Salmon shortages leave grizzly bears stressed

New Scientist, 10 August 2012

SALMON shortages on Canada’s west coast may leave grizzlies there more stressed than the average bear.

Heather Bryan at the University of Calgary in Alberta, Canada, working with the Raincoast Conservation Foundation in British Columbia, collected hair from grizzly and black bears across a 5000-square-kilometre area of British Columbia between 2009 and 2011. She looked for correlations between diet and hormone levels through DNA analysis, stable isotope analysis, and by quantifying hormone levels in the hair.

Male grizzly bears that depend on having salmon in their diet had higher levels of the stress hormone cortisol when they ate less fish. Studies in other mammals suggest that chronically high cortisol levels may suppress the immune system, leaving animals vulnerable to disease.

Coastal grizzlies also had higher levels of testosterone than their non-salmon-eating relatives in the interior. “That might be related to social interaction,” says Bryan. “Since there are more bears on the coast, they have a higher population density and potentially more competition over limited resources like salmon.”

Further monitoring should help predict how the coastal grizzlies will respond to environmental change, since many acquire 80 to 90 per cent of their dietary protein from salmon. Bryan presented her results at the Ecological Society of America meeting in Portland, Oregon, this week.

Click here to read the article on New Scientist website.

Help us protect KELÁ_EKE Kingfisher Forest

Together with Pender Islands Conservancy, we are raising funds to purchase and permanently protect a 45 acre forested property on the edge of the Salish Sea. The KELÁ_EKE Kingfisher Forest is located within the Coastal Douglas-fir (CDF) biogeoclimatic zone, one of the most biodiverse ecosystems in Canada. It is also among the most threatened in Canada. Protecting these forests is an investment in our collective future.

We’ve just announced a donation matching campaign to support the purchase and permanent protection of KELÁ_EKE Kingfisher Forest. Every dollar donated before December 31, 2022 will be matched by anonymous donors. This is a chance for you to double your impact!