Davis Strait polar bear habitat well above average for the first week of winter

The region inhabited by the Davis Strait subpopulation of polar bears dips as far south as James Bay and has a history of highly variable sea ice coverage.

Canadian Arctic Jan 7 2016_CIS

For the last two years Davis Strait sea ice in March has been well above average, while other years it been well below. You might be surprised to hear that 1969 had the lowest February/March ice coverage over the entire the 1969-2002 record (Johnston et al. 2005: 211), which ice charts show now extend to 2015 (see below). Reports of sealers working north of Newfoundland and in the Gulf of St. Lawrence in the first few decades of the 20th century show this variability has likely always been a characteristic of the area (Ryan 2014).

Remarkably, this year’s ice coverage for the first week in January is well above what they were in 2014 and 2015 – even though those two years were above average by March. In fact, there hasn’t been this much polar bear habitat in the Southern Labrador Sea in the first week of January since at least 1993.

Davis Strait subpopulation boundaries in context of the whole (courtesy Environment Canada):

Davis Stait in EC context

Sea ice graphs for the week of 1 January 1971-2016, for Northern Davis Strait, Northern Labrador Sea, Southern Labrador Sea (Canadian Ice Service) – which together make up Davis Strait polar bear habitat at this time of year:

Davis Strait same week 1 Jan 1971-2016

Davis Strait Northern Labrador same week 1 Jan 1971-2016

Davis Strait Southern Labrador same week 1 Jan 1971-2016

Here is the record for the entire East Coast ice coverage (the region covered by the Johnston et el. 2005 study), for the week of 12 March, 1969-2015 (note the scale):


East Coast same week 12 Mar 1969-2015

Here’s what that mid-March ice coverage looked like last year:

Sea ice extent Canada 2015 March 12 CIS

Johnston, D.W., Friedlaender, A.S., Torres, L.G., Lavigne, D.M. 2005. Variation in sea ice cover on the east coast of Canada from 1969-2002: climate variability and implications for harp and hooded seals. Climate Research 29:209-222. http://www.int-res.com/abstracts/cr/v29/n3/p209-222/ Pdf here.

Ryan, S. 2014. Appendix 3: Chafe’s “Notes of the Voyages” 1924-1941, In The Last of the Ice Hunters: An Oral History of the Newfoundland Seal Hunt, pg. 445-457. Flanker Press, St. John’s. [Contains critical notes about ice conditions between 1924 and 1941 and where harp seals were found in those years]

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