Monitoring and managing the public health risk posed by marine biotoxins is a daunting challenge. With expansive coastlines, 1000s of seafood species, and dozens of biotoxins, monitoring cannot occur everywhere at once. Improving the cost-effectiveness of biotoxin monitoring is thus critical to expanding coverage to include more species, toxins, and locations. Notably, understanding the rate at which seafood species depurate biotoxins can be used to optimize the cadence of monitoring. We conducted a systematic review to collate marine biotoxin depuration rates and synthesize the factors that influence them; identify knowledge gaps, best practices, and research priorities; and generate predictions of depuration rates for unstudied species. We found that only 85 marine species have been studied for their biotoxin depuration rates. Depuration rates for non-bivalves and for toxins besides paralytic shellfish toxins (PSTs) are especially understudied. Depuration half-lives varied from 0.03 to 1269 days based on species, toxin, tissue, and environmental conditions. In general, depuration accelerates with increased temperature and food availability, with implications for aquaculture siting, depuration enhancement, and biotoxin monitoring. We identified unstudied bivalve and finfish species that are highly produced and vulnerable to HABs that are high priorities for future research. Finally, we used a Bayesian regression model to predict PST depuration rates for 102 unstudied bivalve species, the only clade-syndrome with sufficient training data. These predictions can guide efficient monitoring and management until laboratory- or field-based depuration rates become available. We recommend that future studies directly estimate depuration rates to ensure their comparability across studies and utility to managers.

Oceans provide essential benefits to people and the economy, underpinned by the extent and condition of marine ecosystems and infrastructure—or ‘blue’ capital. However, the impacts of climate change on blue capital have been largely overlooked in influential indicators such as the social cost of carbon (SCC). Here we integrate the latest ocean science and economics into a climate-economy model, capturing climate change impacts on corals, mangroves, seaports, fisheries and mariculture to estimate their welfare repercussions at a global scale. Conceptually, this ocean-based SCC (blue SCC) represents a component of the total SCC currently omitted in standard estimates. We estimate the 2020 blue SCC to be US48 per tCO2 (US38–70, 25th–75th percentile) with baseline discounting, representing an almost doubling of the SCC estimate from the same model without considering ocean-related impacts. The blue SCC increases to US168 for a discount rate of 2

Background Micronutrient inadequacies are estimated to affect billions of people worldwide, yet these estimates exclude fortification. There are no global estimates of the impact of current fortification programmes on micronutrient inadequacies. We aimed to estimate how improving existing programmes or establishing new ones affects the prevalence of micronutrient inadequacies and to estimate their global costs. Methods In this modelling study, we estimated the prevalence of inadequate intakes of 13 micronutrients across 185 countries by integrating global modelled dietary intake data from the Global Dietary Database, with fortification programme parameters from the Global Fortification Data Exchange. We modelled six scenarios: no fortification, current fortification, improved compliance, aligned standards, aligned standards with improved compliance, and aligned standards with improved compliance and expanded coverage. Implementation costs were calculated as the sum of premix, industry-related, and government costs across five fortified foods: wheat flour, maize flour, oil, rice, and salt. Findings Compared with no fortification, current fortification programmes prevent 7·0 billion inadequate person-nutrient intakes annually at a global cost of $1·06 billion (mean of $0·18 [SD 0·28] per person, 2021 US$, across the five fortified foods), with iodine fortification alone preventing 3·3 billion inadequacies. Despite current fortification, 38·6 billion inadequate intakes persist. Improving compliance would prevent 13·1 billion inadequacies at a global cost of $3·48 billion annually (mean $0·23 [SD 0·33] per person). Aligning standards and improving compliance would prevent 17·2 billion inadequacies at $6·56 billion annually (mean $0·63 [SD 0·53] per person). Aligning standards, improving compliance, and expanding coverage would prevent 24·7 billion inadequacies at $9·19 billion annually (mean $1·15 [SD 0·58] per person), although 20·9 billion inadequacies would remain. Interpretation Fortification is a cost-effective intervention that greatly reduces micronutrient inadequacies, particularly for iodine and iron. Improving compliance offers immediate gains. Aligning with international guidelines and expanding programmes could triple their effects but cannot eliminate all inadequacies, underscoring the importance of complementary approaches to improve diet quality. Funding Swiss Agency for Development and Cooperation and the Gates Foundation.

Researchers and policymakers increasingly recognize the contribution of aquatic food systems, such as fisheries, to food security and nutrition. Yet governing fisheries for nutrition objectives is complicated by the multiple overlapping processes that shape availability and access to nutrients over time, including fishing sustainability, climate change, trade dynamics, and consumer preferences. Anticipating the effect of governance interventions to sustain or enhance nutritional benefits from fisheries entails accounting for these multiple interacting influences. We develop an analytical approach to link available data on aquatic foods production, nutrition, distribution, and potential climate impacts to evaluate the nutrition implications of fishery management and post-harvest allocation interventions. We demonstrate this approach using national and publicly available datasets for five case study countries: Peru, Chile, Indonesia, Sierra Leone, and Malawi. As examples, we evaluate the potential to enhance domestic supply of key nutrients to nutritionally-vulnerable populations by (a) dynamically adjusting fishing effort in response to climate impacts on fish stocks, and (b) retaining aquatic foods currently diverted via trade or foreign fishing. The results indicate substantial differences across countries in terms of anticipated climate change effects, with potential for substantially increased nutrition yield in Chile and Peru under adaptive management, vs more modest yield increases in Indonesia. The impacts of post-harvest allocation policies related to foreign fishing, exports, fishing sector, and subnational trade also vary, with exports weighing heavily on nutrient availability in Sierra Leone. This methodological approach represents a step toward operationalizing calls to manage fisheries as part of national food and nutrient supplies, in light of climate change risks.

Worldwide, exploited fish populations are increasingly affected by the combined effects of warming and fishing. Disentangling the relative effects of these factors is challenging yet crucial for designing management strategies. We used a temperature-dependent population dynamics model to assess the impacts of lake warming and fishing on 521 freshwater fish populations in the Midwestern United States-a transitional zone between cold- and warmwater species. Overall, most warmwater species (65% of populations) exhibited increases in productivity from warming, while slightly more than half of the cool-/cold-water species (53% of populations) experienced reduced productivity. Populations closer to their carrying capacity showed greater resilience to warming. For the majority of populations (92%), fishing had a more pronounced effect on population dynamics than warming during the time period examined. Therefore, while warming is likely to increasingly threaten many fish populations, effective local fishery management remains a key lever to mitigate these impacts.

Mariculture is one of the fastest growing global markets. Although it has potential to improve livelihoods and facilitate economic growth, it can negatively impact marine biodiversity. Here we estimate local cumulative environmental impacts from current and future (2050) mariculture production on marine biodiversity (20,013 marine fauna), while accounting for species range shifts under climate change. With strategic planning, the 1.82-fold increase in finfish and 2.36-fold increase in bivalve production needed to meet expected global mariculture demand in 2050 could be achieved with up to a 30.5% decrease in cumulative impact to global marine biodiversity. This is because all future mariculture farms are strategically placed in sea areas with the lowest cumulative impact. Our results reveal where and how much mariculture impacts could change in the coming decades and identify pathways for countries to minimize risks under expansion of mariculture and climate change through strategic planning.

Large-scale food fortification (LSFF) is a widely accepted intervention to alleviate micronutrient deficiencies, yet policy implementation is often incomplete and its effects on diet costs are not well established. We estimated the extent to which LSFF reduces the cost of nutrient-adequate diets using retail food prices and fortification policy data from 89 countries. In total, we modeled 5,874 least-cost diets across 22 sex-age groups and 3 nutrient-adequacy scenarios: meeting nutrient requirements only; adding minimum intakes for starchy staples and fruits and vegetables; and aligning food group shares with national consumption patterns. Assuming 90% implementation of existing LSFF standards, we found median cost reductions of 1.7%, 2.4%, and 4.5% across the three scenarios. Cost reductions varied widely by sex-age groups, national fortification strategies and food price structures. These findings highlight that LSFF may improve diet affordability when policies are carefully designed for local contexts, making it a valuable complement to other efforts that improve access to nutritious diets.

The identification of efficient management strategies that reduce protected species bycatch while also minimizing impacts on fishing livelihoods is a global conservation challenge. Identifying such strategies requires understanding levels of bycatch relative to management targets as well as the relationship between bycatch risk and potential management actions. In this study, we use ratio estimation to reconstruct bycatch of select marine mammal and seabird species in the California >= 3.5" set gillnet fishery from 1981 to 2022 and random forest models to identify potential drivers and hotspots of bycatch risk. We find that bycatch has dropped precipitously since the 1980s as a result of management-induced reductions in fishing effort, but at significant costs to fisheries participation and revenues. Recent marine mammal bycatch ranges from 0.1 % to 4.0 % of the potential biological removal and marine mammal populations are recovering. Spatial-temporal correlates of bycatch risk were more important than fishing-related correlates of risk, suggesting that spatial-temporal closures would reduce bycatch more reliably than mesh size or soak time restrictions. For each species, we identified 1-3 hotspots of bycatch risk as candidates for temporary seasonal closures. Bycatch risk for harbor seal (Phoca vitulina) and California sea lion (Zalophus californianus), the species with the greatest bycatch risk, is especially high from April 1st to June 15th, suggesting that hotspot closures during this 2.5-month time period could be particularly efficient. Our study also highlights the value of competing multiple sample balancing approaches to identify methods that best predict rare bycatch events.

Marine protected areas (MPAs) are widely implemented tools for long-term ocean conservation and resource management. Assessments of MPA performance have largely focused on specific ecosystems individually and have rarely evaluated performance across multiple ecosystems either in an individual MPA or across an MPA network. We evaluated the conservation performance of 59 MPAs in California's large MPA network, which encompasses 4 primary ecosystems (surf zone, kelp forest, shallow reef, deep reef) and 4 bioregions, and identified MPA attributes that best explain performance. Using a meta-analytic framework, we evaluated the ability of MPAs to conserve fish biomass, richness, and diversity. At the scale of the network and for 3 of 4 regions, the biomass of species targeted by fishing was positively associated with the level of regulatory protection and was greater inside no-take MPAs, whereas species not targeted by fishing had similar biomass in MPAs and areas open to fishing. In contrast, species richness and diversity were not as strongly enhanced by MPA protection. The key features of conservation effectiveness included MPA age, preimplementation fisheries pressure, and habitat diversity. Important drivers of MPA effectiveness for single MPAs were consistent across MPAs in the network, spanning regions and ecosystems. With international targets aimed at protecting 30% of the world's oceans by 2030, MPA design and assessment frameworks should consider conservation performance at multiple ecologically relevant scales, from individual MPAs to MPA networks.

Quota allocation, which divides fishing catch or effort between regions, sectors, subsectors, individuals, and/or seasons, is one of the most important and contentious processes in fisheries management. Quota allocation policies often aim to advance fairness and equity goals by preserving levels of historical participation and access. However, this reliance on historical patterns makes allocation policies vulnerable to climate change, which is shifting the accessibility of marine resources among historical and new participants. Despite this, there is little guidance on best practices for adapting allocation policies to climate change. In the United States, regional flexibility to design locally relevant allocation policies has innovated a diversity of approaches that can be studied for their climate vulnerability and/or adaptivity. Here, we conduct a systematic review of allocation policies used in U.S. federal fisheries (491 stocks, 42 management plans, 8 regions) and a brief review of allocation policies in international fisheries, which we use to identify best practices for climate-adaptive quota allocation. We find that allocation policies are used to manage 49% of federally managed stocks. Although most policies are based on historical catch, many include features that promote climate adaptiveness, including the ability to transfer quota between states, sectors, or individuals; adjustment of allocations on the basis of current resource distribution or abundance; set aside of quota to support research and experimentation; and gradual phase-in of policy changes. Ultimately, we provide eight globally transferable recommendations for improving the ability of allocation policies to advance their fairness and equity goals under climate change.

There have been few documented extinctions of fished species, but many bioeconomic models predict that open-access incentives make extinction possible. Open-access multi-species fisheries can cause species' extinction if other, faster-growing species maintain profits at fatal effort levels. Even target species can be profitably harvested to extinction if their prices rise sufficiently as they are depleted. Here, we explore interactions between these potential extinction mechanisms by modelling an open-access multi-species fishery with one or multiple fleets exploiting two species, each with different growth rates, ex-vessel prices, and price dynamics. Increases in the strong stock's (the stock with higher productivity relative to fishing susceptibility) price as it is depleted increase the range of conditions under which the weak stock can be driven extinct and shrinks the range of bioeconomic parameters in which both species can coexist under open-access. Catch hyperstability - whereby species become easier to catch as they are depleted - makes the weak stock weaker as it is depleted and further narrows the scope for coexistence. Fleet diversity in targeting ability can prevent weak stock extinction, as competition or switching balances species abundances. With few documented global fished-species extinctions, our results raise important questions, which we discuss. Is the apparent lack of extinctions largely due to management? Are more species in lightly-managed fisheries threatened with extinction than previously acknowledged? Have more extinctions than we realize already happened in data- and management-poor fisheries? Or have fishes' high fecundity and the oceans' vastness provided protection against extinction that is uncaptured by existing theoretical models?

Coral reef fisheries are a vital source of nutrients for thousands of nutritionally vulnerable coastal communities around the world. Marine protected areas are regions of the ocean designed to preserve or rehabilitate marine ecosystems and thereby increase reef fish biomass. Here, we evaluate the potential effects of expanding a subset of marine protected areas that allow some level of fishing within their borders (sustainable-use MPAs) to improve the nutrition of coastal communities. We estimate that, depending on site characteristics, expanding sustainable-use MPAs could increase catch by up to 20%, which could help prevent 0.3-2.85 million cases of inadequate micronutrient intake in coral reef nations. Our study highlights the potential add-on nutritional benefits of expanding sustainable-use MPAs in coral reef regions and pinpoints locations with the greatest potential to reduce inadequate micronutrient intake level. These findings provide critical knowledge given international momentum to cover 30% of the ocean with MPAs by 2030 and eradicate malnutrition in all its forms.

BACKGROUND:Inadequate micronutrient intakes and related deficiencies are a major challenge to global public health. Analyses over the past 10 years have assessed global micronutrient deficiencies and inadequate nutrient supplies, but there have been no global estimates of inadequate micronutrient intakes. We aimed to estimate the global prevalence of inadequate micronutrient intakes for 15 essential micronutrients and to identify dietary nutrient gaps in specific demographic groups and countries. METHODS:In this modelling analysis, we adopted a novel approach to estimating micronutrient intake, which accounts for the shape of a population's nutrient intake distribution and is based on dietary intake data from 31 countries. Using a globally harmonised set of age-specific and sex-specific nutrient requirements, we then applied these distributions to publicly available data from the Global Dietary Database on modelled median intakes of 15 micronutrients for 34 age-sex groups from 185 countries, to estimate the prevalence of inadequate nutrient intakes for 99·3% of the global population. FINDINGS:On the basis of estimates of nutrient intake from food (excluding fortification and supplementation), more than 5 billion people do not consume enough iodine (68% of the global population), vitamin E (67%), and calcium (66%). More than 4 billion people do not consume enough iron (65%), riboflavin (55%), folate (54%), and vitamin C (53%). Within the same country and age groups, estimated inadequate intakes were higher for women than for men for iodine, vitamin B12, iron, and selenium and higher for men than for women for magnesium, vitamin B6, zinc, vitamin C, vitamin A, thiamin, and niacin. INTERPRETATION:To our knowledge, this analysis provides the first global estimates of inadequate micronutrient intakes using dietary intake data, highlighting highly prevalent gaps across nutrients and variability by sex. These results can be used by public health practitioners to target populations in need of intervention. FUNDING:The National Institutes of Health and the Dutch Ministry of Foreign Affairs.

Despite the global importance of inland fisheries, data available for stock assessment is often limited. Data-limited methods that use length composition data offer a potential approach to assessing more inland fisheries. We assessed the population status of three fish species in Lake Hovsgol, Mongolia through length-based spawning potential ratio (LBSPR) analysis and evaluation of trends in eight length-based indicators of population status, catch-per-unit-effort (CPUE), and body size. Hovsgol grayling (Thymallus nigrescens) were not yet overfished, but CPUE and body size declined due to targeting of large, mature fish. Lenok (Brachymystax lenok) were experiencing overfishing, especially of small, immature fish, which contributed to size-structure truncation. The burbot (Lota lota) population was healthy according to most indicators, but the lack of local life history information exacerbated already large uncertainties. Continued monitoring and improved coordination among fishers, managers, and scientists will be critical to enhancing the sustainability of these fisheries.

Both the ecological and social dimensions of fisheries are being affected by climate change. As a result, policymakers, managers, scientists and fishing communities are seeking guidance on how to holistically build resilience to climate change. Numerous studies have highlighted key attributes of resilience in fisheries, yet concrete examples that explicitly link these attributes to social-ecological outcomes are lacking. To better understand climate resilience, we assembled 18 case studies spanning ecological, socio-economic, governance and geographic contexts. Using a novel framework for evaluating 38 resilience attributes, the case studies were systematically assessed to understand how attributes enable or inhibit resilience to a given climate stressor. We found population abundance, learning capacity, and responsive governance were the most important attributes for conferring resilience, with ecosystem connectivity, place attachment, and accountable governance scoring the strongest across the climate-resilient fisheries. We used these responses to develop an attribute typology that describes robust sources of resilience, actionable priority attributes and attributes that are case specific or require research. We identified five fishery archetypes to guide stakeholders as they set long-term goals and prioritize actions to improve resilience. Lastly, we found evidence for two pathways to resilience: (1) building ecological assets and strengthening communities, which we observed in rural and small-scale fisheries, and (2) building economic assets and improving effective governance, which was demonstrated in urban and wealthy fisheries. Our synthesis presents a novel framework that can be directly applied to identify approaches, pathways and actionable levers for improving climate resilience in fishery systems.

Marine protected areas (MPAs) are widely used for ocean conservation, yet the relative impacts of various types of MPAs are poorly understood. We estimated impacts on fish biomass from no-take and multiple-use (fished) MPAs, employing a rigorous matched counterfactual design with a global dataset of >14,000 surveys in and around 216 MPAs. Both no-take and multiple-use MPAs generated positive conservation outcomes relative to no protection (58.2% and 12.6% fish biomass increases, respectively), with smaller estimated differences between the two MPA types when controlling for additional confounding factors (8.3% increase). Relative performance depended on context and management: no-take MPAs performed better in areas of high human pressure but similar to multiple-use in remote locations. Multiple-use MPA performance was low in high-pressure areas but improved significantly with better management, producing similar outcomes to no-take MPAs when adequately staffed and appropriate use regulations were applied. For priority conservation areas where no-take restrictions are not possible or ethical, our findings show that a portfolio of well-designed and well-managed multiple-use MPAs represents a viable and potentially equitable pathway to advance local and global conservation.

Marine heatwaves are increasingly affecting marine ecosystems, with cascading impacts on coastal economies, communities, and food systems. Studies of heatwaves provide crucial insights into potential ecosystem shifts under future climate change and put fisheries social- ecological systems through “stress tests” that expose both vulnerabilities and resilience. The 2014– 16 Northeast Pacific heatwave was the strongest and longest marine heatwave on record and resulted in profound ecological changes that impacted fisheries, fisheries management, and human livelihoods. Here, we synthesize the impacts of the 2014– 2016 marine heatwave on US and Canada West Coast fisheries and extract key lessons for preparing global fisheries science, management, and industries for the future. We set the stage with a brief review of the impacts of the heatwave on marine ecosystems and the first systematic analysis of the economic

Abstract Calls for using marine protected areas (MPAs) to achieve goals for nature and people are increasing globally. While the conservation and fisheries impacts of MPAs have been comparatively well‐studied, impacts on other dimensions of human use have received less attention. Understanding how humans engage with MPAs and identifying traits of MPAs that promote engagement is critical to designing MPA networks that achieve multiple goals effectively, equitably and with minimal environmental impact. In this paper, we characterize human engagement in California's MPA network, the world's largest MPA network scientifically designed to function as a coherent network (124 MPAs spanning 16% of state waters and 1300 km of coastline) and identify traits associated with higher human engagement. We assemble and compare diverse indicators of human engagement that capture recreational, educational and scientific activities across California's MPAs. We find that human engagement is correlated with nearby population density and that site “charisma” can expand human engagement beyond what would be predicted based on population density alone. Charismatic MPAs tend to be located near tourist destinations, have long sandy beaches and be adjacent to state parks and associated amenities. In contrast, underutilized MPAs were often more remote and lacked both sandy beaches and parking lot access. Synthesis and applications: These results suggest that achieving MPA goals associated with human engagement can be promoted by developing land‐based amenities that increase access to coastal MPAs or by locating new MPAs near existing amenities during the design phase. Alternatively, human engagement can be limited by locating MPAs in areas far from population centres, coastal amenities or sandy beaches. Furthermore, managers may want to prioritize monitoring, enforcement, education and outreach programmes in MPAs with traits that predict high human engagement. Understanding the extent to which human engagement impacts the conservation performance of MPAs is a critical next step to designing MPAs that minimize tradeoffs among potentially competing objectives. Read the free Plain Language Summary for this article on the Journal blog.

Dynamic ocean management, which leverages near real-time data to adaptively shift management in response to changing ocean conditions, is gaining attention as an alternative to static approaches for managing dynamic fisheries challenges. While promising, dynamic management can be data-intensive, costly, and difficult to implement, and its value relative to simpler static approaches should be evaluated before being applied, especially when endangered species and economically crucial fisheries are at risk. Here, we use management strategy evaluation to compare static and dynamic management strategies for reducing humpback whale (Megaptera novaeangliae) entanglement risk in the highly lucrative California Dungeness crab (Metacarcinus magister) trap fishery. We find that simple gear reductions outperform dynamic management strategies across several measures of performance. Gear reductions maintain uninterrupted fishing seasons and high fisheries catch and effectively prevent whale entanglement risk by directly reducing the number of vertical trap lines. Furthermore, gear re-ductions are robust to delayed openings resulting from biotoxin contamination and low meat quality, do not depend on the availability or accuracy of entanglement risk indicators, add no new management costs or enforcement challenges, and avoid biases in geographical equity. Dynamic management strategies, which pro-actively or reactively respond to indicators of entanglement risk, struggle to achieve their intended benefits because they are implemented after long logistical delays and because they redistribute rather than reduce entanglement risk. Bycatch threatens protected species and valuable fisheries around the world and models like the one developed here present valuable tools for weighing solutions to complex fisheries and conservation challenges.

The rapid development of seafood trade networks alongside the decline in biomass of many marine populations raises important questions about the role of global trade in fisheries sustainability. Mounting empirical and theoretical evidence shows the importance of trade development on commercially exploited species. However, there is limited understanding of how the development of trade networks, such as differences in connectivity and duration, affects fisheries sustainability. In a global analysis of over 400,000 bilateral trade flows and stock status estimates for 876 exploited fish and marine invertebrates from 223 territories, we reveal patterns between seafood trade network indicators and fisheries sustainability using a dynamic panel regression analysis. We found that fragmented networks with strong connectivity within a group of countries and weaker links between those groups (modularity) are associated with higher relative biomass. From 1995 to 2015, modularity fluctuated, and the number of trade connections (degree) increased. Unlike previous studies, we found no relationship between the number or duration of trade connections and fisheries sustainability. Our results highlight the need to jointly investigate fisheries and trade. Improved coordination and partnerships between fisheries authorities and trade organizations present opportunities to foster more sustainable fisheries.