Grizzlies and salmon: Too much of a good thing?

Even grizzly bears should watch what they eat. It turns out that grizzlies that gorge themselves on salmon during the summer spawning season have much higher levels of contaminants in their bodies than their cousins who rely more on berries, plants and insects, according to Peter Ross of Canada’s Department of Fisheries and Oceans.

Reporting in an article to be published Sept. 15 in the American Chemical Society journal, Environmental Science & Technology, Canadian researchers say the difference in the concentration of persistent organic pollutants (POPs) is “profound” between grizzly bears who eat lots of salmon and those that don’t. The measurements were made by examining hair and fat samples from two groups of grizzly bears in the British Columbia region of Canada. One group included bears that had a steady diet of terrestrial foods, the other group included bears that shifted to marine food when the salmon returned from the Pacific Ocean to spawn.

Although the overall contaminant concentrations in the grizzlies are lower than many other species of animals that consume marine food, the researchers — from Canada’s Department of Fisheries and Oceans, the University of Victoria and Raincoast Conversation Society — say the reproductive window of the bears could be vulnerable to health impacts.