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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]