Update Feb 12, 2013 – I now have a copy of the Derocher et al in press paper. If anyone would like to see it, please send me a note via the “Commments-Tips” page above
Andrew Derocher, an known polar bear advocate, has been making headlines again, this time promoting a new “policy paper” he is lead author on that has just been accepted for publication. He and his colleagues simply refuse to accept that the polar bear has been saved (population numbers have rebounded dramatically since protective legislation was introduced in 1973) and it seems all they can think of to do now is press for ever more restrictive regulations.
The timing of the release of this paper is very convenient: Fish and Wildlife biologists and polar bear activists worldwide are actively campaigning to get CITES, at their meeting next month, to make it illegal to trade in legally harvested polar bear parts (see previous post here). Canada is also under international pressure to up-list the status of the polar bear to “threatened,” see post here.
The article itself is behind a paywall (abstract and co-author list below), so it is unlikely that many people outside the choir of conservation advocate subscribers of the journal will ever read it, so Derocher is talking it up big time, with the help of his university PR department. Timely indeed. [h/t WUWT]
[Jan. 27, 2013: a follow-up to this post is
in progress - here.]
Did you know there used to be resident polar bears on two small islands in the Bering Sea? Given how much we don’t know about the polar bears of the Bering Sea, the bears that used to den and spend their summers on the St. Matthew Islands are a bright spot. These islands lay at the southern-most limit of the modern “Chukchi Sea” subpopulation (see Fig. 1) and were uninhabited by people when they were discovered in the 1760s – but they were a haven for polar bears.
We have details of the polar bears that gave birth and summered there because a US government biologist (Henry Wood Elliott) and a US navy Lieutenant (Washburn Maynard) surveyed the islands in 1874. Elliott wrote both an official report and a popular magazine article (for Harper’s Weekly Journal of Civilization) in 1875 describing the polar bears they saw; Maynard wrote a separate report in 1876. By 1899, there were none left, victims of the relentless slaughter of polar bears everywhere in the Arctic in that era (see previous discussion here).
Figure 1. St. Matthew Island is in the Bering Sea off the west coast of Alaska at about 60°N latitude. Compare this to the southern end of James Bay, Canada (which has a stable population of polar bears) at about 53 0N and Churchill, Manitoba (the so-called “polar bear capital of the world) at 58 046’N. Maps from Wikipedia.
Figure 2. A drawing of polar bears on St. Matthew Island that accompanied the May 1, 1875 Harper’s Weekly Journal of Civilization article written by Henry Elliot. See here.
Posted in Life History, Sea ice habitat
Tagged Bering Sea, Chukchi, commercial harvest, Elliott, Hudson Bay, Klein, Rozell, sea ice extent, St. Matthew Island, triplets
In Part 1 of the Western Hudson Bay (WHB) polar bear story, I promised to explore the idea that rather than declining due to the effects of global warming, WHB polar bear populations may simply be returning to ‘normal’ after the rapid population increase that followed the intense over-harvests that occurred between 1890 and 1930 and again from 1945 to 1970.
Derocher and Stirling (1995:1664) had this to say about the life history features (like incidence of triplets and age of weaning) that made the polar bears of WHB unique:
“The results of our analyses suggest that the unique reproductive characteristics of polar bears in western Hudson Bay in the 1960s and 1970s were either a function of a population increasing from a depleted state and feeding on a relatively abundant prey base, or density-independent fluctuations in prey population size, or availability due to sea ice variation.“
In my last post, I discussed some of the evidence for how polar bear reproductive characteristics had changed since 1985. But how different were WHB polar bears, before and after 1985, from the other populations that had been dramatically reduced between 1890 and 1970, such as those in Svalbard/Barents Sea and Davis Strait?
There are two factors to consider in this recovery from over-harvest: population size changes and reproductive characteristics. Turns out, we don’t know much about the Davis Strait subpopulation but we do know a bit about Svalbard/Barents Sea bears since the 70s. And the Svalbard/Barents Sea vs. WHB comparison is a bit of an eye-opener.
Chock this post up as another example of mind-blowing information you sometimes find while looking for something else.
In their dendrochronology paper on trees associated with polar bear dens in western Hudson Bay, Scott and Stirling (2002:157) reference an MA thesis in Geography by James Honderich (1991), in regards to a discussion of denning frequency during the period 1850-1899, “when polar bear hides were more or less traded consistently.”
It turns out the James Honderich’s thesis is actually a summary of polar bear harvests in Canada from about 4,000 years ago to 1935. The number of polar bears taken by Arctic explorers (1594 to mid-1900s), Hudson’s Bay Company fur traders (from 1670 to 1935) and Arctic whalers (1820s-1935) were calculated from a variety of historical sources. This post is a summary of the results for the period 1800-1935. It is likely you have never seen this astonishing information before and the implications for polar bear biology are substantial. Continue reading
Posted in Population, Uncategorized
Tagged commercial harvest, Davis Strait, fur traders, genetics, Honderich, Hudson Bay, Stirling, Svalbard, Uspenski, whalers