W Hudson Bay polar bears now on the ice hunting but killer whales could be trapped

According to reports from folks on the ground in Western Hudson Bay, most polar bears were out on the ice resuming seal hunting by the 20th or 21st November at the latest (some got started quite a bit earlier). That’s less than 2 weeks later than the average date in the 1980s (which was November 8).

Sea ice Canada 25 Nov 2015_with Churchill

However, the rather odd pattern of freeze-up this year may not be good news for any killer whales still remaining in Hudson Bay – their access to the open ocean is already virtually blocked by ice.

UPDATE 26 November 2015: What a difference a day makes! Look at the spectacular ice development overnight along the west coast of Hudson Bay and in the central portion of the bay since yesterday (below).

Canadian Arctic Nov 26 2015_CIS


It’s important to note that because of the effects of winds, shore ice can be scarce around Churchill but plentiful elsewhere along Western Hudson Bay during the fall freeze-up period – as has been evident this year.

Churchill, don’t forget, is merely the centre of the Western Hudson Bay region – not all bears travel through Churchill waiting for the ice to form but those that do are the most visible to the most people. This year, WHB bears to the north and south of Churchill apparently had access to ice sooner than Churchill bears. Eventually however, the ice did settle in and even Churchill bears were able to return to the ice and resume hunting for seals.

In a recent blog post, Kelsey Eliasson at PolarBearAlley, pointed out that there was enough ice by November 10th for bears to hunt seals 250 km south off York Factory (“Nanuk Lodge,” click on the link for pictures and description of wind pushing ice ashore)  but not off Churchill, where winds have been pushing newly-formed ice offshore. That’s why, in the sea ice charts, the ice has been there one day and gone the next.

Instead of being the first place the ice formed in W Hudson Bay, Cape Churchill was one of the last regions to see ice this year. That’s just natural variability due to prevailing winds: ice off Churchill got pushed offshore by winds from the west and south more so than did ice that formed to the north and south, which you can see on the CIS animated sea ice map for the last 10 days.

However, right on schedule for the recent average of when most bears have left, most bears in Churchill were on the ice by November 21. Kelsey tweeted on November 24 that bears held in jail by Conservation were being released for the season.

Here are the Churchill Polar Bear Alert problem bear reports for the last few weeks: November 2-8; November 16-22.

Bad news for killer whales?

The strong pattern of ice formation in Foxe Basin and Hudson Strait this year could catch off-guard any killer whales that have entered Hudson Bay to prey on seals and/or beluga: if they haven’t left yet, they may be trapped by thick ice in Hudson Strait and be unable to get out at all.

Recall that in 2013, a pod of a dozen killer whales became trapped by ice in early January. They soon escaped from the bit of open water they’d taken refuge at but it was considered unlikely that they made it out of Hudson Bay alive.

This year, as sea ice in the northern portion of the Bay and in Hudson Strait continues to expand and thicken, any killer whales that haven’t made it out already (or who don’t leave soon), could be trapped.

Compare the ice extent at the end of November 2012, below (less than two months before the whale shown above were known to be trapped) with the extent of ice this year almost a week away from the end of November: you’ll see that access through Hudson Strait is pretty much blocked off.

Sea ice extent Canada 2012_ Hudson Bay freeze-up Nov 30 2012

Canadian Arctic Nov 25 2015_CIS

There may still be enough pockets of loose or thin ice in Hudson Strait that killer whales could get through but that’s not going to last long – a few days at most, I expect.

 

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