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Climate change is shifting the distribution of fish stocks that straddle between exclusive economic zones (EEZ), challenging transboundary fisheries management. Here, we examine the projected sharing of jointly managed transboundary fish stocks between Canada and the United States. We hypothesize that ocean warming will alter the sharing of fish stocks between the two countries, and that such changes will intensify under a high carbon emission scenario. We look at the specific cases of the International Pacific Halibut Commission that manages Pacific halibut (Hippoglossus stenolepis) and a resource sharing arrangement in the Gulf of Maine for cod (Gadus morhua), haddock (Melanogrammus aeglefinus), and yellowtail flounder (Limanda ferruginea) to discuss the management consequences of shifts in transboundary stocks. We rely on multiple Earth system models' simulations and species distribution models to estimate the change in catch potential and stock share ratio of each transboundary stock in the 21st century under two climate change scenarios. Results show that, even under a low emission scenario, most transboundary fish stocks sharing ratios, i.e., the proportion of the total catch of a fish stock taken by a given country, will change by 2050 relative to present. The overall reduction in catch potential, in addition to the changes in stock-share will further exacerbate trade-offs between changes in species catch potential. Such trade-offs in the Atlantic and Pacific regions will be amplified if a high emission scenario is followed, relative to a low carbon emission scenario. Based on the simulation results, we examine possible solution options to reduce climate risks on transboundary fish stocks and fisheries. [ABSTRACT FROM AUTHOR]

We apply the concept of threat points in game theory to explore the stability of current joint management arrangements for shared transboundary fish stocks between Canada and the United States. We use three examples to explore the effects of projected impacts of climate change on the productivity and distribution of these stocks between the exclusive economic zones of the two countries. The three stocks that we study are: Atlantic cod (Gadus morhua) and yellowtail flounder (Limanda ferruginea) within the Gulf of Maine, and Pacific halibut (Hippoglossus stenolepis) in the Pacific Coast. We define a threat point as the payoffs that the fisheries in Canada and the United States take home given the current management agreement between the two countries. This is an application of John Nash's threat point, defined as the minimum payoffs that each player in a game theoretic model must receive for the solution to a cooperative game to be stable, which is usually the outcome of a noncooperative game. First, we compute the threat points, that is, the current profits that Canada and the United States derive from the three shared stocks, respectively. Next, we build an ensemble of climate-marine ecosystem and economic models and use them to determine how climate change is likely to change current profits received by each country relative to the shifts in their threat points. We find that in some cases the profits obtained by fisheries in Canada and the United States would change under climate change both in absolute and relative terms resulting in relative changes in threat points. These relative changes in threat points serve as the basis for our discussion of the stability of current transboundary management agreements between Canada and the United States for these important shared stocks in the face of climate change. [ABSTRACT FROM AUTHOR]

The East China Sea (ECS) Large Marine Ecosystem (LME) is a globally significant fishing ground, but the absence of cooperative regional management impedes the future sustainability of ECS fisheries. To navigate around nationally focused perspectives, we provide an up to date synthesis about the socio-economic importance and status of ECS fisheries at the ecosystem level, which is currently lacking in the literature. Our review indicates that ECS LME fisheries contribute around 6 million t in catch and USD 13 billion in landed value annually, and employ up to an estimated 1.4 million, the majority of who are small-scale fishers. However, the fisheries benefits are threatened by intense fishing pressure and rapid economic development which exacerbates the effects of overfishing. The future of ECS fisheries also faces climate uncertainties, which has already been associated with shifts in species distribution and spatial distribution of fishing effort. At the LME level, political disputes that inhibit crucial multilateral fisheries management threaten the future sustainability of ECS fish stocks, and also weaken the effects of national management measures which have largely failed to address fisheries overcapacity and coastal marine degradation. Continuing on a path focussed on national interests without considering LME wide dynamics risks jeopardising the significant fisheries socio-economic and ecological benefits that accrue to all LME countries. Thus, our review emphasises the urgency for multilateral ECS fisheries management to enhance ecosystem resilience so that fisheries resources can continue to support the region's human, social, and economic well-being into the future. [ABSTRACT FROM AUTHOR]

A third of global fish stocks are overexploited and many are economically underperforming, resulting in potential unrealized net economic benefits of USD 51 to 83 billion annually. However, this aggregate view, while useful for global policy discussion, may obscure the view for those actors who engage at a regional level. Therefore, we develop a method to associate large companies with their fishing operations and evaluate the biological sustainability of these operations. We link current fish biomass levels and landings to the revenue streams of the companies under study to compute potentially unrealized fisheries revenues and profits at the level of individual firms. We illustrate our method using two case studies: anchoveta (Engraulis ringens; Engraulidae) in Peru and menhaden in the USA (Brevoortia patronus and B. tyrannus; Clupeidae). We demonstrate that both these fisheries could potentially increase their revenues compared to the current levels of exploitation. We estimate the net but unrealized fishery benefits for the companies under question. This information could be useful to investors and business owners who might want to be aware of the actual fisheries performance options of the companies they invest in. [ABSTRACT FROM AUTHOR]

Climate change is causing fish stocks to shift, upending the social-ecological systems that rely on the historic distributions of these stocks and creating or exacerbating fisheries conflicts. The movements of internationally shared stocks between Exclusive Economic Zones (EEZs) or between EEZs and the high seas are especially concerning because they bring into play a variety of geopolitical factors and equity issues surrounding missing or conflicting regulations of jurisdictional boundary zones. Though many studies have explored the responses to and repercussions of shifting stocks on fisheries management, there is a dearth of interdisciplinary case studies that provide insight into the complexity of conflict formation in shifting transboundary fisheries, and that highlight the initial response stages where inclusion of proactive and cooperative measures can greatly improve a system's resilience to conflict. Our study helps to fill this gap by drawing on the knowledge of a diverse group of experts to analyze four case studies where transboundary stock shifts, geopolitical or governance tensions, and uncertainty regarding the future of the marine environment collide. Through synthesis of case study findings, we create a causal model of fishery conflict, within which we highlight factors that may heighten or mitigate the risk of conflict over shifting resources such as complex histories of power imbalance, unequal access to resources, or a lack of consistent and transparent data collection. Cooperation and equitable decision-making processes are recognized as vital components of internationally shared stock management which can promote lasting, effective, and conflict-resilient fisheries. [ABSTRACT FROM AUTHOR]

The WTO Agreement on Fisheries Subsidies adopted in June 2022 is potentially a step forward for ocean sustainability. Yet, its success in removing fisheries subsidies contributing to illegal, unreported, and unregulated (IUU) fishing, and overfishing more generally, will depend on its scope, its effective interpretation, and broad implementation. Here we focus on Article 5.1, which, in its narrowest interpretation prohibits fishing subsidies in areas not covered by Exclusive Economic Zones (EEZs) and Regional Fishery Management Organizations (RFMOs) but in its broadest interpretation prohibits subsidies for any unregulated fisheries in the high seas. This study finds that only ∼1.35% of the high seas are not spatially covered by at least one RFMO, and most of that area are frozen parts of the high seas with little to no fishing. This means that if Article 5.1 is interpreted to mean the area of the high seas not managed under RFMOs, then the effect of Article 5.1 will be minimal or non-existent even if the article is fully implemented. Many RFMOs, however, are only mandated to regulate a few species, such as tunas. Much of the potential impact of Article 5.1 thus could rest on the definition of the 'competence of a relevant RFMO,' which we argue should be defined based on both area and species of competence. To make the Article meaningful in terms of removing harmful subsidies that impact the sustainability of high seas fish stocks, additional clarifying provisions to Article 5.1 to reaffirm that it applies to both unregulated areas and species outside of the competence of relevant RFMOs are needed. • Article 5 prohibits subsidies provided to fishing outside national jurisdictions and the competence of RFMOS. • We find that only 1.35% of the area of the high seas are outside the geographical jurisdiction of RFMOs. • A geographical interpretation of Article 5.1 would achieve little for protecting fish against harmful subsidies. • Article 5 must be based on both species and areas not under the competence and relevance of RFMOs to reduce overfishing. [ABSTRACT FROM AUTHOR]

Harmful fisheries subsidies contribute to overfishing leading to environmental and societal impacts. If only fisheries and ecosystems within the subsidising nations' jurisdiction were affected, then unilateral actions might be sufficient to help safeguard our ocean and the people reliant upon it. However, just as fish move between jurisdictions, so too do the subsidised fishing fleets that target them. As such, the impacts and solutions to subsidies-induced overfishing are often matters of international concern. Mapping the distribution and flows of harmful subsidies is therefore key to understanding these concerns, informing multilateral reform, and empowering impacted nations to strengthen the terms of access to their waters and resources. Here we quantify the amount of harmful fisheries subsidies that supports fishing in the high seas, domestic and foreign waters. We estimate that between 20% and 37% of all harmful fisheries subsidies support fishing in foreign waters or the high seas, that is outside the jurisdictions of the subsidising nations. We show that harmful subsidies primarily originate from nations with high-Human Development Index (HDI), strong fisheries management capacity and relatively sustainable fish stocks, yet disproportionately impact nations with low or very low-HDI, lower management capacity and more vulnerable fish stocks—40% of the harmful subsidies that support fishing in very low-HDI nations waters originate from high-HDI and very-high HDI nations. We show that Asia, Europe, and North America, are net subsidy sources; they provide more harmful subsidies to their fishing fleets than their respective ecosystems are impacted by; while Africa, South, Central America and Caribbean, and Oceania are net subsidy-sinks. This discrepancy between the source of harmful subsidies and the nations that are ultimately impacted is unsustainable and unjust. Prohibiting all harmful subsidies to distant-water fishing and fishing in the high seas—with narrow exceptions for Small Island Developing States—should be prioritised to support the advancement of sustainable and equitable fisheries worldwide. • We quantify the amount of harmful subsidies supporting fishing in the high seas, domestic and foreign waters. • Between 20% and 37% of harmful subsidies support fishing in foreign waters or the high seas. • Harmful subsidies unequally affect low or very low-HDI nations, with low management capacity and vulnerable fish stocks. • Asia, Europe and N. America are net subsidy sources; providing more harmful subsidies than their ecosystems are affected by. • Marine ecosystems within Africa, Oceania, South, Central America, and Caribbean, are net subsidy-sinks. [ABSTRACT FROM AUTHOR]

Harmful fisheries subsidies have historically contributed to fleet overcapacity and continue to be allocated to the fishing industry to artificially maintain its profitability. However, in this contribution we show that removing harmful subsidies and reducing overfishing will help to recover the resource biomass, subsequently leading to increased levels of sustainable catches, income and well-being of fishers, and reduces inequities in income and consumption when fish stocks are not effectively managed. Maintaining harmful fisheries subsidies is socially and economically inefficient. Taking the example of the EU fishing fleet, one of the largest fishing fleets in the world, we use the total factor productivity to show that small-scale fishing fleet's productivity is almost two-fold in the North Atlantic and 16% higher in the Mediterranean and Black seas compared to large-scale vessels. This result is explained because the harmful fisheries subsidies disproportionately allocated to large-scale vessels introduce distortions in the efficient allocation of inputs. With critical WTO negotiations ongoing regarding the global rules on fisheries subsidies, the EU must take advantage of the opportunity to lead a desirable transformative change while also supporting developing nations to truly achieve global sustainable and equitable fisheries. [ABSTRACT FROM AUTHOR]

Overfishing threatens coral reefs worldwide, yet there is no reliable estimate on the number of reef fishers globally. We address this data gap by quantifying the number of reef fishers on a global scale, using two approaches - the first estimates reef fishers as a proportion of the total number of marine fishers in a country, based on the ratio of reef-related to total marine fish landed values. The second estimates reef fishers as a function of coral reef area, rural coastal population, and fishing pressure. In total, we find that there are 6 million reef fishers in 99 reef countries and territories worldwide, of which at least 25% are reef gleaners. Our estimates are an improvement over most existing fisher population statistics, which tend to omit accounting for gleaners and reef fishers. Our results suggest that slightly over a quarter of the world’s small-scale fishers fish on coral reefs, and half of all coral reef fishers are in Southeast Asia. Coral reefs evidently support the socio-economic well-being of numerous coastal communities. By quantifying the number of people who are employed as reef fishers, we provide decision-makers with an important input into planning for sustainable coral reef fisheries at the appropriate scale. [ABSTRACT FROM AUTHOR]

Background: Illegal, Unreported and Unregulated (IUU) fishing is a problem for marine resource managers, leading to depletion of fish stocks and negative impacts on marine ecosystems. These problems are particularly evident in regions with weak governance. Countries responsible for sustainable natural resource management in the Southern Ocean have actively worked to reduce IUU fishing in the region over a period of 15 years, leading to a sequence of three distinct peaks of IUU fishing. Methodology/Principal Findings: We reviewed existing public records relating to IUU fishing in the Southern Ocean between 1995-2009 and related this information to the governance capacity of flag states responsible for IUU vessels. IUU operators used a number of methods to adapt to enforcement actions, resulting in reduced risks of detection, apprehension and sanctioning. They changed fishing locations, vessel names and flag states, and ports for offloading IUU catches. There was a significant decrease in the proportion of IUU vessels flagged to CCAMLR countries, and a significant decrease in the average governance index of flag states. Despite a decreasing trend of IUU fishing, further actions are hampered by the regional scope of CCAMLR and the governance capacity of responsible states. Conclusions/Significance: This is the first study of long-term change in the modus operandi of IUU fishing operators, illustrating that IUU operators can adapt to enforcement actions and that such dynamics may lead to new problems elsewhere, where countries have a limited capacity. This outsourcing of problems may have similarities to natural resource extraction in other sectors and in other regions. IUU fishing is the result of a number of factors, and effectively addressing this major challenge to sustainable marine resource extraction will likely require a stronger focus on governance. Highly mobile resource extractors with substantial funds are able to adapt to changing regulations by exploiting countries and regions with limited capacity. [ABSTRACT FROM AUTHOR]

Rebuilding fish populations worldwide is urgently needed, but socio-economic concerns often slow down or even prevent the process of rebuilding fish stocks. To address this concern we conduct an economic analysis of rebuilding six depleted Canadian fish stocks under different biological and management scenarios. Rebuilding scenario projections are based on underlying fish stock assessments and fish species' life history traits, and thus are also influenced by uncertainties in these parameters. We find that rebuilding generates economic gains for five of the six fish stocks in the long term, with estimated economic gains under the most and least optimistic scenarios reaching up to 11 times and 5 times above the status quo, respectively. In most cases, fishery closure generates higher potential economic gains compared to a low-fishing strategy, regardless of the rate of fish stock recovery. Intergenerational discounting increases estimated economic benefits, thereby emphasizing the importance of taking a long-term perspective to fisheries rebuilding. Our results suggest that bearing the short-term economic costs of rebuilding can lead to future economic benefits, which in the long term are an improvement over maintaining the status quo. • Fisheries rebuilding results in long term economic gains for 5 out of 6 stocks. • Most optimistic scenario estimated economic gain of 11 times above the status quo. • Rebuilding led to NPV losses for yelloweye rockfish, a long lived, choke species. • Fishery closure scenarios resulted in highest projected economic gains. • Bearing short-term economic costs of rebuilding can lead to future benefits. [ABSTRACT FROM AUTHOR]

The effects of climate change on the ocean environment – especially ocean warming, acidification, and sea level rise – will impact fish stocks and fishers in important ways. Likely impacts include changes in fish stocks' productivity and distribution, human migration to and away from coastal areas, stresses on coastal fisheries infrastructure, and challenges to prevailing maritime boundaries. In this paper, we explore these and other related phenomena, in order to assess whether and how the impacts of climate change on fisheries will contribute to the risk of fisheries conflict. We argue that climate change will entail an increase in the conditions that may precipitate fisheries conflict, and thereby create new challenges for existing fisheries management institutions. Several potential changes in fisheries management policy are recommended to avert the growing risk of fisheries-related conflicts. Climate change is radically reshaping the maritime space – and fisheries in particular – in ways that challenge existing governance institutions and mechanisms, and increase the risk of fisheries conflicts. [ABSTRACT FROM AUTHOR]

Consumption of seafood has increased steadily over the past several decades and this trend is expected to continue with projected increases in global population and affluence. Wild capture fisheries catches have likely reached their peak, and therefore any significant increase in future fish supply is expected to come primarily from aquaculture. However, aquaculture continues to rely on wild stocks by using fishmeal to support culture of fed species. Recently, concerns regarding wild fish populations have led to calls for the closure of the high seas (i.e., international waters) to fishing. Such a policy would decrease marine fish catch in the short term while potentially increasing future catch. Here, we assess the potential impacts of closing the high seas to fishing on marine fish catch that goes to reduction into fishmeal. We quantify the potential effects of these changes on the price of fishmeal and profitability of the global aquaculture industry. Not surprisingly, we find a stronger effect of closing the high seas to fishing for high-value carnivorous species such as shrimp and salmonids. Overall, however, our study suggests that the impact of closing the high seas to fishing on aquaculture is likely to be insignificant. [ABSTRACT FROM AUTHOR]

The Arctic remains one of the most pristine marine regions in the world, however climate change and increasing favourable conditions is triggering increasing exploration and development of commercial fisheries. Canada's Arctic marine capture fisheries are currently small relative to fisheries in other regions in Canada but small scale, predominantly Inuit fisheries are more wide spread. In this study, catch data was first used to estimate the current state of Arctic marine fisheries. Next, an integrated modelling approach was used to estimate the current and future fisheries potentials under high and low climate change scenarios. Comparisons of the current (2004–2015) annual reported tonnage and modelled estimates (±standard deviation) suggest that annual sustainable fisheries catch potential could be much greater at 4.07 (±2.86) million tonnes than the current catch of 189 (±6.26) thousand tonnes. Under a high climate change scenario, future (2091–2100) fisheries potential was projected to increase to 6.95 (±5.07) million tonnes of catch, while under low climate change scenario catch potential was similar to estimates of current catch potential. However, the greatest source of variance in catch potential estimates came from parameter uncertainty, followed by scenario and model uncertainty. These results contribute to understanding Canada's Arctic marine ecosystems in the face of a rapidly changing environment, yet proper steps must be taken to ensure cultural preservation for Inuit communities as well as ecological, economic, and social sustainability. • Climate change will increase access to Arctic marine fish stocks in Canada. • Projections show positive increases in fisheries catch and value potential with climate change. • Range shifts driven by ocean warming will lead to increased catch potential. • Ocean acidification may reduce projected increase in catch potential. • Ecological, economic, social and cultural impacts of exploitation must be considered. [ABSTRACT FROM AUTHOR]

Recreational fishing is a vital component of the tourism economy in Baja California Sur (BCS), Mexico, although several artisanal and industrial fisheries continue to operate in the region. The commercial long-liner fleet in particular is widely held to be responsible both for diminishing shark populations and declines in billfish through bycatch. Using available fisheries and ecosystem data, we develop an Ecopath with Ecosim (EwE) model to represent current ecosystem and fishing dynamics in BCS and explore the ecological and economic effects of specific fisheries policy measures. Results suggest that currently mandated bycatch limits for the longlining fleet will have little effect on marlin abundance in the area. In an overfished ecosystem, decreasing fishing effort can result in higher overall catches through population rebuilding. While perhaps ecologically justified, increases in the abundance of sharks, a top predator, can have negative effects on other valued species in the ecosystem. The effects of these trophic dynamics must not be overlooked, as they can negate or even reverse desired outcomes from fisheries management. [Copyright &y& Elsevier]

• More transboundary fish stocks are expected under climate change, complicating fisheries management. • Linked game theory—ecosystem models test ecosystem-based co-management strategies. • Cooperative, ecosystem-based management of Pacific sardine improves profitability over all fisheries. • Managers must account for the key role of forage fish for ecosystems as well as other fisheries. Transboundary fish stocks complicate sustainable fishing strategies, particularly when stakeholders have diverse objectives and regulatory and governance frameworks. Pacific sardine (Sardinops sagax) in the California Current is shared by up to three fishing nations— Canada, the United States, and Mexico—and climate-driven abundance and distribution dynamics can complicate cooperative fisheries, leading to overfishing. This study builds on previous analyses by integrating ecosystem linkages into a game theory model of transboundary sardine fisheries under various climate scenarios. Cooperative fishing strategies that account for the ecosystem-wide value of sardine as forage for other species result in increased economic benefits compared to strategies that only account for the single-species value of sardine fisheries to a given fishing country. Total ecosystem landed value is maximized at a sardine fishing rate only somewhat lower than sardine F MSY , which is more precautionary but still allows the fishery to operate. Incorporating ecosystem dynamics into management-applicable models can highlight ways in which ecosystem-based fisheries management can improve both sustainability and profitability and help managers prioritize wider ecological research. Ecosystem-based management will be increasingly required to understand and adapt to the observed rapid shifts in species distributions due to climate change, and to design strategies to achieve sustainable and profitable fisheries amidst changing ecosystems. [ABSTRACT FROM AUTHOR]