Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print.
Atlantic bluefin tuna (Thunnus thynnus) are a large, highly migratory fish distributed throughout the North Atlantic Ocean and adjacent seas currently managed as two discrete stocks: western and eastern. Both stocks forage in the North Atlantic, and a high degree of intermixing occurs, which combined with limited single-stock survey data makes it difficult to assess the abundance and status of individual populations. In this study, we used movement patterns from a multidecadal tagging dataset to create monthly distribution maps for these two major stocks. We then used these maps to separate the overall catch records into stock-specific catch (catch per unit effort, CPUE) time series. We identified an increase in the past two decades in the proportion of catch estimated to come from the eastern stock, attributable to a decrease in CPUE in regions dominated by the western stock, relative to other regions. The stock-specific catch series can be used to improve the accuracy of stock assessments and inform spatial management.

中文翻译：

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基于观察到的空间分布的大西洋蓝鳍金枪鱼 (Thunnus thynnus) 的原产地产量估计

加拿大渔业和水产科学杂志，提前印刷。
大西洋蓝鳍金枪鱼 (Thunnus thynnus) 是一种大型、高度洄游的鱼类，分布在整个北大西洋和邻近海域，目前作为两个独立的种群进行管理：西部和东部。两种种群均在北大西洋觅食，且存在高度混杂，再加上单一种群调查数据有限，难以评估个体种群的丰度和状况。在这项研究中，我们使用来自多年代标记数据集的运动模式来创建这两个主要股票的月度分布图。然后，我们使用这些地图将整体捕捞记录分离为特定于种群的捕捞量（每单位努力的捕捞量，CPUE）时间序列。我们发现过去 20 年估计来自东部种群的渔获量比例有所增加，归因于西部存量占主导的地区相对于其他地区的 CPUE 下降。特定种群的捕捞系列可用于提高种群评估的准确性并为空间管理提供信息。