A National Park Service researcher holds a brook trout in Mount Rainier National Park, Washington. Scientists have found low levels of mercury found in fish from National Parks in Western States.
Collin Eagles-Smith
I am a Research Ecologist with the USGS Forest and Rangeland Ecosystem Science Center in Corvallis, Oregon. My research focuses on the interactions among ecological processes, contaminant bioaccumulation, and effects on wild populations.
My work specifically focuses on (1) the ecological factors regulating contaminant bioaccumulation and trophic transfer, with an emphasis on food web processes and contaminant cycling, (2) land use practices and ecosystem restoration effects on contaminant cycling through food webs, and (3) the sublethal effects of contaminants on individuals and contaminant-induced impairment to reproduction in the wild. My research is broadly applied across taxa - primarily fish and waterbirds, and habitat types - including lakes, freshwater wetlands, agricultural fields, and estuarine habitats.
Professional Experience
2010-present: Supervisory Research Ecologist, USGS Forest and Rangeland Ecosystem Science Center, Corvallis, OR
2007-2010: Wildlife Biologist, USGS Western Ecological Research Center, Davis, CA
2003-2007: Biologist, U.S. Fish and Wildlife Service, Sacramento, CA
Education and Certifications
Ph.D., Ecology, University of California, Davis, CA (2006)
B.S., Environmental Resource Sciences - Magna Cum Laude, University of California, Davis, CA (2000)
Science and Products
Contaminant Ecology Research Team (FRESC)
Prey Availability
Wildfires Increase Mercury Concentrations in Headwater Streams
The Dragonfly Mercury Project
Ecologically-Driven Exposure Pathways Science Team
Scientists Provide an Understanding of Anticoagulant Rodenticide Exposure in Non-Target Bird Species
Nationwide Occurrence
Bioaccumulation of Mercury in Fish Varied by Species and Location in the Chesapeake Bay Watershed—Summary of Existing Data and a Roadmap for Integrated Monitoring
Dragonfly Larvae are Effective Bioindicators of Mercury Exposure in Fish and Amphibians—Results of Citizen Science in 100 National Parks and Protected Places
Roadmap to Understanding Factors Influencing Mercury Exposure and Adverse Health Effects
Scientists Identify Processes that Affect Fish Mercury Concentrations in Estuarine Wetlands
Ecosystem Effects of Increased Coal Transport Across the Pacific Northwest
Contaminant Ecology Research Team (FRESC)
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
Ecosystem Metabolism Data for Brownlee Reservoir, Snake River, Idaho/Oregon, 2017-2023 Ecosystem Metabolism Data for Brownlee Reservoir, Snake River, Idaho/Oregon, 2017-2023
Total mercury and methylmercury concentrations in biota from the Hells Canyon Reservoir Complex on the Snake River, Idaho and Oregon, USA Total mercury and methylmercury concentrations in biota from the Hells Canyon Reservoir Complex on the Snake River, Idaho and Oregon, USA
Mercury concentrations in amphibian tissues and egg masses, fish tissues and sediment in subarctic, freshwater systems near Churchill, Manitoba, 2015-2019 Mercury concentrations in amphibian tissues and egg masses, fish tissues and sediment in subarctic, freshwater systems near Churchill, Manitoba, 2015-2019
Total mercury concentrations in bat tissues and blood from southwestern U.S. National Parks in 2023 Total mercury concentrations in bat tissues and blood from southwestern U.S. National Parks in 2023
Mercury in biota from Clear Lake, California (ver. 3.0, August 2024) Mercury in biota from Clear Lake, California (ver. 3.0, August 2024)
Mercury in soil, water, sediment, and biota in headwater streams associated with wildfires in the northwestern U.S., 2021-2022 Mercury in soil, water, sediment, and biota in headwater streams associated with wildfires in the northwestern U.S., 2021-2022
Mercury concentrations in dragonfly larvae from the Willamette River Basin, 2023 Mercury concentrations in dragonfly larvae from the Willamette River Basin, 2023
Mercury Stable Isotope Assessment of Dragonflies and Fish Tissues across United States National Parks Mercury Stable Isotope Assessment of Dragonflies and Fish Tissues across United States National Parks
Mercury in bird blood and benthic aquatic invertebrates in Plumas National Forest, 2015-2016 Mercury in bird blood and benthic aquatic invertebrates in Plumas National Forest, 2015-2016
Hydrological, Chemical, and Biological Characterization of the Snake River and Associated Tributaries and Irrigation Drains from River Mile 448 to 346, 2022 Hydrological, Chemical, and Biological Characterization of the Snake River and Associated Tributaries and Irrigation Drains from River Mile 448 to 346, 2022
Bibliography of hydrological and ecological research in the Great Basin terminal lakes, USA Bibliography of hydrological and ecological research in the Great Basin terminal lakes, USA
Modeled Pacific salmon escapement biomass and nutrient and contaminant concentrations across western North America, 1976-2015 (version 2.0, October 2024) Modeled Pacific salmon escapement biomass and nutrient and contaminant concentrations across western North America, 1976-2015 (version 2.0, October 2024)

A National Park Service researcher holds a brook trout in Mount Rainier National Park, Washington. Scientists have found low levels of mercury found in fish from National Parks in Western States.
Unknown lake in Mt. Rainier National Park
Unknown lake in Mt. Rainier National Park
Frozen fish samples awaiting mercury analysis
Frozen fish samples awaiting mercury analysis
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
Independent and interactive effects of disease and methylmercury on demographic rates across multiple amphibian populations Independent and interactive effects of disease and methylmercury on demographic rates across multiple amphibian populations
Climate-driven deoxygenation of lakes alters the nutrient-toxin profile of a food fish Climate-driven deoxygenation of lakes alters the nutrient-toxin profile of a food fish
Sampling dragonflies for mercury analysis in Grand Canyon National Park, 2018–2024: A contribution of the Dragonfly Mercury Project Sampling dragonflies for mercury analysis in Grand Canyon National Park, 2018–2024: A contribution of the Dragonfly Mercury Project
Selenium differentially influences methylmercury retention across mayfly life stages Selenium differentially influences methylmercury retention across mayfly life stages
Mercury trophic transfer to a freshwater biosentinel: Quantifying controlled bioaccumulation in larval dragonflies Mercury trophic transfer to a freshwater biosentinel: Quantifying controlled bioaccumulation in larval dragonflies
Contrasting magnitude and timing of pulsed aqueous methylmercury bioaccumulation across a reservoir food web Contrasting magnitude and timing of pulsed aqueous methylmercury bioaccumulation across a reservoir food web
Ecosystem drivers of freshwater mercury bioaccumulation are context-dependent: Insights from continental-scale modeling Ecosystem drivers of freshwater mercury bioaccumulation are context-dependent: Insights from continental-scale modeling
Methylmercury in subarctic amphibians: Environmental gradients, bioaccumulation, and estimated flux Methylmercury in subarctic amphibians: Environmental gradients, bioaccumulation, and estimated flux
Imperiled Great Basin terminal lakes: Synthesizing ecological and hydrological science gaps and research needs for waterbird conservation Imperiled Great Basin terminal lakes: Synthesizing ecological and hydrological science gaps and research needs for waterbird conservation
Riparian methylmercury production increases riverine mercury flux and food web concentrations Riparian methylmercury production increases riverine mercury flux and food web concentrations
A meta-analysis of mercury biomagnification in freshwater predatory invertebrates: Community diversity and dietary exposure drive variability A meta-analysis of mercury biomagnification in freshwater predatory invertebrates: Community diversity and dietary exposure drive variability
Continental-scale nutrient and contaminant delivery by Pacific salmon Continental-scale nutrient and contaminant delivery by Pacific salmon
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Per- and Polyfluoroalkyl Substances (PFAS) in U.S. Tapwater: Comparison of Public-Supply and Underserved Private-Well Exposures and Associated Health Implications Per- and Polyfluoroalkyl Substances (PFAS) in U.S. Tapwater: Comparison of Public-Supply and Underserved Private-Well Exposures and Associated Health Implications
Mercury Condition Index Tool Mercury Condition Index Tool
To request an interview, contact fresc_outreach@usgs.gov or call (541) 750-1030.
Science and Products
Contaminant Ecology Research Team (FRESC)
Prey Availability
Wildfires Increase Mercury Concentrations in Headwater Streams
The Dragonfly Mercury Project
Ecologically-Driven Exposure Pathways Science Team
Scientists Provide an Understanding of Anticoagulant Rodenticide Exposure in Non-Target Bird Species
Nationwide Occurrence
Bioaccumulation of Mercury in Fish Varied by Species and Location in the Chesapeake Bay Watershed—Summary of Existing Data and a Roadmap for Integrated Monitoring
Dragonfly Larvae are Effective Bioindicators of Mercury Exposure in Fish and Amphibians—Results of Citizen Science in 100 National Parks and Protected Places
Roadmap to Understanding Factors Influencing Mercury Exposure and Adverse Health Effects
Scientists Identify Processes that Affect Fish Mercury Concentrations in Estuarine Wetlands
Ecosystem Effects of Increased Coal Transport Across the Pacific Northwest
Contaminant Ecology Research Team (FRESC)
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
Ecosystem Metabolism Data for Brownlee Reservoir, Snake River, Idaho/Oregon, 2017-2023 Ecosystem Metabolism Data for Brownlee Reservoir, Snake River, Idaho/Oregon, 2017-2023
Total mercury and methylmercury concentrations in biota from the Hells Canyon Reservoir Complex on the Snake River, Idaho and Oregon, USA Total mercury and methylmercury concentrations in biota from the Hells Canyon Reservoir Complex on the Snake River, Idaho and Oregon, USA
Mercury concentrations in amphibian tissues and egg masses, fish tissues and sediment in subarctic, freshwater systems near Churchill, Manitoba, 2015-2019 Mercury concentrations in amphibian tissues and egg masses, fish tissues and sediment in subarctic, freshwater systems near Churchill, Manitoba, 2015-2019
Total mercury concentrations in bat tissues and blood from southwestern U.S. National Parks in 2023 Total mercury concentrations in bat tissues and blood from southwestern U.S. National Parks in 2023
Mercury in biota from Clear Lake, California (ver. 3.0, August 2024) Mercury in biota from Clear Lake, California (ver. 3.0, August 2024)
Mercury in soil, water, sediment, and biota in headwater streams associated with wildfires in the northwestern U.S., 2021-2022 Mercury in soil, water, sediment, and biota in headwater streams associated with wildfires in the northwestern U.S., 2021-2022
Mercury concentrations in dragonfly larvae from the Willamette River Basin, 2023 Mercury concentrations in dragonfly larvae from the Willamette River Basin, 2023
Mercury Stable Isotope Assessment of Dragonflies and Fish Tissues across United States National Parks Mercury Stable Isotope Assessment of Dragonflies and Fish Tissues across United States National Parks
Mercury in bird blood and benthic aquatic invertebrates in Plumas National Forest, 2015-2016 Mercury in bird blood and benthic aquatic invertebrates in Plumas National Forest, 2015-2016
Hydrological, Chemical, and Biological Characterization of the Snake River and Associated Tributaries and Irrigation Drains from River Mile 448 to 346, 2022 Hydrological, Chemical, and Biological Characterization of the Snake River and Associated Tributaries and Irrigation Drains from River Mile 448 to 346, 2022
Bibliography of hydrological and ecological research in the Great Basin terminal lakes, USA Bibliography of hydrological and ecological research in the Great Basin terminal lakes, USA
Modeled Pacific salmon escapement biomass and nutrient and contaminant concentrations across western North America, 1976-2015 (version 2.0, October 2024) Modeled Pacific salmon escapement biomass and nutrient and contaminant concentrations across western North America, 1976-2015 (version 2.0, October 2024)

A National Park Service researcher holds a brook trout in Mount Rainier National Park, Washington. Scientists have found low levels of mercury found in fish from National Parks in Western States.
A National Park Service researcher holds a brook trout in Mount Rainier National Park, Washington. Scientists have found low levels of mercury found in fish from National Parks in Western States.
Unknown lake in Mt. Rainier National Park
Unknown lake in Mt. Rainier National Park
Frozen fish samples awaiting mercury analysis
Frozen fish samples awaiting mercury analysis
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
Independent and interactive effects of disease and methylmercury on demographic rates across multiple amphibian populations Independent and interactive effects of disease and methylmercury on demographic rates across multiple amphibian populations
Climate-driven deoxygenation of lakes alters the nutrient-toxin profile of a food fish Climate-driven deoxygenation of lakes alters the nutrient-toxin profile of a food fish
Sampling dragonflies for mercury analysis in Grand Canyon National Park, 2018–2024: A contribution of the Dragonfly Mercury Project Sampling dragonflies for mercury analysis in Grand Canyon National Park, 2018–2024: A contribution of the Dragonfly Mercury Project
Selenium differentially influences methylmercury retention across mayfly life stages Selenium differentially influences methylmercury retention across mayfly life stages
Mercury trophic transfer to a freshwater biosentinel: Quantifying controlled bioaccumulation in larval dragonflies Mercury trophic transfer to a freshwater biosentinel: Quantifying controlled bioaccumulation in larval dragonflies
Contrasting magnitude and timing of pulsed aqueous methylmercury bioaccumulation across a reservoir food web Contrasting magnitude and timing of pulsed aqueous methylmercury bioaccumulation across a reservoir food web
Ecosystem drivers of freshwater mercury bioaccumulation are context-dependent: Insights from continental-scale modeling Ecosystem drivers of freshwater mercury bioaccumulation are context-dependent: Insights from continental-scale modeling
Methylmercury in subarctic amphibians: Environmental gradients, bioaccumulation, and estimated flux Methylmercury in subarctic amphibians: Environmental gradients, bioaccumulation, and estimated flux
Imperiled Great Basin terminal lakes: Synthesizing ecological and hydrological science gaps and research needs for waterbird conservation Imperiled Great Basin terminal lakes: Synthesizing ecological and hydrological science gaps and research needs for waterbird conservation
Riparian methylmercury production increases riverine mercury flux and food web concentrations Riparian methylmercury production increases riverine mercury flux and food web concentrations
A meta-analysis of mercury biomagnification in freshwater predatory invertebrates: Community diversity and dietary exposure drive variability A meta-analysis of mercury biomagnification in freshwater predatory invertebrates: Community diversity and dietary exposure drive variability
Continental-scale nutrient and contaminant delivery by Pacific salmon Continental-scale nutrient and contaminant delivery by Pacific salmon
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Per- and Polyfluoroalkyl Substances (PFAS) in U.S. Tapwater: Comparison of Public-Supply and Underserved Private-Well Exposures and Associated Health Implications Per- and Polyfluoroalkyl Substances (PFAS) in U.S. Tapwater: Comparison of Public-Supply and Underserved Private-Well Exposures and Associated Health Implications
Mercury Condition Index Tool Mercury Condition Index Tool
To request an interview, contact fresc_outreach@usgs.gov or call (541) 750-1030.