It’s the middle of July – do researchers know where their Hudson Bay polar bears are?

If so, they’re not saying. This year, with higher-than-average sea ice, we’ve heard much less than usual about the location of tagged Hudson Bay polar bears. Odd, isn’t it?

Hudson Bay breakup 2015_2014_14 July

By this time last year, Polar Bears International rep Alysa McCall had published two reports on the location WHB polar bears tagged by the University of Alberta research team led by Andrew Derocher (Fig. 1 below).

Figure 1. Sea ice coverage and locations of female polar bears with tracking collars for 30 June 2014 and 8 July 2014 (black, Western Hudson Bay bears; blue, Southern Hudson Bay bears), courtesy Alysa McCall, Polar Bears International. Click to enlarge.

Figure 1. Sea ice coverage and locations of female polar bears with tracking collars for 30 June 2014 and 8 July 2014 (black, Western Hudson Bay bears; blue, Southern Hudson Bay bears), courtesy Alysa McCall, Polar Bears International. Click to enlarge.

This year, there’s been nothing: not a single PBI mention of WHB breakup. Derocher tweeted a track map on 6 July (2/9 bears ashore), with no updates since, but PBI’s “Bear Tracker” has not been updated since 2 July. Compare this year’s ice cover on Hudson Bay (and elsewhere in Canada) to last year on this date (14 July): quite a difference.

First, the last known location of the U of A’s collared bears, at 6 July 2015:

Figure 2. Tweet from Andrew Derocher noting 2 out of 9 collared WHB females were onshore on 6 July 2015. Click to enlarge.

Figure 2. Tweet from Andrew Derocher noting 2 out of 9 U of A collared WHB females were onshore on 6 July 2015. Click to enlarge.

Sea ice at 14 July 2015 vs. 2014 (Fig. 3): remember that most WHB polar bears usually come ashore about 28 days after the “breakup” point is reached (date of 30% coverage over WHB). Some bears stay on the ice to the bitter end (see Fig. 1, 8 July 2014), which means this year they may not leave the ice until August.

Figure 3. Sea ice in Canada 2015 vs. 2014 at 14 July. Hudson Bay, Davis Strait and Eastern Beaufort Sea.

Figure 3. Sea ice in Canada 2015 (top) vs. 2014 at 14 July. Hudson Bay, Davis Strait and Eastern Beaufort Sea. Click to enlarge.

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