Michael Dodrill
Michael is a Fish Biologist working for the USGS, Columbia River Research Laboratory.
Science and Products
Proximal and distal factors associated with the decline in secondary invertebrate prey production in the Colorado River, Glen Canyon, Arizona.
Using a bioenergetic model, demographic data for the Rainbow Trout (Oncorhynchus mykiss) population were compiled and used to estimate total prey consumption in the Colorado River, Glen Canyon , AZ. Additionally, other data including invertebrate diet, drift, and benthic measurements were used to make generalized estimates of daily production rates for the most common benthic invertebrate taxa. Th
Humpback chub (Gila cypha) and mean daily water temperature data, western Grand Canyon - 2000 to 2016
These data were compiled to examine patterns of humpback chub (Gila cypha) in western Grand Canyon from just below Havasu Creek at river kilometer (rkm) 253 (Lees Ferry is rkm 0) downriver to Pearce Ferry at rkm 451. These data represent mean daily water temperatures in degrees Celsius from two USGS gaging locations (2005-2016), catches of individual humpback chub in hoop nets (2005-2016), total l
Gross primary production estimates and associated light, sediment, and water quality data from the Colorado River below Glen Canyon Dam
These data were compiled to model the effects of flow regime and bed grain size distributions on rates of gross primary production (GPP) in the Colorado River below Glen Canyon Dam, AZ, USA. The objectives of our study were to quantify daily and weekly scale effects of an experimental flow regime on GPP in the Colorado River. The experimental flow was conducted at Glen Canyon Dam from May-August i
Rainbow trout diet and invertebrate drift data from 2012-2015 for the Colorado River, Grand Canyon, Arizona
These data were compiled to explore the foraging ecology of Rainbow Trout (Oncorhynchus mykiss) in the Colorado River, Grand Canyon, Arizona. These data represent samples characterizing the availability of drifting invertebrate prey (hereafter, drift) and use of these invertebrate prey by rainbow trout determined by gut samples (hereafter, diets). Drift and diet sampling occurred in five distinct
Marginalizing Bayesian population models - data for examples in the Grand Canyon region, southeastern Arizona, western Oregon USA - 1990-2015
These data were compiled here to fit various versions of Bayesian population models and compare their performance, primarily the time required to make inferences using different softwares and versions of code. The humpback chub data were collected by US Geological Survey and US Fish and Wildlife service in the Colorado and Little Colorado Rivers from April 2009 to October 2017. Adult fish were cap
Filter Total Items: 18
U.S. Geological Survey Grand Canyon Monitoring and Research Center: Proceedings of the fiscal year 2023 annual reporting meeting to the Glen Canyon Dam Adaptive Management Program
This proceedings is prepared for the USBR and Glen Canyon Dam Adaptive Management Program (GCDAMP) to account for work conducted and products delivered in FY 2023 by SBSC's Grand Canyon Monitoring and Research Center (GCMRC) and to inform the Technical Work Group of science conducted by GCMRC and its cooperators in support of the GCDAMP. It includes a summary of accomplishments, modifications to w
Authors
Andrew Alan Schultz, Gregory Mark Anderson, David Topping, Ronald E. Griffiths, David Dean, Paul Grams, Keith Kohl, Gerard Lewis Salter, Matthew A. Kaplinski, Katherine Chapman, Erich R. Mueller, Emily C. Palmquist, Bradley J. Butterfield, Joel B. Sankey, Bridget Deemer, Charles Yackulic, Lindsay Erika Hansen, Drew Elliot Eppehimer, Theodore Kennedy, Anya Metcalfe, Jeffrey Muehlbauer, Morgan Ford, Michael Dodrill, Maria C. Dzul, Pilar Rinker, Michael J. Pillow, David Ward, Josh Korman, Molly A.H. Webb, James A. Crossman, Eric J Frye, David L. Rogowski, Kimberley Dibble, Lucas Bair, Joshua Abbott, Thomas Gushue, Erica Paige Byerley, Joseph E Thomas, Thomas A. Sabol, Bryce Anthony Mihalevich
Insectivorous bat foraging tracks the availability of aquatic flies (Diptera)
Rivers and their adjacent riparian zones are model ecosystems for observing cross-ecosystem energy transfers. Aquatic insects emerging from streams, for example, are resource subsidies that support riparian consumers such as birds, spiders, lizards, and bats. We collaborated with recreational river runners in Grand Canyon, Arizona, USA, to record acoustic bat activity and sample riparian insects u
Authors
Anya Metcalfe, Carol Fritzinger, Theodore J. Weller, Michael Dodrill, Jeffrey Muehlbauer, Charles Yackulic, Brandon P. Holton, Cheyenne Maxime Szydlo, Laura E. Durning, Joel B. Sankey, Theodore Kennedy
Declines in prey production during the collapse of a tailwater Rainbow Trout population are associated with changing reservoir conditions
ObjectiveUnderstanding how energy moves through food webs and limits productivity at various trophic levels is a central question in aquatic ecology and can provide insight into drivers of fish population dynamics since many fish populations are food limited. In this study, we seek to better understand what factors drove a decline of >85% in the number of Rainbow TroutOncorhynchus mykiss found in
Authors
Michael D. Yard, Charles Yackulic, Josh Korman, Michael Dodrill, Bridget Deemer
Simulating post-dam removal effects of hatchery operations and disease on juvenile Chinook salmon (Oncorhynchus tshawytscha) production in the Lower Klamath River, California
Executive SummaryThe Federal Energy Regulatory Commission has been considering the approval to breach four dams on lower Klamath River in southern Oregon and northern California. Approval of this application would allow for Strikeouts indicate text deletion hereafter. decommissioning and dam removal, beginning as early as 2023. This action would affect Klamath River salmon (Oncorhynchus ssp.) popu
Authors
Russell W. Perry, John M. Plumb, Michael J. Dodrill, Nicholas A. Som, H. Eve Robinson, Nicholas J. Hetrick
Extending the Stream Salmonid Simulator to accommodate the life history of coho salmon (Oncorhynchus kisutch) in the Klamath River Basin, Northern California
In this report, we apply the stream salmonid simulator (S3) to coho salmon (Oncorhynchus kisutch) in the Klamath River Basin by extending the original model to account for life history and disease dynamics specific to coho salmon. This version of S3 includes tracking of three separate life-history strategies representing the different time periods and ages at which fish leave natal tributaries suc
Authors
Michael J. Dodrill, Russell W. Perry, Nicholas A. Som, Christopher V. Manhard, Julie D. Alexander
Experimental reductions in sub-daily flow fluctuations increased gross primary productivity for 425 river kilometers downstream
Aquatic primary production is the foundation of many river food webs. Dams change the physical template of rivers, often driving food webs toward greater reliance on aquatic primary production. Nonetheless, the effects of regulated flow regimes on primary production are poorly understood. Load following is a common dam flow management strategy that involves sub-daily changes in water releases prop
Authors
Bridget Deemer, Charles Yackulic, Robert O Hall Jr., Michael Dodrill, Theodore Kennedy, Jeffrey Muehlbauer, David Topping, Nicholas Voichick, Michael D. Yard
Quantifying the effects of tides, river flow, and barriers on movements of Chinook Salmon smolts at junctions in the Sacramento–San Joaquin River Delta using multistate models
Successful migration of Chinook Salmon (Oncorhynchus tshawytscha) smolts seaward in the Sacramento – San Joaquin River Delta (hereafter, Delta) requires navigating a network of numerous branching channels. Within the Delta, several key junctions route smolts either towards more direct paths to the ocean or towards the interior Delta, an area associated with decreased survival. Movements within the
Authors
Michael Dodrill, Russell Perry, Adam Pope, Xiaochun Wang
As the prey thickens: Rainbow trout select prey based upon width not length
Drift-feeding fish are typically considered size-selective predators. Yet, few studies have explicitly tested which aspect of prey “size” best explains size selection by drift-foraging fish. Here, we develop a Bayesian discrete choice model to evaluate how attributes of both prey and predator simultaneously influence size-selective foraging. We apply the model to a large dataset of paired inverteb
Authors
Michael Dodrill, Charles Yackulic, Theodore Kennedy, Michael D. Yard, Josh Korman
Changes in prey, turbidity, and competition reduce somatic growth and cause the collapse of a fish population
Somatic growth exerts strong control on patterns in the abundance of animal populations via effects on maturation, fecundity, and survival rates of juveniles and adults. In this paper, we quantify abiotic and biotic drivers of rainbow trout growth in the Colorado River, AZ, and the resulting impact on spatial and temporal variation in abundance. Inferences are based on approximately 10,000 observa
Authors
Josh Korman, Michael D. Yard, Maria C. Dzul, Charles Yackulic, Michael Dodrill, Bridget Deemer, Theodore Kennedy
Trends in oyster populations in the northeastern Gulf of Mexico: An assessment of river discharge and fishing effects over time and space
Within the Big Bend region of the northeastern Gulf of Mexico, one of the least developed coastlines in the continental USA, intertidal and subtidal populations of eastern oyster Crassostrea virginica (hereafter referred to as “oyster”) are a critical ecosystem and important economic constituent. We assessed trends in intertidal oyster populations, river discharge, and commercial fishing activity
Authors
J. F Moore, W. E Pine, P. C Frederick, Sarah Becker, Marcos Moreno, Michael Dodrill, Matthew Boone, L Sturmer, Simeon Yurek
A need for speed in Bayesian population models: A practical guide to marginalizing and recovering discrete latent states
Bayesian population models can be exceedingly slow due, in part, to the choice to simulate discrete latent states. Here, we discuss an alternative approach to discrete latent states, marginalization, that forms the basis of maximum likelihood population models and is much faster. Our manuscript has two goals: 1) to introduce readers unfamiliar with marginalization to the concept and provide worked
Authors
Charles B. Yackulic, Michael J. Dodrill, Maria C. Dzul, Jamie S. Sanderlin, Janice A. Reid
Population expansion of Humpback chub in western Grand Canyon and hypothesized mechanisms
Humpback chub, Gila cypha, is an endangered warm water fish endemic to the Colorado River basin of southwestern North America. In Grand Canyon National Park, cold hypolimnetic water-release temperatures from Glen Canyon Dam have largely precluded successful spawning and recruitment of humpback chub in the mainstem Colorado River. Therefore, the species has utilized the warmer, more saline, and fre
Authors
David R. VanHaverbeke, Dennis M. Stone, Michael Dodrill, Kirk L. Young, Michael J. Pillow
Science and Products
Proximal and distal factors associated with the decline in secondary invertebrate prey production in the Colorado River, Glen Canyon, Arizona.
Using a bioenergetic model, demographic data for the Rainbow Trout (Oncorhynchus mykiss) population were compiled and used to estimate total prey consumption in the Colorado River, Glen Canyon , AZ. Additionally, other data including invertebrate diet, drift, and benthic measurements were used to make generalized estimates of daily production rates for the most common benthic invertebrate taxa. Th
Humpback chub (Gila cypha) and mean daily water temperature data, western Grand Canyon - 2000 to 2016
These data were compiled to examine patterns of humpback chub (Gila cypha) in western Grand Canyon from just below Havasu Creek at river kilometer (rkm) 253 (Lees Ferry is rkm 0) downriver to Pearce Ferry at rkm 451. These data represent mean daily water temperatures in degrees Celsius from two USGS gaging locations (2005-2016), catches of individual humpback chub in hoop nets (2005-2016), total l
Gross primary production estimates and associated light, sediment, and water quality data from the Colorado River below Glen Canyon Dam
These data were compiled to model the effects of flow regime and bed grain size distributions on rates of gross primary production (GPP) in the Colorado River below Glen Canyon Dam, AZ, USA. The objectives of our study were to quantify daily and weekly scale effects of an experimental flow regime on GPP in the Colorado River. The experimental flow was conducted at Glen Canyon Dam from May-August i
Rainbow trout diet and invertebrate drift data from 2012-2015 for the Colorado River, Grand Canyon, Arizona
These data were compiled to explore the foraging ecology of Rainbow Trout (Oncorhynchus mykiss) in the Colorado River, Grand Canyon, Arizona. These data represent samples characterizing the availability of drifting invertebrate prey (hereafter, drift) and use of these invertebrate prey by rainbow trout determined by gut samples (hereafter, diets). Drift and diet sampling occurred in five distinct
Marginalizing Bayesian population models - data for examples in the Grand Canyon region, southeastern Arizona, western Oregon USA - 1990-2015
These data were compiled here to fit various versions of Bayesian population models and compare their performance, primarily the time required to make inferences using different softwares and versions of code. The humpback chub data were collected by US Geological Survey and US Fish and Wildlife service in the Colorado and Little Colorado Rivers from April 2009 to October 2017. Adult fish were cap
Filter Total Items: 18
U.S. Geological Survey Grand Canyon Monitoring and Research Center: Proceedings of the fiscal year 2023 annual reporting meeting to the Glen Canyon Dam Adaptive Management Program
This proceedings is prepared for the USBR and Glen Canyon Dam Adaptive Management Program (GCDAMP) to account for work conducted and products delivered in FY 2023 by SBSC's Grand Canyon Monitoring and Research Center (GCMRC) and to inform the Technical Work Group of science conducted by GCMRC and its cooperators in support of the GCDAMP. It includes a summary of accomplishments, modifications to w
Authors
Andrew Alan Schultz, Gregory Mark Anderson, David Topping, Ronald E. Griffiths, David Dean, Paul Grams, Keith Kohl, Gerard Lewis Salter, Matthew A. Kaplinski, Katherine Chapman, Erich R. Mueller, Emily C. Palmquist, Bradley J. Butterfield, Joel B. Sankey, Bridget Deemer, Charles Yackulic, Lindsay Erika Hansen, Drew Elliot Eppehimer, Theodore Kennedy, Anya Metcalfe, Jeffrey Muehlbauer, Morgan Ford, Michael Dodrill, Maria C. Dzul, Pilar Rinker, Michael J. Pillow, David Ward, Josh Korman, Molly A.H. Webb, James A. Crossman, Eric J Frye, David L. Rogowski, Kimberley Dibble, Lucas Bair, Joshua Abbott, Thomas Gushue, Erica Paige Byerley, Joseph E Thomas, Thomas A. Sabol, Bryce Anthony Mihalevich
Insectivorous bat foraging tracks the availability of aquatic flies (Diptera)
Rivers and their adjacent riparian zones are model ecosystems for observing cross-ecosystem energy transfers. Aquatic insects emerging from streams, for example, are resource subsidies that support riparian consumers such as birds, spiders, lizards, and bats. We collaborated with recreational river runners in Grand Canyon, Arizona, USA, to record acoustic bat activity and sample riparian insects u
Authors
Anya Metcalfe, Carol Fritzinger, Theodore J. Weller, Michael Dodrill, Jeffrey Muehlbauer, Charles Yackulic, Brandon P. Holton, Cheyenne Maxime Szydlo, Laura E. Durning, Joel B. Sankey, Theodore Kennedy
Declines in prey production during the collapse of a tailwater Rainbow Trout population are associated with changing reservoir conditions
ObjectiveUnderstanding how energy moves through food webs and limits productivity at various trophic levels is a central question in aquatic ecology and can provide insight into drivers of fish population dynamics since many fish populations are food limited. In this study, we seek to better understand what factors drove a decline of >85% in the number of Rainbow TroutOncorhynchus mykiss found in
Authors
Michael D. Yard, Charles Yackulic, Josh Korman, Michael Dodrill, Bridget Deemer
Simulating post-dam removal effects of hatchery operations and disease on juvenile Chinook salmon (Oncorhynchus tshawytscha) production in the Lower Klamath River, California
Executive SummaryThe Federal Energy Regulatory Commission has been considering the approval to breach four dams on lower Klamath River in southern Oregon and northern California. Approval of this application would allow for Strikeouts indicate text deletion hereafter. decommissioning and dam removal, beginning as early as 2023. This action would affect Klamath River salmon (Oncorhynchus ssp.) popu
Authors
Russell W. Perry, John M. Plumb, Michael J. Dodrill, Nicholas A. Som, H. Eve Robinson, Nicholas J. Hetrick
Extending the Stream Salmonid Simulator to accommodate the life history of coho salmon (Oncorhynchus kisutch) in the Klamath River Basin, Northern California
In this report, we apply the stream salmonid simulator (S3) to coho salmon (Oncorhynchus kisutch) in the Klamath River Basin by extending the original model to account for life history and disease dynamics specific to coho salmon. This version of S3 includes tracking of three separate life-history strategies representing the different time periods and ages at which fish leave natal tributaries suc
Authors
Michael J. Dodrill, Russell W. Perry, Nicholas A. Som, Christopher V. Manhard, Julie D. Alexander
Experimental reductions in sub-daily flow fluctuations increased gross primary productivity for 425 river kilometers downstream
Aquatic primary production is the foundation of many river food webs. Dams change the physical template of rivers, often driving food webs toward greater reliance on aquatic primary production. Nonetheless, the effects of regulated flow regimes on primary production are poorly understood. Load following is a common dam flow management strategy that involves sub-daily changes in water releases prop
Authors
Bridget Deemer, Charles Yackulic, Robert O Hall Jr., Michael Dodrill, Theodore Kennedy, Jeffrey Muehlbauer, David Topping, Nicholas Voichick, Michael D. Yard
Quantifying the effects of tides, river flow, and barriers on movements of Chinook Salmon smolts at junctions in the Sacramento–San Joaquin River Delta using multistate models
Successful migration of Chinook Salmon (Oncorhynchus tshawytscha) smolts seaward in the Sacramento – San Joaquin River Delta (hereafter, Delta) requires navigating a network of numerous branching channels. Within the Delta, several key junctions route smolts either towards more direct paths to the ocean or towards the interior Delta, an area associated with decreased survival. Movements within the
Authors
Michael Dodrill, Russell Perry, Adam Pope, Xiaochun Wang
As the prey thickens: Rainbow trout select prey based upon width not length
Drift-feeding fish are typically considered size-selective predators. Yet, few studies have explicitly tested which aspect of prey “size” best explains size selection by drift-foraging fish. Here, we develop a Bayesian discrete choice model to evaluate how attributes of both prey and predator simultaneously influence size-selective foraging. We apply the model to a large dataset of paired inverteb
Authors
Michael Dodrill, Charles Yackulic, Theodore Kennedy, Michael D. Yard, Josh Korman
Changes in prey, turbidity, and competition reduce somatic growth and cause the collapse of a fish population
Somatic growth exerts strong control on patterns in the abundance of animal populations via effects on maturation, fecundity, and survival rates of juveniles and adults. In this paper, we quantify abiotic and biotic drivers of rainbow trout growth in the Colorado River, AZ, and the resulting impact on spatial and temporal variation in abundance. Inferences are based on approximately 10,000 observa
Authors
Josh Korman, Michael D. Yard, Maria C. Dzul, Charles Yackulic, Michael Dodrill, Bridget Deemer, Theodore Kennedy
Trends in oyster populations in the northeastern Gulf of Mexico: An assessment of river discharge and fishing effects over time and space
Within the Big Bend region of the northeastern Gulf of Mexico, one of the least developed coastlines in the continental USA, intertidal and subtidal populations of eastern oyster Crassostrea virginica (hereafter referred to as “oyster”) are a critical ecosystem and important economic constituent. We assessed trends in intertidal oyster populations, river discharge, and commercial fishing activity
Authors
J. F Moore, W. E Pine, P. C Frederick, Sarah Becker, Marcos Moreno, Michael Dodrill, Matthew Boone, L Sturmer, Simeon Yurek
A need for speed in Bayesian population models: A practical guide to marginalizing and recovering discrete latent states
Bayesian population models can be exceedingly slow due, in part, to the choice to simulate discrete latent states. Here, we discuss an alternative approach to discrete latent states, marginalization, that forms the basis of maximum likelihood population models and is much faster. Our manuscript has two goals: 1) to introduce readers unfamiliar with marginalization to the concept and provide worked
Authors
Charles B. Yackulic, Michael J. Dodrill, Maria C. Dzul, Jamie S. Sanderlin, Janice A. Reid
Population expansion of Humpback chub in western Grand Canyon and hypothesized mechanisms
Humpback chub, Gila cypha, is an endangered warm water fish endemic to the Colorado River basin of southwestern North America. In Grand Canyon National Park, cold hypolimnetic water-release temperatures from Glen Canyon Dam have largely precluded successful spawning and recruitment of humpback chub in the mainstem Colorado River. Therefore, the species has utilized the warmer, more saline, and fre
Authors
David R. VanHaverbeke, Dennis M. Stone, Michael Dodrill, Kirk L. Young, Michael J. Pillow