Management Strategy Evaluation Research Articles

Climate-mediated stock redistribution causes increased risk and challenges for fisheries management

Abstract The environmental conditions that marine populations experience are being altered because of climate change. In particular, changes in temperature and increased variability can cause shifts in spatial distribution, leading to changes in local physiological rates and recruitment success. Yet, management of fish stocks rarely accounts for variable spatial dynamics or changes in movement rates when estimating management quantities such as stock abundance or maximum sustainable yield. To address this concern, a management strategy evaluation (MSE) was developed to evaluate the robustness of the international management system for Pacific hake, an economically important migratory stock, by incorporating spatio-temporal population dynamics. Alternative hypotheses about climate-induced changes in age-specific movement rates, in combination with three different harvest control rules (HCR), were evaluated using a set of simulations that coupled single-area estimation models with alternative operating models representing spatial stock complexity. Movement rates intensified by climate change caused a median decline in catches, increased annual catch variability, and lower average spawning biomass. Impacts varied by area and HCR, underscoring the importance of spatial management. Incorporating spatial dynamics and climate change effects into management procedures for fish stocks with spatial complexity is warranted to mitigate risk and uncertainty for exploited marine populations.

In Pursuit of Ecosystem-Based Management for Narragansett Bay: An Overview of Previous Models and Roadmap for Future Research

Ecosystem models have emerged as vital tools for evaluating management strategies and are increasingly used by policymakers. We reviewed the history of modeling and identified research gaps based on policy needs for ecosystem-based management of Narragansett Bay (RI, USA)—a highly-impacted system with a history of research and monitoring dating back to the 1950s. There is a need to disentangle the impacts of nutrient reductions versus climate change on species interactions as well as understand the ecological and socio-economic tradeoffs of management actions. Within this context, we consider the following to be important for future research and creation of ecosystem models for Narragansett Bay: (i) account for multi-scale processes and patterns through two-way model coupling; (ii) incorporate human behavior as part of model predictions; and (iii) lessen the impact of model uncertainty by identifying robust management strategies that will sustain resources under a range of potential future scenarios. Ecosystem modeling that builds on prior models and is informed by knowledge gaps will be a powerful tool to operationalize ecosystem-based management in Narragansett Bay and globally, providing sustainable pathways for nature and people.

Shaping sustainable harvest boundaries for marine populations despite estimation bias

AbstractBiased estimates of population status are a pervasive conservation problem. This problem has plagued assessments of commercial exploitation of marine species and can threaten the sustainability of both populations and fisheries. We develop a computer‐intensive approach to minimize adverse effects of persistent estimation bias in assessments by optimizing operational harvest measures (harvest control rules) with closed‐loop simulation of resource‐management feedback systems: management strategy evaluation. Using saithe (Pollachius virens), a bottom water, apex predator in the North Sea, as a real‐world case study, we illustrate the approach by first diagnosing robustness of the existing harvest control rule and then optimizing it through propagation of biases (overestimated stock abundance and underestimated fishing pressure) along with select process and observation uncertainties. Analyses showed that severe biases lead to overly optimistic catch limits and then progressively magnify the amplitude of catch fluctuation, thereby posing unacceptably high overharvest risks. Consistent performance of management strategies to conserve the resource can be achieved by developing more robust control rules. These rules explicitly account for estimation bias through a computational grid search for a set of control parameters (threshold abundance that triggers management action, Btrigger, and target exploitation rate, Ftarget) that maximize yield while keeping stock abundance above a precautionary level. When the biases become too severe, optimized control parameters—for saithe, raising Btrigger and lowering Ftarget—would safeguard against a overharvest risk (<3.5% probability of stock depletion) and provide short‐term stability in catch limit (<20% year‐to‐year variation), thereby minimizing disruption to fishing communities. The precautionary approach to fine‐tuning adaptive risk management through management strategy evaluation offers a powerful tool to better shape sustainable harvest boundaries for exploited resource populations when estimation bias persists. By explicitly accounting for emergent sources of uncertainty, our proposed approach ensures effective conservation and sustainable exploitation of living marine resources even under profound uncertainty.

Evaluation of harvest control rules for a group of interacting commercial stocks using a multispecies MSE framework

In this study, a multispecies gadget model (GadCap) simulating the interactions among the Flemish Cap cod (Gadus morhua), redfish (Sebastes spp.), and shrimp (Pandalus borealis) has been incorporated as the operating model in a management strategy evaluation (MSE) framework (a4a-FLR) to test the performance of multiple combinations of harvest control rules (HCRs) for the three stocks when recruitment uncertainty and assessment error are accounted for. The results indicate that due to the strong trophic interactions, it is not possible to achieve the precautionary exploitation of all the stocks at the same time. Maintaining shrimp biomass above the limit reference point (Blim) would require unsustainable fishing pressure on cod and redfish to reduce predation mortality. In contrast, maintaining cod biomass above Blim would involve high predation on and high risk of collapse of the shrimp and redfish stocks. The implementation of alternative two-stage HCRs would reduce predation, resulting in higher productivity and lower probability of collapse for cod and redfish. The results of this study support the need of accounting for species interactions when designing management strategies for a group of interdependent commercial stocks.

Testing and evaluation of crowd management strategies at religious gatherings in India using agent-based modelling and simulation

Testing and evaluation of crowd management strategies at religious gatherings in India using agent-based modelling and simulation

Understanding the Etiology of Pancytopenias in the CAR T-Cell Therapy Setting: What We Know and What We Don't?

Chimeric antigen receptor T-cell (CAR T-cell) therapy represents an innovative and transformative therapy for patients with relapsed and/or refractory (R/R) hematological malignancies. CAR T-cell therapy was first approved in R/R diffuse large B-cell lymphoma (DLBCL) and acute lymphoblastic leukemia, today the use of CAR T-cell therapy has expanded to multiple myeloma and other lymphoma subtypes such as follicular and mantle cell lymphoma. It is also being explored in earlier lines of therapy in DLBCL. CAR T-cell therapy is associated with a unique toxicity profile and development of cytopenias post CAR T-cell therapy has been reported in all pivotal clinical trials and is now considered a related side effect. Here, we provide an in-depth evaluation of etiologies, consequences, and current management strategies for cytopenias following CAR T-cell therapy.

The rationale for heterogeneous inclusion of ecosystem trends and variability in ICES fishing opportunities advice

Incorporation of ecosystem information into fish stock assessments and management advice, a cornerstone of delivering ecosystem-based fisheries management (EBFM), occurs often implicitly, faces multiple challenges, and remains often unquantified in terms of scope and scale. This paper provides a comprehensive overview of the inclusion of ecosystem trends and variability in ICES fishing opportunities advice in the Northeast Atlantic, by covering 87% of stocks corresponding to 99% of landings. Just under 50% of all stock assessments considered ecosystem information and the majority of management strategy evaluations did so in at least one way. Almost 73% of the data-rich stocks incorporated ecosystem trends and variability in at least one way, and almost 55% of short-term forecasts did so. Stock (individual growth rate) and fisheries (landings) characteristics largely explained the observed patterns of incorporation of ecosystem information into advice, with pelagic species and stocks with higher landings having higher instances of incorporation. Early stages of the advice process (closer to data analysis and methods development) had greater inclusion of ecosystem information, though this inclusion was generally implicit and not explicit, e.g. based on a hypothesis of environmental influence on stock dynamics. Moving towards explicit instructions and routine documentation of the inclusion of ecosystem information in fishing opportunities advice will accelerate the path to the EBFM in a consistent and transparent manner.

Crocs, Inc.: Managing Corporate Resources (Strategic Perspectives)

The role of the strategic management process in organizations is to produce the best strategic plan that an organization can adopt based on its individual qualities and market position to achieve a superior competitive position in the market. The purpose of this study is to evaluate how the strategic management process can be utilized by Crocs, Inc. (Crocs) to gain and maintain a long-run competitive position in the footwear industry. This analysis considers and applies the three stages of the strategic management process, strategy formulation, strategy implementation, and strategy evaluation, to Crocs, utilizing Crocs’ current company data and strategic position and applying strategic management process tools. Analysis results feature a recommended vision and mission statement for Crocs, the best strategies for Crocs to pursue, how Crocs can progress toward achieving such strategies (through certain policies, risk considerations, and financial projections), and how the company can successfully evaluate and adapt strategies if necessary. This analysis implies how Crocs may best utilize the strategic management process to achieve success as a company in the footwear industry.

Evaluating Strategies for Managing Anthropogenic Mortality on Marine Mammals: An R Implementation With the Package RLA

Bycatch, the undesirable and non-intentional catch of non-target species in marine fisheries, is one of the main causes of mortality of marine mammals worldwide. When quantitative conservation objectives and management goals are clearly defined, computer-based procedures can be used to explore likely population dynamics under different management scenarios and estimate the levels of anthropogenic removals, including bycatch, that marine mammal populations may withstand. Two control rules for setting removal limits are the Potential Biological Removal (PBR) established under the US Marine Mammal Protection Act and the Removals Limit Algorithm (RLA) inspired from the Catch Limit Algorithm (CLA) developed under the Revised Management Procedure of the International Whaling Commission. The PBR and RLA control rules were tested in a Management Strategy Evaluation (MSE) framework. A key feature of PBR and RLA is to ensure conservation objectives are met in the face of the multiple uncertainties or biases that plague real-world data on marine mammals. We built a package named RLA in the R software to carry out MSE of control rules to set removal limits in marine mammal conservation. The package functionalities are illustrated by two case studies carried out under the auspices of the Oslo and Paris convention (OSPAR) (the Convention for the Protection of the Marine Environment of the North-East Atlantic) Marine Mammal Expert Group (OMMEG) in the context of the EU Marine Strategy Framework Directive. The first case study sought to tune the PBR control rule to the conservation objective of restoring, with a probability of 0.8, a cetacean population to 80% of carrying capacity after 100 years. The second case study sought to further develop a RLA to set removals limit on harbor porpoises in the North Sea with the same conservation objective as in the first case study. Estimation of the removals limit under the RLA control rule was carried out within the Bayesian paradigm. Outputs from the functions implemented in the package RLA allows the assessment of user-defined performance metrics, such as time to reach a given fraction of carrying capacity under a given level of removals compared to the time needed given no removals.

Testing length-based reference points in a management strategy evaluation for cuckoo ray (Leucoraja naevus) and thornback ray (Raja clavata)

Abstract Elasmobranchs grow relatively slowly and mature at a relatively high age, leading to longer generation time. Due to low fecundity of these stocks, sufficient numbers of mature individuals are important to ensure a viable recruitment level and sustainable management. Length-based indicators (LBIs), such as the mean length and the mean length of the largest 5% in the catch, can be used to characterize the length distribution of exploited stocks and aid a data-limited assessment. Reference points for these indicators are calculated using basic life history parameters. Using cuckoo ray, Leucoraja naevus, and thornback ray, Raja clavata, as example species, we apply management strategy evaluations to test the performance of LBI-based harvest control rules (HCRs) in their ability to recover overexploited stocks. We illustrate the importance of the stock–recruitment relationship for the management outcome. If immature individuals are targeted by the fishery, HCRs perform better in terms of stock recovery when coupled with reference points, which account for the maturation schedule of the stock. The sensitivity of reference points to parameter misspecification means that elasmobranchs stocks in which immature individuals are exploited by the fishery may require more precautionary reference points, with consideration of the trade-off between biomass recovery and yield.

Effects of re-specifying the Northern Prawn Fishery bioeconomic model to include banana prawns

The Northern Prawn Fishery (NPF) is one of Australia’s most valuable federally managed fisheries. It has also been a focus for modelling in Australia, with over 40 years of development of bioeconomic, stock assessment and management strategy evaluation models that have been used to varying degrees to inform management. The current management model has been in operation for over 10 years and is used to set the total allowable effort (TAE) for the tiger prawn (Penaeus semisulcatus and P. esculentus) component of the fishery, historically undertaken after a mid-year closure. The success of management has resulted in increased stocks of tiger prawns, and a fishery before the mid-year closure during which fishing for banana prawns was historically the main activity. While the current management model includes the consequences of fishing for tiger prawns during the first season in terms of which weeks are available for fishing for tiger prawns when estimating the TAE, the lack of explicit inclusion of banana prawns in the bioeconomic modelling has resulted in concerns that the TAE may be biased, as effort is allocated in the model to tiger prawns that, in reality, should be applied to banana prawns. The current model was consequently extended to include an explicit banana prawn component, and a range of scenarios undertaken to explore the impact of this on the management advice. It was found that the current model overestimates the optimal level of effort to be applied to tiger prawns except during periods of very low banana prawn abundance. Banana prawns, which vary substantially inter-annually due largely to environmental drivers, were also found to be the key driver of the level of overall fishery profit, suggesting that greater attention to this component of the fishery may be necessary to achieve the objective of maximizing net economic returns from the NPF.

Redesigning harvest strategies for sustainable fishery management in the face of extreme environmental variability

AbstractShort‐lived, fast‐growing species that contribute greatly to global capture fisheries are sensitive to fluctuations in the environment. Uncertainties in exact stock–environment relationships have meant that environmental variability and extremes have been difficult to integrate directly into fisheries management. We applied a management strategy evaluation approach for one of Australia's large prawn stocks to test the robustness of harvest control rules to environmental variability. The model ensemble included coupled environmental‐population models and an alternative catchability scenario fitted to historical catch per unit effort data. We compared the efficacy of alternative management actions to conserve marine resources under a variable environment while accounting for fisher livelihoods. Model fits to catch per unit effort were reasonably good and similar across operating models (OMs). For models that were coupled to the environment, environmental parameters for El Niño years were estimated with good associated precision, and OM3 had a lower AIC score (77.61) than the base model (OM1, 80.39), whereas OM2 (AIC 82.41) had a similar AIC score, suggesting the OMs were all plausible model alternatives. Our model testing resulted in a plausible subset of management options, and stakeholders selected a permanent closure of the first fishing season based on overall performance of this option; ability to reduce the risk of fishery closure and stock collapse; robustness to uncertainties; and ease of implementation. Our simulation approach enabled the selection of an optimal yet pragmatic solution for addressing economic and conservation objectives under a variable environment with extreme events.

Evaluation of Various Stress Management Strategies among Chennai People - A Cross Sectional Study

Background: Feeling stressed is a part of everyone's life. A feeling of emotional or physical tension is known as stress. Relaxation strategies play an important role in overcoming stress.
 Objective: To evaluate the different stress patterns, their perceived stress and effects of different stress management strategies.
 Methods: A cross sectional study was conducted through a convenience sampling method. The participants were administered with a self developed questionnaire consisting of 11 questions. The responses were collected using google forms. Descriptive statistics, frequency analysis and chi square test was used to analyse the data.
 Results: The present study reported that the majority of respondents were stressed due to academic and personal reasons and among the various stress relaxation methods, respondents felt that music and yoga relieved them from stress.
 Conclusion: The study concluded an innovative finding that music and yogic exercises when adopted provided a decent stress management strategy that suits the respondents.

Cost-benefit evaluation of management strategies for an invasive amphibian with a stage-structured model

Management strategies for invasive populations should be designed to maximise efficacy and efficiency, i.e. to accomplish their goals while operating with the least resource consumption. This optimisation is often difficult to achieve in stage-structured populations, because costs, benefits and feasibility of removing individuals may vary with stage. We use a spatially-explicit stage-structured model to assess efficacy of past, present and alternative control strategies for invasive guttural toads, Sclerophrys gutturalis, in Cape Town. The strategies involve removal of variable proportions of individuals at different life-history stages and spatial scales. We also quantify the time necessary to implement each strategy as a proxy of financial resources and we correct strategy outcomes by implementation of time to estimate efficiency. We found that the strategy initially pursued in Cape Town, which did not target any specific stage, was less efficient than the present strategy, which prioritises adult removal. The initial strategy was particularly inefficient because it did not reduce the population size despite allocating consistent resources to remove eggs and tadpoles. We also found that such removal might be detrimental when applied at high levels. This counter-intuitive outcome is due to the ‘hydra effect’: an undesired increase in population size caused by removing individuals before overcompensatory density dependence. Strategies that exclusively remove adults ensure much greater management efficiency than those that also remove eggs and tadpoles. Available management resources should rather be allocated to increase the proportion of adult guttural toads that are removed or the spatial extent at which this removal is pursued.

Histological technique to detect the physiological age of the malaria vector mosquito Anopheles pharoensis (Diptera: Culicidae).

The risk of malaria recurrence increases due to the main vector, Anopheles pharoensis. The physiological age of the mosquito population is needed to expect malaria vector dynamics. The number of completed gonotrophic cycles is of great importance in determining the physiological age of females. A technique has been described that focuses on the number of dilatations remaining in the ovarioles after each oviposition to determine how many blood meals have been taken. At each gonotrophic cycle, the chances of infection of the vectors are repeated. The histological changes that occur immediately in the ovarioles and ovulation itself were studied. Under the influence of the contractions of the ovarian muscles, the eggs begin to move over the distal end of the ovariole into the inner oviduct. The terminal pedicle is markedly dilated near the diameter of the eggs. After the expulsion of the mature eggs, ovariole dilations were found at the point of their development in the terminal pedicle due to the accumulation of nurse cell remnants and follicular epithelium. The results were used to develop epidemiological localization and to evaluate the effectiveness of antimalaria interventions. The ovarian inspection often provides a technique to distinguish nulliparous from parous female anophelines. In addition, this study can provide basic entomological knowledge on the physiological age of mosquitoes by considering the histological changes in the ovaries, which allow the evaluation of vector management strategies in the field.

Multi-Indicator Harvest Strategies for Data-Limited Fisheries: A Practitioner Guide to Learning and Design

As the world population grows, fisheries practitioners will be under increased pressure to address global challenges in data-limited fisheries management. With a focus on addressing localized and case-specific management needs, we provide a practical guide to the design and development of multi-indicator frameworks for fishery management. In a data-limited context, indicators are observations or estimates of the state of the fishery resource that are typically proxies for variables of interest, rather than quantities such as stock biomass estimated from data-rich stock assessments. Indicator frameworks structure the integration and interpretation of indicators to guide tactical fishery decision-making, often when the application of more formal analytical assessments is not feasible, yet where indicators in combination provide insight into stock status. With a focus on multi-indicator frameworks, we describe a pragmatic approach for their development via a set of organizational steps, considering a wide spectrum of types and severity of information limitations. We highlight where multi-indicator frameworks can be insightful and informative in relation to single indicator approaches but also point to potential pitfalls, with emphasis on critical evaluation and detection of performance flaws during the design phase using methods such as management strategy evaluation.

Exploring trade‐offs in mixed fisheries by integrating fleet dynamics into multispecies size‐spectrum models

Abstract Ecosystem‐based fisheries management aims to ensure ecologically sustainable fishing while maximising socio‐economic benefits. Achieving this goal for mixed fisheries requires better understanding of the effects of competing fishing fleets on shared resources and economic performance. Proposed management strategies that promote either specialisation or diversification of catches may result in unintended consequences for ecosystem‐based management. Here, we ask the following questions: does increased or decreased competition among fleets lead to better ecological and socio‐economic fishery outcomes? How effective are currently proposed management strategies for achieving these outcomes? We integrated fleet dynamics into a multispecies size‐spectrum model and parameterised this model to represent Australian Southern and Eastern Scalefish and Shark Mixed Fishery. We compared the fishery status quo to two extreme scenarios: no competition, where each species is fished only by one fleet (specialisation); and maximal competition, where all fleets catch all species (diversification). To answer our second question, we considered three more plausible scenarios resulting from proposed management strategies: decreased competition due to reduced bycatch, and increased competition due to increased catches of under‐utilised or valuable species. We used indicators to explore scenarios' outcomes. Our model reproduced observed trends in fishing effort and yield. Extreme scenarios showed that a fishery dependent on single species management structures is more likely to achieve ecosystem‐based management objectives if fleets do not compete, while maximal competition can lead to socio‐economic loss as management buffers the ecological impact of diversifying. The more plausible scenarios showed little improvement over the status quo, with mixed ecological and negative economic effects. Synthesis and applications. Our model can be applied to assess mixed fisheries ecosystem‐based management strategies. Our results show that, under single species management approaches, greatest outcomes can be achieved when fleets are specialised, whereas managing fleets that catch similar species is unlikely to be successful. They question the effectiveness of these management approaches in providing resilience for mixed fisheries facing changes and highlight the need to account for fleet interactions in the evaluation of management strategies to avert unintended risks.

Innovativity in Legislative, Political and Organizational Frameworks of Sustainable Land Management in Benin

Agricultural lands are increasingly degraded due to various human actions (overgrazing, intensive use of chemical inputs) and the consequences of climate change. In Benin, 62% of agricultural land were degraded in 2017. In this regard, Sustainable Land Management measures are highlighted by various public decisions. This study analyzed the political, legislative, and organizational frameworks of Sustainable Land Management in Benin. It was carried out through content analysis of laws, decrees, and Sustainable Land Management policy documents to highlight the place of innovativity in institutional and organizational framework in Sustainable Land Management in Benin. Results reveal that the various frameworks analyzed are oriented towards developing practice-based innovations through the implementation of Sustainable Land Management measures, support to actors in the implementation of Sustainable Land Management innovations and the monitoring and evaluation of Sustainable Land Management strategies. The capacity to innovate is also promoted through the strengthening of the technical, institutional, material, and financial capacities of the actors. On the other hand, the propensity to innovate component of Innovativity is hardly addressed in Sustainable Land Management public policies in Benin. It is therefore necessary to direct agricultural policies towards an institutionalization of the strengthening of the propensity to innovate of agricultural producers for a long-term appropriation of Sustainable Land Management measures in Benin.

Heuristics for the sustainable harvest of wildlife in stochastic social-ecological systems.

Sustainable wildlife harvest is challenging due to the complexity of uncertain social-ecological systems, and diverse stakeholder perspectives of sustainability. In these systems, semi-complex stochastic simulation models can provide heuristics that bridge the gap between highly simplified theoretical models and highly context-specific case-studies. Such heuristics allow for more nuanced recommendations in low-knowledge contexts, and an improved understanding of model sensitivity and transferability to novel contexts. We develop semi-complex Management Strategy Evaluation (MSE) models capturing dynamics and variability in ecological processes, monitoring, decision-making, and harvest implementation, under a diverse range of contexts. Results reveal the fundamental challenges of achieving sustainability in wildlife harvest. Environmental contexts were important in determining optimal harvest parameters, but overall, evaluation contexts more strongly influenced perceived outcomes, optimal harvest parameters and optimal harvest strategies. Importantly, simple composite metrics popular in the theoretical literature (e.g. focusing on maximizing yield and population persistence only) often diverged from more holistic composite metrics that include a wider range of population and harvest objectives, and better reflect the trade-offs in real world applied contexts. While adaptive harvest strategies were most frequently preferred, particularly for more complex environmental contexts (e.g. high uncertainty or variability), our simulations map out cases where these heuristics may not hold. Despite not always being the optimal solution, overall adaptive harvest strategies resulted in the least value forgone, and are likely to give the best outcomes under future climatic variability and uncertainty. This demonstrates the potential value of heuristics for guiding applied management.

Bibliometric Analysis of Dental Erosion (2011–2020)

During the past decade, an increase in the number of studies about dental erosion has been observed. The aim of the present study was to describe the current trends in published scientific articles related to dental erosion between 2011 and 2020. Data of the authors, year and language of publication were analyzed. A bibliometric analysis of the articles published in PubMed was conducted using the MeSH terms (dental erosion) and (tooth erosion) using the Boolean operator OR/AND. A sample of n = 1090 articles published during the past ten years (2011–2020) was obtained. The variables analyzed were the language of the article, the year of publishing, the number of authors, the affiliations of the first and last author and the relationship between them. The countries of origin of the first and last author were ranked according to the number of publications, led by Brazil, the UK, and the USA. During the analysis of the type of article, we observed that 79.4% of all publications were research articles. In recent years, a significant increase in research articles on dental erosion has been observed, especially in Brazil and the UK, with a high number of publications of translational articles in humans and cross-sectional observational studies. The main findings in this article will help researchers, academics and students to characterize scientific results regarding dental erosion, to evaluate management strategies and to identify important topics and issues that will help design future research.