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.

中文翻译：

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气候变化下北美跨界渔业管理面临的挑战

气候变化正在改变跨越专属经济区 (EEZ) 的鱼类种群的分布，对跨界渔业管理构成挑战。在这里，我们研究了加拿大和美国之间共同管理的跨界鱼类种群的预计共享。我们假设海洋变暖将改变两国之间的鱼类资源共享，并且这种变化将在高碳排放情景下加剧。我们看看国际太平洋大比目鱼委员会管理太平洋大比目鱼 (Hippoglossus stenolepis) 的具体案例以及缅因湾鳕鱼 (Gadus morhua)、黑线鳕 (Melanogrammus aeglefinus) 和鲽鱼 (Limanda ferruginea) 的资源共享安排讨论跨界种群转移的管理后果。我们依靠多个地球系统模型的模拟和物种分布模型来估计 21 世纪两种气候变化情景下每个跨界种群的捕捞潜力和种群份额比率的变化。结果表明，即使在低排放情景下，到 2050 年，大多数跨界鱼类种群共享比率，即特定国家捕获的鱼类种群总捕获量的比例，将相对于现在发生变化。捕捞潜力的整体下降，加上种群份额的变化，将进一步加剧物种捕捞潜力变化之间的权衡。如果遵循高排放情景，相对于低碳排放情景，大西洋和太平洋地区的这种权衡将被放大。根据仿真结果，