Overkill - trophy hunting slams BC's Grizzly bears
Anna Taylor
7th February 2014
In BC, Canada, a surge in trophy hunting may be reducing Grizzly bear populations, writes Anna Taylor. A new study finds evidence of serious Grizzly bear 'overkill' from multiple causes of mortality - in which trophy hunting is a big contributor.
In one area, trophy hunters killed 24 more grizzlies than the quota allowed, and overhunting was particularly prevalent for female bears that are critical for a sustainable population.
The British Columbia Government claims that the quotas they set for the number of Grizzly bears allowed to be killed each year ensure that hunting practices are sustainable.
But a new study into the management of Grizzly bears in BC, published in the open-access journalPLoS ONE, finds that so-called 'overkills' occurred in half the Grizzly bear populations.
The findings are also relevant to the USA and proposals to strip Grizzly bears of federal protection under the Endangered Species Act.
Worrying discoveries
Scientists set out to test the BC Government's claim and made some worrying discoveries. Kyle Artelle, from Simon Fraser University and lead author of the study, explains:
"We tested how well managers were able to maintain grizzly bear kill rates below limits their own biologists have deemed sustainable.
"This assessment was straightforward - for a given population and across three management periods we simply compared the number of bears the province said could sustainably die ('mortality limits') by human-caused kills to the number that actually died."
Too many unknowns
To do this his team looked at three key quantities that carry considerable uncertainty: population estimates; population growth rates; and the number of unreported human-caused bears deaths, including poaching kills.
The population growth rates are key in this, says Artelle, because they are used to estimate how many bears can be killed in a given population without causing declines.
"You can imagine how these might contribute to undetected overkills - for instance if you assume a population is a given size and set your hunting quotas accordingly, if it turns out the population is actually smaller, then the hunting quotas you set would have been too high.
"We addressed this quantitatively and found that, based on unaddressed uncertainty, overkill rate might indeed be considerably higher than previously assumed."
They found that overkills - defined as taking place when the number of kills exceeds the mortality limits that are set by the government - occurred in half of the populations that are open to hunting. Dr Artelle says that hunting is adding to the other problems faced by the bears:
"Although these were caused by a mix of hunting and other human-caused kills - road and rail accidents, self-defence kills, 'problem bear' kills and so on - we found that almost all overkills could have been prevented by reducing or eliminating the hunt."
Hunting quotas breached
In one area, trophy hunters killed 24 more grizzlies than the quota allowed, and overhunting was particularly prevalent for female bears that are critical for a sustainable population. This shows that guidelines that encourage hunters to avoid females are clearly inadequate.
There is considerable uncertainty about Grizzly bear population growth rates and unreported human kills, as well as how hunting affects other aspects of Grizzly bear biology such as genetics, social interactions and evolutionary processes.
It is also uncertain exactly how long different populations take to recover from population declines, the effects of changes to food availability and cumulative effects of other threats to grizzlies, logging and development for example.
Population uncertainties
Of great concern is the uncertainty of total population size. The current best estimate is 15,000 Grizzly bears in British Columbia - however the figure could be higher or lower.
It appears that few on-the-ground surveys have actually been done, with the estimate being largely based on computer modelling or expert opinion.
The government claims the management of the Grizzly bear hunt is based on "sound science" - yet Jessie Housty, tribal councillor of the Heiltsuk First Nation, doubts this.
On the Central BC Coast, where government sanctioned trophy hunting is at odds with tribal law that prohibits it, she emphasises that no inventories have been conducted.
"How could the government possibly have a solid understanding of these bears they condemn to the hunt without setting foot in our Territory?"
These are known unknowns
The government is failing to take all of these uncertainties into account when setting hunting limits, says Dr Artelle.
"This uncertainty in and of itself is not inherently a problem - uncertainty exists in all management. The problem in BC Grizzly bear management is that the uncertainty is simply ignored.
"Although the government maintains their targets are conservative, a simple comparison between their own limits and their own records of kill rates show that is clearly not the case."
Dr Chris Darimont, science director at the Raincoast Conservation Foundation (RCF) and a co-author of the study, is worried:
"Ignoring uncertainty - in dimensions such as true population size - is like playing Russian Roulette. As the history of wildlife management has shown repeatedly, the consequences of not accounting for the unknowns are grave."
The RCF has raised concerns about BC's Grizzly trophy hunt in the past. The European Union banned the import of BC Grizzly bear parts in 2002 due to their concerns over sustainability.
Hunting quotas should be halved - or banned
There is one very simple solution to the problem of overkills - reduce the hunt.
"If the government wants to ensure mortality levels are kept below limits set by their own biologists their targets need to be reduced," says Dr Artelle.
The scientists found that the BC government could reduce the risk to their Grizzly bears by cutting its hunting quotas by at least a half, which would reduce the probability of overkills by an average of 85%.
British Columbia is one of the last strongholds for North American Grizzly bears. Since European colonization, they have lost half of their continental range, and even in BC around one third of populations have either gone extinct or are currently threatened.
Multiple threats
"We know that grizzly bears are highly vulnerable to management error - because of their reproductive biology populations that suffer declines often don't recover, or take considerable time to do so", said Dr Artelle.
"And at a provincial level the trend is not promising - through recent decades we have seen an overall trend of more and more populations gaining threatened status or disappearing altogether.
"We also know that grizzlies face a variety of other threats that are not yet fully understood, from declining salmon stocks on BC's coast, white-bark pine failures inland, and climate change and development pressures throughout the province.
"Given the considerable threats many argue that grizzly managers should err on the side of caution, which our analyses strongly suggest they are not currently doing."
Yet hunting increased
Despite these threats to the Grizzlies, during the study period, between 2001 and 2011, hunting mortality actually increased. For this reason, many people in BC are in favour of the complete elimination of trophy hunting in their province.
The Coastal First Nations, an alliance of nine BC First Nations, have called upon Premier Christy Clark to end the hunt by organizing a petition.
They have banned trophy hunting in their expansive traditional territories in BC's Great Bear Rainforest because they believe that the government is risking the long-term survival of the bears.
Jessie Housty says: "Our responsibility as First Nations is to step into that regulatory vacuum, and protect the bears in our territories."
80% of BC residents oppose the grizzly hunt
Environmentalists are also strongly opposed to the hunt, as are 80% of British Columbians, according to a recent McAllister Research Poll.
Throughout North America it is being recognised that hunting must be stopped in order to protect Grizzly bears. Yet in BC, despite widespread disapproval and bad science, the hunt looks set to continue. Dr Artelle concludes:
"In other jurisdictions, such as the province of Alberta and the Kenai peninsula in Alaska, hunts have been closed due to sustainability concerns. In BC there has been a trend through time of a growing number of populations gaining threatened status.
"Whereas history from within and beyond the province suggests cautious management might be warranted, our research found that current management entails considerable risk, suggesting that continued overkills are likely."
Anna Taylor is a freelance science journalist, specialising in environmental issues and new discoveries in conservation biology. She posts regular blogs on Conservation Jobs.
Anna has also worked in conservation and conservation research for RSPB and other employers in the UK, Africa and the Amazon. She has a BSc in Conservation Biology and a Masters in Ecology and Environmental Biology.
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