Well, its International Polar Bear Day whatever that means… there’s some NGOs promoting eco-solutions and that’s good, personally I prefer the ‘Stink For The Bears’ campaign that asks everyone not to shower (I’m way ahead of the curve on that one!) Its also ‘Pink T-Shirt’ day as in Anti-Bullying Day which is a worthy cause as well.
Anyway, for International Polar Bear Day… I thought I would do a little ‘State of the Polar Bears of Churchill’ update…
Western Hudson Bay Population – Chesterfield Inlet, NU to Manitoba/Ontario border, majority within Wapusk National Park
Just how may bears are there in western Hudson Bay?
The Canadian Wildlife Service estimate is 935 bears (794-1076 bears – Regehr et al., 2007). This is based on a helicopter mark-recapture effort, in which bears are tranquilized, marked and then recaptured over a series of years. This study centres on the traditional summer territory of Churchill’s bear, Wapusk National Park about 12,000 km2. It should be noted that in late 2003, the population was estimated at 977 bears. Helicopter studies have been used in this area from 1984-2004 in August and early October.
A more recent aerial study by the Government of Nunavut and Manitoba indicated a population estimate of 1,000 bears (715-1398 bears: Hedman/Atkinson, 2011). This style of survey is more passive. Here, an airplane flies transects over the entire population range and uses a co-operative sight-resight strategy. Spot a bear, confirm the sighting and add it to the list.
There is generally a greater margin of error with sight-resight aerial studies, they do have the benefit of covering the entire range of western Hudson Bay bears (Chesterfield Inlet to the Manitoba-Ontario border). Given that this entire population is land-based in the study period (August), many of us are hopeful, given its non-invasive nature, that this will be adopted as the main population study technique.
Has there been a 22% decline from 1987-2004?
This number is based on the Canadian Wildlife Servce mark-recapture studies. The population was actually listed as a lower number from 1984-1986, however, the current study area was expanded in 1987 to current levels (basically Wapusk National Park). Therefore, you can only truly compare the results from 1987 onwards.
In short, yes, the CWS study has found a 22% decline over its study period. However, a quick glance at the CWS numbers and you will see that between 1989 and 1992, the western Hudson Bay population estimates dropped from ±1,300 to ±1,000 – that’s about 23% in three years… The tricky thing with these numbers is that 20-25-30% fluctuations in wildlife populations is not really shocking to people who have some connection to ‘the land’.
Over the years, accepted population estimates have included 1000 bears (average from 1979-1992), 1,194 bears (1987), 1,200 bears (1996) and 935 bears (2004) and 1000 bears (2011).
In the early 1990s, there was concern that there were actually more bears east of the Nelson River than previously assumed. For this reason, an estimated 200 bears were added to the population, this resulted in new numbers… 1200-1350 bears (1987-1992) up from the 1000 bear estimate. In general, the ‘management’ population in western Hudson Bay was 1,000 bears in the 1980s, 1200 bears in the 1990s and now 900 bears in the 2000s.
It is a little difficult to tell if current CWS models take into account the Cape Tatnum bears. If we are to believe the mid-1990s estimates, we could actually be looking at 935 bears (plus another 150-200 bears outside the study area). As you can see, its a little complicated… but from what I can see, around a 1000 bears is a reasonable number.
For many of us, our problems arise from this need by scientists to put a ‘smoothed curve’ on wildlife population trends… it just doesn’t work that way.
Is Breakup and Freezeup in Western Hudson Bay Changing?
The latest available research indicates a statistically significant change in breakup, however, no statistical change in freezeup has ever been proven (Gagnon and Gough, 2005). The change in breakup has only become statistically significant in recent years, back in 1999, it was only ‘approaching’ statistical significance.
When you hear, the ice breaks up ‘three weeks earlier’, this is a slightly misleading statement – one that I wish would not be used actually. It takes the data from 1984 (July 12 breakup) and 2003 (June 21) and compares them individually (19.5 days earlier). This is an exagerration of the actual trend and merely confuses the debate. For example, if we compare 1984 and 2004 – you get a very different result… you can’t just pick and choose random years to compare… 1984 was the 3rd highest ice cover year (behind 1992 and 1983). So while, the ice situation is quite worrying, this stat is just bogus.
How Many Bears are Handled in Western Hudson Bay?
Between 1984 and 2004, CWS lists 3,306 ‘captures’ of 1,963 individual bears. Mean date of handling being September 10th. Over this same period, Manitoba Conservation (Polar Bear Alert) handled 963 bears (1,417 times) and euthanized approximately 95 problem bears.
So, in a population of approximately 1,000 bears, there have been 4,723 encounters in which handling and drugging occurs over 20 years. Extrapolate those results forward and you have 6,500+ encounters from 1984-2012. Basically, about 20-25% of this population may be handled each and every year.
These results do not include bears impacted by helicopter tours and those hazed but not handled by Polar Bear Alert officers.
Concerns with Polar Bear Research
There are a few studies that indicate that this level of drugging and handling have little effect. However, it has been proven that pregnant females will relocate if handled in the fall, the birthweights of female cubs are statistically lower and, in general, cub size is lower than non-handled bears (although not significant). Plus, not one person that I know believes that handling three month old cubs and their mother at possibly THE most critical time of the year (just after emerging from the den) is not detrimental to their health.
What is most concerning is that even though, as we are told, the ice conditions on all of Hudson Bay are declining. The other two populations, Foxe Basin and Southern Hudson Bay, appear to be relatively stable compared to Western Hudson Bay. If we are to believe the current numbers and trends, why are these populations not crashing as well? The only difference I can see is the level of intensive handling for research purposes.
I mean look at the study from 1993-1996
Fall 1993 – 150 bears handled
Spring 1994 – 100 bears handled, 33 females with COYs
Fall 1994 – 170 bears handled
Spring 1995 – 64 bears handled, 22 females with COYs
Fall 1995 – 177 bears handled
Spring 1996 – 14 females handled, 12 collars deployed
If the denning area produces 200-300 cubs each year, scientists impacted the lives of 20-30% of animals that already only have a 50% chance of survival. This is worrisome.
Concerns with Helicopter Tourism
Given that the vast majority of handling occurs in August and October, there is a significant chance that pregnant females will be disturbed – either by direct handling or simply by the noise of the helicopter flying overhead. Both significant handling and simply flying overhead have been proven to impact the health of female cubs.
Now, add to the fact that helicopter tours not regularly fly over and visit the maternity denning area through October and November, and you start getting a bit concerned. A great way to help bears might be to lobby tour companies, Polar Bears International and World Wildlife Fund to cease their denning area tours given the scientific evidence. Basically, there is no need for people to ‘climb inside a vacant polar bear den’ if there is a chance that the flight out there disturbs even one pregnant female.
A lot of us feel that the current ‘decline’ in western Hudson Bay is as much due to bears leaving the study area or just getting better at hiding from helicopters as it is to sea ice.