For many environmental indicators, the sustainable status can change because of changes in either the monitored state or the policy goal. Fisheries provide an intensively monitored setting to investigate the relative impacts of such change. Key fisheries sustainability indicators comprise the ratio between fishing pressure or biomass and their respective reference levels. We developed a retrospective database of population status, reference point changes and reported reasons for changes for all data-rich stocks in the ICES region. We derived methods to distinguish the impacts of either source of change (monitored state or policy goal) on sustainable status. We found that reference points changed frequently (64% of populations had reference point changes) with varying magnitudes. Contrary to expectation, reference point changes were often not compensated by changes in the state thus significantly impacting inferred sustainability status and dependent scientific advice. Across a range of life histories and assessments, changes in reference points dominate retrospective revisions in status over the full time series. Overall, status before and after the change of reference point had no significant directional differences that would suggest reference point change effecting movement towards or away from sustainability. Although multiple factors have contributed to reference point changes, our results show that the reference point definition and the technical basis for estimation were the most important reasons for change. Recognizing that reference points are not constant in time but rather form reference series is paramount to quantifying present and historical sustainability. Properly documenting, justifying and quantifying the impacts of such change is an ongoing challenge.

中文翻译：

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移动参考点目标和对渔业可持续性的影响

对于许多环境指标而言，可持续状态可能会因监测状态或政策目标的变化而发生变化。渔业提供了一个密切监测的环境来调查这种变化的相对影响。关键渔业可持续性指标包括捕捞压力或生物量与其各自参考水平之间的比率。我们为 ICES 地区所有数据丰富的种群开发了一个关于种群状况、参考点变化和报告变化原因的回顾性数据库。我们推导出方法来区分任一变化源（受监控的状态或政策目标）对可持续状态的影响。我们发现参考点经常变化（64% 的人群有参考点变化），幅度不同。与预期相反，参考点的变化往往无法通过状态的变化来补偿，从而显着影响推断的可持续性状态和相关的科学建议。在一系列生活史和评估中，参考点的变化主导了整个时间序列中状态的回顾性修订。总体而言，参考点变化前后的状态没有显着的方向差异，表明参考点变化会影响走向或远离可持续性的运动。尽管多种因素促成了参考点的变化，但我们的结果表明，参考点的定义和估计的技术基础是最重要的变化原因。认识到参考点在时间上不是恒定的，而是形成参考系列对于量化当前和历史可持续性至关重要。正确记录、证明和量化此类变化的影响是一项持续的挑战。