Social-ecological interactions, management panaceas, and the future of wild fish populations

A two-phase approach to elicit and measure beliefs on management strategies: Fishers supportive and aware of trade-offs associated with stock enhancement

Understanding fisher beliefs and attitudes towards specific management strategies can help inform and improve fisheries management, and thus stock sustainability. Previous studies highlight a lack of fisher awareness regarding environmental issues influencing the systems they utilise and the negative impacts of specific strategies, such as stock enhancement. Our study used a two-phase approach to first elicit and then measure the strength of common fishers' beliefs and associated attitudes regarding stock enhancement. Specifically, this research focused on recreational fishers of an estuarine crab fishery (Portunus armatus) in south-western Australia. The results demonstrate that recreational fishers believe stock enhancement could have strong positive outcomes, but also recognise that this management strategy could lead to some negative outcomes, though the latter are perceived as less likely to happen. This contrasts with previous research on fisheries stocking and demonstrates the value of using the two-phase approach to clarify fishers' perceptions of particular management approaches. To reduce fisher dissatisfaction with management actions, careful communication on the benefits and costs of stock enhancement is recommended. Our study highlights the significance of integrating social sciences into fisheries research, and the need to better understand fishing community beliefs to ensure effective management of the fishery.

How ecological processes shape the outcomes of stock enhancement and harvest regulations in recreational fisheries

Fish stocking and harvest regulations are frequently used to maintain or enhance freshwater recreational fisheries and contribute to fish conservation. However, their relative effectiveness has rarely been systematically evaluated using quantitative models that account for key size- and density-dependent ecological processes and adaptive responses of anglers. We present an integrated model of freshwater recreational fisheries where the population dynamics of two model species affect the effort dynamics of recreational anglers. With this model, we examined how stocking various fish densities and sizes (fry, fingerlings, and adults) performed relative to minimum-length limits using a variety of biological, social, and economic performance measures, while evaluating trade-offs. Four key findings are highlighted. First, stocking often augmented the exploited fish population, but size- and density-dependent bottlenecks limited the number of fry and fingerlings surviving to a catchable size in self-sustaining populations. The greatest enhancement of the catchable fish population occurred when large fish that escaped early bottlenecks were stocked, but this came at the cost of wild-stock replacement, thereby demonstrating a fundamental trade-off between fisheries benefits and conservation. Second, the relative performance of stocking naturally reproducing populations was largely independent of habitat quality and was generally low. Third, stocking was only economically advisable when natural reproduction was impaired or absent, stocking rates were low, and enough anglers benefitted from stocking to offset the associated costs. Fourth, in self-sustaining fish populations, minimum-length limits generally outperformed stocking when judged against a range of biological, social and economic objectives. By contrast, stocking in culture-based fisheries often generated substantial benefits. Collectively, our study demonstrates that size- and density-dependent processes, and broadly the degree of natural recruitment, drive the biological, social, and economic outcomes of popular management actions in recreational fisheries. To evaluate these outcomes and the resulting trade-offs, integrated fisheries-management models that explicitly consider the feedbacks among ecological and social processes are needed.

Peer pressure on the riverbank: Assessing catch-and-release anglers' willingness to sanction others' (bad) behavior

Given the well-documented impacts of angler behavior on the biological fitness of angled and released fish, optimizing the conservation value of catch-and-release angling hinges on the extent to which anglers are willing to adopt recommended best practices and refrain from harmful ones. One potentially powerful mechanism underlying adoption of best practices is the social pressure anglers can apply to one another to enforce community norms and values. Past work in other domains demonstrates that forms of interpersonal communication-including social sanctioning-can foster context-appropriate social norms and increase cooperative behavior; yet to date, little research has examined these dynamics in the context of species conservation. We conducted in-person and online surveys to explore the role of social sanctioning in the context of an internationally renowned wild steelhead (Oncorhynchus mykiss) fishery in British Columbia, Canada. We investigated how diverse social-psychological and demographic factors influence anglers' past and future sanctioning propensity. Results highlight that perceived capacity to influence the angling practices of others and professed concerns about one's own reputation were strongly predictive of both past and future sanctioning. Furthermore, while anglers reported relatively low-levels of past sanctioning behavior, most anglers simultaneously expressed a strong desire to sanction others in the future. Identifying ways to increase the social desirability and visibility of sanctioning actions could assist resource managers in promoting adoption and maintenance of best practices. More broadly, our findings underscore a significant yet underappreciated role for wildlife users and enthusiasts in cultivating a shared conservation ethic to help ensure biological conservation.

Site closure management strategies and the responsiveness of conservation outcomes in recreational fishing

We develop and use an empirically based model, which integrates fishing behaviour and a coral reef system, to evaluate outcomes from site closure strategies to manage the effects of recreational fishing. The model is designed to estimate management effects in complex settings with two-way feedback effects (between fishing and ecosystem dynamics) as well as spillover effects where the closure of a site (or sites) leads to the redistribution of fishing effort. An iconic coral reef system is used as a case study. The results demonstrate that some site closure strategies provide little incremental benefits over less stringent approaches. They also show that some strategies targeting more sites are actually inferior to more limited strategies, demonstrating that, in the analysis of complex problems involving feedback effects and substitutions, there is little substitute for the use of empirically based and sound modelling as the basis for informed conservation decision making and stakeholder consultation. These findings have direct relevance not only for policies aimed at improving recreational fishing management but also for securing the supply of marine ecosystem services.

Participatory adaptive management leads to environmental learning outcomes extending beyond the sphere of science

Resolving uncertainties in managed social-ecological systems requires adaptive experimentation at whole-ecosystem levels. However, whether participatory adaptive management fosters ecological understanding among stakeholders beyond the sphere of science is unknown. We experimentally involved members of German angling clubs (n = 181 in workshops, n = 2483 in total) engaged in self-governance of freshwater fisheries resources in a large-scale ecological experiment of active adaptive management of fish stocking, which constitutes a controversial management practice for biodiversity and ecosystem functioning when conducted inappropriately. The collaborative ecological experiments spanned several years and manipulated fish densities in 24 lakes with two species. In parallel, we experimentally compared changes in ecological knowledge and antecedents of proenvironmental behavior in stakeholders and managers who were members of a participatory adaptive management treatment group, with those receiving only a standard lecture, relative to placebo controls. Using a within-subjects pretest-posttest control design, changes in ecological knowledge, environmental beliefs, attitudes, norms, and behavioral intentions were evaluated. Participants in adaptive management retained more knowledge of ecological topics after a period of 8 months compared to those receiving a standard lecture, both relative to controls. Involvement in adaptive management was also the only treatment that altered personal norms and beliefs related to stocking. Critically, only the stakeholders who participated in adaptive management reduced their behavioral intentions to engage in fish stocking in the future. Adaptive management is essential for robust ecological knowledge, and we show that involving stakeholders in adaptive management experiments is a powerful tool to enhance ecological literacy and build environmental capacity to move toward sustainability.

Social-ecological outcomes in recreational fisheries: the interaction of lakeshore development and stocking

Many ecosystems continue to experience rapid transformations due to processes like land use change and resource extraction. A systems approach to maintaining natural resources focuses on how interactions and feedbacks among components of complex social-ecological systems generate social and ecological outcomes. In recreational fisheries, residential shoreline development and fish stocking are two widespread human behaviors that influence fisheries, yet emergent social-ecological outcomes from these potentially interacting behaviors remain under explored. We applied a social-ecological systems framework using a simulation model and empirical data to determine whether lakeshore development is likely to promote stocking through its adverse effects on coarse woody habitat and thereby also on survival of juvenile and adult fish. We demonstrate that high lakeshore development is likely to generate dependency of the ecosystem on the social system, in the form of stocking. Further, lakeshore development can interact with social-ecological processes to create deficits for state-level governments, which threatens the ability to fund further ecosystem subsidies. Our results highlight the value of a social-ecological framework for maintaining ecosystem services like recreational fisheries.

Insights into fisheries management practices: using the theory of planned behavior to explain fish stocking among a sample of Swiss anglers

Using inadequate management tools often threatens the natural environment. This study focuses on the example of Swiss recreational fishermen (hereafter called “anglers”) as recreational fisheries management stakeholders. In recreational fisheries, fish stocking conducted by anglers has been identified as one important factor associated with declining fish catches. We therefore aimed to a) gain insights into why anglers want to maintain fish stocking and b) identify entry points for interventions to promote more pro-ecological management practices. Results (N = 349) showed that the majority of anglers think very uncritically about stocking and that they frequently engage in it. We conclude that outcome expectancies and beliefs about risks, in combination with a lack of stocking success controls are the main reasons that anglers retain stocking measures. We suggest that providing anglers with direct experience and feedback about stocking success is suitable to change their intentions regarding stocking and their actual stocking behavior, and thus, to promote more pro-ecological management methods. From a more general perspective, the results of this study are likely to help improve pro-ecological ecosystem management in other domains where problems similar to those in recreational fisheries management might exist.

Species-specific preferences of German recreational anglers for freshwater fishing experiences, with emphasis on the intrinsic utilities of fish stocking and wild fishes

To answer the question, whether anglers have an intrinsic preference for stocking or a preference for catch outcomes (e.g. catch rates) believed to be maintained by stocking, a discrete choice experiment was conducted among a sample of anglers (n = 1335) in Lower Saxony, Germany. After controlling for catch aspects of the fishing experience, no significant influence of two stocking attributes (stocking frequency and composition of the catch in terms of wild v. hatchery fishes) on the utility gained from fishing was found for any of the freshwater species that were studied. It was concluded that the previously documented large appreciation of fish stocking by anglers may be indicative of an underlying preference for sufficiently high catches rather than reflect an intrinsic preference for stocking or the catching of wild fishes per se.

Understanding and managing enhancements: why fisheries scientists should care

Fisheries enhancements are a set of management approaches involving the use of aquaculture technologies to enhance or restore fisheries in natural ecosystems. Enhancements are widely used in inland and coastal fisheries, but have received limited attention from fisheries scientists. This paper sets out 10 reasons why fisheries scientists should care about understanding and managing enhancements. (1) Enhancements happen, driven mostly by resource users and managers rather than scientists. (2) Enhancements create complex fisheries systems that encompass and integrate everything fisheries stakeholders can practically manage. (3) Enhancements emerge in fisheries where the scope for technical and governance control is high, and they synergistically reinforce both. (4) Successful enhancements expand management options and achievable outcomes. (5) Many enhancements fail or do ecological harm but persist regardless. (6) Effective science engagement is crucial to developing beneficial enhancements and preventing harmful ones. (7) Good scientific guidance is available to aid development or reform of enhancements but is not widely applied. (8) Enhancement research advances, integrates and unifies the fisheries sciences. (9) Enhancements provide unique opportunities for learning about natural fish populations and fisheries. (10) Needs, opportunities and incentives for enhancements are bound to increase.

Effect of Game Management on Wild Red-Legged Partridge Abundance

The reduction of game and fish populations has increased investment in management practices. Hunting and fishing managers use several tools to maximize harvest. Managers need to know the impact their management has on wild populations. This issue is especially important to improve management efficacy and biodiversity conservation. We used questionnaires and field bird surveys in 48 hunting estates to assess whether red-legged partridge Alectoris rufa young/adult ratio and summer abundance were related to the intensity of management (provision of supplementary food and water, predator control and releases of farm-bred partridges), harvest intensity or habitat in Central Spain. We hypothesized that partridge abundance would be higher where management practices were applied more intensively. Variation in young/adult ratio among estates was best explained by habitat, year and some management practices. Density of feeders and water points had a positive relationship with this ratio, while the density of partridges released and magpies controlled were negatively related to it. The variables with greatest relative importance were feeders, releases and year. Variations in post-breeding red-legged partridge abundance among estates were best explained by habitat, year, the same management variables that influenced young/adult ratio, and harvest intensity. Harvest intensity was negatively related to partridge abundance. The other management variables had the same type of relationship with abundance as with young/adult ratio, except magpie control. Variables with greatest relative importance were habitat, feeders, water points, releases and harvest intensity. Our study suggests that management had an overall important effect on post-breeding partridge abundance. However, this effect varied among tools, as some had the desired effect (increase in partridge abundance), whereas others did not or even had a negative relationship (such as release of farm-reared birds) and can be thus considered inefficient or even detrimental. We advise reconsidering their use from both ecological and economical points of view.