Synergies in Harvest Management for Fishing and Hunting

Symposium
ROOM: RSCC, A6
SESSION NUMBER: 7820
 
We propose an integrated fisheries and wildlife Symposium on the status of the science of setting harvest regulations. Presenters will provide current research and critical reviews that will address life-history characteristics of harvested populations, evolutionary and behavioral effects of harvest on fish and wildlife, political and social realities in harvest decisions, the use of Integrated Population Models to improve management decisions, the use of formal decision-making processes to select harvest regulations, frameworks to choose monitoring schemes to support harvest decisions, effects of harvest regulations on angler and hunter behaviors, and the effects of various regulations such as catch-and-release fishing, length limits for fish, point systems for deer, and bag limits for waterfowl. We aim to provide timely information that will ultimately assist managers to make better decisions and justify decisions to their supervisors. Harvest management is omnipresent as a decision mandate for state and federal agencies, and is closely tied to funding of state agencies. This Symposium will gather scientists to highlight unique and innovative approaches for management of recreational harvest of fish and wildlife, and we believe the joint TWS-AFS meeting provides the unique opportunity to bring fisheries and wildlife scientists together for an interdisciplinary overview of harvest management. Presenters will be encouraged to address potential implications to both fish and wildlife. The setting should broaden presenters’ and audience-members’ understanding of current harvest-management approaches, which may generate a unifying conceptual model of harvest management. To leverage the Symposium and authors’ contributions, we plan to invite authors to contribute to a future publication on Harvest Management to be used by agency personnel and university professors to enhance future development and implementation of recreational-harvest regulations for fish and wildlife.

8:00AM Welcoming Remarks
 
8:20AM The Social and Political Context of Harvest Management
  Tim Hiller
Contemporary wildlife management includes highly technical decisions that typically occur under increasingly complex and scrutinized scenarios. Scientifically based information continues to be challenged, including for making effective and defensible decisions related to harvest management. Informed decision-making is not simply about ensuring sustainability of harvest, but extends well beyond ecological factors. This confluence of influences includes substantial social and political considerations that, if dismissed, may have undesirable consequences, particularly for highly polarized topics. At times, such influences may be beneficial for meeting public (and legislative) approval, but can also hinder agency management objectives and state management authority. Alternative facts, unfortunately, can also shape social and political directions on controversial topics and further complicate management. Among the more consistently controversial topics for state agencies and legislatures is furbearer management. Examples abound where socio-political constraints and pressures seem to be resulting in the disregard of science as the proper tool to discharge wildlife policy. Recent and proposed legislative approaches continue to challenge and erode state management authority for furbearers. To explore issues, I will focus on harvest management of bobcats, a species for which certain groups routinely express fundamental opposition to consumptive use in social and political forums.
8:40AM A Decision Analytical Framework for Developing Harvest Regulations
  Michael Runge
The development of harvest regulations for fish or wildlife is a complex decision that needs to weigh multiple objectives, consider a set of alternative regulatory options, integrate scientific understanding about the population dynamics of the harvested species as well as the human response to regulations, account for uncertainty, and provide an avenue for feedback from monitoring programs. The field of decision analysis provides a framework for structuring such decisions and tools for navigating the components. At the center of any harvest management endeavor is a set of objectives that may include providing harvest opportunity, conserving the harvested population long into the future, and satisfying hunters; tools from multi-criteria decision analysis are useful in finding the right balance among competing objectives. The population dynamics of harvested populations are often stochastic; tools from risk analysis and dynamic optimization can be used to find state-dependent policies that manage variation. Finally harvest regulations are often set in the face of uncertainty; value-of-information methods can be used to evaluate the importance of that uncertainty, and adaptive management methods can be used to manage it. I will illustrate these concepts with an ongoing project to develop hunting regulations for northern pintails (Anas acuta).
9:00AM Choosing an Optimal Duck Season: Integrating Hunter Values with Duck Migration Data
  Angela Fuller, Joshua Stiller, William Siemer, Kelly Perkins
State wildlife agencies frequently struggle to identify optimal hunting season dates for migratory game bird species that meet the diverse interests of stakeholders. Many approaches have been used to ensure the regulated community is involved in the decision-making process including public hearings, hunter season-date preference surveys, and hunter task forces. However, these approaches may not necessarily reflect the opinions and values of all stakeholders. To address these challenges, we used a decision analytical framework that included a duck hunter survey of a representative sample of the regulated community in each hunting zone in New York State. Rather than asking duck hunters about their season date preferences, we asked them to rank six objectives describing what they value in their hunting experience. Four of the objectives described duck species availability (i.e., abundance or immigration). We used eBird’s STEM Models to estimate abundance and immigration rates of ducks in each waterfowl zone. We evaluated unique season date alternatives to determine which alternative best satisfied the competing objectives of duck hunters in each zone. The approach we developed successfully involved avid duck hunters in the development stages, while ensuring a representative sample of all stakeholders were represented in the final decision-making process.
9:20AM Using Structured Decision Making to Incorporate Ecological and Social Values into Harvest Decisions: Case Studies of Walleye, Deer, and Turkey
  Kelly F. Robinson, Angela Fuller, Michael L. Jones
Harvest decisions for fish and wildlife populations typically include ecological, economic, and social values. Using decision analysis (i.e., structured decision making and adaptive management) as a framework for multi-objective decision making for setting harvest regulations can lead to a more transparent and resilient decision. The steps of this process include opportunities for inclusion of stakeholders’ concerns, either through multi-party collaborative workshops or the use of social science techniques to elicit values and predict consequences of management actions. We present three case studies of using decision analysis to determine stakeholders’ objectives, identify alternative harvest strategies, predict the consequences of these alternatives on all objectives, and make tradeoffs among objectives. Case studies of white-tailed deer (Odocoileus virginianus) and wild turkey (Meleagris gallapavo) in New York State provide examples of combining predictive population modeling and implementation of survey instruments statewide to determine optimal region-specific harvest regulations. Harvest management of walleye (Sander vitreus) provides an example of the inclusion of commercial and recreational angler groups in a series of workshops to aid in decision making about harvest quotas for one of the world’s largest freshwater fisheries.
09:40AM Break
1:10PM Structured Decision Making Provides Insight When Selecting a Preferred Population Monitoring Program
  Jonathan Cummings, Therese Donovan
Population monitoring programs typically aim to meet many objectives, but standard analyses mainly consider a monitoring program’s ability to effectively estimating population size and trend. Structured decision making aids both in the discovery of additional objectives, and in evaluating the trade-offs between them. Rather than relying solely on metrics such as the coefficients of error for abundance and trend estimates, the use of multiple criteria decision analysis in the structured decision making approach can translate these metrics and those for all other objectives into a relative performance score. We simulated a fisher (Martes pennanti) population and its monitoring to evaluate monitoring programs in the state of Vermont, USA. The state fish and wildlife department questioned the costs associated with continued use of necropsies to collect data. Using structured decision making to identify and score the importance of objectives in addition to estimation effectiveness – management cost, citizen engagement, and disease detection – we found that despite the costs of the necropsy monitoring program it best achieves the state’s objectives, a conclusion that may not have been reached from a standard analysis focused solely on the effectiveness of abundance and trend estimation.
1:30PM Effects of Regulations and Pricing on Participation in Recreational Fishing
  Richard Melstrom
This paper examines the effects of regulations and pricing on participation in a recreational fishery. The harvest restrictions and area closures that agencies use to manage recreational harvest can have significant effects on fishing behavior. Fisheries analysts and managers can study these effects by simulating behaviors in recreation demand models. This paper develops a recreation demand model of individual participation, avidity and site choice from survey data on paddlefish anglers. I identify the effects of catch and harvest limits in the model using anglers’ responses to a hypothetical fishing location question. Combining hypothetical with actual behavioral data can produce a model that accurately describes in situ behaviors and predicts the effects of regulations not yet in place. I use the model to predict the effects of changes in harvest policies, site access and fishing costs. The results show how managers can use regulations and pricing to adjust the location and intensity of effort in a fishery.
1:50PM Effects of Wildlife Density on Hunter Satisfaction
  James Martin
Wildlife management agencies have a complicated task navigating multiple stakeholder groups, complicated ecological systems, and budgetary constraints when making harvest decisions. Actions possibly taken in harvest problems—setting bag limits, seasons, party size, animal size—are used primarily to satisfy two objectives. First, because wildlife species are held in a public trust, there are legal mandates to manage them for long-term abundance and persistence. Second, because of the importance of hunters and anglers to the financial solvency of agencies and the long-standing culture of hunting and fishing in the US, managers aim to make management decisions that satisfy stakeholder values. These fundamental objectives oftentimes conflict—that is, maximizing abundance of a species long-term will come at a tradeoff in hunter and angler satisfaction. When selecting among alternative strategies, it is advantageous to know the relationship between animal abundance or density and hunter or angler satisfaction. However, this relationship is not well-quantified in the literature. I will discuss overarching patterns from the literature for certain taxa and present a case-study involving northern bobwhites (Colinus virginianus) on public land in Georgia. Furthermore, I will discuss how decision makers can begin to monitor these two important state variables to improve future decisions.
2:10PM Non-Linear Responses of Angler Harvest Rates and Size Selectivity to Shifts in Population Abundance, Size Structure, and Regulations
  Zachary S. Feiner, Alexander W. Latzka, Max H. Wolter
Understanding relationships between population characteristics (abundance, size structure), human exploitation (harvest rates, size selectivity), and regulation (size or bag limits) can elucidate the quality of user experiences and impact of management actions. Non-linear dynamics may occur when users alter behavior to maintain exploitation rates even as wild populations change (e.g., hyperstability in fisheries), which may mask population declines or produce unexpected management outcomes. We examined responses of angler exploitation to variation in population characteristics and management in three popular, harvest-oriented and liberally-managed Wisconsin panfish fisheries (bluegill Lepomis macrochirus, black crappie Pomoxis nigromaculatus, and yellow perch Perca flavescens), using fisheries-independent and creel data across ~250 lakes from 1990 to 2017. We specifically investigated relationships between i) population abundance and angler catch rates, ii) population size structure and angler size-selectivity, and iii) regulation (increasingly restrictive bag limits), catch rates, and size-selectivity. Catch rates were consistently and significantly hyperstable and size-selectivity exhibited non-linear relationships with population size structure. Anglers also selected for larger fish under more restrictive regulations. Angler exploitation may show limited responses to shifting fish populations unless changes are substantial, but their behavior may be altered by restrictive regulation, providing a framework for predicting management impacts on natural resource utilization.
2:30PM Harvest Regulations Can Affect the Evolutionary Impacts of Harvests on Fish and Wildlife.
  Marco Festa-Bianchet
Intense, selective harvests can lead to the evolution of behavior, life-history traits and phenotypes. Those changes may affect population growth or modify ecosystem structure. Harvest-induced evolution of life-history traits has mostly been reported for fish, of morphology for trophy-hunted ungulates and of behavior for many taxa. Regulations can promote evolutionary change by allowing intense and selective harvests which modify the fitness consequences of a trait, often in opposition to natural or sexual selection. Regulations can lower those selective impacts by reducing harvest rate and selectivity, or promoting genetic rescue. Regulations that mimic patterns of natural mortality may be most effective in reducing evolutionary impacts. In fish and other species with indeterminate growth, impacts of selective harvest on life-history traits appear to be greater than in species with determinate growth, which may have less flexibility in age-specific allocation to growth and reproduction. Behavioral changes, such as timidity syndrome in sports fisheries, can have ecosystem consequences and are difficult to address through regulations. Harvest rate appears to be more important than selectivity in leading to evolutionary change. Contrasting regulations for two mountain ungulates, ibex and bighorn sheep, lower and increase the opportunity for hunting-induced evolution of horn size.
2:50PM Refreshment Break
3:20PM Evolving Regulations for a Changing World
  Lyndsie Wszola
It has become increasingly clear that regulated harvest and even regulations themselves can induce ecological and evolutionary changes in population stage and size structure, especially in fisheries. Harvest-induced evolution tends to reduce fish age and size at maturity, whether length-limits are in place or not, because intensive fish harvest favors early reproduction even without intentional size selection. Reducing age and size at maturity has a cascading series of effects for aquatic food webs whose complexity and importance demand novel inferential and predictive approaches. Moreover, the ecological and evolutionary consequences of changes in fish size and age structure likely vary as a function of fish life history and trophic relationships. We integrate a stage-structured eco-evolutionary model of harvest-induced changes in size and stage structure with a meta-analysis of fish life history to assess how size-specific harvest regulations affect population stability, extinction risk, and recovery potential under ecologically and evolutionarily-induced changes in population stage structure. Our approach incorporates emerging evolutionary theory with the wealth of available fisheries data to provide a framework for evaluating regulations in the context of a changing world.
3:40PM Making Harvest Management Decisions Robust to Uncertainty
  Andrew Tyre, Brigitte Tenhumberg
Population managers regularly make decisions in the face of uncertainty about vital rates such as survival and fecundity of the species they want to manage. Perhaps more important are structural uncertainties such as the degree of density dependence (e.g. compensatory mortality) in vital rates. We consider (st)age-structured population models where vital rates depend either on the age or size of members of the population. For these types of models, managers typically perform a sensitivity or elasticity analysis to evaluate the effect of changing one vital rate at a time on the population growth rate. This method ignores that the effect of changing one vital rate depends on the value of all other vital rates. We show how to account for the effect of simultaneously changing several vital rates when the distributional properties of uncertainties are unknown. For populations that are not affected by density-dependence there is an analytical solution for a minimum population growth rate. For populations with density dependence we use Monte Carlo simulations. Using these strategies involves a shift from maximizing objectives to guaranteeing some minimum performance on objectives. Finally, we discuss how the density independent model is robust to structural uncertainty when the goal is population persistence.
4:00PM Individual Heterogeneity in Vital Rates and Harvest Strategies: Quantifying the “Doomed Surplus” Hypothesis
  Todd Arnold
Population ecologists have long recognized density-dependence as an important process ameliorating the effects of harvest, but individual heterogeneity in vital rates can also have far-reaching consequences for harvest strategies. Hypotheses about survival heterogeneity date back more than 75 years to Errington, who wrote of a “doomed surplus” that could be safely harvested given individuals were likely to die anyway of natural causes; however, Errington’s idea remained a conceptual model for decades. In this presentation, I use models recognizing individual variation in vital rates to formally integrate heterogeneity into harvest management. If harvest mortality and natural mortality are positively correlated, heterogeneity can increase harvest potential, but other scenarios involving heterogeneity could lead to a reduction in harvest potential. I conclude with an empirical analysis of survival heterogeneity among 20 populations of North American waterfowl and webless migratory gamebirds, where I demonstrate that individual heterogeneity in survival is widespread and involves a sizable component of the population with very low survival probabilities. For harvest managers, the existence of a highly vulnerable subcomponent provides potential for compensation of harvest or other anthropogenic losses, provided that harvest is disproportionately focused on this “doomed surplus.”
4:20PM Do Antler and Horn Harvest Regulations Meet Ungulate Management Objectives?
  Daniel Morina, Christopher Hansen, Lonnie Hansen, Joshua Millspaugh
Many state and provincial wildlife agencies use antler and horn harvest regulations to manipulate ungulate population characteristics with various management objectives including increased doe harvest, shifting age structure toward older males, more trophy animals in a specific management unit, and greater hunter satisfaction. Perceived efficacy of these regulations is controversial as results have varied across regions and taxa. Research has assessed the progress of many management efforts; however, a broad synthesis of antler and horn harvest regulations is lacking within the literature. We compiled results from antler and horn harvest regulation efforts across North America to examine which systems have met management objectives. We also determined conditions in which a regulation was effective (e.g., region, species) and time required to achieve management objectives. Finally, we addressed the potential long-term consequences and considerations of antler and horn harvest regulations such as loss of genetic variation and selective genetic changes within a population. Our synthesis of the various antler and horn harvest regulations will help managers decide which system, if any, will be most effective for meeting their species- and geographic-specific management objectives.
4:40PM Shifting Paradigms in Fisheries Management: Is Harvest Mortality Still a Concern for Largemouth Bass?
  Andrea Sylvia, Brandon Maahs, Michael J. Weber
Understanding and regulating harvest rates is a foundational concept of fisheries and wildlife management. Historically, harvest mortality of many game species was high; however, paradigms of how stakeholders utilize fisheries and wildlife resources have shifted in recent decades to the point that some species traditionally harvested may no longer represent a consumptive resource. One example of this potential paradigm shift is Largemouth Bass where many anglers currently practice catch and release. Thus, harvest regulations may no longer provide the anticipated benefits. We used a three-year capture-recapture passive and active tagging dataset and a multistate Cormack-Jolly-Seber model to determine if bass harvest rates are still a relevant management concern in the Midwest. Monthly non-harvest mortality rates ranged from 0.03-0.14, were highest during summer, and inversely related to water temperature. In contrast, harvest rates were very low (0.006-0.026) but varied among months, with highest harvest observed in June and July. Our results indicate that harvest rates of bass are lower than other mortality sources. Thus, harvest regulations aimed at manipulating populations may no longer be effective. Alternatively, understanding and managing factors affecting non-harvest mortality, a common practice in wildlife management, rarely considered in fisheries, is likely to have larger population-level effects.
5:00PM Harvest As a Tool to Manage Populations of Undesirable or Overabundant Fish and Wildlife Species
  Craig Paukert, Elisabeth Webb
Harvest regulations (e.g., seasons, bag/possession/size limits) can be a valuable tool to manage populations of wildlife and sport fish species considered desirable by hunters and anglers. However, harvest regulations have also been used to attempt control populations of overabundant or nonnative species. Although harvest regulations may be similar as for desirable populations, regulations for overabundant species are often reversed not to protect certain species/sizes, and age groups (e.g., reproducing adults, juveniles) but to allow or increase harvest of these demographic groups. The Light Goose Conservation Order is an example where liberalized bag limits and extended seasons have been used in an attempt to control overabundant light goose populations. Smallmouth Bass, a popular sport fish, is not native to Ontario but has been established due to warming temperatures. Therefore, managers have allowed harvest of Smallmouth Bass on certain fish management zones to control this nonnative species. However, success of these regulations is often linked to angler/hunter participation and willingness or opportunity to harvest sufficient individuals in the appropriate demographic groups. Thus, understanding factors that influence population parameters, as well as hunter participation levels and success, is critical to using harvest regulations to effectively reduce populations of overabundant or nonnative species.
5:20PM Concluding Remarks
 

 
Organizers: Kevin L. Pope, Larkin A. Powell, PhD
 

Symposium
Location: Reno-Sparks CC Date: September 30, 2019 Time: 8:00 am - 5:30 pm