Assistant Unit Leader - Montana Cooperative Fishery Research Unit
Research Interests
- Fish ecology
- Fishery stock assessment
- Fishery management regulations and tools
- Native and non-native species interactions
Teaching Interests
- Fisheries Science
- Fisheries Techniques
Professional Experience
Assistant Unit Leader, Montana Cooperative Fishery Research Unit, 1994-
Education and Certifications
Ph D South Dakota State University 1993
Science and Products
Filter Total Items: 37
Accuracy of histology, endoscopy, ultrasonography, and plasma sex steroids in describing the population reproductive structure of hatchery-origin and wild white sturgeon
Hatchery-origin white sturgeon Acipenser transmontanus in the lower Columbia River, Canada are approaching puberty, and describing the reproductive structure of the population is critical to determine if they are capable of contributing to spawning events in the wild, a key management uncertainty. Few studies have compared the accuracy of available tools (histology, ultrasound, endoscopy, and plas
Authors
Paige A. C. Maskill, James A. Crossman, Molly A. H. Webb, Marco M. Marrello, Christopher S. Guy
Diets and stable isotope signatures of native and nonnative Leucisid fishes advances our understanding of the Yellowstone Lake food web
(1) Many forage fishes, such as Leucisids (minnows) have depauperate studies on diet composition or stable isotope signatures, as these fishes are often only viewed as food for higher trophic levels. The need exists to understand and document the diet and stable isotope signatures of Leucisids (redside shiner, longnose dace, lake chub) in relation to the community ecology and food-web dynamics in
Authors
Hayley C. Glassic, Christopher S. Guy, Todd M. Koel
Quantifying the spatial structure of invasive lake trout in Yellowstone Lake to improve suppression efficacy
Invasive Lake Trout Salvelinus namaycush have altered the once-pristine Yellowstone Lake ecosystem through top-down effects by consuming Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri. To conserve Yellowstone Cutthroat Trout and restore the ecosystem, a Lake Trout gillnetting program was implemented to suppress the invasive population. We evaluated the spatial structure of Lake Trout in
Authors
Jacob R. Williams, Christopher S. Guy, Patricia E. Bigelow, Todd M. Koel
Burbot (Lota lota) exhibit plasticity in life-history traits in a small drainage at the southwestern-most extent of the species’ native range
Little is known about the life-history traits exhibited by burbot (Lota lota) throughout their circumpolar range. Monitoring PIT-tagged burbot between lentic and lotic habits and collection of demographic data (length, age, sex, and maturity) were used to answer the following questions in the Torrey Creek drainage of west-central Wyoming, USA: 1) is there plasticity in the life-history traits of
Authors
Jeff Glaid, Christopher S. Guy, Paul C. Gerrity
Gonad size measured by ultrasound to assign stage of maturity in Burbot
We measured gonad size (diameter and circumference) by ultrasound and used it as a metric to assign stage of maturity in Burbot Lota lota from Lake Roosevelt, Washington. We collected paired gonad tissue and ultrasound measurements monthly from November 2017 to March 2018 and processed gonad tissue for histological analysis to confirm stage of maturity. We measured gonad diameter and circumference
Authors
Lauren M. McGarvey, Jason E. Ilgen, Molly A. H. Webb, Christopher S. Guy, Jason G. McLellan
Life history and population dynamics
Lake charr Salvelinus namaycush life history and population dynamics metrics were reviewed to evaluate populations inside (n = 462) and outside (n = 24) the native range. Our goals were to create a database of metrics useful for evaluating population status and to test for large-scale patterns between metrics and latitude and lake size. An average lake charr grew from a 69-mm length at age-0 (L0)
Authors
Michael J Hansen, Christopher S. Guy, Charles R. Bronte, Nancy A. Nate
A paradoxical knowledge gap in science for critically endangered fishes and game fishes during the sixth mass extinction
Despite unprecedented scientific productivity, Earth is undergoing a sixth mass extinction. The disconnect between scientific output and species conservation may be related to scientists studying the wrong species. Given fishes have a high extinction rate, we assessed the paradox between scientific productivity and science needed for conservation by comparing scientific output created for critical
Authors
Christopher S. Guy, Tanner L. Cox, Jacob R . Williams, Colter D. Brown, Robert W. Eckelbecker, Hayley C. Glassic, Madeline C. Lewis, Paige A. C. Maskill, Lauren M. McGarvey, Michael J. Siemiantkowski
Carcass deposition to suppress invasive lake trout causes differential mortality of two common benthic invertebrates in Yellowstone Lake
Invasive species require management to mitigate their harmful effects on native biodiversity and ecosystem processes. However, such management can also have negative, unintended consequences on non-target taxa, ecosystem processes, and food web dynamics. In Yellowstone Lake, invasive lake trout (Salvelinus namaycush) have caused a decline in the native Yellowstone cutthroat trout (Oncorhynchus cla
Authors
Michelle A. Briggs, Lindsey K. Albertson, Dominique R. Lujan, Lusha M. Tronstad, Hayley C. Glassic, Christopher S. Guy, Todd M. Koel
Uncovering process domains in large rivers: Patterns and potential drivers of benthic substrate heterogeneity in two North American riverscapes
Identifying and understanding functional process domains (sensu Montgomery, 1999) in rivers is paramount for linking the physical habitat template to ecosystem structure and function. To date, efforts to do this have been rare, especially in large rivers, as they require appropriate tools for quantifying habitat heterogeneity with fine-scale resolution across broad spatial extents. In this study,
Authors
E.A Scholl, W. F. Cross, C. V. Baxter, Christopher S. Guy
Could ecological release buffer suppression efforts for non-native lake trout (Salvelinus namaycush) in Yellowstone Lake, Yellowstone National Park?
Yellowstone Lake in Yellowstone National Park, USA, has the longest ongoing suppression program for non-native lake trout (Salvelinus namaycush) in the western USA. Harvest data from the suppression program, along with data from an assessment program initiated in 2011, was used to estimate lake trout abundance and mortality rates. Abundance and biomass estimates were used to estimate stock–recruit
Authors
John M. Syslo, Travis O. Brenden, Christopher S. Guy, Todd M . Koel, Patricia E. Bigelow, Philip D . Doepke, Jeffrey L. Arnold, Brian D. Ertel
Presence of microplastics in the food web of the largest high-elevation lake in North America
Microplastics have been documented in aquatic and terrestrial ecosystems throughout the world. However, few studies have investigated microplastics in freshwater fish diets. In this study, water samples and three trophic levels of a freshwater food web were investigated for microplastic presence: amphipods (Gammarus lacustris), Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri), and lake
Authors
Stephanie C. Driscoll, Hayley C. Glassic, Christopher S. Guy, Todd. M. Koel
Fort Peck paddlefish population survival and abundance in the Missouri River
Excessive fishing pressure can induce population declines or complete collapse of fisheries. Unless commercial and recreational fisheries for K-selected fishes, or those with slow growth and late maturation, are carefully managed, declines in abundance or fishery collapse is probable. Paddlefish Polyodon spathula,are a K-selected species that experienced historical declines in abundance as a resul
Authors
Hayley C. Glassic, Christopher S. Guy, Jay J. Rotella, Cody J. Nagel, David A. Schmetterling, Steven R. Dalbey
Science and Products
- Publications
Filter Total Items: 37
Accuracy of histology, endoscopy, ultrasonography, and plasma sex steroids in describing the population reproductive structure of hatchery-origin and wild white sturgeon
Hatchery-origin white sturgeon Acipenser transmontanus in the lower Columbia River, Canada are approaching puberty, and describing the reproductive structure of the population is critical to determine if they are capable of contributing to spawning events in the wild, a key management uncertainty. Few studies have compared the accuracy of available tools (histology, ultrasound, endoscopy, and plasAuthorsPaige A. C. Maskill, James A. Crossman, Molly A. H. Webb, Marco M. Marrello, Christopher S. GuyDiets and stable isotope signatures of native and nonnative Leucisid fishes advances our understanding of the Yellowstone Lake food web
(1) Many forage fishes, such as Leucisids (minnows) have depauperate studies on diet composition or stable isotope signatures, as these fishes are often only viewed as food for higher trophic levels. The need exists to understand and document the diet and stable isotope signatures of Leucisids (redside shiner, longnose dace, lake chub) in relation to the community ecology and food-web dynamics inAuthorsHayley C. Glassic, Christopher S. Guy, Todd M. KoelQuantifying the spatial structure of invasive lake trout in Yellowstone Lake to improve suppression efficacy
Invasive Lake Trout Salvelinus namaycush have altered the once-pristine Yellowstone Lake ecosystem through top-down effects by consuming Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri. To conserve Yellowstone Cutthroat Trout and restore the ecosystem, a Lake Trout gillnetting program was implemented to suppress the invasive population. We evaluated the spatial structure of Lake Trout inAuthorsJacob R. Williams, Christopher S. Guy, Patricia E. Bigelow, Todd M. KoelBurbot (Lota lota) exhibit plasticity in life-history traits in a small drainage at the southwestern-most extent of the species’ native range
Little is known about the life-history traits exhibited by burbot (Lota lota) throughout their circumpolar range. Monitoring PIT-tagged burbot between lentic and lotic habits and collection of demographic data (length, age, sex, and maturity) were used to answer the following questions in the Torrey Creek drainage of west-central Wyoming, USA: 1) is there plasticity in the life-history traits ofAuthorsJeff Glaid, Christopher S. Guy, Paul C. GerrityGonad size measured by ultrasound to assign stage of maturity in Burbot
We measured gonad size (diameter and circumference) by ultrasound and used it as a metric to assign stage of maturity in Burbot Lota lota from Lake Roosevelt, Washington. We collected paired gonad tissue and ultrasound measurements monthly from November 2017 to March 2018 and processed gonad tissue for histological analysis to confirm stage of maturity. We measured gonad diameter and circumferenceAuthorsLauren M. McGarvey, Jason E. Ilgen, Molly A. H. Webb, Christopher S. Guy, Jason G. McLellanLife history and population dynamics
Lake charr Salvelinus namaycush life history and population dynamics metrics were reviewed to evaluate populations inside (n = 462) and outside (n = 24) the native range. Our goals were to create a database of metrics useful for evaluating population status and to test for large-scale patterns between metrics and latitude and lake size. An average lake charr grew from a 69-mm length at age-0 (L0)AuthorsMichael J Hansen, Christopher S. Guy, Charles R. Bronte, Nancy A. NateA paradoxical knowledge gap in science for critically endangered fishes and game fishes during the sixth mass extinction
Despite unprecedented scientific productivity, Earth is undergoing a sixth mass extinction. The disconnect between scientific output and species conservation may be related to scientists studying the wrong species. Given fishes have a high extinction rate, we assessed the paradox between scientific productivity and science needed for conservation by comparing scientific output created for criticalAuthorsChristopher S. Guy, Tanner L. Cox, Jacob R . Williams, Colter D. Brown, Robert W. Eckelbecker, Hayley C. Glassic, Madeline C. Lewis, Paige A. C. Maskill, Lauren M. McGarvey, Michael J. SiemiantkowskiCarcass deposition to suppress invasive lake trout causes differential mortality of two common benthic invertebrates in Yellowstone Lake
Invasive species require management to mitigate their harmful effects on native biodiversity and ecosystem processes. However, such management can also have negative, unintended consequences on non-target taxa, ecosystem processes, and food web dynamics. In Yellowstone Lake, invasive lake trout (Salvelinus namaycush) have caused a decline in the native Yellowstone cutthroat trout (Oncorhynchus claAuthorsMichelle A. Briggs, Lindsey K. Albertson, Dominique R. Lujan, Lusha M. Tronstad, Hayley C. Glassic, Christopher S. Guy, Todd M. KoelUncovering process domains in large rivers: Patterns and potential drivers of benthic substrate heterogeneity in two North American riverscapes
Identifying and understanding functional process domains (sensu Montgomery, 1999) in rivers is paramount for linking the physical habitat template to ecosystem structure and function. To date, efforts to do this have been rare, especially in large rivers, as they require appropriate tools for quantifying habitat heterogeneity with fine-scale resolution across broad spatial extents. In this study,AuthorsE.A Scholl, W. F. Cross, C. V. Baxter, Christopher S. GuyCould ecological release buffer suppression efforts for non-native lake trout (Salvelinus namaycush) in Yellowstone Lake, Yellowstone National Park?
Yellowstone Lake in Yellowstone National Park, USA, has the longest ongoing suppression program for non-native lake trout (Salvelinus namaycush) in the western USA. Harvest data from the suppression program, along with data from an assessment program initiated in 2011, was used to estimate lake trout abundance and mortality rates. Abundance and biomass estimates were used to estimate stock–recruitAuthorsJohn M. Syslo, Travis O. Brenden, Christopher S. Guy, Todd M . Koel, Patricia E. Bigelow, Philip D . Doepke, Jeffrey L. Arnold, Brian D. ErtelPresence of microplastics in the food web of the largest high-elevation lake in North America
Microplastics have been documented in aquatic and terrestrial ecosystems throughout the world. However, few studies have investigated microplastics in freshwater fish diets. In this study, water samples and three trophic levels of a freshwater food web were investigated for microplastic presence: amphipods (Gammarus lacustris), Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri), and lakeAuthorsStephanie C. Driscoll, Hayley C. Glassic, Christopher S. Guy, Todd. M. KoelFort Peck paddlefish population survival and abundance in the Missouri River
Excessive fishing pressure can induce population declines or complete collapse of fisheries. Unless commercial and recreational fisheries for K-selected fishes, or those with slow growth and late maturation, are carefully managed, declines in abundance or fishery collapse is probable. Paddlefish Polyodon spathula,are a K-selected species that experienced historical declines in abundance as a resulAuthorsHayley C. Glassic, Christopher S. Guy, Jay J. Rotella, Cody J. Nagel, David A. Schmetterling, Steven R. Dalbey