title: Estimating Mercury Exposure of Piscivorous Birds and Sport Fish Using Prey Fish Monitoring.
abstract: Methylmercury is a global pollutant of aquatic ecosystems, and monitoring programs need tools to predict mercury exposure of wildlife. We developed equations to estimate methylmercury exposure of piscivorous birds and sport fish using mercury concentrations in prey fish. We collected original data on western grebes (Aechmophorus occidentalis) and Clark's grebes (Aechmophorus clarkii) and summarized the published literature to generate predictive equations specific to grebes and a general equation for piscivorous birds. We measured mercury concentrations in 354 grebes (blood averaged 1.06 ± 0.08 μg/g ww), 101 grebe eggs, 230 sport fish (predominantly largemouth bass and rainbow trout), and 505 prey fish (14 species) at 25 lakes throughout California. Mercury concentrations in grebe blood, grebe eggs, and sport fish were strongly related to mercury concentrations in prey fish among lakes. Each 1.0 μg/g dw (∼0.24 μg/g ww) increase in prey fish resulted in an increase in mercury concentrations of 103% in grebe blood, 92% in grebe eggs, and 116% in sport fish. We also found strong correlations between mercury concentrations in grebes and sport fish among lakes. Our results indicate that prey fish monitoring can be used to estimate mercury exposure of piscivorous birds and sport fish when wildlife cannot be directly sampled.
authors.affiliation: U.S. Geological Survey , Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive, Suite D, Dixon, California 95620, United States.
authors.forename: Joshua T
authors.initials: JT
authors.lastname: Ackerman
authors.affiliation: U.S. Geological Survey , Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive, Suite D, Dixon, California 95620, United States.
authors.forename: C Alex
authors.initials: CA
authors.lastname: Hartman
authors.affiliation: U.S. Geological Survey , Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, Oregon 97331, United States.
authors.forename: Collin A
authors.initials: CA
authors.lastname: Eagles-Smith
authors.affiliation: U.S. Geological Survey , Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive, Suite D, Dixon, California 95620, United States.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Herzog
authors.affiliation: San Francisco Estuary Institute , 4911 Central Avenue, Richmond, California 94804, United States.
authors.forename: Jay
authors.initials: J
authors.lastname: Davis
authors.affiliation: California Department of Fish and Wildlife , 7544 Sandholdt Road, Moss Landing, California 95039, United States.
authors.forename: Gary
authors.initials: G
authors.lastname: Ichikawa
authors.affiliation: Moss Landing Marine Laboratories , 7544 Sandholdt Road, Moss Landing, California 95039, United States.
authors.forename: Autumn
authors.initials: A
authors.lastname: Bonnema
mesh_terms: D000818:Animals; D001492:Bass / Q000502:physiology; D001717:Birds / Q000502:physiology*; D002140:California; D017753:Ecosystem; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D005260:Female; D005399:Fishes; D060106:Lakes; D008628:Mercury / Q000032:analysis* / Q000097:blood; D008767:Methylmercury Compounds / Q000032:analysis; D010063:Ovum / Q000187:drug effects / Q000378:metabolism; D011235:Predatory Behavior; D018570:Risk Assessment / Q000379:methods; D014337:Trout / Q000378:metabolism / Q000502:physiology; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D008767:Methylmercury Compounds; D014874:Water Pollutants, Chemical; D008628:Mercury