Accounting for movement and mixing in stock assessment is important for managing sustainable fisheries, particularly for highly migratory species. However, many fisheries management approaches continue to use single-stock, single-area models to assess mixed-population stocks that are known to have complex movement dynamics. We evaluated a single-stock, single-area stock assessment model’s performance on fishery pseudodata generated using a spatially complex operating model that incorporates movement and mixing of simulated Atlantic bluefin tuna-like populations. Structural model misspecification produced positively biased perceptions of size and productivity of the smaller western population, based on supplement by the larger eastern population, and negatively biased perceptions of the size and productivity of the eastern population due to net movement of fish out of the eastern stock area. This bias could lead to unintended overexploitation of the smaller western population and potential for foregone yield of the larger eastern population. Our findings provide a greater understanding of the effects of movement and mixing on single-stock, single-area model-based management approaches and emphasize the importance of explicitly considering these dynamics in ensuring the sustainability of highly migratory species like Atlantic bluefin tuna.

中文翻译：

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混合种群渔业种群评估的绩效：大西洋蓝鳍金枪鱼的说明性案例

在种群评估中考虑迁移和混合对于管理可持续渔业，特别是高度迁徙物种尤其重要。但是，许多渔业管理方法继续使用单一种群，单一区域模型来评估已知具有复杂运动动态的混合种群种群。我们使用空间复杂的操作模型（结合模拟大西洋蓝鳍金枪鱼类种群的移动和混合）生成的渔业伪数据评估了单种群，单区域种群评估模型的性能。结构模型的误分类在较小的西方人口的补充下，对较小的西方人口的规模和生产率产生了正向偏见，以及由于鱼类从东部种群中净迁出而对东部人口规模和生产力的看法产生了负面偏见。这种偏见可能导致较小的西部人口的意外过度开发，并可能导致较大的东部人口放弃产量。我们的发现提供了对移动和混合对单一种群，单一区域模型管理方法的影响的更好理解，并强调了明确考虑这些动态因素以确保高度迁徙物种（如大西洋蓝鳍金枪鱼）可持续性的重要性。