Many otherwise intelligent people believe only a few hundred polar bears remain

The other day, I got a call from an international journalist who admitted he’d done no research into the polar bear issue but believed, based on media reports he’d heard, that there must only be about 100-200 bears remaining in the Arctic. I know he’s not alone.

polar-bears-3-large_USGS

This journalist was utterly astonished to learn that the IUCN Red List assessment in 2015 put the polar bear population total at 22,000-31,000 bears and demanded proof that this was true.

Here is a summary of the Red List report, with references and links to the report:

The 2015 IUCN Red List assessment update for polar bears (published 18 November 2015) states that the global polar bear population is 22,000 – 31,000 (26,000), that the current trend is ‘unknown’ and that there is only a 70% chance that polar bear numbers will decline by 30% in 35 years (with virtually zero chance that the numbers will decline by 80% or more by 2050) – in other words, zero chance of extinction. [Detailed in a document called 22823 Ursus maritimus]. It classifies the polar bear as ‘vulnerable’ to extinction based on predictions of future sea ice decline due to global warming [similar to ‘threatened’ by other organizations] Pdf here.

Below is a list of what truly worrying species declines look like: that is, animals whose numbers have actually declined, no prophesies involved (Adler 2008).

Some truly troubling population declines

Here I offer some perspective on the issue of what constitutes a truly “startling” population decline. Below are some actual population numbers that have been documented for marine mammals classified as “endangered” or “vulnerable”– these are actual declines, not “projections” or “predictions.” The cause of many of the declines is over-hunting but others have not yet been explained (Steller sea lion western stock; NE Atlantic hooded seal).

Steller sea lion (Eumetopias jubatus), western stock (Aleutians to northern Gulf of Alaska, declared endangered by the ESA in 1993): declined to approximately 18,000 individuals in 2000, from about 140,000 in the 1950s, an 87% reduction (NMFS 2008) due to unknown or unconfirmed causes.

Hooded seal (Cystophora cristata) is considered ‘vulnerable’ by the IUCN due to actual population declines (85-90 % over the last 40-60 years) in the Northeast Atlantic (off East Greenland) that are so far unexplained. Populations in the Northwest Atlantic, however, are stable or increasing, which is probably why you never hear of this.

According to Norwegian authorities:

“In the most recent two decades [from 2007], the stock appeared to have stabilized at a low level of approximately 71 thousand. This may be only 10-15% of the level observed 60 years ago. …However, results from a Norwegian aerial survey in 2007 suggested that current pup production (15 thousand) was lower than observed in a comparable 1997 survey (24 thousand). Scientists believe that the populations decline is due to mass mortality caused by PDV (occurring among seal in the Northeast Atlantic) or Brucella (occurring in Jan Mayen hooded seals). However, there are yet no observations of carcasses or diseased animals to support this hypothesis. [my bold]

Gray whale (Eschrichtius robustus): declined to approximately 200-300 individuals by 1938 after decades of over-hunting, recovered to 21,113 by 1987/88. Pre-decline numbers unknown. (Clapham et al. 1999:47).

Sea otter (Enhydra lutris): declined to less than 2,000 individuals by 1911 after many decades of over-hunting, recovered to approximately 100,000 by the mid-1980s. Since then, the population in SW Alaska (northern Gulf of Alaska and the Aleutians) had a second overall decline of 55-67%, with some local declines of over 90% (Sea Otter Recover Team 2007:6; USFWS 2005).

Northern elephant seal (Mirounga angustirostris): declined to approximately 20-100 individuals by 1900 after decades of over-hunting, recovered to approximately 175,000 by 2000. Pre-decline numbers unknown (Weber et al 2000:1287).

Guadalupe fur seal (Arctocephalus townsendi): declined to approximately 60 individuals by 1928 after decades of over-hunting, recovered to 12,176 by 2003. Pre-decline numbers unknown (Rick et al. 2009:488).

In summary, several truly endangered marine mammal species were notable for their populations having dropped by 87% or more over several decades, in some cases leaving only a few hundred individuals or less remaining over the entire range of the species or subspecies.

In contrast, polar bear numbers since being declared ‘vulnerable’ by the IUCN Red List in 1982 have only increased – from a low of perhaps 5,000-10,000 in the 1960s to perhaps 31,000 in 2015. Compare that to a species that is still considered truly endangered, the Amur tiger: once reduced to 20-30 animals, it is now (2015) estimated to number 350  480-540 individuals.

Children and naive adults alike are being frightened needlessly through vague and misleading statements that lead them to believe polar bears are as rare as Siberian tigers. 

[Vague and misleading statements like this, for example]

Whatever the future may or may not hold for them, polar bears are currently thriving. That’s not just my opinion but the conclusion drawn by the Red List team of the world’s most respected conservation organization, the International Union for the Conservation of Nature. While the IUCN has allowed predictions of future population declines to be used in species assessments, at least they’ve limited these prophesies of doom to three generations and insisted on strict statistical guidelines.

References
Adler, J.H. 2008. An animal to save the world: climate change and the polar bear. The New Atlantis Summer:111-115. http://www.thenewatlantis.com/publications/an-animal-to-save-the-world

Clapham, P. J., Young, S. B. and Brownell Jr., R. T. 1999. Baleen whales: conservation issues and the status of the most endangered populations. Mammal Review 29:35-60.

Rick, T. C., DeLong, R. L., Erlandson, J. M., Braje, T. J., Jones, T. L., Kennett, D. J., Wake, T. A., and Walker, P. L. 2009. A trans-Holocene archaeological record of Guadalupe fur seals (Arctocephalus townsendi) on the California coast. Marine Mammal Science 25:487-502.

Sea Otter Recovery Team 2007. Recovery strategy for the sea otter (Enhydra lutris) in Canada. Species at Risk Act Recovery Strategy Series. Fisheries and Oceans Canada, Vancouver.

Weber, D. S., Stewart, B. S., Garza, J. C., and Lehman, N. 2000. An empirical genetic assessment of the severity of the northern elephant seal population bottleneck. Current Biology 10:1287-1290.

USFWS 2005. Endangered and threatened wildlife and plants; determination of Threatened Status for the Southwest Alaska distinct population segment of the northern sea otter (Enhydra lutris kenyoni); final rule. Federal Register 70:46366.

USFWS 2008. Endangered and threatened wildlife and plants; determination of Threatened Status for the polar bear (Ursus maritimus) throughout its range; final rule. Federal Register 73:28211-28303.

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