Despite continued calls for the application of ecosystem-based fisheries management, tactical fisheries management continues to be heavily reliant on single-species stock assessments. These stock assessments rarely quantitatively integrate the effects of ecosystem processes on fish stock productivity. This lack of integration is ultimately driven by the complexity of interactions between populations, ecosystems and fisheries, which produces uncertainty when defining which processes to include and how to include them. Models developed using a structured hypothesis testing framework would allow formalizing uncertainties while underscoring the importance of incorporating different population and ecosystem processes to explain non-stationary stock productivity. Here, we develop a conceptual framework for extending and comparing population dynamics models of increasing complexity. We illustrate the utility of the framework by investigating the population and ecosystem processes that most likely affected the differential recovery of two flatfish populations (American plaice and yellowtail flounder) on the Newfoundland Grand Banks over the past three decades. We found that yellowtail flounder population dynamics were primarily driven by recruitment variability, which was negatively affected by warmer climatological conditions, as indicated by an integrated regional climate index. Meanwhile, American plaice population dynamics were affected by a combination of temporal variability in recruitment and natural mortality, where natural mortality increased during colder than average conditions. By exploring hypotheses about the effects of population and ecosystem processes on population dynamics, this modelling framework will improve understanding about the drivers of shifts in population productivity while serving as a transparent and robust approach to support ecosystem-based fisheries management.

中文翻译：

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测试日益复杂的模型以制定生态系统知情的渔业建议

尽管人们不断呼吁应用基于生态系统的渔业管理，但战术渔业管理仍然严重依赖单一物种种群评估。这些种群评估很少定量地整合生态系统过程对鱼类种群生产力的影响。这种缺乏整合的最终原因是人口、生态系统和渔业之间相互作用的复杂性，这在定义要包括哪些过程以及如何包括它们时产生了不确定性。使用结构化假设检验框架开发的模型将允许形式化不确定性，同时强调纳入不同种群和生态系统过程来解释非平稳种群生产力的重要性。在这里，我们开发了一个概念框架，用于扩展和比较日益复杂的人口动态模型。我们通过调查过去三十年来最有可能影响纽芬兰大浅滩上两种比目鱼种群（美国鲽鱼和黄尾鲽）差异恢复的种群和生态系统过程来说明该框架的实用性。我们发现，黄尾牙鲆种群动态主要是由补充变异性驱动的，正如综合区域气候指数所示，这种变异性受到气候条件变暖的负面影响。与此同时，美洲鲽鱼种群动态受到补充和自然死亡率的时间变化的综合影响，其中自然死亡率在比平均条件更冷的情况下增加。通过探索关于人口和生态系统过程对人口动态影响的假设，该建模框架将增进对人口生产力变化驱动因素的理解，同时作为支持基于生态系统的渔业管理的透明和稳健的方法。