The productivity susceptibility analysis (PSA) is a widely used method to rapidly assess species risk to fishing activities in data-poor fisheries. A step in ecological risk assessments and used in data-poor assessment for sustainable fisheries certification programmes (e.g. MSC) and recommendation lists (e.g. Seafood Watch), the PSA is semi-quantitative, yet little attention has been given to the theoretical basis of this analysis. Current thresholds designating low-, medium- and high-risk categories divide the PSA plot by equal area, assuming area corresponds to likelihood. We show that plot area does not correspond to likelihood, however, and existing thresholds need revision due to the non-uniform distribution of vulnerability scores on the PSA plot. The probability of medium risk assignment increases with the number of attributes used to characterize productivity and susceptibility. Here, we present a novel and statistically robust method to derive vulnerability, where threshold values between the risk categories are adjusted with the number of attributes used in the assessment. Our comprehensive framework accounts for all variations in the method, including logarithmic scaling of axes, weighting of attributes and scoring procedures. Simulated results across a range of conditions and comparative evaluation of 302 species in five studies show that one-third of species may be re-categorized with the new PSA approach. Importantly, the existing PSA approach underestimates risk by up to 35% when compared with the new method. These findings have strong implications for management of data-poor fisheries. We recommend adoption of this approach to the PSA to better resolve species’ risk.

中文翻译：

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重新定义缺乏数据的渔业中的风险

生产力敏感性分析 (PSA) 是一种广泛使用的方法，用于快速评估数据贫乏渔业中捕捞活动的物种风险。作为生态风险评估的一个步骤，并用于可持续渔业认证计划（例如 MSC）和推荐清单（例如海鲜观察）的数据贫乏评估，PSA 是半定量的，但很少有人注意到这一点的理论基础分析。当前指定低、中和高风险类别的阈值将 PSA 图除以相等的面积，假设面积对应于可能性。然而，我们表明绘图区域与可能性不对应，并且由于 PSA 绘图上漏洞分数的非均匀分布，现有阈值需要修改。中等风险分配的概率随着用于表征生产力和敏感性的属性数量增加而增加。在这里，我们提出了一种新颖且具有统计鲁棒性的方法来推导脆弱性，其中风险类别之间的阈值根据评估中使用的属性数量进行调整。我们的综合框架考虑了该方法的所有变化，包括轴的对数缩放、属性加权和评分程序。在一系列条件下的模拟结果和五项研究中 302 种物种的比较评估表明，三分之一的物种可能会使用新的 PSA 方法重新分类。重要的是，与新方法相比，现有的 PSA 方法低估了高达 35% 的风险。这些发现对缺乏数据的渔业管理具有重要意义。我们建议在 PSA 中采用这种方法，以更好地解决物种风险。