Polar bear habitat update – more spring sea ice around Svalbard than 2014 & 2012

Polar bear habitat for the last week of March is well above average in eastern Canada for the second year in a row. The very low extent of ice in the Sea of Okhotsk – which has contributed strongly to the low maximum extent this year – is irrelevant to our discussion, since no polar bears live there.

Polar_Bear_male_Regehr photo_March 21 2010_labeled

There is a bit more concentrated ice around Svalbard than last year (or in 2012), although ice in the Barents Sea in general is still below average due to the state of the Atlantic Multidecadal Oscillation (AMO). The state of the AMO and its effects on Barents Sea polar bear sea ice habitat has nothing to do with global warming: it’s a cycle that has been documented for centuries (Miles et al. 2014).

Still, there is plenty enough sea ice for polar bear hunting: this is the beginning of the critical feeding time for all polar bears (see here and here), but especially for the survival of new cubs-of-the-year, so I have a few words about Western Hudson Bay cubs below.

Have a look for yourself.
Update: Added 20 March 2015, comparison maps from Cryosphere Today for 2006 vs. 2015.

Figure 1. Sea ice concentration in Canada at 19 March 2015. Canadian Ice Services.

Figure 1. Sea ice concentration in Canada at 19 March 2015. Canadian Ice Services (CIS).

And from the National Snow and Ice Data Center (NSIDC), sea ice extent for 18 March 2015 (Fig. 2):

Figure 2. Sea ice extent at 18 March 2015. NSIDC.

Figure 2. Sea ice extent at 18 March 2015. NSIDC.

From CIS, graph showing variation in the ice cover over the Canadian East Coast (i.e., southern Davis Strait), for the week of March 19: well above average for the second year in a row (Figure 3.).

Figure 3. Sea ice cover over the east coast of Canada for the week March 19, 1969-2015. CIS.

Figure 3. Sea ice cover over the east coast of Canada for the week March 19, 1969-2015. CIS. Click to enlarge.

Also from CIS, a graph showing variation in the ice cover over the northern portion of the Davis Strait polar bear subpopulation region, for the week of March 19: higher than average again for the second year in a row. In fact, early spring ice cover in Davis Strait has been above average for three out of the last four years (Fig. 4): that’s good news for northern Davis Strait bears.

Figure 4. Sea ice cover over (northern) Davis Strait, Canada, for the week March 19, 1971-2015

Figure 4. Sea ice cover over the northern portion of Davis Strait, Canada, for the week March 19, 1971-2015. Note how high the ice cover was in 2012. Click to enlarge.

From the Norwegian Ice Service, sea ice concentration maps for this year (18 March 2015) back to 2010 via their archive (Fig. 5) — click to enlarge.

Figure 5. Sea ice concentration maps for 18th or 19th of March, 2015-2010. Norwegian Ice Service.

Figure 5. Sea ice concentration maps for 18th or 19th of March, 2015-2010. Norwegian Ice Service. Click to enlarge.

UPDATE, added 20 March 2015, comparison of sea ice concentration at 17 March 2006 vs. 2015 (courtesy Cryosphere Today, University of Illinois), below:

Sea ice March 17 2006 vs 2015 Cryosphere Today

Cubs of the Year – an update from W. Hudson Bay

Figure 6. USGS photo of a female with new cubs on the ice, in Alaska.

Figure 6. USGS photo of a female with new cubs on the ice, in Alaska.

Since this is the season that polar bear females emerge with their new cubs (Fig. 6) and then head out on the sea ice to hunt, a few words about Western Hudson Bay cub production this year. Kelsey Eliasson, on the ground near Churchill, Manitoba (at Watchee Lodge), had this to say about the current cub season on that area of the coast:

Well, another cub season is just about wrapped up along Hudson Bay and this one seems to show positive results. During my week at Watchee Lodge, the guides were saying that all of the family groups that they have worked with this year are twin cubs as opposed to past years where it is a bit of a mixed bag. However, tracks of a mother with single cub passed through but a family of triplets were also tracked. Several bears broke out of their den and headed straight out on the ice before any of the photographers could catch up to them. Either way, its been a very good season at Watchee.

We staked out one den during my stay and the female that emerged was a very healthy looking bear with two small cubs. In fact, she looked comparable to bears in October… not one with an additional four months fast and cubs to nurse. This means she either found a carcass on the shore in the summer and fattened up or had a phenomenal seal hunting season.” [my bold]

References
Miles, M. W., D. V. Divine, T. Furevik, E. Jansen, M. Moros, and A. E. J. Ogilvie. 2014. A signal of persistent Atlantic multidecadal variability in Arctic sea ice.Geophysical Research Letters 41, doi:10.1002/2013GL058084. http://onlinelibrary.wiley.com/doi/10.1002/2013GL058084/abstract

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