the rest here (also here). Nunavut (red) map below (Churchill is south of the Nunavut border along the western shore of Hudson Bay, in the province of Manitoba):

As noted above, neither of the two fatal attacks this summer took place within or near Nunavut communities: they took place in areas where local residents go to hunt, fish, and collect eggs. In other words, there are naturally-occurring attractants on the Nunavut landscape that draw polar bears and people to the same locations. If there are indeed more bears now than there were 30 years ago, as seems very likely, this puts Nunavut residents at risk while they go about their subsistence lifestyle.

Attractants in communities are another issue and improvements are definitely needed. But as I recently pointed out, Churchill had serious polar bear problems in the 1960s and 70s (Kearney 1989; Stirling et al. 1977) but it took years of money and effort for the community to gain an upper hand on the situation.

Also, for the second year in a row, freeze-up along Western Hudson Bay (WH) has been earlier than average: sea ice conditions have not gotten worse over the last few years.

With respect to polar bear numbers in the regions where the fatal attacks took place (WH and Foxe Basin), researchers always seem to quote the average of a range of estimates without emphasizing that the upper end of that range is as likely to be correct as the average or the lower end of the range. An aerial survey of the entire WH region in 2011 generated a count of 1030 bears (range 754-1406), which is still the official estimate (since other surveys did not cover the entire region). If the upper end of the 2011 estimate (1406) reflects the true population size, it would be a substantial increase over the 794-1076 bears (avearge 935) estimated to have existed in 2004 (Regehr et al. 2007).

The science of polar bear counts in WH is complicated by differences in methodology between survey years, statistically insignificant differences, and wide confidence limits: it is not as straightforward as Derocher and others make it out to be. Foxe Basin was last surveyed in 2010: the population count (2100-3200, average 2580) was similar to the previous count (Stapleton et al. 2016), although methods were different. Foxe Basin bears there were found to be doing so well that some of the heaviest polar bears in the Arctic were found there. Although the population is currently considered ‘stable’ it is entirely possible that actual numbers in that region are now close to the upper end of the 2014 estimated range (i.e. 3200) even though this would not count as an ‘increase.’

References

Aars, J., Marques,T.A, Lone, K., Anderson, M., Wiig, Ø., Fløystad, I.M.B., Hagen, S.B. and Buckland, S.T. 2017. The number and distribution of polar bears in the western Barents Sea. Polar Research 36:1. 1374125. doi:10.1080/17518369.2017.1374125

Crawford, J. & Quakenbush, L. 2013. Ringed seals and climate change: early predictions versus recent observations in Alaska. Presentation by Justin Crawfort, 28th Lowell Wakefield Fisheries Symposium, March 26–29, Anchorage, AK. Available online http://seagrant.uaf.edu/conferences/2013/wakefield-arctic-ecosystems/program.php [accessed June 7, 2013].

Crawford, J.A., Quakenbush, L.T. & Citta, J.J. 2015. A comparison of ringed and bearded seal diet, condition and productivity between historical (1975–1984) and recent (2003–2012) periods in the Alaskan Bering and Chukchi seas. Progress in Oceanography 136:133-150.

Crockford, S.J. 2017. Testing the hypothesis that routine sea ice coverage of 3-5 mkm2 results in a greater than 30% decline in population size of polar bears (Ursus maritimus). PeerJ Preprints 2 March 2017. Doi: 10.7287/peerj.preprints.2737v3 Open access. https://doi.org/10.7287/peerj.preprints.2737v3

Crockford, S.J. 2018. State of the Polar Bear Report 2017. Global Warming Policy Foundation Report #29. London. pdf here.

Kearney, S.R., 1989. The Polar Bear Alert Program at Churchill, Manitoba. In: Bromely, M. (Ed.), Bear–People Conflict: Proceedings of a Symposium on Management Strategies, Yellowknife, Northwest Territories Department of Renewable Resources, pp. 83–92. [courtesy M. Dyck, Gov’t of Nunavut] Pdf here.

Peacock, E., Taylor, M.K., Laake, J. & Stirling, I. 2013. Population ecology of polar bears in Davis Strait, Canada and Greenland. Journal of Wildlife Management 77:463–476.

Regehr, E.V., Laidre, K.L, Akçakaya, H.R., Amstrup, S.C., Atwood, T.C., Lunn, N.J., Obbard, M., Stern, H., Thiemann, G.W., & Wiig, Ø. 2016. Conservation status of polar bears (Ursus maritimus) in relation to projected sea-ice declines. Biology Letters 12: 20160556. http://rsbl.royalsocietypublishing.org/content/12/12/20160556

Rode, K. and Regehr, E.V. 2010. Polar bear research in the Chukchi and Bering Seas: A synopsis of 2010 field work. Unpublished report to the US Fish and Wildlife Service, Department of the Interior, Anchorage. pdf here.

Rode, K.D., Douglas, D., Durner, G., Derocher, A.E., Thiemann, G.W., and Budge, S. 2013. Variation in the response of an Arctic top predator experiencing habitat loss: feeding and reproductive ecology of two polar bear populations. Oral presentation by Karyn Rode, 28th Lowell Wakefield Fisheries Symposium, March 26-29. Anchorage, AK.

Rode, K.D., Regehr, E.V., Douglas, D., Durner, G., Derocher, A.E., Thiemann, G.W., and Budge, S. 2014. Variation in the response of an Arctic top predator experiencing habitat loss: feeding and reproductive ecology of two polar bear populations. Global Change Biology 20(1):76-88. http://onlinelibrary.wiley.com/doi/10.1111/gcb.12339/abstract

Rode, K. D., R. R. Wilson, D. C. Douglas, V. Muhlenbruch, T.C. Atwood, E. V. Regehr, E.S. Richardson, N.W. Pilfold, A.E. Derocher, G.M Durner, I. Stirling, S.C. Amstrup, M. S. Martin, A.M. Pagano, and K. Simac. 2018. Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity. Global Change Biology http://onlinelibrary.wiley.com/doi/10.1111/gcb.13933/full

Rode, K.D., Wilson, R.R., Regehr, E.V., St. Martin, M., Douglas, D.C. & Olson, J. 2015. Increased land use by Chukchi Sea polar bears in relation to changing sea ice conditions. PLoS One 10 e0142213.

Stapleton S., Atkinson, S., Hedman, D., and Garshelis, D. 2014. Revisiting Western Hudson Bay: using aerial surveys to update polar bear abundance in a sentinel population. Biological Conservation 170: 38-47. http://www.sciencedirect.com/science/article/pii/S0006320713004618#

Stapleton, S., Peacock, E. & Garshelis, D. 2016. Aerial surveys suggest long-term stability in the seasonally ice-free Foxe Basin (Nunavut) polar bear population. Marine Mammal Science 32:181-201.

Stirling I, Jonkel C, Smith P, Robertson R, Cross D. 1977. The ecology of the polar bear (Ursus maritimus) along the western coast of Hudson Bay. Canadian Wildlife Service Occasional Paper No. 33. pdf here.

Regehr, E.V., Lunn, N.J., Amstrup, S.C. and Stirling, I. 2007. Effects of earlier sea ice breakup on survival and population size of polar bears in Western Hudson Bay. Journal of Wildlife Management 71:2673-2683.