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Brian Irwin, PhD

Assistant Unit Leader - Georgia Cooperative Fish and Wildlife Research Unit

Research Interests

My research interests are in the areas of ecological change, fish population dynamics, and decision making linked to conservation and management of natural resources. Current projects involve using quantitative models to explore how populations respond to anthropogenic and natural influences.

Teaching Interests

My courses introduce concepts and analyses relevant to conservation decision making and sustainable use of exploited natural resources.

Professional Experience

  • Assistant Unit Leader, Georgia Cooperative Fish and Wildlife Research Unit, 2012-

Education and Certifications

  • Ph D Cornell University 2006

  • MS Auburn University 2001

  • BS University of Illinois 1998

Science and Products

link
Fog over the Sante Fe River, Florida

Turning Uncertainty into Useful Information for Conservation Decisions

We routinely encounter uncertainty when we make decisions – from picking a new morning coffee to choosing where to live. Even decisions that are supported by science contain some level of remaining uncertainty. In the context of conservation and wildlife management, the potential for uncertainty to influence decisions is perhaps most obvious when we think about predicting how actions (or non-actio
By
Climate Adaptation Science Centers
link

Turning Uncertainty into Useful Information for Conservation Decisions

We routinely encounter uncertainty when we make decisions – from picking a new morning coffee to choosing where to live. Even decisions that are supported by science contain some level of remaining uncertainty. In the context of conservation and wildlife management, the potential for uncertainty to influence decisions is perhaps most obvious when we think about predicting how actions (or non-actio
Learn More
Filter Total Items: 23

Life-history connections to long-term fish population trends in a species-rich temperate river

Fishes exhibit a diverse range of traits encompassing life-history strategies, feeding behaviours and spawning behaviours. These traits mediate fish population responses to changing environmental conditions such as those caused by anthropogenic stressors. The Conasauga River, located in northwestern Georgia and southeastern Tennessee, USA, hosts a diverse assemblage of over 75 species of freshwate
Authors
Andrew J. Nagy, Mary Freeman, Brian J. Irwin, Seth J. Wenger
By
Ecosystems Mission Area, Eastern Ecological Science Center

Managing the threat of infectious disease in fisheries and aquaculture using structured decision making

Fisheries and aquaculture provide food and economic security, especially in the developing world, but both face challenges from infectious disease. Here, we consider management of disease issues from a structured decision-making perspective to examine how infectious disease can threaten seafood production and influence management decisions. For both wild fisheries and aquaculture, disease-manageme
Authors
Brian J. Irwin, Megan M. Tomamichel, Marc E. Frischer, Richard J. Hall, Alaina D. E. Davis, Thomas H. Bliss, Pejman Rohani, James E. Byers
By
Cooperative Research Units

Refining capture-recapture recruitment estimation methods for Atlantic sturgeon

The Atlantic sturgeon Acipenser oxyrinchus oxyrinchus was once of great commercial importance in many coastal rivers of the eastern USA. Over the 19th and 20th centuries, most historical stocks of Atlantic sturgeon were depleted by human activities. Estimating recruitment for the remaining populations is challenging due to sampling constraints, limited age data, and natural variability. However, r
Authors
M.A. Baker, E.C. Ingram, D.L. Higginbotham, Brian J. Irwin, A.G. Fox
By
Cooperative Research Units

Perceived constraints and negotiations to trout fishing in Georgia based on angler specialization level

Anglers face constraints that influence participation and dropout rates. Some recreational anglers may be able to negotiate constraints by altering the timing or frequency of participation, acquiring new skills, or modifying nonrecreational aspects such as family or work responsibilities. We consider data collected via a mail survey from Georgia-resident trout license holders to identify both perc
Authors
H. J. TenHarmsel, B. B. Boley, Brian J. Irwin, Cecil A. Jennings
By
Cooperative Research Units

Using video survey to examine the effect of habitat on gag grouper encounter

Gag is a reef fish that was declared overfished in the Gulf of Mexico (GOM) in 2009. Although Gag are no longer listed as overfished, fisheries managers are concerned that stocks may not be recovering. Our objective was to identify habitat characteristics important to Gag, and their effect on the probability of Gag occurrence. We obtained data from three separate fisheries-independent video survey
Authors
G. Alvarez, D. Gandy, Brian J. Irwin, Cecil A. Jennings, Adam Fox
By
Cooperative Research Units

An importance–satisfaction analysis of trout license holders in Georgia

As anglers become increasingly diverse, fisheries managers are challenged to find ways to satisfy users with divergent preferences while conserving a limited resource on a limited budget. With this management challenge in mind, this study combines previous angler specialization research with an importance–satisfaction analysis (ISA) to aid fisheries managers in better understanding users with dive
Authors
H. J. TenHarmsel, B. B. Boley, Brian J. Irwin, Cecil A. Jennings
By
Cooperative Research Units

Age truncation of alewife in Lake Michigan

Empirical evidence has shown increased variability in harvest and recruitment of exploited fish populations, which can result directly from exploitation or indirectly from interactions between external drivers and the internal dynamics of age-structured populations. We investigated whether predation in a freshwater system could affect a prey fish population, in the same way fishing affects targete
Authors
T. Vidal, Brian J. Irwin, Charles P. Madenjian, S. J. Wenger
By
Ecosystems Mission Area, Cooperative Research Units, Great Lakes Science Center

The dream and the reality: Meeting decision-making time frames while incorporating ecosystem and economic models into management strategy evaluation

Atlantic herring (Clupea harengus) in the Northwest Atlantic have been managed with interim harvest control rules (HCRs). A stakeholder-driven management strategy evaluation (MSE) was conducted that incorporated a broad range of objectives. The MSE process was completed within 1 year. Constant catch, conditional constant catch, and a biomass-based (BB) HCR with a 15% restriction on the interannual
Authors
J.J. Deroba, S.K. Gaichas, Min-Yang Lee, Rachael G. Feeney, D. Boelke, Brian J. Irwin
By
Cooperative Research Units

Integrating management strategy evaluation into fisheries management: Advancing best practices for stakeholder inclusion based on an MSE for Northeast US Atlantic herring

The New England Fishery Management Council used management strategy evaluation (MSE) to evaluate possible harvest control rules for Atlantic herring (Clupea harengus), the first MSE in the US and perhaps globally to use open-invitation, public workshops for input. Stakeholder inclusion can increase both realism and likelihood of use by managers, but inclusivity is not achieved easily. Here, self-s
Authors
Rachael G. Feeney, Deirdre V. Boelke, Jonathan J Deroba, Sarah Gaichas, Brian J. Irwin, Min-Yang Lee
By
Cooperative Research Units

Using variance structure to quantify responses to perturbation in fish catches

We present a case study evaluation of gill-net catches of Walleye Sander vitreus to assess potential effects of large-scale changes in Oneida Lake, New York, including the disruption of trophic interactions by double-crested cormorants Phalacrocorax auritus and invasive dreissenid mussels. We used the empirical long-term gill-net time series and a negative binomial linear mixed model to partition
Authors
Tiffany E. Vidal, Brian J. Irwin, Tyler Wagner, Lars G. Rudstam, James R. Jackson, James R. Bence
By
Cooperative Research Units

Adapting inland fisheries management to a changing climate

Natural resource decision makers are challenged to adapt management to a changing climate while balancing short-term management goals with long-term changes in aquatic systems. Adaptation will require developing resilient ecosystems and resilient management systems. Decision makers already have tools to develop or ensure resilient aquatic systems and fisheries such as managing harvest and riparian
Authors
Craig P. Paukert, Bob A. Glazer, Gretchen J. A. Hansen, Brian J. Irwin, Peter C. Jacobson, Jeffrey L. Kershner, Brian J. Shuter, James E. Whitney, Abigail J. Lynch
By
Cooperative Research Units

Optimization of scat detection methods for a social ungulate, the wild pig, and experimental evaluation of factors affecting detection of scat

Collection of scat samples is common in wildlife research, particularly for genetic capture-mark-recapture applications. Due to high degradation rates of genetic material in scat, large numbers of samples must be collected to generate robust estimates. Optimization of sampling approaches to account for taxa-specific patterns of scat deposition is, therefore, necessary to ensure sufficient sample c
Authors
David A. Keiter, Fred L. Cunningham, Olin E. Rhodes, Brian J. Irwin, James Beasley
By
Cooperative Research Units

Science and Products

link
Fog over the Sante Fe River, Florida

Turning Uncertainty into Useful Information for Conservation Decisions

We routinely encounter uncertainty when we make decisions – from picking a new morning coffee to choosing where to live. Even decisions that are supported by science contain some level of remaining uncertainty. In the context of conservation and wildlife management, the potential for uncertainty to influence decisions is perhaps most obvious when we think about predicting how actions (or non-actio
By
Climate Adaptation Science Centers
link

Turning Uncertainty into Useful Information for Conservation Decisions

We routinely encounter uncertainty when we make decisions – from picking a new morning coffee to choosing where to live. Even decisions that are supported by science contain some level of remaining uncertainty. In the context of conservation and wildlife management, the potential for uncertainty to influence decisions is perhaps most obvious when we think about predicting how actions (or non-actio
Learn More
Filter Total Items: 23

Life-history connections to long-term fish population trends in a species-rich temperate river

Fishes exhibit a diverse range of traits encompassing life-history strategies, feeding behaviours and spawning behaviours. These traits mediate fish population responses to changing environmental conditions such as those caused by anthropogenic stressors. The Conasauga River, located in northwestern Georgia and southeastern Tennessee, USA, hosts a diverse assemblage of over 75 species of freshwate
Authors
Andrew J. Nagy, Mary Freeman, Brian J. Irwin, Seth J. Wenger
By
Ecosystems Mission Area, Eastern Ecological Science Center

Managing the threat of infectious disease in fisheries and aquaculture using structured decision making

Fisheries and aquaculture provide food and economic security, especially in the developing world, but both face challenges from infectious disease. Here, we consider management of disease issues from a structured decision-making perspective to examine how infectious disease can threaten seafood production and influence management decisions. For both wild fisheries and aquaculture, disease-manageme
Authors
Brian J. Irwin, Megan M. Tomamichel, Marc E. Frischer, Richard J. Hall, Alaina D. E. Davis, Thomas H. Bliss, Pejman Rohani, James E. Byers
By
Cooperative Research Units

Refining capture-recapture recruitment estimation methods for Atlantic sturgeon

The Atlantic sturgeon Acipenser oxyrinchus oxyrinchus was once of great commercial importance in many coastal rivers of the eastern USA. Over the 19th and 20th centuries, most historical stocks of Atlantic sturgeon were depleted by human activities. Estimating recruitment for the remaining populations is challenging due to sampling constraints, limited age data, and natural variability. However, r
Authors
M.A. Baker, E.C. Ingram, D.L. Higginbotham, Brian J. Irwin, A.G. Fox
By
Cooperative Research Units

Perceived constraints and negotiations to trout fishing in Georgia based on angler specialization level

Anglers face constraints that influence participation and dropout rates. Some recreational anglers may be able to negotiate constraints by altering the timing or frequency of participation, acquiring new skills, or modifying nonrecreational aspects such as family or work responsibilities. We consider data collected via a mail survey from Georgia-resident trout license holders to identify both perc
Authors
H. J. TenHarmsel, B. B. Boley, Brian J. Irwin, Cecil A. Jennings
By
Cooperative Research Units

Using video survey to examine the effect of habitat on gag grouper encounter

Gag is a reef fish that was declared overfished in the Gulf of Mexico (GOM) in 2009. Although Gag are no longer listed as overfished, fisheries managers are concerned that stocks may not be recovering. Our objective was to identify habitat characteristics important to Gag, and their effect on the probability of Gag occurrence. We obtained data from three separate fisheries-independent video survey
Authors
G. Alvarez, D. Gandy, Brian J. Irwin, Cecil A. Jennings, Adam Fox
By
Cooperative Research Units

An importance–satisfaction analysis of trout license holders in Georgia

As anglers become increasingly diverse, fisheries managers are challenged to find ways to satisfy users with divergent preferences while conserving a limited resource on a limited budget. With this management challenge in mind, this study combines previous angler specialization research with an importance–satisfaction analysis (ISA) to aid fisheries managers in better understanding users with dive
Authors
H. J. TenHarmsel, B. B. Boley, Brian J. Irwin, Cecil A. Jennings
By
Cooperative Research Units

Age truncation of alewife in Lake Michigan

Empirical evidence has shown increased variability in harvest and recruitment of exploited fish populations, which can result directly from exploitation or indirectly from interactions between external drivers and the internal dynamics of age-structured populations. We investigated whether predation in a freshwater system could affect a prey fish population, in the same way fishing affects targete
Authors
T. Vidal, Brian J. Irwin, Charles P. Madenjian, S. J. Wenger
By
Ecosystems Mission Area, Cooperative Research Units, Great Lakes Science Center

The dream and the reality: Meeting decision-making time frames while incorporating ecosystem and economic models into management strategy evaluation

Atlantic herring (Clupea harengus) in the Northwest Atlantic have been managed with interim harvest control rules (HCRs). A stakeholder-driven management strategy evaluation (MSE) was conducted that incorporated a broad range of objectives. The MSE process was completed within 1 year. Constant catch, conditional constant catch, and a biomass-based (BB) HCR with a 15% restriction on the interannual
Authors
J.J. Deroba, S.K. Gaichas, Min-Yang Lee, Rachael G. Feeney, D. Boelke, Brian J. Irwin
By
Cooperative Research Units

Integrating management strategy evaluation into fisheries management: Advancing best practices for stakeholder inclusion based on an MSE for Northeast US Atlantic herring

The New England Fishery Management Council used management strategy evaluation (MSE) to evaluate possible harvest control rules for Atlantic herring (Clupea harengus), the first MSE in the US and perhaps globally to use open-invitation, public workshops for input. Stakeholder inclusion can increase both realism and likelihood of use by managers, but inclusivity is not achieved easily. Here, self-s
Authors
Rachael G. Feeney, Deirdre V. Boelke, Jonathan J Deroba, Sarah Gaichas, Brian J. Irwin, Min-Yang Lee
By
Cooperative Research Units

Using variance structure to quantify responses to perturbation in fish catches

We present a case study evaluation of gill-net catches of Walleye Sander vitreus to assess potential effects of large-scale changes in Oneida Lake, New York, including the disruption of trophic interactions by double-crested cormorants Phalacrocorax auritus and invasive dreissenid mussels. We used the empirical long-term gill-net time series and a negative binomial linear mixed model to partition
Authors
Tiffany E. Vidal, Brian J. Irwin, Tyler Wagner, Lars G. Rudstam, James R. Jackson, James R. Bence
By
Cooperative Research Units

Adapting inland fisheries management to a changing climate

Natural resource decision makers are challenged to adapt management to a changing climate while balancing short-term management goals with long-term changes in aquatic systems. Adaptation will require developing resilient ecosystems and resilient management systems. Decision makers already have tools to develop or ensure resilient aquatic systems and fisheries such as managing harvest and riparian
Authors
Craig P. Paukert, Bob A. Glazer, Gretchen J. A. Hansen, Brian J. Irwin, Peter C. Jacobson, Jeffrey L. Kershner, Brian J. Shuter, James E. Whitney, Abigail J. Lynch
By
Cooperative Research Units

Optimization of scat detection methods for a social ungulate, the wild pig, and experimental evaluation of factors affecting detection of scat

Collection of scat samples is common in wildlife research, particularly for genetic capture-mark-recapture applications. Due to high degradation rates of genetic material in scat, large numbers of samples must be collected to generate robust estimates. Optimization of sampling approaches to account for taxa-specific patterns of scat deposition is, therefore, necessary to ensure sufficient sample c
Authors
David A. Keiter, Fred L. Cunningham, Olin E. Rhodes, Brian J. Irwin, James Beasley
By
Cooperative Research Units
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