Brian J Irwin

Brian J Irwin
United States Geological Survey | USGS · Cooperative Research Units Program

PhD

About

53
Publications
7,567
Reads
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888
Citations
Additional affiliations
July 2018 - present
University of Georgia
Position
  • Professor (Associate)
March 2012 - June 2018
University of Georgia
Position
  • Professor (Assistant)
March 2012 - present
GA Cooperative Research Unit
Position
  • Research Assistant

Publications

Publications (53)
Article
Full-text available
The tricolored bat (Perimyotis subflavus), once common in the eastern United States, has experienced significant mortality due to white‐nose syndrome (WNS), a fungal disease that primarily affects bats hibernating in caves and mines. In coastal regions of the southeastern United States, where caves and mines are scarce, tricolored bats often use ro...
Article
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...
Article
Full-text available
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 bot...
Article
Full-text available
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, lim...
Article
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 non‐recreational aspects such as family or work responsibilities. We consider data collected via a mail survey from Georgia‐r...
Article
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 p...
Article
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 importance‐satisfaction analysis (ISA) to aid fisheries m...
Article
Full-text available
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, bu...
Article
Full-text available
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...
Article
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...
Article
Managing inland fisheries in the 21st century presents several obstacles, including the need to view fisheries from multiple spatial and temporal scales, which usually involves populations and resources spanning sociopolitical boundaries. Though collaboration is not new to fisheries science, inland aquatic systems have historically been managed at...
Article
Long‐term sampling of fisheries data is an important source of information for making inferences about the temporal dynamics of populations that support ecologically and economically important fisheries. For example, time series of catch‐per‐effort data are often examined for the presence of long‐term trends. However, it is also of interest to know...
Article
Full-text available
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 a...
Article
Full-text available
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,...
Article
We applied a management strategy evaluation (MSE) model to examine the potential cost-effectiveness of using pheromone-baited trapping along with conventional lampricide treatment to manage invasive sea lamprey. Four pheromone-baited trapping strategies were modeled: (1) stream activation wherein pheromone was applied to existing traps to achieve 1...
Technical Report
Full-text available
Irwin, B., B. Crawford, T. Gancos Crawford, and C. Moore. 2016. Turning uncertainty in useful information for conservation decisions. Southeast Climate Science Center Fact Sheet 2016-02.
Article
Full-text available
The proliferation of double-crested cormorants (DCCOs; Phalacrocorax auritus) in North America has raised concerns over their potential negative impacts on game, cultured and forage fishes, island and terrestrial resources, and other colonial water birds, leading to increased public demands to reduce their abundance. By combining fish surplus produ...
Article
Full-text available
The St. Marys River (SMR) historically has been a major producer of sea lampreys (Petromyzon marinus) in the Laurentian Great Lakes. In the early 2000s, a decision analysis (DA) project was conducted to evaluate sea lamprey control policies for the SMR; this project suggested that an integrated policy of trapping, sterile male releases, and Baylusc...
Article
Full-text available
Intracranial abscess disease is a cause of natural mortality for mature male white-tailed deer (Odocoileus virginianus). Most cases of abscesses are associated with bacterial infection by Trueperella (Arcanobacterium) pyogenes, but a complete understanding of the epidemiology of this disease is lacking. We quantified the effects of individual chara...
Conference Paper
Development of statistical indicators to detect and forecast large-scale change (i.e., regime shifts) in ecological systems could prove to be a valuable tool for the prediction of fish population dynamics, timely management and effective monitoring of fisheries resources. Switching between alternate basins of attraction in aquatic ecosystems can oc...
Conference Paper
Monitoring programs are frequently relied upon to support conservation decisions. Quantifying the population dynamics of rare and elusive species (e.g., threatened or endangered species), however, is a challenging process for both methodological and statistical reasons. Such species often occur in low numbers and may also be behaviorally cryptic. A...
Conference Paper
Applying a mating pheromone component to traps has been found to enhance trap capture of invasive Great Lakes sea lamprey. Management-scale tests have yielded valuable data on the cost and efficacy of pheromone-enhanced trapping as a potential control method. We utilized this information in a management strategy evaluation model, which explicitly a...
Conference Paper
The Department of Interior Northeast Climate Science Center (NE CSC) conducts research that responds to the regional natural resource management community’s needs to anticipate, monitor, and adapt to climate change. We will highlight ongoing work at the NE CSC that seeks to better understand climate impacts on freshwater and coastal fish and fish h...
Conference Paper
Background/Question/Methods Predicting population responses to large-scale change requires an understanding of how population dynamics vary over space and time. For a variety of important metrics, monitoring programs are generally assumed to provide such information. For example, observed indices may vary among repeated samples from a single loca...
Article
Full-text available
Forests are socioeconomically and ecologically important ecosystems that are exposed to a variety of natural and anthropogenic stressors. As such, monitoring forest condition and detecting temporal changes therein remain critical to sound public and private forestland management. The National Parks Service's Vital Signs monitoring program collects...
Article
The success of natural resource management depends on monitoring, assessment and enforcement. In support of these efforts, reference points (RPs) are often viewed as critical values of management-relevant indicators. This paper considers RPs from the standpoint of objective-driven decision making in dynamic resource systems, guided by principles of...
Article
Monitoring to detect temporal trends in biological and habitat indices is a critical component of fisheries management. Thus, it is important that management objectives are linked to monitoring objectives. This linkage requires a definition of what constitutes a management-relevant “temporal trend.” It is also important to develop expectations for...
Article
Partitioning total variability into its component temporal and spatial sources is a powerful way to better understand time series and elucidate trends. The data available for such analyses of fish and other populations are usually nonnegative integer counts of the number of organisms, often dominated by many low values with few observations of rela...
Conference Paper
Oneida Lake provides a rare, detailed experiment chronicling the walleye and yellow perch population responses to the rise and fall of double-crested cormorant abundance from management actions. In response to previous studies showing significant negative impacts of cormorant predation on percid populations in the lake, a gradient of cormorant mana...
Article
We estimated economic injury levels (EILs) and associated optimal control budgets for sea lamprey Petromyzon marinus for each of the Great Lakes using common assumptions and consistent methods. The lake‐specific EILs are defined as equilibrium sea lamprey abundances below which incremental increases in control expenditures do not pay for themselves...
Conference Paper
In the Laurentian Great Lakes, parasitic sea lamprey (Petromyzon marinus) attack large-bodied hosts, such as lake trout (Salvelinus namaycush), and cause substantial mortality. These attacks leave wounds, or marks, on surviving lake trout hosts. Estimates of the resulting marking rates are used to evaluate the success of a multi-million dollar sea...
Conference Paper
Partitioning total variability into multiple temporal and spatial sources (i.e., variance components) is a powerful approach to accommodate complex data structures. For example, an environmental state variable may vary among repeated samples from a single site, from site-to-site within a lake, from lake-to-lake, and over time. Models for estimating...
Article
Full-text available
Multiple objectives associated with recreational fishing, combined with multiple uncertainties, pose real challenges for management. We suggest that applying formal decision-making frameworks to partnership-based policy evaluations can prove beneficial to recreational fisheries management. We describe how a sequence of workshops can be used to enga...
Conference Paper
Lake trout (Salvelinus namaycush), lake whitefish (Coregonus clupeaformis), and bloater (Coregonus hoyi) constitute the majority of commercial harvest in Lake Huron’s cold-water fish community. Lake trout were nearly extirpated from Lake Huron in the mid 1900s. Rehabilitation efforts are ongoing and have contributed to increased observations of wil...
Conference Paper
Fishery-independent surveys are widely used to collect data on yellow perch and walleye across the Great Lakes basin. Although used to fulfill many objectives, one of the most common uses of survey data is to infer changes in relative abundance over time, based on indices such as catch per effort (CPE). However, our ability to detect changes in CPE...
Article
Full-text available
Models of entire managed systems, known as operating models or management strategy evaluation (MSE) models, have been developed in recent years to more fully account for uncertainty in multiple steps of fishery manage-ment. Here we describe an operating model of sea lamprey management in the Great Lakes and use the model to compare alternative mana...
Article
Full-text available
We present long-term (>40-year) patterns in the density of age-0 yellow perch Perca flavescens in Oneida Lake at four early life stages (at egg deposition, at the attainment of a total length of 18 mm, on 1 August, and on 15 October), from which we calculated mortality and growth rates during the three intervals between these early life stages. At...
Article
In the southern basin of Lake Michigan, yellow perch (Perca flavescens) are ecologically and economically important. However, there is no explicit harvest policy for the management of this resource, the authority for which is shared among four U.S. states. We used decision analysis and projections from a stochastic simulation model to aid managers...
Article
We used a spatially explicit stochastic simulation model to evaluate whether source–sink population dynamics would affect performance of alternative harvest policies for yellow perch, Perca flavescens, in southern Lake Michigan. The model contained four management areas in southern Lake Michigan representing each U.S. state's waters. We parameteriz...
Article
Full-text available
We used three long-term data sets (gill nets, trawls, and adult population estimates) for walleye (Sander vitreus) to simultaneously estimate density, gear catchabilities, and mortality using an age-structured, nonlinear model. Model constraints included a fixed natural mortality rate and age- and gear-specific but time-invariant catchabilities. Tr...
Article
Full-text available
1 This technical report is identical in content to a project completion report submitted to the Great Lakes Fishery Commission.
Article
Four decades of observations on the limnology and fishes of Oneida Lake, New York, USA, provided an opportunity to investigate causes of mortality during winter, a period of resource scarcity for most juvenile fishes, in age-0 yellow perch (Perca flavescens) and age-0 white perch (Morone americana). This time series contains several environmental (...
Conference Paper
Full-text available
Coincident with an increasing Double-crested Cormorant population on Oneida Lake, New York, were declines in numbers of sport fish in the 1990s, most notable in walleye and yellow perch. Analysis of over 40 years of data shows higher juvenile mortality for both species in the '90s compared to the previous three decades. We have studied Cormorant di...
Article
Gizzard shad Dorosoma cepedianum is an important prey fish that is capable of influencing both the upper and lower trophic levels in aquatic systems. Contrary to our predictions, during the 4 years after a selective reduction of gizzard shad in Walker County State Fishing Lake (WCL), Alabama, the sport fish population structure did not decline as g...
Article
Gizzard shad Dorosoma cepedianum is an important fish species that can have strong effects on aquatic communities throughout the southeastern and midwestern USA. Gizzard shad often become overabundant, competitively reducing growth and recruitment of sport fishes. Using field data and bioenergetics simulations, we evaluated the potential for largem...

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