Accepted sea otter population estimate at 1911 as inaccurate as rejected polar bear estimate for 1960s

Sea otter specialists, without shame or apology, routinely use a benchmark figure of ‘about 2,000’ for the pre-protection population size of the species at 1911 based on extremely limited evidence yet polar bear specialists refuse to accept a benchmark figure for the 1960s despite the existence of eight published estimates made by experts at the time. Sea otters came much closer to extinction than polar bears did and are not out of the woods yet, for reasons that are not entirely understood (Doroff et al. 2021).

Andrew Derocher, 22 February 2022: ‘There never was a population estimate of global abundance in the 1960s.’

Derocher’s statement and those of his colleagues, discussed at length in The Polar Bear Catastrophe That Never Happened, makes them look biased and unprofessional. There is absolutely no rational scientific justification for holding this stance.

Sea Otter Benchmark Estimate

According to the 2020 assessment of sea otters by the IUCN Sea Otter Specialist Group:

‘The world-wide population of Sea Otters decreased to approximately 2,000 animals by the end of the commercial fur trade in 1911 (Kenyon 1969).’

Actually, nowhere in his monograph does Kenyon state categorically that the number of sea otters remaining at 1911 was ‘about 2,000’. That determination appears to have been made by others, based on records cited by Kenyon (1969: 139), of numbers of otter skins taken by hunters just before and after 1911 date in Alaska, extrapolated across the entire Pacific range of the sea otter.

In other words, there was no range-wide survey of sea otters in the early 1900s or records of any sort from anywhere other than a few isolated locations in Alaska. Yet, the IUCN Sea Otter Specialist Group, without shame or apology, use the figure of ‘about 2,000’ as the benchmark population size for the species at the time protections were put in place in 1911 (Doroff et al. 2021).

Not only that, but sea otter specialists also provide a pre-commercial hunting population size estimate of the species, even though it similarly was ‘just a guess’ based on available evidence (hunting records) that are in no way comparable to modern population surveys:

In the early 1700s, the worldwide population was estimated to be between 150,000 (Kenyon 1969) and 300,000 individuals (Johnson 1982), occurring along the North Pacific from northern Japan to the central Baja Peninsula in Mexico.

No one mocks or insults them for that statement either.

Polar Bear Benchmark Estimate

In my book (Crockford 2019: 101-106), I cited a number of polar bear specialist who had made estimates of polar bear numbers in the 1960s, that included: Harington (1965, Canada), Larsen (1972, Norway), Lentfer (1965, USA), Jonkel (1969, Canada), Brooks (1965, USA), Lønø (1970, Norway), Scott (1959, USA) and Uspenski (1961, Russia). I stated my professional opinion was that a plausible global population size in the 1960s was about 10,000 (range 5,000-15,000), based on the reports and papers these men wrote about how they had come to their decisions, which indicated they had used the best information available at the time. Polar bear specialist Markus Dyck, who died doing polar bear research earlier this year, also used this figure of ‘about 10,000’ as a reasonable estimate for the 1960s.

Scientists attending a polar bear conference in 1965 cited some of the same publications cited above when discussing the global population size at that time (Anonymous 1966).

However, since polar bears became the icon for human-caused global warming, IUCN specialists insist that no legitimate benchmark figure exists (e.g. Amsturp 2012). There has been nothing but derision for anyone who dared to suggest an estimate of the polar bear population size prior to being given protected status in 1973 (e.g. Dykstra 2008; Romm 2007). Anyone who suggests a figure (except for Markus Dyck, who was one of their own), is publicly ridiculed and slandered for speaking out on the topic.

On top of that, PBSG members insist that any of the global population estimates they’ve ever made cannot be used to assess the conservation health of the species (Durner et al. 2018). After 60 years of research and many millions of dollars on surveys of easily accessible regions (where they routinely extrapolate a small subsample to estimate a regional total), they refuse to extrapolate or provide plausible estimates for other regions (like East Greenland and the Laptev Sea in Russia) that have never been surveyed. On the rare occasion that they have done so, they low-ball the estimates to an unbelievable degree (e.g. Hamilton and Derocher 2018).

This is not an inconsequential issue.

How can the public be expected to assess the efficacy of polar bear conservation measures (which many pay for through their taxes) if there is no way of determining whether numbers have increased or decreased over time – yet are expected to accept without challenge the output of computer models that predict a catastrophic future?


Amstrup, S.C. 2012. “The future of polar bears.” Submission to the Association of Zoos and Aquariums, no date.

Anonymous 1966. Polar Bears: Proceedings of the First International Scientific Conference on the Polar Bear, Fairbanks, Alaska, 6-10 September 1965. US Dept. of Interior. 72 pg.

Brooks, J.W. and Lentfer, J. W. 1965. The polar bear: a review of management and research activities in Alaska with recommendations for coordinated international studies. Unpublished report of the Alaska Department of Fish and Game, Juneau. Presented at the First International Meeting of Scientists on Polar Bear, University of Alaska, Sept. 6-11, 1965.

Crockford, S.J. 2019. The Polar Bear Catastrophe That Never Happened. Global Warming Policy Foundation, London. Available in paperback and ebook formats.

Doroff, A., Burdin, A. and Larson, S. 2021. Enhydra lutris. The IUCN Red List of Threatened Species 2021: e.T7750A164576728.

Durner, G.M., Laidre, K.L, and York, G.S. (eds). 2018. Polar Bears: Proceedings of the 18th Working Meeting of the IUCN/SSC Polar Bear Specialist Group, 7–11 June 2016, Anchorage, Alaska. Gland, Switzerland and Cambridge, UK: IUCN.

Dykstra, P. 2008. “Magic number: A sketchy “fact” about polar bears keeps going…and going…and going.” Society of Environmental Journalists News Magazine, Summer (online 15 August).

Hamilton, S. and Derocher, A.E. 2019. Assessment of global polar bear abundance and vulnerability. Animal Conservation 22(1):83-95.

Harington, C.R. 1965. The life and status of the polar bear. Oryx 8: 169-176.

Jonkel, C. 1969. Polar bear research in Canada. Canadian Wildlife Service Progress Notes 13.

Kenyon, K.W. 1969. The sea otter in the eastern Pacific Ocean. Marine Mammal Science 10(4): 492-496.

Larsen, T. 1972. Norwegian polar bear hunt, management  and research.Bears: Their Biology and Management 2: 159-164.

Lentfer, J.W. 1970. Polar bear research and conservation in Alaska, 1968-1969. Pg. 43-66 (Appendix VI), in Anonymous (eds.) Polar Bears: Proceedings of the 2nd Working Meeting of the Polar Bear Specialists Group, IUCN/SSC, 2-4 February 1970, Morges, Switzerland. IUCN Publications New Series, Supplementary paper No. 29. Gland, Switzerland and Cambridge UK, IUCN.

Lønø, O. 1970. The polar bear (Ursus maritimus Phipps) in the Svalbard area. Norsk Polarinstitutt Skrifter 149.

Romm, J. 2007. “On the myth that polar bear populations are flourishing.” Grist, 11 September. [Originally written for a project of the Center for American Progress Action Fund].

Scott, R. F., Kenyon, K. W., Buckley, J. L., and Olsen, S. T., 1959. Status and management of the polar bear and Pacific walrus. Transactions of the Twenty-Fourth North American Wildlife Conference 24: 366–373.

Uspenski, S. M., 1961. Animal Population Estimates in the Soviet Arctic, Priroda No. 8: 33–41. (reprinted in 1962 as Polar Record 71(11): 195–196).

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