The research by SFU and University of Victoria scientists, published today in Public Library of Science, a peer-reviewed journal, says about 300 grizzly bears are killed by trophy hunters every year in B.C.
The B.C. government claims that's a sustainable harvest, since it estimates there are about 15,000 grizzlies in B.C.
But researchers say their analysis of 10 years of the government's data from 2001 to 2011 raises serious questions about that conclusion.
SFU biologist Kyle Artelle says in half the population groups around the province where hunting is permitted, more grizzlies have been killed than even government targets allow.
In at least one regional population, hunters killed 24 more bears than the local quota allowed.
"It does cast some doubt that management is safeguarding the future of these populations," said Artelle.
Population estimates questioned
The study also raises larger concerns about the accuracy of the government's population estimates.
Artelle says that even wildlife managers don't know how many bears are out there because on-the-ground surveys have only been done for about 15 percent of the province, meaning most population estimates come from computer models or expert opinion.
And she says, because of the wide range of potential errors in those estimates, the hunting quotes may be too lax.
"In a way it's a bit like a game of Russian roulette. The data just don't let us have a precise picture on how big that threat is. But it is a considerable risk based on that uncertainty."
The researchers say the government should learn from the mistakes made by fisheries managers that allowed overfishing to lead to the collapse of many fish stocks.
“Grizzly bears’ low rate of reproduction makes them highly vulnerable and slow to recover from population declines," said Artelle.
The B.C. government could reduce the risk to the province's grizzly bear population by cutting its hunting quotas in half, she says.
According to the researchers, trophy hunting of grizzlies is allowed in 50 of the 57 population units in B.C., including B.C.’s Great Bear Rainforest, where the alliance of Coastal First Nations has banned the activity. The provincial government doesn’t recognize the First Nations' ban.
The grizzly bear hunt is managed by the Ministry of Forests, Lands and Natural Resources. A spokesperson said the ministry will review the report.