Gill net float at entrance to backwater habitat set to capture Grass Carp in the lower Huron River, OH. Photo credit: James Roberts, USGS.
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."
Science and Products
Science pages by this scientist
Improve Control Efficiency Through Better Understanding of Grass Carp Movements and Habitat Use
The goal of this project is to address the threat of invasive Grass Carp by developing a comprehensive understanding of seasonal movements, habitat use, and areas of aggregation to determine when and where eradication efforts would be most effective.
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.
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...
Multimedia related to this scientist
A Lone Net Float
Gill net float at entrance to backwater habitat set to capture Grass Carp in the lower Huron River, OH. Photo credit: James Roberts, USGS.
Releasing a Grass Carp with an Acoustic Tag
Tagged Grass Carp swimming away after being release post telemetry surgery into the Sandusky River, OH. Photo credit: James Roberts, USGS.
Tagged Grass Carp swimming away after being release post telemetry surgery into the Sandusky River, OH. Photo credit: James Roberts, USGS.
Sampling at an Elevated Railroad Bridge
USGS Great Lakes Science Center technician Jared Lesniewicz processes an ichthyoplankton sample during a survey assessing grass carp spawning in the Cuyahoga River, a Lake Erie tributary in Cleveland, Ohio. As of the 2024 sampling season, no grass carp spawning has been documented in the Cuyahoga River. Photo Credit: James Roberts, USGS.
USGS Great Lakes Science Center technician Jared Lesniewicz processes an ichthyoplankton sample during a survey assessing grass carp spawning in the Cuyahoga River, a Lake Erie tributary in Cleveland, Ohio. As of the 2024 sampling season, no grass carp spawning has been documented in the Cuyahoga River. Photo Credit: James Roberts, USGS.
Grass Carp Eggs
An ichthyoplankton net sample within a collection bucket from the Sandusky River in May of 2022. Grass carp (Ctenopharyngodon idella) eggs are pictured in the foreground (semi-transparent spheres). Photo Credit: James Roberts, USGS
An ichthyoplankton net sample within a collection bucket from the Sandusky River in May of 2022. Grass carp (Ctenopharyngodon idella) eggs are pictured in the foreground (semi-transparent spheres). Photo Credit: James Roberts, USGS
Blocknet Backlog
Downstream blocknet as part of an electrofishing survey of the fish community in Sevenmile Creek, Pictured Rocks National Lakeshore in northern Michigan. Photo credit: James Roberts, USGS.
Downstream blocknet as part of an electrofishing survey of the fish community in Sevenmile Creek, Pictured Rocks National Lakeshore in northern Michigan. Photo credit: James Roberts, USGS.
Holding Pattern
Fish in a holding net waiting to be measured following an electrofishing survey of Sevenmile Creek in Pictured Rocks National Lakeshore, Michigan. Photo credit: James Roberts, USGS.
Fish in a holding net waiting to be measured following an electrofishing survey of Sevenmile Creek in Pictured Rocks National Lakeshore, Michigan. Photo credit: James Roberts, USGS.
Day at the Beach
A slimy sculpin from Miners Creek in Pictured Rocks National Lakeshore, Michigan. Photo credit: James Roberts, USGS.
A slimy sculpin from Miners Creek in Pictured Rocks National Lakeshore, Michigan. Photo credit: James Roberts, USGS.
Science and Products
Science pages by this scientist
Improve Control Efficiency Through Better Understanding of Grass Carp Movements and Habitat Use
The goal of this project is to address the threat of invasive Grass Carp by developing a comprehensive understanding of seasonal movements, habitat use, and areas of aggregation to determine when and where eradication efforts would be most effective.
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.
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...
Multimedia related to this scientist
A Lone Net Float
Gill net float at entrance to backwater habitat set to capture Grass Carp in the lower Huron River, OH. Photo credit: James Roberts, USGS.
Gill net float at entrance to backwater habitat set to capture Grass Carp in the lower Huron River, OH. Photo credit: James Roberts, USGS.
Releasing a Grass Carp with an Acoustic Tag
Tagged Grass Carp swimming away after being release post telemetry surgery into the Sandusky River, OH. Photo credit: James Roberts, USGS.
Tagged Grass Carp swimming away after being release post telemetry surgery into the Sandusky River, OH. Photo credit: James Roberts, USGS.
Sampling at an Elevated Railroad Bridge
USGS Great Lakes Science Center technician Jared Lesniewicz processes an ichthyoplankton sample during a survey assessing grass carp spawning in the Cuyahoga River, a Lake Erie tributary in Cleveland, Ohio. As of the 2024 sampling season, no grass carp spawning has been documented in the Cuyahoga River. Photo Credit: James Roberts, USGS.
USGS Great Lakes Science Center technician Jared Lesniewicz processes an ichthyoplankton sample during a survey assessing grass carp spawning in the Cuyahoga River, a Lake Erie tributary in Cleveland, Ohio. As of the 2024 sampling season, no grass carp spawning has been documented in the Cuyahoga River. Photo Credit: James Roberts, USGS.
Grass Carp Eggs
An ichthyoplankton net sample within a collection bucket from the Sandusky River in May of 2022. Grass carp (Ctenopharyngodon idella) eggs are pictured in the foreground (semi-transparent spheres). Photo Credit: James Roberts, USGS
An ichthyoplankton net sample within a collection bucket from the Sandusky River in May of 2022. Grass carp (Ctenopharyngodon idella) eggs are pictured in the foreground (semi-transparent spheres). Photo Credit: James Roberts, USGS
Blocknet Backlog
Downstream blocknet as part of an electrofishing survey of the fish community in Sevenmile Creek, Pictured Rocks National Lakeshore in northern Michigan. Photo credit: James Roberts, USGS.
Downstream blocknet as part of an electrofishing survey of the fish community in Sevenmile Creek, Pictured Rocks National Lakeshore in northern Michigan. Photo credit: James Roberts, USGS.
Holding Pattern
Fish in a holding net waiting to be measured following an electrofishing survey of Sevenmile Creek in Pictured Rocks National Lakeshore, Michigan. Photo credit: James Roberts, USGS.
Fish in a holding net waiting to be measured following an electrofishing survey of Sevenmile Creek in Pictured Rocks National Lakeshore, Michigan. Photo credit: James Roberts, USGS.
Day at the Beach
A slimy sculpin from Miners Creek in Pictured Rocks National Lakeshore, Michigan. Photo credit: James Roberts, USGS.
A slimy sculpin from Miners Creek in Pictured Rocks National Lakeshore, Michigan. Photo credit: James Roberts, USGS.