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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]

Individual transferable quotas (ITQs) are a type of catch share system, which is a tool used by some governments to manage fisheries. Technical reasons for taking a rather cautious approach to the implementation of ITQs have been provided previously. In the current contribution, I first highlight the strengths and weaknesses of ITQs and then provide suggestions on how to design and implement these quotas to mitigate their weaknesses. ITQs need to be designed carefully as part of a broad ecosystem-based management scheme to meet the three generally accepted objectives of modern fisheries management: ecological, economic, and social sustainability. [ABSTRACT FROM AUTHOR]

Accounts of fishing conflicts have been rising globally, particularly between small-scale and industrial vessels. These conflicts involve verbal or physical altercations, and may include destruction of boats, assault, kidnapping, and murder. Current scholarship around industrial/small-scale fishing conflicts theorizes them as a form of resource conflict, where fish scarcity is the dominant contributor to conflict and competition. Alternatively, conflicts may be driven by spatial competition, concentrating where there are increased encounters, unrelated to resource status. Current policies to address these conflicts focus on enforcing the separation of small-scale and industrial vessels; however, this broad spatial separation has yet to be evaluated for deterring conflicts. Here we employ a novel spatial analysis to estimate the locations of industrial/small-scale conflicts at sea in Ghana, West Africa. Using data from narrative reports over the period of 1985 to 2014, we combine qualitative information on depth and shoreline indicators to analyze conflict locations. We find virtually all expected conflict locations (98%) occurred within the zone meant to exclude industrial vessels, and conflicts concentrated primarily around major ports. Our results suggest conflicts are likely more related to spatial patterns of vessel presence than patterns of resource use. These findings suggest a critical need for evidence-based and contextual information on the drivers of fisheries conflicts, rather than continued reliance on assumptions of resource scarcity. They also suggest that nuanced policies that reduce vessel encounter and clarify exclusive spatial rights may be more important in responding to these conflicts than approaches designed to broadly separate fleets or increase fish stocks. [ABSTRACT FROM AUTHOR]