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James J Roberts, PhD

James J Roberts is a Research Fisheries Biologist based in Huron, OH.

James has broad research expertise and investigates the ecological consequences of stressors like invasive species, climate change, and eutrophication for aquatic systems and specifically fish populations. There are three overall themes his research is split between (Invasive species, native fish ecology/conservation, and climate changes effects) which are all related to the conservation and management of aquatic species and systems.  

Currently, he is investigating the movement, behavior, and habitat use of Grass Carp, an invasive species in the Great Lakes. He has also conducted research in the Laurentian Great Lakes examining the ecological consequences of seasonal hypolimnetic hypoxia, dead zones, in Lake Erie. Specifically, he studied the effects (behavioral, physiological, and inter-specific) of hypoxia on the benthic fish assemblage of Lake Erie, while focusing on yellow perch. Previously, James has explored the potential effects climate change may have on the persistence of Cutthroat Trout in stream and lake habitats throughout the Southern Rocky Mountain region."

Professional Experience

  • Research Fisheries Biologist, USGS 2020-present; Great Lakes Science Center

  • Fish Biologist, USGS 2015-2020; Colorado Water Science Center

  • Research Ecologist-Mendenhall Fellow, USGS 2012-2015; Fort Collins Science Center

Education and Certifications

  • Ph.D. University of Michigan

  • M.S. University of Wyoming

  • B.S. University of Michigan

Science and Products

Science pages by this scientist

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Scientists work on insect traps in the Prairie Pothole region of North Dakota.

Aquatic Ecology and Contaminants

The Aquatic Ecology and Contaminants Team investigates critical ecological processes operating in aquatic and riparian ecosystems and how these processes are affected by human activities. We address questions through a combination of field studies, laboratory experiments, and modeling, while working at multiple levels of biological organization from cells through ecosystems. Topics include land...
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Land Management Research Program, Fort Collins Science Center
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Aquatic Ecology and Contaminants

The Aquatic Ecology and Contaminants Team investigates critical ecological processes operating in aquatic and riparian ecosystems and how these processes are affected by human activities. We address questions through a combination of field studies, laboratory experiments, and modeling, while working at multiple levels of biological organization from cells through ecosystems. Topics include land...
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A cutthroat trout up close. James Roberts photo. USGS.

Ecological Responses to Fish Reclamation Treatments

Piscicides have been used in Rocky Mountain stream and lakes to restore native fish populations. In the last two decades concerns over piscicide effects to non-target organisms, primarily aquatic invertebrates, has increased. Although piscicides have been used for more than 70 years the impact to invertebrate assemblages has not been well studied and is largely unknown. Given the importance a...
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Ecosystems Mission Area, Water Resources Mission Area, Species Management Research Program, Fort Collins Science Center
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Ecological Responses to Fish Reclamation Treatments

Piscicides have been used in Rocky Mountain stream and lakes to restore native fish populations. In the last two decades concerns over piscicide effects to non-target organisms, primarily aquatic invertebrates, has increased. Although piscicides have been used for more than 70 years the impact to invertebrate assemblages has not been well studied and is largely unknown. Given the importance a...
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A cutthroat trout up close. James Roberts photo. USGS.

Climate Change and Trout

Cold-water fishes like trout, salmon, and charr are especially vulnerable to shifting conditions related to climate change; for example, warmer temperatures and more variable hydroclimate. Native cutthroat trout of the southern Rocky Mountains now only occupy a tiny fraction of their historic habitats because of stressors such as non-native fishes, habitat fragmentation, and detrimental land...
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Ecosystems Mission Area, Species Management Research Program, Fort Collins Science Center
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Climate Change and Trout

Cold-water fishes like trout, salmon, and charr are especially vulnerable to shifting conditions related to climate change; for example, warmer temperatures and more variable hydroclimate. Native cutthroat trout of the southern Rocky Mountains now only occupy a tiny fraction of their historic habitats because of stressors such as non-native fishes, habitat fragmentation, and detrimental land...
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Cover image SIR 2017-5162

Characterization of Water Quality and Biology in the Fountain Creek Watershed

Monument and Fountain Creeks and their respective watersheds, located in the Front Range of Colorado, serve as important drainages for surface runoff, waste-water treatment operations, and as a water supply for downstream agricultural needs. As population growth continues in these watersheds, more and more pressures are being applied to the receiving streams, especially Fountain Creek.
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Colorado Water Science Center
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Characterization of Water Quality and Biology in the Fountain Creek Watershed

Monument and Fountain Creeks and their respective watersheds, located in the Front Range of Colorado, serve as important drainages for surface runoff, waste-water treatment operations, and as a water supply for downstream agricultural needs. As population growth continues in these watersheds, more and more pressures are being applied to the receiving streams, especially Fountain Creek.
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Native westslope cutthroat trout swim in the north fork of the Flathead River in northwestern Montana.

The Past as a Prelude to the Future: Assessing Climate Effects on Native Trout in the U.S.

Salmonids (a family of fish that includes salmon, trout, and char) are a keystone species for both aquatic and terrestrial ecosystems, and can be an early warning indicator of ecosystem health. Salmonids also have strong societal values and contribute enormously to regional economies and Native American cultures. Today, many native salmonid populations are small, highly fragmented, and isolated fr
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Climate Adaptation Science Centers
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The Past as a Prelude to the Future: Assessing Climate Effects on Native Trout in the U.S.

Salmonids (a family of fish that includes salmon, trout, and char) are a keystone species for both aquatic and terrestrial ecosystems, and can be an early warning indicator of ecosystem health. Salmonids also have strong societal values and contribute enormously to regional economies and Native American cultures. Today, many native salmonid populations are small, highly fragmented, and isolated fr
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Data releases by this scientist

Dataset for temporal influences on selenium partitioning, trophic transfer, and exposure in a major U.S. river

The trace element selenium is an essential element with a narrow window between concentrations needed to support life and those that cause toxicity to egg laying organisms. Selenium bioaccumulation in aquatic organisms is primarily the result of trophic transfer through food webs and is poorly predicted by dissolved concentrations in freshwater bodies. To better understand the hydrologic and biolo
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Wyoming-Montana Water Science Center

Invertebrate community data from native trout lakes and streams in the Southern Rocky Mountains

Native trout in the West suffer a high degree of vulnerability, as highlighted by cutthroat trout, a group of 14 subspecies, most of which have been petitioned for listing under the Endangered Species Act (ESA). In the Southern Rocky Mountains, greenback cutthroat trout (Oncorhynchus clarkii stomias; GBCT) are listed as threatened under the ESA, and few populations remain, in part because of the i
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Colorado Water Science Center

Fish tissue mercury and selenium concentrations in Upper Colorado River Basin: 1962-2011

These data were compiled to study mercury and selenium concentrations in fish species and assemblages in lotic waterbodies across the Upper Colorado River Basin. Data were compiled from State and Federal agencies. This data table contains raw concentration data, as well as standardized concentrations corrected for differences based on sample type (i.e., tissue type), species-specific bioaccumulati
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Southwest Biological Science Center

Multimetric Index macroinvertebrate values from the Fountain Creek Basin, Colorado 2005 to 2016.

These data have been collected as part of a cooperative project in between the U.S. Geological Survey Colorado Water Science Center, Colorado Springs Utility, and Colorado Springs Engineering. This project began in 2005 and has collected macroinvertebrate samples from Fountain Creek and its tributaries to monitor the biological condition of this watershed. Provided in this data release are Multime
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Fort Collins Science Center

Datasets of ecological communities (invertebrates and fish), streamflow, habitat, and water quality to examine the presence of trends in ecological communities from the Fountain Creek basin, Colorado, USA, 2003-2016.

These data were used for an analysis as part of a long-term project monitoring the biological communities, habitat, and water quality of the Fountain Creek Basin. Biology, habitat, and water quality data have been collected at 10 sites starting in 2003. These data include annual samples of aquatic invertebrate communities, fish communities, water quality, and quantitative riverine habitat collecte
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Colorado Water Science Center

Multimedia related to this scientist

Electrofishing in a Shallow River
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Fish in a Holding Net
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Slimy Sculpin in the Sand
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Publications by this scientist

Filter Total Items: 20

U.S. Geological Survey invasive carp strategic framework, 2023–27

U.S. Geological Survey (USGS) research has supported management of Hypophthalmichthys nobilis (bighead carp), Mylopharyngodon piceus (black carp), Ctenopharyngodon idella (grass carp), and H. molitrix (silver carp), hereafter referred to collectively as invasive carps, for over a decade. This strategic framework identifies thematic research areas to guide funding decisions for USGS invasive carp r
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Duane Chapman, Jon Amberg, Robin Calfee, Enrika Hlavacek, Jon Hortness, P. Ryan Jackson, David C. Kazyak, Brent Knights, James Roberts
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Ecosystems Mission Area

Stream size, temperature, and density explain body sizes of freshwater salmonids across a range of climate conditions

Climate change and anthropogenic activities are altering the body sizes of fishes, yet our understanding of factors influencing body size for many taxa remains incomplete. We evaluated the relationships between climate, environmental, and landscape attributes and the body size of different taxa of freshwater trout (Salmonidae) in the USA. Hierarchical spatial modeling across a gradient of habitats
Authors
Robert K. Al-Chokhachy, Benjamin Letcher, Clint C. Muhlfeld, Jason Dunham, Timothy Joseph Cline, Nathaniel P. Hitt, James Roberts, David Schmetterling
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Ecosystems Mission Area, Fort Collins Science Center, Eastern Ecological Science Center, Northern Rocky Mountain Science Center

Fisheries research and monitoring activities of the Lake Erie Biological Station, 2020

This report presents biomass-based summaries of fish communities in the West Basin of Lake Erie derived from USGS bottom trawl surveys conducted from 2013 to 2020 during June and September. The survey design provided temporal and spatial coverage that did not exist in the interagency trawl database, and thus complemented the August ODNR-OMNRF effort to reinforce stock assessments with more robust
Authors
Kevin R. Keretz, Patrick Kočovský, Richard Kraus, James Roberts, Joseph Schmitt
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Ecosystems Mission Area, Great Lakes Science Center

Temporal influences on selenium partitioning, trophic transfer, and exposure in a major U.S. river

Hydrologic and irrigation regimes mediate the timing of selenium (Se) mobilization to rivers, but the extent to which patterns in Se uptake and trophic transfer through recipient food webs reflect the temporal variation in Se delivery is unknown. We investigated Se mobilization, partitioning, and trophic transfer along approximately 60 river miles of the selenium-impaired segment of the Lower Gunn
Authors
Jessica E Brandt, James Roberts, Craig A. Stricker, Holly Rogers, Patricia Nease, Travis S. Schmidt
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Ecosystems Mission Area, Water Resources Mission Area, Fort Collins Science Center, Great Lakes Science Center, Wyoming-Montana Water Science Center

Mercury and selenium concentrations in fishes of the Upper Colorado River Basin, southwestern United States: A retrospective assessment

Mercury (Hg) and selenium (Se) are contaminants of concern for fish in the Upper Colorado River Basin (UCRB). We explored Hg and Se in fish tissues (2,324 individuals) collected over 50 years (1962–2011) from the UCRB. Samples include native and non-native fish collected from lotic waterbodies spanning 7 major tributaries to the Colorado River. There was little variation of total mercury (THg) in
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Natalie K. Day, Travis Schmidt, James Roberts, Barbara C. Osmundson, James Willacker, Collin Eagles-Smith
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Ecosystems Mission Area, Colorado Water Science Center, Southwest Biological Science Center

Predicting persistence of Rio Grande Cutthroat Trout populations in an uncertain future

The Rio Grande Cutthroat Trout Oncorhynchus clarkii virginalis (RGCT ) occupies just 12% of its ancestral range. As the southernmost subspecies of Cutthroat Trout, we expect a warming climate to bring additional stressors to RGCT populations, such as increased stream temperatures, reduced streamflows, and increased incidence of wildfire. We developed a Bayesian network (BN ) model using site‐speci
Authors
Mathew P. Zeigler, Kevin B. Rogers, James Roberts, Andrew Todd, Kurt D. Fausch
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Ecosystems Mission Area, Fort Collins Science Center

Estimating lake–climate responses from sparse data: An application to high elevation lakes

Although many studies demonstrate lake warming, few document trends from lakes with sparse data. Diel and seasonal variability of surface temperatures limit conventional trend analyses to datasets with frequent repeated observations. Thus, remote lakes, including many high elevation lakes, are underrepresented in trend analyses. We used a Bayesian technique to analyze sparse data that explicitly i
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Kyle R. Christianson, Brett M. Johnson, Mevin Hooten, James Roberts
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Ecosystems Mission Area, Cooperative Research Units, Fort Collins Science Center

Comparability among four invertebrate sampling methods and two multimetric indexes, Fountain Creek Basin, Colorado, 2010–2012

The U.S. Geological Survey (USGS), in cooperation with Colorado Springs City Engineering and Colorado Springs Utilities, analyzed previously collected invertebrate data to determine the comparability among four sampling methods and two versions (2010 and 2017) of the Colorado Benthic Macroinvertebrate Multimetric Index (MMI). For this study, annual macroinvertebrate samples were collected concurre
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James F. Bruce, James Roberts, Robert E. Zuellig
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Water Resources Mission Area, Colorado Water Science Center

Changes in biological communities of the Fountain Creek Basin, Colorado, 2003–2016, in relation to antecedent streamflow, water quality, and habitat

The analysis described in this report is part of a longterm project monitoring the biological communities, habitat, and water quality of the Fountain Creek Basin. Biology, habitat, and water-quality data have been collected at 10 sites since 2003. These data include annual samples of aquatic invertebrate communities, fish communities, water quality, and quantitative riverine habitat. This report e
Authors
James Roberts, James F. Bruce, Robert E. Zuellig
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Water Resources Mission Area, Colorado Water Science Center

Thermal regimes of Rocky Mountain lakes warm with climate change

Anthropogenic climate change is causing a wide range of stresses in aquatic ecosystems, primarily through warming thermal conditions. Lakes, in response to these changes, are experiencing increases in both summer temperatures and ice-free days. We used continuous records of lake surface temperature and air temperature to create statistical models of daily mean lake surface temperature to assess th
Authors
James Roberts, Kurt D. Fausch, Travis S. Schmidt, David M. Walters
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Water Resources Mission Area, Climate Research and Development Program, Land Change Science Program, Colorado Water Science Center

Effects of internal phosphorus loadings and food-web structure on the recovery of a deep lake from eutrophication

We used monitoring data from Lake Lugano (Switzerland and Italy) to assess key ecosystem responses to three decades of nutrient management (1983–2014). We investigated whether reductions in external phosphorus loadings (Lext) caused declines in lake phosphorus concentrations (P) and phytoplankton biomass (Chl a), as assumed by the predictive models that underpinned the management plan. Additionall
Authors
Fabio Lepori, James Roberts
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Water Resources Mission Area, Colorado Water Science Center

Nonnative trout invasions combined with climate change threaten persistence of isolated cutthroat trout populations in the southern Rocky Mountains

Effective conservation of Cutthroat Trout Oncorhynchus clarkii lineages native to the Rocky Mountains will require estimating effects of multiple stressors and directing management toward the most important ones. Recent analyses have focused on the direct and indirect effects of a changing climate on contemporary ranges, which are much reduced from historic ranges owing to past habitat loss and no
Authors
James Roberts, Kurt D. Fausch, Mevin Hooten, Douglas P. Peterson
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Water Resources Mission Area, Ecosystems Mission Area, Fort Collins Science Center, Colorado Water Science Center

Non-USGS Publications**

Isaak, D.J., C.C. Muhlfeld, A.S. Todd, R. Al-Chokhatchy, J.J. Roberts, K.D. Fausch, J.L. Kershner, and S.W. Hostetler. 2012 The past as prelude to the future: Retrospective assessments for anticipating future climate vulnerabilities of salmonid fishes in the Rocky Mountain West. Fisheries 37(12): 542-556.
Goto, D., K. Lindelof, D.L. Fanslow, S.A. Ludsin, J.J. Roberts, H.A. Vanderploeg, A.F. Wilson, and T.O. Höök. 2012. Indirect consequences of hypolimnetic hypoxia on
zooplankton growth in a large eutrophic lake. Aquatic Biology 16: 217-227.
Roberts, J.J., P.A. Grecay, S.A. Ludsin, S.A. Pothoven, H.A. Vanderploeg, and T.O. Höök. 2012 Evidence of hypoxic foraging forays by yellow perch (Perca flavescens) and potential consequences for prey consumption. Freshwater Biology 57: 922-937.
Roberts, J.J., T.O. Hook, S.A. Ludsin, S.A. Pothoven, H.A. Vanderploeg, and S.B. Brandt. 2009. Effects of hypolimnetic hypoxia in Lake Erie's central basin on foraging and distribution of yellow perch. Journal of Experimental Marine Biology and Ecology. 131:S132-S142.
Roberts, J.J. and F.J. Rahel. 2008. Irrigation canals as sink habitat for trout and other fishes in a Wyoming drainage. Transactions of the American Fisheries Society. 137:951-961.
Roberts, J.J. and F.J. Rahel. 2005. Accuracy of aerial telemetry in fisheries studies. North American Journal of Fisheries Management. 25:660-666.
Roberts, J.J. 2010. The ecological consequences of hypoxia for yellow perch (Perca flavescens) in Lake Erie. Doctoral Dissertation. 181 pp.

**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.

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