title: Terrestrial Scavenging of Marine Mammals: Cross-Ecosystem Contaminant Transfer and Potential Risks to Endangered California Condors (Gymnogyps californianus).
abstract: The critically endangered California condor (Gymnogyps californianus) has relied intermittently on dead-stranded marine mammals since the Pleistocene, and this food source is considered important for their current recovery. However, contemporary marine mammals contain persistent organic pollutants that could threaten condor health. We used stable carbon and nitrogen isotope, contaminant, and behavioral data in coastal versus noncoastal condors to quantify contaminant transfer from marine mammals and created simulation models to predict the risk of reproductive impairment for condors from exposure to DDE (p,p'-DDE), a major metabolite of the chlorinated pesticide DDT. Coastal condors had higher whole blood isotope values and mean concentrations of contaminants associated with marine mammals, including mercury (whole blood), sum chlorinated pesticides (comprised of ∼95% DDE) (plasma), sum polychlorinated biphenyls (PCBs) (plasma), and sum polybrominated diphenyl ethers (PBDEs) (plasma), 12-100-fold greater than those of noncoastal condors. The mean plasma DDE concentration for coastal condors was 500 ± 670 (standard deviation) (n = 22) versus 24 ± 24 (standard deviation) (n = 8) ng/g of wet weight for noncoastal condors, and simulations predicted ∼40% of breeding-age coastal condors have DDE levels associated with eggshell thinning in other avian species. Our analyses demonstrate potentially harmful levels of marine contaminant transfer to California condors, which could hinder the recovery of this terrestrial species.
authors.affiliation: Division of Biological Sciences, Ecology, Behavior, and Evolution Section, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Kurle
authors.affiliation: Department of Ecology, Montana State University , Bozeman, Montana 59717-3460, United States.
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Bakker
authors.affiliation: The Nature Conservancy , 258 Main Street, Lander, Wyoming 82520, United States.
authors.forename: Holly
authors.initials: H
authors.lastname: Copeland
authors.affiliation: Ventana Wildlife Society , 19045 Portola Drive, Suite F-1, Salinas, California 93908, United States.
authors.forename: Joe
authors.initials: J
authors.lastname: Burnett
authors.affiliation: Pinnacles National Park, National Park Service , 5000 Highway 146, Paicines, California 95043, United States.
authors.forename: Jennie
authors.initials: J
authors.lastname: Jones Scherbinski
authors.affiliation: United States Fish and Wildlife Service , 2493 Portola Road, Suite B, Ventura, California 93003, United States.
authors.forename: Joseph
authors.initials: J
authors.lastname: Brandt
authors.affiliation: Department of Microbiology and Environmental Toxicology, University of California , Santa Cruz, California 95064, United States.
authors.forename: Myra E
authors.initials: ME
authors.lastname: Finkelstein
mesh_terms: D000818:Animals; D001717:Birds; D002140:California; D003633:Dichlorodiphenyl Dichloroethylene; D017753:Ecosystem; D006843:Hydrocarbons, Chlorinated; D011078:Polychlorinated Biphenyls
chemical_list: D006843:Hydrocarbons, Chlorinated; D003633:Dichlorodiphenyl Dichloroethylene; D011078:Polychlorinated Biphenyls