W. Hudson Bay polar bear numbers declined 27% in 2021 but not because of missing ice: secret paper

As will become apparent tomorrow, Western Hudson Bay polar bear numbers apparently declined 27% between 2017 and 2021 but not because of sea ice loss. This fact, gleaned from a secret government report leaked to the media, emerged just before Christmas last year and spread around the world. I commented on it here at the time.

It will also be apparent tomorrow why that government report is still unavailable. Thursdays are when the big two science magazines publish their papers, which means associated news stores promoting preferred narratives are embargoed until then. Stay tuned.

Thanks to a less-than-newsworthy paper waiting to be published in Arctic Science by one of Andrew Derocher’s many students, I now have the title of this secret government report:

Atkinson, S., Boulanger, N.J., Campbell, M., Trim, V., Ware, J. and Roberto-Charron, A. 2022. Aerial survey of the Western Hudson Bay polar bear subpopulation 2021. Final Report, Igloolik, NU.

Not surprisingly, all of the news stories reporting on this report stated or implied a strong association between this purported population decline and lack of sea ice due to ‘climate change’. However, sea ice conditions have been particularly good over the last five years – for both freeze-up and breakup dates – calling into question how ‘lack of sea ice’ could possibly be blamed for the apparent decline.

A Reuters story (dated 23 December 2022) admitted this was the case and included another critical caveat that only one news outlet I saw bothered to mention, which happened to be BBC News:

Scientists cautioned a direct link between the population decline and sea ice loss in Hudson Bay wasn’t yet clear, as four of the past five years have seen moderately good ice conditions. Instead, they said, climate-caused changes in the local seal population might be driving bear numbers down.

As I pointed out in a previous post regarding conditions during the period of the Atkinson study:

The purported 27% population decline between 2017 and September 2021 would have required a large number of bears to have died very quickly of starvation over the spring of 2021, even though they were in good shape beforehand. That premise is hard to swallow without some kind of corroborating evidence.

That leads to any even bigger question. How does a population of polar bears supposedly decline by 40% over 10 years – from about 1030 in 2011 to about 618 in 2021 – without significant numbers of bears in poor or very poor condition being documented in the years immediately before the counts were done, especially for the most-studied – and probably the most photographed – subpopulation in the world?

Where are all the studies reporting starving and dying bears, as happened when bears were starving in the 1980s in Western Hudson Bay (Calvert et al. 1986; Derocher and Stirling 1992, 1995; Ramsay and Stirling 1988; Stirling et al. 1980)?

Apparently, as of this day in 2023, those reports are nowhere to be found.

References

Calvert, W., Stirling, I., Schweinsburg, R.E., Lee, L.J., Kolenosky, G.B., Shoesmith, M., Smith, B., Crete, M. and Luttich, S. 1986. Polar bear management in Canada 1982-84. In: Polar Bears: Proceedings of the 9th meeting of the Polar Bear Specialists Group IUCN/SSC, 9-11 August, 1985, Edmonton, Canada. Anonymous (eds). Gland, Switzerland and Cambridge UK, IUCN. pg. 19-34.

Derocher, A.E. and Stirling, I. 1992. The population dynamics of polar bears in western Hudson Bay. pg. 1150-1159 in D. R. McCullough and R. H. Barrett, eds. Wildlife 2001: Populations. Elsevier Sci. Publ., London, U.K. See abstract below:

Abstract: Reproductive output of polar bears in western Hudson Bay declined through the 1980’s from higher levels in the 1960’s and 1970’s. Age of first reproduction increased slightly and the rate of litter production declined from 0.45 to 0.35 litters/female/year over the study, indicating that the reproductive interval had increased. Recruitment of cubs to autumn decreased from 0.71 to 0.53 cubs/female/year. Cub mortality increased from the early to late 1980’s. Litter size did not show any significant trend or significant annual variation due to an increase in loss of the whole litter. Mean body weights of females with cubs in the spring and autumn declined significantly. Weights of cubs in the spring did not decline, although weights of both female and male cubs declined over the study. The population is approximately 60% female, possibly due to the sex-biased harvest. Although estimates of population size are not available from the whole period over which we have weight and reproductive data, the changes in reproduction, weight, and cub mortality are consistent with the predictions of a densitydependent response to increasing population size. [my bold]

Derocher, A.E. and Stirling, I. 1995. Temporal variation in reproduction and body mass of polar bears in western Hudson Bay. Canadian Journal of Zoology73:1657-1665. http://www.nrcresearchpress.com/doi/abs/10.1139/z95-197

Ramsay, M.A. and Stirling, I. 1988. Reproductive biology and ecology of female polar bears (Ursus maritimus). Journal of Zoology London 214:601-624. http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.1988.tb03762.x/abstract

Stirling, I., Schweinsburg, R.E., Kolenasky, G.B., Juniper, I., Robertson, R.J., and Luttich, S. 1980. Proceedings of the 7th meeting of the Polar Bear Specialists Group IUCN/SSC, 30 January-1 February, 1979, Copenhagen, Denmark. Gland, Switzerland and Cambridge UK, IUCN., pg. 45-53.http://pbsg.npolar.no/en/meetings/ pdf of except here.