Polar bear mating season winds down with lots of sea ice habitat available

Habitat for polar bears is abundant worldwide as the prime feeding season passes its peak and mating season for sexually mature bears winds down.

JR1_1266.tif

Battle among polar bear males for the right to mate, from this 2011 DailyMail story here.

There is much more ice than usual around Svalbard in the Barents Sea and off Newfoundland and southern Labrador, home to ‘Davis Strait’ bears. There have been no media reports of polar bears onshore anywhere (since the third week of April in Newfoundland and late January in Svalbard).

Sea ice map below for 12 May 2017:

Svalbard ice extent 2017 May 12_NIS

Compare the extent and concentration of ice around Svalbard above (at 12 May 2017) to conditions that prevailed on the same date in 2015 (below), considered a “good ice” year for local polar bears (and the year of the last population size count which registered an increase over the 2004 count):

Svalbard ice extent 2015 May 12_NIS

There hasn’t been this much ice in the area at this point in the season for many years, especially to the north of Svalbard, and levels since late April have been above even the long-term average (disregard the huge downward blip, which is clearly a sensor malfunction of some kind):

Svalbard ice extent 2017 May 12 graph_NIS

In fact, ice is pretty solid throughout the Barents Sea and East Greenland at this time:

Barents Sea ice extent 2017 May 12_NIS

Across the Atlantic, the situation is similar, with unseasonably heavy sea ice off eastern North America and the Southern Beaufort Sea.

Newfoundland East daily ice conc 13 May 2017_CIS

Sea ice levels off Newfoundland this year in the first week of May have not been so heavy in more than two decades — only 1991 had more ice — and this has been severely affecting local fishermen along the north coast, many of whom have been unable to get their boats out to start spring fishing (a phenomenon which last occurred in 2007):

East Newfoundland same week_ ice coverage 7 May 1968-2017

Sea ice is just beginning to melt on Hudson Bay and Southern Beaufort but not off Labrador and Newfoundland:

Sea ice Canada 2017 May 14 CIS

But last year, melt was further along at this point in time, in all three of those regions:

Sea ice extent Canada 2016 May 13 CIS

Similarly, in 2015:

Sea ice Canada 2015 May 14_CIS

Compare the above to late May 2013, when there was no ice off Newfoundland, open water off Churchill in Western Hudson Bay, and only a hint of melt in the Southern Beaufort:

Sea ice in Canada May 23 2013

So, the implied message that unusually bad current ice conditions are to blame for a number of polar bears in poor condition sighted by polar bear specialist Andrew Derocher and his research team over the last few weeks (on the sea ice off Churchill and to the north) really stand out as yet another odd comment.

and

and

Communities in Western Hudson Bay had a lot of snow in March, especially Churchill.

Churchill blizzard_2017_CBC_seaport-hotel-on-kelsey-blvd-in-churchill early March

Consequently, more bears than usual in poor condition in spring are a good indication (in my opinion) that deep snow over ringed seals birthing caves have negatively affected the availability of ringed seal pups for hungry bears in that region (thick snow hides the pupping lairs well, making them much harder for bears to find).

There may also be fewer ringed seals in general. A marked decline was noted after the late freeze-up in 2010, a phenomenon noted by seal researchers based on data up to 2013 (see Ferguson et al. 2017 paper here), and which may have recurred with late freeze-up in 2016. But as Kelsey Eliasson pointed out last month, 2016 was a strong El Nino year and the last time one of those hit in 1998, Churchill area polar bears in Western Hudson Bay bears also did not fare well — but they did recover when conditions moderated over the following years (more on WHB bears later).

Worldwide, there is still about 13 million km2 of sea ice habitat for polar bears (zoom in on the original here), since there are no bears in the Sea of Okhotsk:

masie_all_r00_v01_2017133_4km 2017 May 13

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