Hudson Bay Sea Ice Freeze-Up in 2022 Like the 1980s for the 5th Time Since 2015

From Polar Bear Science

Susan Crockford,

This is the fifth year out of the last seven that enough sea ice has formed along the west coast of Hudson Bay by mid-November for bears to be able to head out to the ice, just as it did in the 1980s.

‘Green dot’ problem bear released from Churchill holding facility on 10 November 2022. Dorota Walkoski photo.

One of the independent polar bear guides on the ground near Churchill had this to say about the bears and freeze-up conditions this year:

“Bears started leaving on November 10; conservation emptied the jail on the 10th as well.”

‘The jail’ is the Churchill Polar Bear Alert Program’s ‘holding facility’. While the Alert program folks have not released a report for this week (gee, I wonder why?), nearby tourist outfit Great White Bear Tours not only confirmed the bears were released from jail but posted a picture of a ‘green dot bear’: the mark put on problem bears released from the holding facility to keep track of them. Bears are not released before there is ample ice along shore for them to move out. Great White Bear Tours have been tracking bears moving offshore.

This information suggests the average date for bears leaving shore will likely turn out to be 12-14 November, again earlier than the average for the 1980s (16 Nov +/- 5 days) (Castro de la Guardia et al. 2017). That makes five out of the last seven years (2017, 2018, 2019, 2020, 2022) since 2015 that bears have left about the same time as they did in the 1980s.

While there are still be a few bears on the shore of Wapusk National Park that seem to be in no hurry to leave, a few stragglers doesn’t mean there isn’t ice available for hunting.

Sea ice conditions on Hudson Bay

Sea ice coverage for week of 12 November, 1971-2022:

This amount of ice is more than the long term average for this time of year (week of 14 November), according to the following CIS comparison chart, where blue is more than average and dark blue is much more than average:

How that looks on the usual ice chart for Canada, 16 November 2022:

Bears in no hurry to leave shore

Some bears in good condition appear to be in no hurry to get out onto the ice, as the images below from 12-17 November on the shore of Wapusk National Park, courtesy Explore.org. This phenomenon seems to mirror the reluctance of some bears in early summer to leave the retreating ice even when there is very little left.

Only a couple of WH bears tagged by Andrew Derocher’s team had left shore by 11 November and he hasn’t yet updated this information. As he’s done in the past, chances are he won’t post another tracking map until the bears are all offshore, so we won’t be able to tell when most of them left. But perhaps he’ll surprise us this year.

References

Castro de la Guardia, L., Myers, P.G., Derocher, A.E., Lunn, N.J., Terwisscha van Scheltinga, A.D. 2017. Sea ice cycle in western Hudson Bay, Canada, from a polar bear perspective. Marine Ecology Progress Series 564: 225–233. http://www.int-res.com/abstracts/meps/v564/p225-233/

via Watts Up With That?

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November 18, 2022 at 04:16AM

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