HR: 0800h
AN: B21D-0919    [Abstracts]
TI: Salmon-Eating Grizzly Bears Exposed to Elevated Levels of Marine Derived Persistent Organic Pollutants
AU: Christensen, J R
EM: ChristensenJ@pac.dfo-mpo.gc.ca
AF: School of Earth and Ocean Sciences, E-Hut University of Victoria , Victoria, bc V8W 2Y2 Canada
AU: Ross, P S
EM: RossPe@pac.dfo-mpo.gc.ca
AF: Institute of Ocean Sciences, Department of Fisheries and Oceans 9860 West Saanich Rd, Sidney, BC V8L 4B2 Canada
AU: * Whiticar, M J
EM: whiticar@uvic.ca
AF: School of Earth and Ocean Sciences, E-Hut University of Victoria , Victoria, bc V8W 2Y2 Canada
AB: The coastal grizzly bears of British Columbia (BC, Canada) rely heavily on salmon returning from the Pacific Ocean, whereas interior bears do not have access to or readily utilize this marine-derived food source. Since salmon have been shown to accumulate persistent organic pollutants (POPs) from the North Pacific Ocean, we hypothesized that salmon consumption by grizzly bears would be reflected by an increase in the POP burden. To test this hypothesis we collected hair and fat tissue from grizzlies at various locations around BC to compare salmon-eating (coastal) grizzlies to non-salmon-eating (interior) grizzlies. We characterized the feeding habits for each bear sampled by measuring the stable carbon and nitrogen isotope signature of their hair. The positive relationship between 13C/12C and 15N/14N isotopic ratios suggests that the majority of the meat portion of the diet of coastal grizzlies is coming from salmon, rather than from terrestrial or freshwater sources. By contrast, stable isotope ratios revealed that interior bears have an almost exclusive vegetarian diet with no marine influence. As hypothesized, the coastal grizzly bears have significantly greater OC pesticide and lower-brominated PBDE congener body burden than the interior grizzlies. We also found a positive relationship between C and N isotope ratios and these same POP contaminants in bear tissue. Overall, these results demonstrate that Pacific salmon represents a significant vector delivering both OC pesticides and PBDEs to BC coastal grizzly bears.
UR: http://www.biogeochemistry.uvic.ca
DE: 4805 Biogeochemical cycles (1615)
DE: 4840 Microbiology
DE: 4870 Stable isotopes
DE: 1055 Organic geochemistry
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting