5/26/2015 11:34:31 PM
Curious Ice Breakup on Hudson Bay
It's an ill wind that blows no good and perhaps that's the way to look at Hudson Bay this year. Recent high winds from the northwest pushed the sea ice out of that part of Hudson Bay, causing polar bear habitat to virtually vanish from the area more than a month earlier than normal. Perhaps the "good" is that the bears from southern Hudson Bay will be able to hang out longer on the ice than normal.
Our collared bears are doing what they can to stay out on the ice but most have been forced to hang out on the thin rim of ice that hangs along the coast. The hunting conditions aren't likely very good there. With so little habitat, there's likely some serious competition for every seal kill.
Bear "I" seems to have been lucky (or smarter than your average bear). She stayed out far enough from shore that she might have benefited from the winds: she still has lots of ice.
Bear "P" is north of 60°. She has technically passed from the range of the Western Hudson Bay subpopulation, through the Foxe Basin subpopulation, and is now residing in the Davis Strait subpopulation! In all our years of tracking (I deployed the first satellite collar there in 1991), we've never had a bear make such a movement. Perhaps she knows something the other bears don't. Given where she's at now, we won't likely get a chance to recollar her anytime soon (if ever).
Ice conditions this year are surprising. Anyone living in the eastern U.S. or Canada is painfully aware of what the winter was like. One might have thought that the wickedly cold weather might have built up some thick ice in Hudson Bay. If this did happen, then the rapid contraction of the ice, which has folded up in the eastern part of the bay, shouldn't have happened. Winds play an important part in the distribution of sea ice. This year, it seems to have been a major factor in the Hudson Bay.
We won't really know what the spring has been like for the bears until we get some reports back on their condition from the wildlife biologists in Manitoba or until researchers head out in late August. Fingers crossed that the western Hudson Bay bears are OK, but I'd rather be a polar bear from southern Hudson Bay this year. Of course, if the winds swing around, all bets are off.
Dr. Andrew E. Derocher is a professor of biological sciences at the University of Alberta. He is also the author of Polar Bears: A Complete Guide to Their Biology and Behavior. Follow him on Twitter: @AEDerocher.
A map of collared bears from the Western Hudson Bay population shows wide diversity in movements. One bear, P, traveled all the way over to Davis Strait, a first since collaring began. Map created by the Derocher Lab, University of Alberta, May 25, 2015 © Derocher Lab