Status of Canadian polar bear populations has been changed – more good news

According to maps dated June 2014, Environment Canada (EC) has changed the trend status of several Canadian subpopulations — without any announcement or publicly-available documents explaining the basis of the changes.

Figure 3. "Series of Circumpolar Polar Bear Subpopulation and Status Trend Maps 2010, 2013 & 2014" Note the asterisk below the 2014 map, which is dated "June 2014" and is different in its status assessment from the one released in February 2013 by the PBSG. Original here.

Figure 1. Environment Canada’s “Map 4: Series of Circumpolar Polar Bear Subpopulation and Status Trend Maps 2010, 2013 & 2014.” Original here.

And would it surprise you to learn that virtually all of these status changes reveal more good news about polar bears?

Surprisingly, the June 2014 EC status assessments for many Canadian subpopulations are very different from the 2013 assessment released by the Polar Bear Specialist Group back in February 2014.

Have a look at the map above (Fig. 1), number 4 in the EC series, where the boundary change discussed in my last post is noted below the 2014 map.

Data sources for this composite map are stated to be “Canadian subpopulation status provided by Canada’s Polar Bear Technical Committee. Others provided by the IUCN/SSC Polar Bear Specialist Group December [2013].” The date on this map is June 2014.1

A larger version of the Canadian portion of the 2014 status map is provided as a separate map (Fig. 2, below).

Figure 4. Environment Canada's "Map 3: 2014 Canadian Polar Bear Subpopulation and Status Map," original here.

Figure 2. Environment Canada’s “Map 3: 2014 Canadian Polar Bear Subpopulation and Status Map,” original here. This is just a close-up of the Canadian portion of the 2014 status map shown in Fig. 1.

There are rather large differences between these June 2014 status assessments and the PBSG 2013 Status Table published in February 2014 (Fig. 3 below, see my post here), which as of 27 October had not been changed.

Some of the differences come from a qualification in the EC (Polar Bear Technical Committee) assessments for “declining” and “increasing” — as in, there is “likely declining” and “likely increasing.” The PBSG don’t use such nuances of opinion but they actually say quite a lot about the level of uncertainty that should be acknowledged in some cases.

Here is a summary of the differences — June 2014 EC status first, PBSG 2013 status (at Feb. 2014) in brackets — good news upgrades in red:

W. Hudson Bay (WH), EC says “Likely Stable” (PBSG, “Declining”)
S. Beaufort (SB), EC says “Likely Declining” (PBSG, “Declining”)         Davis Strait (DS), EC says “Likely Increasing” (PBSG, “Stable”)
Kane Basin (KB), EC says “Data Deficient” (PBSG, “Declining”)
Baffin Bay (BB), EC says “Likely Declining” (PBSG, “Declining”)
Gulf of Boothia (GB), EC says “Likely Stable” (PBSG, “Stable”)
Viscount Melville (VM), EC says “Likely Stable” (PBSG, “Data Deficient”)
N. Beaufort (NB), EC says “Likely Stable” (PBSG, “Stable”)

Figure 4. PBSG 2013 Status Table published in February 2014. This is a screencap taken the morning of October 27 2014.

Figure 3. PBSG 2013 Status Table published in February 2014. This is a screencap taken the morning of October 27 2014. Click to enlarge.

In all, eight out of the thirteen polar bear subpopulation assessments have changed, most for the better. This includes upgrades to both of the groups formerly considered by the PBSG to be in the most trouble, i.e., “declining” (WHB and SB): WHB is now “likely stable” (see this discussion) and SB is now only “likely declining” according to Canada’s Polar Bear Technical Committee. In addition, Davis Strait bears have gone from “stable” to “likely increasing.”

Since most of the world’s polar bears reside in Canada, this is very good news indeed but so far, most of it is based on undocumented information2 — why the changes to Viscount Melville and N. Beaufort, for example or to the three subpopulations for which population estimates have not been completed or the results published, including Baffin Bay (discussed here), Southern Beaufort (discussed here and here), and M’Clintock Channel (discussed here and here).

It may sound awfully familiar that good news about polar bears is not being shouted from the rooftops. Recall last year when there was good news about the Chukchi Sea population? That information was relayed so softly that virtually no one except readers to this blog heard about it.

I have to say, I’m very disappointed to report Environment Canada using the same tactics.

Footnote 1: The author of this web page is not identified but I assume that a major part was played by biologist Nick Lunn (Canadian Wildlife Service), who is the most senior member of Environment Canada’s polar bear research team and a member of the Polar Bear Technical Committee (and also, an “advisor” to activist conservation organization Polar Bears International and a member of Polar Bear Specialist Group, see his PBSG profile below (click to enlarge).

Nick Lunn_PBSG profile_PolarBearScience_Oct 27 2014

Oddly enough, I could not find online any complete list of current or past members of the Polar Bear Technical Committee nor any summary or notice of the 2014 meeting: all I found was a note that USGS biologist Todd Atwood attended the get-together, which was apparently held 4-6 February 2014 in Montreal.

However, from an online announcement about last years meeting, I found out that:

The Polar Bear Technical Committee meets annually to discuss research, harvest and management of polar bears in Canada, and to provide advice to the Polar Bear Administrative Committee on the status of Canadian polar bear populations.

The committee is made up of technical representatives from each of the provinces and territories that have the management authority for polar bears (Manitoba, Newfoundland and Labrador, Northwest Territories, Nunavut, Ontario, Québec and Yukon).”

[The latest date stamp on the web page with these maps is 8 September 2014 and as there are five maps with different dates, perhaps not all the maps were posted at that time]

Footnote 2: The exception to this is Western Hudson Bay: even though the results of almost 10 years of mark-recapture work on polar bears in this region have not yet been made public, a recently peer-reviewed published paper on aerial survey population estimates (Stapleton et al. 2014), discussed here, almost certainly forms the basis for the upgrade to that subpopulation trend status. That paper also pinpointed serious deficiencies in previous mark-recapture studies:

“Our results suggest that mark–recapture estimates may have been negatively biased due to limited spatial sampling. We observed large numbers of bears summering in southeastern WH, an area not regularly sampled by mark–recapture.” Stapleton et al. 2014.

Stapleton S., Atkinson, S., Hedman, D., and Garshelis, D. 2014. Revisiting Western Hudson Bay: using aerial surveys to update polar bear abundance in a sentinel population. Biological Conservation 170:38-47. http://www.sciencedirect.com/science/article/pii/S0006320713004618#

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