Grizzlies show more stress when they don't get enough salmon
By Contributor
Salmon declines could have long-term effects on grizzly bear health, conclude authors of a study published Nov. 27 in the scientific journal PLOS ONE.
The researchers examined stress and reproductive hormones of salmon-eating grizzly bears from coastal British Columbia. Their results, obtained from analysis of tiny tufts of hair, revealed higher levels of the stress hormone, cortisol, in coastal bears that consumed less salmon.
“This pattern would occur if bears are nutritionally stressed by lack of salmon or if bears experience social stress caused by intense competition when salmon numbers are low,” explained Dr. Heather Bryan, Hakai postdoctoral researcher at UVic, Raincoast Conservation Foundation biologist, and primary author. “Either way, imagine how stressful it would be if the food required to sustain you and your family through winter were scarce.”
According to Judit Smits, professor in Veterinary Medicine at the University of Calgary and co-author, “The stress hormone, cortisol, is essential in helping bears cope with day-to-day changes and challenges, but when elevated in the long-term, it is associated with many negative health effects that can ultimately affect individuals and populations”
“Our findings highlight the importance of managing fisheries in a way that ensures enough salmon are allowed past fish nets to meet the needs of bears and other wildlife.” said Dr. Chris Darimont, UVic professor, Raincoast science director, and co-author. “While Canada’s existing policy for conserving Wild Salmon considers allocation of salmon to bears and other wildlife, the reality is that fisheries quotas are set based on human use alone,” added Chris Genovali, Raincoast’s Executive Director.
“The study provides important new information about bears in our Territory,” said William Housty, bear researcher and director of the Heiltsuk-driven research initiative Coastwatch. “As salmon people ourselves, we know the feeling of stress when salmon numbers are low.”
The study was conducted by scientists from the Raincoast Conservation Foundation, University of Victoria, and University of Calgary in collaboration with the Heiltsuk Integrated Resource Management Department on behalf of the Heiltsuk Nation and the Qqs Projects Society, a Heiltsuk-run non-governmental organization.
— originally published by the Raincoast Conservation Foundation
Comments