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Constraint scores for fishery attributes associated with data availability and resourcing (top row) and associated recommendation scores for alternative fishery guidance options (bottom row). The constraint scores, ranging from 0 (no concern or constraint) to 3 (high concern or constraint), are used to illustrate differences among (hypothetical) extreme cases, i.e., fisheries with, a no data or resources, b data and resource rich, c no data and resource rich, and d data rich and no resources. recommendation scores, ranging from 0 (no focus) to 3 (high focus), for the guidance options associated with data, assessment and governance, availability, and resourcing, for the (hypothetical) extreme cases of e no data or resources, f data and resource rich, g no data and resource rich, and h data rich and no resources
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The term “data-limited fisheries” is a catch-all to generally describe situations lacking data to support a fully integrated stock assessment model. Data conditions range from data-void fisheries to those that reliably produce quantitative assessments. However, successful fishery assessment can also be limited by resources (e.g., time, money, capac...
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Recent efforts in ocean mapping of seafloor habitat have made data increasingly available. For bottom-dwelling and/or sessile species, there is often a strong relationship between population productivity and habitat, and stock assessment models are likely to be improved by the inclusion of habitat. Here, we extend a recently developed spatio-tempor...
Citations
... Influential life-history attributes associated with small-bodied species are reviewed below. In addition, beneficial attributes of snapshot LBSPR metrics are linked to fisheries policies that may be most effective to support stakeholders using simplified indicators such as multispecies biomass criteria (McClanahan et al. 2015;McClanahan 2018), local knowledge (Johannes et al. 2000), or indicator species that appeared to work best within the LBSPR framework (Barnett et al. 2019;Cope et al. 2023). ...
The growing use of data-poor fisheries models provides unprecedented access to compelling stock metrics and management scenarios for coral-reef fisheries. Yet, it remains unclear how well the assumptions surrounding data-poor models derived from extensive cold-water fisheries fit the life histories and ecology of tropical coral-reef fishes. The present study compared the outcomes from length-based spawning potential ratio (LBSPR) models versus observed trends from a novel meta-analysis of nine fisheries-independent (FI) and fisheries-dependent (FD) data streams across Micronesia. Thirty target species that comprised over 70% of landings were examined across temporal and spatial fishing pressure gradients associated with FI and FD streams. Cluster analyses using normalised effect sizes from over 140 statistical tests grouped the stocks based on the magnitudes of decline in (proportional) biomass and size-structure. Interestingly, many species with the greatest declines had modelled SPR and fishing mortality outcomes that did not trigger management based on established thresholds. These inconsistencies were attributed to several factors: variable compensatory density dependence across species, rapid growth over short time periods for small-bodied species leading to hyper-sensitive switch points in SPR metrics, and unusually long lifespans that did not always correlate with body sizes or growth rates. The complexity of life histories appeared to limit the use of snapshot data-poor models for depicting relative stock status across species; however, data-poor outcomes through time for each species better aligned with FI and FD trends. We generalise management guidance for a common and dominant group of tropical Pacific species. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
... It is well known and accepted that simple assessment methods based only on catch and CPUE series are often too simple to adequately explain complex population dynamics (Maunder, 2003;Punt and Szuwalski, 2012;Wang et al., 2014). Unfortunately, it is also common that there is insufficient data and technical capacity to apply more complex analyses to inform management decisions for many stocks (Cope et al., 2023). The increased uncertainty associated with basing management actions on limited data can result in increased risk, so it is critical that the performance and limitations of such methods are understood. ...
Biomass dynamics models are a common stock assessment method applied in-data limited situations. We present a management strategy based on a new constrained biomass dynamics model (‘dynamic tier 4’) as an alternative to the currently applied empirical management strategy (‘empirical tier 4’) used in Australia’s Southern and Eastern Scalefish and Shark Fishery (SESSF). The dynamic tier 4 management strategy is constrained because the biomass dynamics model on which it is based involves the assumption that yield corresponding to the biomass target occurred during a pre-specified set of reference years. This is the same assumption that is made by the empirical tier 4 management strategy. Management strategy evaluation is used to evaluate performance among three ways of accounting for error when fitting the dynamic tier 4 approach, and to evaluate performance against the empirical tier 4 management strategy as well as a management strategy based on an integrated assessment implemented using Stock Synthesis (‘tier 1’). Finally, the sensitivity of the empirical tier 4 and dynamic tier 4 management strategies to an incorrect choice for the pre-specified reference years is explored. The results demonstrate improved performance by the dynamic tier 4 management strategy compared to the empirical tier 4 management strategy. As expected, the data-rich, tier 1 management strategy had the best performance. The dynamic tier 4 management strategy has a reduced probability of the stock falling below the limit reference point, reduced catch variability and is less sensitive to incorrect reference year choice than the empirical tier 4 management strategy. These results demonstrate that the dynamic tier 4 management strategy is a suitable alternative to the empirical tier 4 management strategy in the SESSF, and more generally, can be considered as a robust option for forming the basis for management recommendations for data-limited situations.
... These models, when incorporating data for all the ages and lengths, help to evaluate the size composition and age structure and to estimate biological parameters accounting for growth changes produced by the effect of fishing. These advantages, among others (Lee et al., 2024), facilitate an informed decision-making process (Cope et al., 2023). However, estimating fish growth within stock assessment models may also present limitations since these models, used to handle a large amount of data, often assume that growth is uniform across the entire population, provide parameters not representative of the species biology influencing the stock status estimation (Lee et al., 2024), or require high computational time. ...
Traditionally, parameters defining life history traits, such as growth, were solely determined through length or age–length databases and then included as fixed in integrated stock assessment models. In current practice, growth parameters are usually estimated within these models (“inside”) and fitted to other datasets. However, for short-lived and small pelagic species, challenges may arise, particularly when there is a high variability in the age–length data or sampling biases are inadequately identified or addressed by these models. To test model effectiveness in capturing the growth dynamics of these species, we propose a comparative analysis following recommended practices for incorporating age–length data into integrated stock assessment models for the specific case of anchovy (Engraulis encrasicolus) stock in the Gulf of Cadiz. The reason is twofold: its significant ecological and economic importance and the need to improve the accuracy of growth parameter estimates used to inform total allowable catch (TAC) scientific advice. The overarching goal of this analysis is to identify the optimal model configuration that provides accurate growth parameter estimates. Our approach shows that random effects can effectively estimate growth in species with high age–length variability. Furthermore, using the obtained estimates as fixed in the stock assessment model reduces computational time and enhances the goodness of fit, resulting in a more efficient model. The results address a significant gap in existing integrated models used for scientific advice, which often do not have the “random effects on parameters” feature. Notably, this framework is widely applicable to other short-lived small pelagic species that typically exhibit a high data variability, offering a valuable solution for improving efficiency and robustness in fisheries management decision-making.
... Successful management of aquatic resources on a global scale requires accurate, up-to-date information not only on their conservation status, but also on their exploitation and trade (Anderson et al. 2019, Blasco et al. 2020, Cope et al. 2023. Publicly available data on sea cucumbers can be found in the Food and Agriculture Organization of the United Nations (FAO) Global Capture Production (FAO 2024c), Global Aquaculture Production (FAO 2024a), and Global Aquatic Trade Statistics (FAO 2024b) databases. ...
Sea cucumbers paradoxically suffer from being both highly prized and commonly disregarded. As an Asian medicine and delicacy, they command fabulous prices and are thus overfished, poached, and trafficked. As noncharismatic animals, many are understudied and inadequately protected. Despite presenting a rich diversity of life histories, members of this broad taxonomic group (class Holothuroidea) are often managed simply as “sea cucumbers” in fisheries worldwide. One cannot imagine fishes (class Pisces) being given the same universal treatment. Yet this may happen for species of sea cucumber that differ on the same fundamental level as tilapia and tuna. As more sea cucumbers reach an endangered status and wild populations become depleted to the point of collapse, critical questions arise about the relevance of established conservation and governance strategies. This article reviews the main threats faced by exploited sea cucumbers, outlines conservation and governance effectiveness, identifies gaps in knowledge, and explores management and research perspectives in the context of climate change and booming fisheries crime. We stress the perilous state of harvested sea cucumbers globally and the urgent need for action.
... Contemporary best practice in single-species stock assessments, when sufficient data are available, involves use of integrated models (Maunder and Punt, 2013;Punt, 2023). These models can incorporate a wide range of information, including catch and abundance indices, length and/or age compositions, and parameters describing the biology of the stock and how it interacts with fisheries, i.e. 'selectivity', which refers to processes affecting the probability of fish being caught and retained (Cope et al., 2023). Due to data and resource limitations, however, such assessments are not feasible for most global fisheries, with many not assessed at all (Costello et al., 2012;Dowling et al., 2015;Blasco et al., 2020). ...
Released (or discarded) fish from recreational and commercial line fisheries can experience significant levels of post-release mortality (PRM), affecting sustainability. Although PRM effects are often considered in data-rich (integrated model) assessments, this is uncommon in data-limited assessments. This study investigates impacts of PRM when applying data-limited, length-based assessment methods for four reef-dwelling demersal fish species in temperate Western Australia (Glaucosoma hebraicum, Chrysophrys auratus, Choerodon rubescens and Epinephelides armatus). These species differ considerably in their biology and susceptibility to PRM. For each species simulations were undertaken to (1) evaluate the reliability of a length-based catch curve (LBCC) method for estimating fishing mortality (F) and selectivity parameters, and (2) predict the impacts of different PRM levels on values of relative biomass, i.e. ratios of fished to unfished equilibrium spawning biomass (B rel), estimated using a length-based equilibrium analysis (LBEA). LBEA extends length-based per-recruit analysis to incorporate a stock-recruitment relationship as well as allow for PRM. On average, estimates of F and selectivity parameters from LBCC for each species were unbiased when applied to simulated data. Precision decreased, however, when LBCC was fitted to data simulated with recruitment variation. For a given F, increased PRM levels reduced B rel for all species, with the extent of impacts varying depending on species biology. LBCC was then applied to two actual datasets, firstly to lengths for all fish that had either been retained or released during historical recreational fishing trips (to estimate gear selectivity), and secondly to length data for retained fish from recent charter fishing (to estimate F and selectivity of landings). The resultant estimates were then used in LBEA to estimate B rel with and without accounting for PRM. Relative impacts of PRM varied among species depending on their biology and size limits. While PRM was predicted to have limited impact on B rel for C. rubescens (as fish are not fully selected by the gear until they attain a relatively large size), accounting for PRM resulted in estimates of B rel (at their current estimated F levels) being reduced by 31% for G. hebraicum, 36% for C. auratus and 23% for E. armatus. It is recommended that, where evidence of PRM exists for a species, this be accounted for in data-limited assessments.
... Continued efforts to collect data on the age structure of the target stocks and to conduct stock assessments using agestructured models are key tasks necessary for the sustainable use of fishery resources. Nevertheless, when forced to conduct stock assessment and management in situations with limited data or resources (Cope et al. 2023), our approach of SSPM-based OMs in MSE is a suitable alternative, albeit with greater uncertainties. ...
A management procedure (MP) automatically calculates an acceptable biological catch from input data, and its performance is quantitatively evaluated by closed-loop simulations of population dynamics with their uncertainties (operating models). In snow crab in the Sea of Japan, an MP based on survey biomass estimates was adopted by stakeholders, rather than a generic MP recommended for data-moderate Japanese stocks. This was done without quantifying its performance owing to data and resource limitations. This study evaluated the performance of the existing MPs and modified the generic MP through closed-loop simulations with state–space surplus production models (SSPMs) conditioned with actual data. The survey-based MP generally worked well to achieve sustainable catch and biomass but tended to be sensitive to the bias in biomass estimates. The modified MP can be more robust to the bias than the survey-based MP with higher catches than the generic MP. This study demonstrates that, although continuing efforts of collecting composition data are inevitable, SSPM could be used as the conditioned operating models even in data-limited situations to sufficiently represent the stock status and its uncertainty.
... Fisheries are complex social-ecological systems (Arlinghaus et al., 2017;Kittinger et al., 2013) that provide food security, livelihoods, culture, meaning, well-being and recreation to millions across the globe (FAO, 2022). Conserving and restoring the ecosystems that fisheries depend on remains a challenge for the Anthropocene that is hindered by a lack of data and its integration into management and conservation Cooke et al., 2019;Cope et al., 2023). About 80% of global fish stocks lack adequate data for a formal stock assessment and will likely never be assessed formally given data and resource limitations (Cope et al., 2023;Costello et al., 2012). ...
... Conserving and restoring the ecosystems that fisheries depend on remains a challenge for the Anthropocene that is hindered by a lack of data and its integration into management and conservation Cooke et al., 2019;Cope et al., 2023). About 80% of global fish stocks lack adequate data for a formal stock assessment and will likely never be assessed formally given data and resource limitations (Cope et al., 2023;Costello et al., 2012). The inclusion of multiple stakeholders is crucial to confront this challenge, and resource users possess rich knowledge, or different ways of knowing, that are mostly untapped Reid et al., 2021). ...
... Conserving aquatic social-ecological systems is a challenge often hampered by a lack of data and its integration into management. This is the case for fisheries, where over 80% of global fish stocks are classified as data-poor; that is, they lack adequate data for a formal stock assessment, and will not be assessed formally given data and resource limitations (Cope et al., 2023;Costello et al., 2012). ...
Social‐ecological systems like fisheries provide food, livelihoods and recreation. However, lack of data and its integration into governance hinders their conservation and management. Stakeholders possess site‐specific knowledge crucial for confronting these challenges. There is increasing recognition that Indigenous and local knowledge (ILK) is valuable, but structural differences between ILK and quantitative archetypes have stalled the assimilation of ILK into fisheries management, despite acknowledged bias and uncertainty in scientific methods. Conducting a systematic review of fisheries‐associated ILK research ( n = 397 articles), we examined how ILK is accessed, applied, distributed across space and species, and has evolved. We show that ILK has generated qualitative, semi‐quantitative and quantitative information for diverse taxa across 98 countries. Fisheries‐associated ILK research mostly targets small‐scale and artisanal fishers (70% of studies) and typically uses semi‐structured interviews (60%). We revealed large variability in sample size ( n = 4–7638), predicted by the approach employed and the data generated (i.e. qualitative studies target smaller groups). Using thematic categorisation, we show that scientists are still exploring techniques, or ‘validating’ ILK through comparisons with quantitative scientific data (20%), and recording qualitative information of what fishers understand (40%). A few researchers are applying quantitative social science methods to derive trends in abundance, catch and effort. Such approaches facilitate recognition of local insight in fisheries management but fall short of accepting ILK as a valid complementary way of knowing about fisheries systems. This synthesis reveals that development and increased opportunities are needed to bridge ILK and quantitative scientific data.
... Fisheries are complex social-ecological systems (Arlinghaus et al., 2017;Kittinger et al., 2013) that provide food security, livelihoods, culture, meaning, well-being and recreation to millions across the globe (FAO, 2022). Conserving and restoring the ecosystems that fisheries depend on remains a challenge for the Anthropocene that is hindered by a lack of data and its integration into management and conservation Cooke et al., 2019;Cope et al., 2023). About 80% of global fish stocks lack adequate data for a formal stock assessment and will likely never be assessed formally given data and resource limitations (Cope et al., 2023;Costello et al., 2012). ...
... Conserving and restoring the ecosystems that fisheries depend on remains a challenge for the Anthropocene that is hindered by a lack of data and its integration into management and conservation Cooke et al., 2019;Cope et al., 2023). About 80% of global fish stocks lack adequate data for a formal stock assessment and will likely never be assessed formally given data and resource limitations (Cope et al., 2023;Costello et al., 2012). The inclusion of multiple stakeholders is crucial to confront this challenge, and resource users possess rich knowledge, or different ways of knowing, that are mostly untapped Reid et al., 2021). ...
... Conserving aquatic social-ecological systems is a challenge often hampered by a lack of data and its integration into management. This is the case for fisheries, where over 80% of global fish stocks are classified as data-poor; that is, they lack adequate data for a formal stock assessment, and will not be assessed formally given data and resource limitations (Cope et al., 2023;Costello et al., 2012). ...
Social-ecological systems like fisheries provide food, livelihoods, and recreation. However, lack of data and its integration into governance hinders their conservation and management. Stakeholders possess site-specific knowledge crucial for confronting these challenges. There is increasing recognition that Indigenous and local knowledge (ILK) is valuable, but structural differences between ILK and quantitative archetypes have stalled the assimilation of ILK into fisheries management, despite acknowledged bias and uncertainty in scientific methods. Conducting a systematic review of fisheries-associated ILK research (n = 397 articles), we examined how ILK is accessed, is applied, is distributed across space and species, and has evolved. We show that ILK has generated qualitative, semi-quantitative, and quantitative information for diverse taxa across 98 countries. Fisheries-associated ILK research mostly targets small-scale and artisanal fishers (70% of studies), and typically uses semi-structured interviews (60%). We revealed large variability in sample size (n = 4 – 7638), predicted by the approach employed, and the data generated (i.e., qualitative studies target smaller groups). Using thematic categorisation, we show that scientists are still exploring techniques, or ‘validating’ ILK through comparisons with quantitative scientific data (20%), and recording qualitative information of what fishers understand (40%). A few researchers are applying quantitative social science methods to derive trends in abundance, catch, and effort. Such approaches facilitate recognition of local insight in fisheries management, but fall short of accepting ILK as a valid complementary way of knowing about fisheries systems. This synthesis reveals that development and increased opportunities are needed to bridge ILK and quantitative scientific data.
... indices, length and/or age compositions, and parameters describing stock biology and how it 61 interacts with fisheries, i.e. 'selectivity', which refers to processes affecting probability of fish 62 being caught and retained or discarded (Cope et al., 2023). Due to data and resource 63 limitations, however, such assessments are not feasible for the majority of global fisheries, 64 with many not assessed at all (Blasco et . ...
Released (or discarded) fish from recreational and commercial line fisheries can experience significant levels of post-release mortality (PRM), which can affect the sustainability of fish stocks. Although effects of PRM are often considered in relatively data-rich (integrated model) assessments, this is uncommon with data-limited assessments. This study investigates the impacts of PRM when applying data-limited length-based methods to data for four reef-dwelling demersal fish species in temperate Western Australia (Glaucosoma hebraicum, Chrysophrys auratus, Choerodon rubescens and Epinephelides armatus).
... Despite their importance, the status of many global fisheries remains unknown or poorly estimated due to a lack of sufficient data or institutional capacity required to conduct traditional stock assessments (Cope et al. 2023). The majority of global fisheries are lacking formal assessment, and studies have estimated that these unassessed fisheries may be in significantly worse condition than assessed fisheries (Costello et al. 2012;Blasco et al. 2020;Hilborn et al. 2020). ...
... Due to the Crevalle Jack's unregulated status, limited research has been done in the region to assess the species' life history (e.g., stock boundaries and migration patterns) or fishery trends (e.g., trends in length and age composition; McBride and McKown 2000;Gervasi et al. 2022b;Jefferson et al. 2022). Therefore, the Crevalle Jack fishery in Florida can be considered data limited, a term that generally describes situations in which the data required to support a fully integrated stock assessment model (including catch time series, indices of abundance, length and age composition, and life history parameters) are missing (Cope et al. 2023). In the Florida Keys, recreational fishing guides have observed a concerning decline in Crevalle Jack catch rates, which is supported by available fisheriesdependent data (Gervasi et al. 2022b). ...
Objective
Fisheries provide countless benefits to human populations but face many threats ranging from climate change to overfishing. Despite these threats and an increase in fishing pressure globally, most stocks remain unassessed and data limited. An abundance of data‐limited assessment methods exists, but each has different data requirements, caveats, and limitations. Furthermore, developing informative model priors can be difficult when little is known about the stock, and uncertain model parameters could create misleading results about stock status. Our research illustrates an approach for rapidly creating robust initial assessments of unregulated and data‐limited fisheries without the need for additional data collection.
Methods
Our method uses stakeholder knowledge combined with a series of data‐limited tools to identify an appropriate stock assessment method, conduct an assessment, and examine how model uncertainty influences the results. Our approach was applied to the unregulated and data‐limited fishery for Crevalle Jack Caranx hippos in Florida.
Result
Results suggested a steady increase in exploitation and a decline in stock biomass over time, with the stock currently overfished and undergoing overfishing. These findings highlight a need for management action to prevent continued stock depletion.
Conclusion
Our approach can help to streamline the initial assessment and management process for unregulated and data‐limited stocks and serves as an additional tool for combating the many threats facing global fisheries.
