Polar bear biologists doing mark-recapture work in Hudson Bay may have misled the world
What exactly are Western Hudson Bay (WHB) polar bear researchers hiding? Since 2004, research on the body condition and cub production of Western Hudson Bay (WHB) polar bears has been carried out but none of the results of these mark-recapture studies have been made public. The researchers all claim that WHB polar bears are struggling to survive because of recent sea ice changes but won’t release the 10 years worth of updated information they possess on the bears or the sea ice. Mark-recapture work entails chasing the bears down with helicopters (including females with newborn cubs), drugging them with a cocktail of sedatives that taint the meat (and perhaps the milk of nursing mothers) for months afterward, installing radio collars or ear tags, extracting a tooth for aging, drawing blood and fat samples, and before it’s all over, posing for a few up-close-and-personal photos with the tiny cubs of drugged females (see photos above and below). Nick Lunn, polar bear researcher for Environment Canada, uses the cub of a drugged female for a photo op. Derocher’s recently graduated MSc student Alysa McCall has a photo op with a WHB cub (from her student page). That’s a lot of stress to the bears and to what end? Detailed biological information about the bears that’s necessary for sound management, we are told. In order to assess the true status of a population, biologists tell us they need to compare the size of litters, the proportion of yearlings (1-2 yrs old), the rate of cub survival, and the weight of adult bears (altogether, these are the so-called “vital rates” of the population). However, I just updated a list I made in this previous post (which has the references) and you should know that by 2014, there has now been: — No published data available for size of WHB litters or proportion of independent yearlings since 1998 (16 yrs ago). — No data on cub survival in WHB since 1992 (22 yrs ago). — No data published on weight of lone WHB females since 2004 (10 yrs ago) — No data published on weight of adult WHB males and females with cubs since 1998 (16 years ago) There has also been no sea ice data published for Hudson Bay since 2004 (10 yrs ago) using the old method of determining breakup/freeze-up (50% ice coverage); using the new method of determining breakup and freeze-up (30% coverage/10% coverage over WHB, respectively), the last year of data is 2009 (5 yrs ago). The Polar Bear Specialist Group (PBSG) promised in February 2014 that this year, polar bear data collected since 2004 in WHB would be released: “A new population estimate based on extensive continued Physical Capture-Recapture will be available in 2014 and, will provide an updated assessment of the long-term trend in population size and vital rates, that is not possible from a single aerial survey.“ [Note that the upgrade to the trend status for the WHB subpopulation recently made by Environment Canada (discussed here) — from “declining” (according the PBSG in February 2014) to “likely stable” (June 2014) — appears to have been based on the publication of a peer-reviewed paper on aerial survey population size estimate (Stapleton et al. 2014, discussed here), not mark-recapture results] And with little more than two months remaining in the year, there has been nary a whisper of what those mark-recapture studies showed. What we have heard is an ever-increasing litany of polar bear woos: “Melting ice is cutting polar bears off from their food source in Hudson Bay, and death rates have soared.” Polar bear biologist Andrew Derocher, in a recent CBC documentary (links to the videos here), said this: “Our estimation is that we probably won’t have polar bears in Churchill once we get out to mid-century … They could be gone in a couple of years.” And Steve Amstrup, spokesperson for Polar Bears International, claimed in an interview a few weeks ago that in WHB: “Only about 3 percent of the western Hudson Bay population, for example, is now composed of yearlings.“ Compared to what? Apparently, Amstrup knows but we aren’t allowed to see the details of the studies that generated that information. Andrew Derocher (University of Alberta) and several of his students (including Patrick Mislan shown above), Nick Lunn (Environment Canada), and conservation activist organization Polar Bears International (led by former USGS biologist Steve Amstrup) have all been doing invasive research on WHB polar bears using mark-recapture methods over the last 10 years but none of the data on body condition, cub survival and litter sizes have been published. Remember this when you hear and read statements from these biologists and other conservation activists over the next few weeks and months. You might even ask yourself: Are polar bear biologists withholding data on Western Hudson Bay mark-recapture work and breakup/freeze-up dates because the results don’t support their claims? Should the recent upgrade to “likely stable“ have happened five years ago — or even earlier? We wait, with baited breath, for evidence that the biologists entrusted with collecting and publishing unbiased scientific data have not been deliberately misleading us about the current status of Western Hudson Bay polar bears.
— gReader Pro
