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Fisheries management is largely based on the principle of achieving the maximum sustainable yield (MSY) with little regard for nutritional value. Management strategies maximizing nutrients rather than yield, however, may provide a smarter contribution to global food and nutrition security. Here, we present a novel fisheries management strategy: fishing at maximum nutritional yield (F MNY), the exploitation rate at which essential nutrients are maximized. Combining top-down population modelling approaches with bottom-up nutrient compositional analysis, we compared nutrient yields across seasons for Europe's most valuable fishery (Atlantic mackerel, Scomber scombrus). F MNY estimates differed between nutrients, but were equal to, or lower than, F MSY. An autumn fishery provided higher amounts of lipids, omega-3 fatty acids, and protein, whereas vitamin D3, and calcium were maximized in winter. Aligning national fisheries policies and nutrition objectives is paramount to realising the potential of seafood in building healthier food systems. Developing novel fisheries management strategies, such as F MNY, where fisheries are optimised for human nutrition will, therefore, contribute to nutrient sustainability and help improve human health and diets. [ABSTRACT FROM AUTHOR]

The quantity of data from many small-scale fisheries is insufficient to allow for the application of conventional assessment methods. Even though in many countries they are moving to closed-loop simulations to assess the performance of different management procedures in data-limited situations, managers in most developing countries are still demanding information on stock status. In this study we use the common metric of harvest rate to evaluate and compare the performance of the following catch-only and length-only assessment models: catch--maximum sustainable yield (Catch-MSY), depletion- based stock reduction analysis (DBSRA), simple Stock Synthesis (SSS), an extension of Catch-MSY (CMSY), length-based spawning potential ratio (LBSPR), length-based integrated mixed effects (LIME), and length-based Bayesian (LBB). In general, results were more biased for slightly depleted than for highly depleted stocks and for long- lived than for short-lived species. Length-based models, such as LIME, performed as well as catch-based methods in many scenarios, and among the catch-based models, the one with the best performance was SSS followed by CMSY. La quantite de donnees issues de nombreuses peches de petite envergure n'est pas assez grande pour permettre l'application de methodes devaluation classiques. Bien que, dans de nombreux pays, l'utilisation de simulations en boucle fermee pour evaluer la performance de differentes procedures de gestion en situation de donnees limitees soit de plus en plus repandue, les gestionnaires dans la plupart des pays en developpement requierent encore de l'information sur l'etat des stocks. Nous utilisons le taux de prises, un parametre repandu, pour evaluer et comparer la performance des modeles d'evaluation suivants bases uniquement sur les prises ou sur la longueur : rendement equilibre maximum--prises (<< Catch-MSY>>), analyse de diminution du stock basee sur l'appauvrissement (<< DBSRA >>), synthese simple des stocks (<< SSS >>), extension du modele Catch-MSY (<< CMSY>>), rapport de la capacite de frai basee sur la longueur (<< LBSPR>>), effets mixtes integres bases sur la longueur (<< LIME >>) et modele bayesien base sur la longueur (<< LBB >>). En general, les resultats sont plus biaises pour les stocks legerement appauvris que pour les stocks tres appauvris et pour les especes plus longevives que pour les especes moins longevives. Les modeles bases sur la longueur, tel que LIME, donnent des resultats aussi bons que les methodes basees sur les prises dans de nombreux scenarios et, parmi les modeles bases sur les prises, le SSS est celui qui donne les meilleurs resultats. [Traduit par la Redaction], Introduction Major commercial fish species usually have substantial sets of data that can be integrated by complex stock assessment models (e.g., Methot and Wetzel 2013); these data may include time [...]

Sprat are commercially valuable and are an important component of the North-East Atlantic ecosystem as major predators of zooplankton, competitors with herring, and prey for piscivorous fish, marine mammals, and seabirds. Despite this, insufficient information exists for Celtic Seas sprat, one of five North-East Atlantic stocks, to estimate stock status. To ensure the sustainable exploitation of sprat, the health of the Celtic Seas ecosystem, and the wider fisheries sector, we conduct a management strategy evaluation to stress test the current single-species advice framework. The aim is to evaluate whether ecosystem objectives can be achieved under single-species maximum sustainable yield and precautionary advice frameworks. An operating model was conditioned on life history theory and strategic information from ecosystem models. We showed that in-year advice using an empirical rule could achieve management objectives and help balance the trade-offs between fishing activities and ecosystem health. The approach allows ecosystem understanding to be incorporated within existing precautionary and maximum sustainable yield frameworks to provide a robust management framework that can meet multiple objectives despite uncertainty. [ABSTRACT FROM AUTHOR]

The Precautionary Approach to Fisheries Management requires an assessment of the impact of uncertainty on the risk of achieving management objectives. However, the main quantities, such as spawning stock biomass (SSB) and fish mortality (F), used in management metrics cannot be directly observed. This requires the use of models to provide guidance, for which there are three paradigms: the best assessment, model ensemble, and Management Strategy Evaluation (MSE). It is important to validate the models used to provide advice. In this study, we demonstrate how stock assessment models can be validated using a diagnostic toolbox, with a specific focus on prediction skill. Prediction skill measures the precision of a predicted value, which is unknown to the model, in relation to its observed value. By evaluating the accuracy of model predictions against observed data, prediction skill establishes an objective framework for accepting or rejecting model hypotheses, as well as for assigning weights to models within an ensemble. Our analysis uncovers the limitations of traditional stock assessment methods. Through the quantification of uncertainties and the integration of multiple models, our objective is to improve the reliability of management advice considering the complex interplay of factors that influence the dynamics of fish stocks. [ABSTRACT FROM AUTHOR]

Fisheries management needs to ensure that resources are exploited sustainably, and the risk of depletion is at an acceptable level. However, often uncertainty about resource dynamics exists, and data availability may differ substantially between fish stocks. This situation can be addressed through tiered systems, where tiers represent different data limitations, and tier‐specific stock assessment methods are defined, aiming for risk equivalence across tiers. As case studies, we selected stocks of European plaice, Atlantic cod and Atlantic herring, where advice is provided by the International Council for the Exploration of the Sea (ICES). We conducted a closed‐loop simulation to compare risk equivalence between the data‐rich ICES MSY rule, based on a quantitative stock assessment, and the revised data‐limited empirical management procedures of the ICES advice framework. The simulations indicated that the data‐limited approaches were precautionary and did not lead to a higher risk of depletion than the data‐rich approach. Although the catch based on generic data‐limited approaches was lower, stock‐specific optimisation improved management performance with catch levels comparable with the data‐rich approach. Furthermore, the simulation indicated the ICES MSY rule can fail to meet management objectives due to increased depletion risk when management reference points are set suboptimally. We conclude that the recent revisions of the ICES system explicitly account for risk equivalence for data‐limited fisheries management and are a major step forward. Finally, we advocate further consideration of simple empirical management procedures irrespective of data limitations due to their ability to meet fisheries management objectives with greater simplicity. [ABSTRACT FROM AUTHOR]

Abstract: Spectacular long-term cycles (around 110 years), independent of human exploitation, have been seen in historical catches of Atlantic bluefin tuna (Thunnus thynnus). Previous studies indicated that such variations could [...]

Abstract: In this study, we examine the performances of current stock assessment methods with respect to their ability to (i) provide estimates of maximum sustainable yield (MSY), [F.sub.MSY], and [B.sub.MSY] [...]

In data-poor situations, length-based indicators (LBIs) and reference points based on life history parameters have been proposed to classify stocks according to conservation status and yield optimization. Given the variety of potential LBIs, life history traits, and fisheries, it is necessary to evaluate the robustness of length-based advice to ensure that despite uncertainty that management objectives will still be met. Therefore, a simulation procedure was employed where an Operating Model conditioned on life history parameters was used to generate pseudo data. Receiver operator characteristics and the true skill score were then used to screen LBIs based on their ability to identify overfishing and recovery. It was found that LBIs performed better for long-lived species with low individual growth rates, those aimed at ensuring the conservation of mature fish performed better than those aimed at the conservation of immature fish, are better at indicating trends than at quantifying exploitation level, and in general were robust to uncertainty about dynamic processes. [ABSTRACT FROM AUTHOR]

Many management bodies require applying the precautionary approach when managing marine fisheries resources to achieve sustainability and avoid exceeding limits. For data-limited stocks, however, defining and achieving management objectives can be difficult. Management procedures can be optimized towards specific management objectives with genetic algorithms. We explored the feasibility of including an objective that limited the risk of a stock falling below various limit reference points in the optimization routine for an empirical data-limited control rule that uses a biomass index, mean catch length, and includes constraints (the "rfb-rule"). This was tested through management strategy evaluation on several fish stocks representing various life-history traits. We show that risk objectives could be met, but more restrictive risk limits can lead to a potential loss of yield. Outcomes were sensitive to simulation conditions such as observation uncertainty, which can be highly uncertain in data-limited situations. The rfb-rule outperforms the method currently applied by ICES, particularly when risk limitation objectives are considered. We conclude that the application of explicit precautionary levels is useful to avoid overfishing. However, we caution against the indiscriminate use of arbitrary risk limits without scientific evaluation to analyse their impact on stock yields and sustainability. [ABSTRACT FROM AUTHOR]

The adoption of the Precautionary Approach requires providing advice that is robust to uncertainty. Therefore, when conducting stock assessment alternative, model structures and data sets are commonly considered. The primary diagnostics used to compare models are to examine residuals patterns to check goodness-of-fit and to conduct retrospective analysis to check the stability of estimates. However, residual patterns can be removed by adding more parameters than justified by the data, and retrospective patterns removed by ignoring the data. Therefore, neither alone can be used for validation, which requires assessing whether it is plausible that a system identical to the model generated the data. Therefore, we use hindcasting to estimate prediction skill, a measure of the accuracy of a predicted value unknown by the model relative to its observed value, to explore model misspecification and data conflicts. We compare alternative model structures based on integrated statistical and Bayesian state-space biomass dynamic models using, as an example, Indian Ocean yellowfin tuna. Validation is not a binary process (i.e. pass or fail) but a continuum; therefore, we discuss the use of prediction skill to identify alternative hypotheses, weight ensemble models and agree on reference sets of operating models when conducting Management Strategy Evaluation. [ABSTRACT FROM AUTHOR]

Many data-limited fish stocks worldwide require management advice. Simple empirical management procedures have been used to manage data-limited fisheries but do not necessarily ensure compliance with maximum sustainable yield objectives and precautionary principles. Genetic algorithms are efficient optimization procedures for which the objectives are formalized as a fitness function. This optimization can be included when testing management procedures in a management strategy evaluation. This study explored the application of a genetic algorithm to an empirical catch rule and found that this approach could substantially improve the performance of the catch rule. The optimized parameterization and the magnitude of the improvement were dependent on the specific stock, stock status, and definition of the fitness function. The genetic algorithm proved to be an efficient and automated method for tuning the catch rule and removed the need for manual intervention during the optimization process. Therefore, we conclude that the approach could also be applied to other management procedures, case-specific tuning, and even data-rich stocks. Finally, we recommend the phasing out of the current generic ICES "2 over 3" advice rule in favour of case-specific catch rules of the form tested here, although we caution that neither works well for fast-growing stocks. [ABSTRACT FROM AUTHOR]

Worldwide, the majorities of fish stocks are data-limited and lack fully quantitative stock assessments. Within ICES, such data-limited stocks are currently managed by setting total allowable catch without the use of target reference points. To ensure that such advice is precautionary, we used management strategy evaluation to evaluate an empirical rule that bases catch advice on recent catches, information from a biomass survey index, catch length frequencies, and MSY reference point proxies. Twenty-nine fish stocks were simulated covering a wide range of life histories. The performance of the rule varied substantially between stocks, and the risk of breaching limit reference points was inversely correlated to the von Bertalanffy growth parameter k ⁠. Stocks with k > 0.32   year−1 had a high probability of stock collapse. A time series cluster analysis revealed four types of dynamics, i.e. groups with similar terminal spawning stock biomass (collapsed, B MSY, 2 B MSY, 3 B MSY). It was shown that a single generic catch rule cannot be applied across all life histories, and management should instead be linked to life-history traits, and in particular, the nature of the time series of stock metrics. The lessons learnt can help future work to shape scientific research into data-limited fisheries management and to ensure that fisheries are MSY compliant and precautionary. [ABSTRACT FROM AUTHOR]

Environmental change has focused the attention of scientists, policy makers and the wider public on the uncertainty inherent in interactions between people and the environment. Governance in fisheries is required to involve stakeholder participation and to be more inclusive in its remit, which is no longer limited to ensuring a maximum sustainable yield from a single stock but considers species and habitat interactions, as well as social and economic issues. The increase in scope, complexity and awareness of uncertainty in fisheries management has brought methodological and institutional changes throughout the world. Progress towards comprehensive, explicit and participatory risk management in fisheries depends on effective communication. Graphic design and data visualisation have been underused in fisheries for communicating science to a wider range of stakeholders. In this paper, some of the general aspects of designing visualisations of modelling results are discussed and illustrated with examples from the EU funded MYFISH project. These infographics were tested in stakeholder workshops, and improved through feedback from that process. It is desirable to convey not just modelling results but a sense of how reliable various models are. A survey was developed to judge reliability of different components of fisheries modelling: the quality of data, the quality of knowledge, model validation efforts, and robustness to key uncertainties. The results of these surveys were visualized for ten different models, and presented alongside the main case study. [ABSTRACT FROM AUTHOR]

Reference points based on fishing mortality ( F) and spawning stock biomass ( SSB) are a requirement of many fisheries management frameworks. SSB is assumed to be a proxy for stock reproductive potential ( SRP). Limit reference points based on SSB are used to indicate the level of biomass below which productivity is affected. SSB fails to account for changes in fecundity, egg viability and sex ratio, and it has been argued that total egg production ( TEP) provides a better reflection of SRP. We explore how accounting for TEP impacts limit reference points and evidence for a relationship between stock and recruit. Time series of SSB and TEP are compared for three North Sea stocks: cod ( Gadus morhua), herring ( Clupea harengus) and plaice ( Pleuronectes platessa). Dynamics based on TEP are different from those based on SSB for cod and plaice, but the stock-recruit relationships were not 'improved' using TEP. Shifts in productivity (spawner per recruit) occur in all three time series and SSB underestimated uncertainty. Yet again, it was shown that assumptions of stationarity about fish population productivity are incorrect. We argue that the use of TEP does improve the realism in our understanding of stock dynamics, and demographically, more complex management strategy evaluation is required to develop management procedures that are robust to uncertainty and integrate F and the demographic health of a stock. Empirical feedback control systems based on fisheries independent indices including surveys of eggs, larvae, recruits, juveniles or spawning adults should be evaluated and compared to traditional approaches. [ABSTRACT FROM AUTHOR]

Abstract: In recent decades there has been steady progress towards a risk-based management approach for fisheries. An important first step in a risk analysis framework is scoping to identify, describe and catalog the sources of uncertainty that might have an impact on a fishery. This paper introduces a methodology based on a range of tools to formalize the process of elicitation of uncertainties, from both experts and stakeholders, for the International Commission for the Conservation of Atlantic Tunas (ICCAT). ICCAT is a regional fisheries management organization responsible for the conservation of tunas and other highly migratory fish in the Atlantic Ocean and its adjacent seas. The aim of the elicitation was to identify and prioritize uncertainties for inclusion in Operating Models for Management Strategy Evaluation (MSE). The tool presented in this paper supports the qualitative prioritization of uncertainties, while also visualizing the degree of consensus among stakeholders on particular issues. Perceptions of uncertainty in fisheries often vary widely among scientists, industry and other interest groups, so tools that can facilitate inclusion and representation of different opinions are useful where decision-making depends on broad agreement and more generally, where effective management depends on commitment from stakeholders. [Copyright &y& Elsevier]

Abstract: The recent overexploitation of East Atlantic and Mediterranean bluefin tuna stock has been well documented in the media where it has become the archetype of overfishing and general mis-management. Beyond the public debate, the crisis also highlighted how the interactions between science and management can change through time according to the awareness of the public opinion. To reflect these issues, the history of Atlantic bluefin tuna overfishing is first described. Then, the major uncertainties that undermine the current scientific advice are summarized and the importance of reducing their impacts by improving knowledge and developing robust scientific framework is considered. The study also discusses how uncertainty was used by different lobbies to discredit science-based management. The recent improvement in bluefin tuna stock status following the implementation of the rebuilding plan shows that, despite uncertainty in the scientific advice, the management of a heavily exploited fish stock can be positive when there is a political will. However, optimizing long-term yields of modern fisheries implies good science. The study concludes by advocating for the implementation of a scientific quota that should be part of the management framework to support the scientific advice. [Copyright &y& Elsevier]

The Marine Stewardship Council is the leader in seafood ecolabel certification. Despite its high impact in promoting sustainable fishing and securing price premiums, a large proportion of fisheries withdraw from the scheme during or after certification. We, therefore, investigate the factors influencing the likelihood of withdrawal. To achieve this, we analysed publicly available information from 301 fisheries that have embarked on the certification process using survival analysis methods to investigate the withdrawal rate. It was found that the fishing gear used, and geographical location were the principal factors affecting the likelihood of withdrawal and that the risk of withdrawal is greatest during the full-assessment process and the first five years of certification. Our study also reviews the uneven global expansion of MSC ecolabelling by region and identifies factors that influence withdrawal and need to be considered in fisheries entering MSC certification. [ABSTRACT FROM AUTHOR]

Ecological risk assessment is a useful methodology for assisting the management of fisheries from an ecosystem perspective. Atlantic tuna fisheries, managed by the International Commission for the Conservation of Atlantic Tunas (ICCAT), are economically important and interact with several bycatch species. In spite of these interactions, no comprehensive ecological risk assessment has been conducted for bycatch species caught in ICCAT fisheries. In this paper, we followed a two stage approach with the objective of assessing the relative risk of species being negatively impacted by Atlantic tuna fisheries. An analysis of the ICCAT bycatch species list (which includes all species reported to have interacted with different tuna fishing gears operating in the Atlantic) revealed that most of these species are caught in longline fisheries, followed by gillnets and purse seines. According to the IUCN red list, 7 species of the ICCAT bycatch list (3 coastal sharks, 3 sea turtles and one seabird) are categorized as critically endangered. In our study, and based on their life history characteristics, marine mammals and coastal sharks caught in ICCAT fisheries showed the highest intrinsic vulnerability values. A productivity susceptibility analysis for the European Union (EU) tropical tuna purse seine fleet and the United States (US) pelagic longline fleet revealed two groups with high relative risk scores. The first one included pelagic and coastal sharks, characterized by relatively low productivities, and the second one included teleosts, characterized by higher productivities but high susceptibility to purse seine and longline gears. Some alternative approaches to conduct productivity susceptibility analyses in the context of ecological risk assessments are discussed. [ABSTRACT FROM PUBLISHER]

Aps, R., Kell, L.T., Lassen, H., and Liiv, I. 2007. Negotiation framework for Baltic fisheries management: striking the balance of interest. – ICES Journal of Marine Science, 64: 858–861. We explore the issue of balancing stakeholder interests in the translation of science-based advice into agreed management measures. We also analyse the outcome of negotiations within the International Baltic Sea Fishery Commission (IBSFC) for setting the total allowable catch (TAC) for Baltic herring, sprat, cod, and salmon between 1977 and 2004. Given the political and economic pressure inherent in fishery management, IBSFC Contracting Parties, as maximizers of economic value, often set the TAC by unit stock in excess of what was considered sustainable. TACs set in excess of sustainable levels of exploitation (decision-overfishing) reflect the relative importance that negotiating parties attribute to the interests of multiple groups participating in the fishing industry. Such decision-overfishing can be seen as management failure to secure public interest in the long-term health of fish populations. The potential political and social causes of overfishing have to be addressed and removed before measures can be implemented that might reach the goal of sustainable development. [ABSTRACT FROM PUBLISHER]

Robustness of both short-term stock biomass recovery and longer-term sustainable management strategies to different plausible climatic change scenarios were evaluated for North Sea cod (Gadus morhua), where climate was assumed to impact growth and recruitment. In the short term, climate change had little effect on stock recovery, which depends instead upon reducing fishing effort to allow existing year classes to survive to maturity. In the longer term, climate change has greater effects on stock status, but higher yields and biomass can be expected if fishing mortality is reduced. Incorporating environmental covariates in stock assessment predictions will not achieve sustainable resource use. The implications of climate change for biological reference points depend upon the mechanism through which temperature acts on recruitment, i.e. on juvenile survival or carrying capacity. It is not possible to distinguish between these processes with stock assessment data sets alone. However, this study indicates that reference points based on fishing mortality appear more robust to uncertainty than those based on biomass. Ideally, simpler management procedures are required that meet pre-agreed management objectives and are robust to uncertainty about the true dynamics. [Copyright &y& Elsevier]

Ecosystem-based management requires the development of indicators that allow anthropogenic impacts to be detected against the background of natural variation. Size-based community metrics are potentially useful indicators because of their theoretical foundation and practical utility. Temporal and spatial patterns in size-based community metrics for Celtic Sea fish are described and calculated using data from the English groundfish survey of the area (1987–2003). The results reveal that the size structure of the community has changed over time, and that a decrease in the relative abundance of larger fish was accompanied by an increase in smaller fish (4–25g). Temporal analyses of the effects of fishing and climate variation suggest that fishing generally has had a stronger effect on size structure than changes in temperature. Therefore, size-based metrics respond clearly to the effects of fishing even in variable environments, reflecting the ubiquity of size-based processes in defining community structure and responses to mortality. Spatial analyses were inconclusive, probably owing to the limited area for which fishing effort, temperature, and survey data were all available. [Copyright &y& Elsevier]