Alexander Zale, PhD
Unit Leader - Montana Cooperative Fishery Research Unit
Dr. Zale’s primary research focus is applied aquatic ecology directed at native fish assemblage restoration, a prominent and pressing ecological and societal issue in Rocky Mountain and Great Plains ecosystems as well as in similar ecosystems worldwide. Other areas of emphasis include thermal biology, especially the generation of empirical data in both the laboratory and field needed to assess the effects of climate change, movement ecology, and recreational fishery management. However, Dr. Zale’s overarching research goal is to answer the applied aquatic research questions that the Unit’s State and Federal Cooperators need to have answered to achieve their missions. He has therefore conducted research on a broad range of topics. His teaching focuses on preparing his students for agency positions. He also teaches a graduate course entitled Human Dimensions of Fish and Wildlife Management.
Research Interests
Aquatic wild life conservation, restoration, and management:
- native fishes,
- prairie fishes,
- thermal ecology,
- sport and commercial fishery management,
- population dynamics and effects of exotic fishes,
- effects of environmental degradation and habitat on recreational salmonid fisheries,
- Central American fisheries.
Teaching Interests
Human Dimensions of Fish and Wildlife Management (WILD 525)
Professional Experience
Dr. Zale began his career with the Cooperative Research Units program in 1975 as an undergraduate technician with the Massachusetts Unit before getting graduate degrees at the Virginia and Florida units. After a postdoc with the Florida Unit, he became the AUL/F at the Oklahoma Unit in 1985 and transferred to the Montana Fishery Unit in 1994, where he subsequently became UL in 2002.
Education and Certifications
Ph D University of Florida 1984
MS Virginia Polytechnic Institute and State University 1980
BS University of Massachusetts 1978
Science and Products
Filter Total Items: 32
Synthesis of climate and ecological science to support grassland management priorities in the North Central Region
Grasslands in the Great Plains are of ecological, economic, and cultural importance in the United States. In response to a need to understand how climate change and variability will impact grassland ecosystems and their management in the 21st century, the U.S. Geological Survey North Central Climate Adaptation Science Center led a synthesis of peer-reviewed climate and ecology literature relevant
Authors
Christine D. Miller Hesed, Heather M. Yocum, Imtiaz Rangwala, Amy Symstad, Jeff M. Martin, Kevin Ellison, David J. A. Wood, Marissa Ahlering, Katherine J. Chase, Shelley Crausbay, Ana D. Davidson, Julie L. Elliott, Jim Giocomo, David Hoover, Toni Klemm, David A. Lightfoot, Owen P. McKenna, Brian W. Miller, Danika Mosher, R. Chelsea Nagy, Jesse B. Nippert, Jeremy Pittman, Lauren M. Porensky, Jilmarie Stephens, Alexander V. Zale
The importance of phenology and thermal exposure to early life history success of nonnative Smallmouth Bass in the Yellowstone River
Knowledge of potential spread by introduced species is critical to effective management and conservation. The Smallmouth Bass Micropterus dolomieu is an example of a fish that has been introduced globally, often spreads after introduction, and has substantial predatory impacts on fish assemblages. Nonnative Smallmouth Bass in the free-flowing Yellowstone River, Montana, have expanded from warmer,
Authors
Nicholas S. Voss, Robert K. Al-Chokhachy, Adam J. Sepulveda, Christine E. Verhille, Michael P. Ruggles, Alexander V. Zale
Evaluation of remote site incubators to incubate wild- and hatchery-origin Westslope Cutthroat Trout embryos
Fish managers must weigh trade-offs among cost, speed, efficiency, and ecological adaptation when deciding how to translocate native salmonids to either establish or genetically augment populations. Remote site incubators (RSIs) appear to be a reasonable strategy, but large-scale evaluations of this method have been limited. We used 129 RSIs to incubate >35,700 eyed embryos of Westslope Cutthroat
Authors
Bradley B. Shepard, Patrick Clancey, Lee M. Nelson, Carter Kruse, Robert K. Al-Chokhachy, Daniel Drinan, Alexander V. Zale
Movements of selected minnows between the lower Yellowstone River and its tributaries
Reduced population connectivity has been implicated as a cause of decreased distributions and abundances of many Great Plains fishes. However, scant empirical evidence quantifying movement and relating the contribution of spatial linkages to population abundances and resilience exists. We used otolith microchemistry analysis to characterize the movements of western silvery minnows (Hybognathus arg
Authors
Michael B. Duncan, Robert G. Bramblett, Alexander V. Zale
It’s complicated…environmental DNA as a predictor of trout and char abundance in streams
The potential to provide inferences about fish abundance from environmental (e)DNA samples has generated great interest. However, the accuracy of these abundance estimates is often low and variable across species and space. A plausible refinement is the use of common aquatic habitat monitoring data to account for attributes that influence eDNA dynamics. We therefore evaluated the relationships bet
Authors
Adam J. Sepulveda, Robert Al-Chokhachy, Matthew Laramie, Kyle Crapster, Ladd Knotek, Brian T. Miller, Alexander V. Zale, David Pilliod
Groundwater upwelling regulates thermal hydrodynamics and salmonid movements during high-temperature events at a montane tributary confluence
The Smith River is a popular recreational sport fishery in western Montana, but salmonid abundances there are thought to be artificially limited by riparian land-use alterations, irrigation water withdrawals, and high summer water temperatures. We used integrated networks of temperature loggers, PIT tag antenna stations, and in situ temperature mapping to investigate the thermal hydrodynamics and
Authors
Thomas David Ritter, Alexander V. Zale, Grant Grisak, Michael J. Lance
Benthic suffocation of invasive lake trout embryos by fish carcasses and sedimentation in Yellowstone Lake
Introduced Lake Trout Salvelinus namaycush threaten native Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri in Yellowstone Lake, Yellowstone National Park, where gill nets have been used to suppress subadult and adult Lake Trout since 1995. However, survival of embryonic and larval life history stages can have profound effects on the population dynamics of Lake Trout. Inducing additional
Authors
Alex S. Poole, Todd M. Koel, Nathan A. Thomas, Alexander V. Zale
Yellowstone Lake ecosystem restoration: A case study for invasive fish management
Invasive predatory lake trout Salvelinus namaycush were discovered in Yellowstone Lake in 1994 and caused a precipitous decrease in abundance of native Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri. Suppression efforts (primarily gillnetting) initiated in 1995 did not curtail lake trout population growth or lakewide expansion. An adaptive management strategy was developed in 2010 that
Authors
Todd M. Koel, Jeffrey L. Arnold, Patricia E. Bigelow, Travis O. Brenden, Jeffery D. Davis, Colleen R. Detjens, Philip D. Doepke, Brian D. Ertel, Hayley C. Glassic, Robert E. Gresswell, Christopher S Guy, Drew J. MacDonald, Michael E. Ruhl, Todd J. Stuth, David P. Sweet, John M. Syslo, Nathan A. Thomas, Lusha M. Tronstad, Patrick J. White, Alexander V. Zale
Two Ocean Pass: An alternative hypothesis for invasion of Yellowstone Lake by lake trout, and implications for future invasions
Preventing the interbasin transfer of aquatic invasive species is a high priority for natural resource managers. Such transfers can be made by humans or can occur by dispersal through connected waterways. A natural surface water connection between the Atlantic and Pacific drainages in North America exists at Two Ocean Pass south of Yellowstone National Park. Yellowstone cutthroat trout Oncorhynchu
Authors
Todd M. Koel, Colleen R. Detjens, Alexander V. Zale
Organic pellet decomposition induces mortality of Lake Trout embryos in Yellowstone Lake
Yellowstone Lake is the site of actions to suppress invasive Lake Trout Salvelinus namaycush and restore native Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri and natural ecosystem function. Although gill netting is effective (Lake Trout λ ≤ 0.6 from 2012 through 2018), the effort costs more than US$2 million annually and only targets Lake Trout age 2 and older. To increase suppression
Authors
Todd M. Koel, Nathan A. Thomas, Christopher S. Guy, Philip D. Doepke, Drew J. MacDonald, Alex S. Poole, Wendy M. Sealey, Alexander V. Zale
Riverine turtles select habitats maintained by natural discharge regimes in an unimpounded large river
Turtle populations are imperiled worldwide, but limited ecological information from unaltered systems hampers science‐based management and conservation of some species, especially riverine turtles such as the spiny softshell (Apalone spinifera). We therefore investigated movements and spatial habitat selection of 54 A. spinifera in 633 river kilometres (rkm) of the least‐altered river in the conte
Authors
Brian J. Tornabene, Matthew E. Jaeger, Robert G. Bramblett, Mark Nelson, Nathan McClenning, Trevor Watson, Alan Ankrum, Kenneth Frazer, Ann Marie Reinhold, Alexander V. Zale
In situ evaluation of benthic suffocation methods for suppression of invasive Lake Trout embryos in Yellowstone Lake
Suppression of invasive Lake Trout Salvelinus namaycush is an important management tool to use in native fish and ecosystem conservation throughout the U.S. Intermountain West. Lake Trout suppression, primarily by gill netting, has been ongoing in Yellowstone Lake, Yellowstone National Park, Wyoming, since 1995. Additional methods that cause mortality of Lake Trout embryos could be used simultaneo
Authors
Nathan A. Thomas, Christopher S. Guy, Todd M. Koel, Alexander V. Zale
Environmental DNA data, fish abundance data, and stream habitat data from northwest Montana and northeast Washington and southern British Columbia, Canada
Field estimates of the abundance of two trout species (bull trout and westslope cutthroat trout) in Montana and rainbow trout in Washington and British Columbia were collected in concert with environmental DNA samples (eDNA) to evaluate if eDNA copy numbers correlated with abundance of trout. In addition, stream habitat data including channel units (pools, riffles), substrate, large woody debris,
Science and Products
- Publications
Filter Total Items: 32
Synthesis of climate and ecological science to support grassland management priorities in the North Central Region
Grasslands in the Great Plains are of ecological, economic, and cultural importance in the United States. In response to a need to understand how climate change and variability will impact grassland ecosystems and their management in the 21st century, the U.S. Geological Survey North Central Climate Adaptation Science Center led a synthesis of peer-reviewed climate and ecology literature relevantAuthorsChristine D. Miller Hesed, Heather M. Yocum, Imtiaz Rangwala, Amy Symstad, Jeff M. Martin, Kevin Ellison, David J. A. Wood, Marissa Ahlering, Katherine J. Chase, Shelley Crausbay, Ana D. Davidson, Julie L. Elliott, Jim Giocomo, David Hoover, Toni Klemm, David A. Lightfoot, Owen P. McKenna, Brian W. Miller, Danika Mosher, R. Chelsea Nagy, Jesse B. Nippert, Jeremy Pittman, Lauren M. Porensky, Jilmarie Stephens, Alexander V. ZaleThe importance of phenology and thermal exposure to early life history success of nonnative Smallmouth Bass in the Yellowstone River
Knowledge of potential spread by introduced species is critical to effective management and conservation. The Smallmouth Bass Micropterus dolomieu is an example of a fish that has been introduced globally, often spreads after introduction, and has substantial predatory impacts on fish assemblages. Nonnative Smallmouth Bass in the free-flowing Yellowstone River, Montana, have expanded from warmer,AuthorsNicholas S. Voss, Robert K. Al-Chokhachy, Adam J. Sepulveda, Christine E. Verhille, Michael P. Ruggles, Alexander V. ZaleEvaluation of remote site incubators to incubate wild- and hatchery-origin Westslope Cutthroat Trout embryos
Fish managers must weigh trade-offs among cost, speed, efficiency, and ecological adaptation when deciding how to translocate native salmonids to either establish or genetically augment populations. Remote site incubators (RSIs) appear to be a reasonable strategy, but large-scale evaluations of this method have been limited. We used 129 RSIs to incubate >35,700 eyed embryos of Westslope CutthroatAuthorsBradley B. Shepard, Patrick Clancey, Lee M. Nelson, Carter Kruse, Robert K. Al-Chokhachy, Daniel Drinan, Alexander V. ZaleMovements of selected minnows between the lower Yellowstone River and its tributaries
Reduced population connectivity has been implicated as a cause of decreased distributions and abundances of many Great Plains fishes. However, scant empirical evidence quantifying movement and relating the contribution of spatial linkages to population abundances and resilience exists. We used otolith microchemistry analysis to characterize the movements of western silvery minnows (Hybognathus argAuthorsMichael B. Duncan, Robert G. Bramblett, Alexander V. ZaleIt’s complicated…environmental DNA as a predictor of trout and char abundance in streams
The potential to provide inferences about fish abundance from environmental (e)DNA samples has generated great interest. However, the accuracy of these abundance estimates is often low and variable across species and space. A plausible refinement is the use of common aquatic habitat monitoring data to account for attributes that influence eDNA dynamics. We therefore evaluated the relationships betAuthorsAdam J. Sepulveda, Robert Al-Chokhachy, Matthew Laramie, Kyle Crapster, Ladd Knotek, Brian T. Miller, Alexander V. Zale, David PilliodGroundwater upwelling regulates thermal hydrodynamics and salmonid movements during high-temperature events at a montane tributary confluence
The Smith River is a popular recreational sport fishery in western Montana, but salmonid abundances there are thought to be artificially limited by riparian land-use alterations, irrigation water withdrawals, and high summer water temperatures. We used integrated networks of temperature loggers, PIT tag antenna stations, and in situ temperature mapping to investigate the thermal hydrodynamics andAuthorsThomas David Ritter, Alexander V. Zale, Grant Grisak, Michael J. LanceBenthic suffocation of invasive lake trout embryos by fish carcasses and sedimentation in Yellowstone Lake
Introduced Lake Trout Salvelinus namaycush threaten native Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri in Yellowstone Lake, Yellowstone National Park, where gill nets have been used to suppress subadult and adult Lake Trout since 1995. However, survival of embryonic and larval life history stages can have profound effects on the population dynamics of Lake Trout. Inducing additionalAuthorsAlex S. Poole, Todd M. Koel, Nathan A. Thomas, Alexander V. ZaleYellowstone Lake ecosystem restoration: A case study for invasive fish management
Invasive predatory lake trout Salvelinus namaycush were discovered in Yellowstone Lake in 1994 and caused a precipitous decrease in abundance of native Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri. Suppression efforts (primarily gillnetting) initiated in 1995 did not curtail lake trout population growth or lakewide expansion. An adaptive management strategy was developed in 2010 thatAuthorsTodd M. Koel, Jeffrey L. Arnold, Patricia E. Bigelow, Travis O. Brenden, Jeffery D. Davis, Colleen R. Detjens, Philip D. Doepke, Brian D. Ertel, Hayley C. Glassic, Robert E. Gresswell, Christopher S Guy, Drew J. MacDonald, Michael E. Ruhl, Todd J. Stuth, David P. Sweet, John M. Syslo, Nathan A. Thomas, Lusha M. Tronstad, Patrick J. White, Alexander V. ZaleTwo Ocean Pass: An alternative hypothesis for invasion of Yellowstone Lake by lake trout, and implications for future invasions
Preventing the interbasin transfer of aquatic invasive species is a high priority for natural resource managers. Such transfers can be made by humans or can occur by dispersal through connected waterways. A natural surface water connection between the Atlantic and Pacific drainages in North America exists at Two Ocean Pass south of Yellowstone National Park. Yellowstone cutthroat trout OncorhynchuAuthorsTodd M. Koel, Colleen R. Detjens, Alexander V. ZaleOrganic pellet decomposition induces mortality of Lake Trout embryos in Yellowstone Lake
Yellowstone Lake is the site of actions to suppress invasive Lake Trout Salvelinus namaycush and restore native Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri and natural ecosystem function. Although gill netting is effective (Lake Trout λ ≤ 0.6 from 2012 through 2018), the effort costs more than US$2 million annually and only targets Lake Trout age 2 and older. To increase suppressionAuthorsTodd M. Koel, Nathan A. Thomas, Christopher S. Guy, Philip D. Doepke, Drew J. MacDonald, Alex S. Poole, Wendy M. Sealey, Alexander V. ZaleRiverine turtles select habitats maintained by natural discharge regimes in an unimpounded large river
Turtle populations are imperiled worldwide, but limited ecological information from unaltered systems hampers science‐based management and conservation of some species, especially riverine turtles such as the spiny softshell (Apalone spinifera). We therefore investigated movements and spatial habitat selection of 54 A. spinifera in 633 river kilometres (rkm) of the least‐altered river in the conteAuthorsBrian J. Tornabene, Matthew E. Jaeger, Robert G. Bramblett, Mark Nelson, Nathan McClenning, Trevor Watson, Alan Ankrum, Kenneth Frazer, Ann Marie Reinhold, Alexander V. ZaleIn situ evaluation of benthic suffocation methods for suppression of invasive Lake Trout embryos in Yellowstone Lake
Suppression of invasive Lake Trout Salvelinus namaycush is an important management tool to use in native fish and ecosystem conservation throughout the U.S. Intermountain West. Lake Trout suppression, primarily by gill netting, has been ongoing in Yellowstone Lake, Yellowstone National Park, Wyoming, since 1995. Additional methods that cause mortality of Lake Trout embryos could be used simultaneoAuthorsNathan A. Thomas, Christopher S. Guy, Todd M. Koel, Alexander V. Zale - Data
Environmental DNA data, fish abundance data, and stream habitat data from northwest Montana and northeast Washington and southern British Columbia, Canada
Field estimates of the abundance of two trout species (bull trout and westslope cutthroat trout) in Montana and rainbow trout in Washington and British Columbia were collected in concert with environmental DNA samples (eDNA) to evaluate if eDNA copy numbers correlated with abundance of trout. In addition, stream habitat data including channel units (pools, riffles), substrate, large woody debris,