Numerous conservation programs are now targeting the mitigation or reduction of anthropogenic pressures to restore biodiversity. The aspirational and ambitious objectives underlying these programs need to translate into timely management actions for maximum impact, a process whose first steps assume efficient monitoring and appropriate indicators. Capitalizing on a well-coordinated stranding network, we developed further a risk-based indicator informing indirectly on pressures resulting in at-sea-mortality events of small cetaceans. This indicator uses Extreme Value Theory to forecast the expected maximum number of cetacean strandings on the French seaboard adjacent to three sub-regions defined by the ’Marine Strategy Framework Directive’ of the European Union. A comparison of forecasts and observations allows (i) a risk assessment, and (ii) inference on the trajectory towards ’Good Environmental Status’ on a time-scale aligning with the 6-years cycle required by the Directive, thereby allowing stakeholders to make informed and timely decisions. We applied the use of the indicators on 3 species illustrating different case studies: the harbour porpoise () in the Channel, the common dolphin () in the Bay of Biscay, and the striped dolphin () in the Western Mediterranean Sea. Our results showed notably how by-catch in fisheries remains a large threat on short-beaked common dolphins, with no sign of abating.

中文翻译：

---

基于风险的小型鲸类极端死亡事件预测：评估随时间变化的趋势和变化

目前，许多保护计划的目标是减轻或减少人为压力，以恢复生物多样性。这些计划背后的雄心勃勃的目标需要转化为及时的管理行动，以实现最大的影响，这一过程的第一步假设有效的监测和适当的指标。利用协调良好的搁浅网络，我们进一步开发了基于风险的指标，间接告知导致小型鲸类动物海上死亡事件的压力。该指标利用极值理论来预测与欧盟“海洋战略框架指令”定义的三个次区域相邻的法国海岸的预期最大鲸类搁浅数量。通过比较预测和观察结果，可以 (i) 进行风险评估，以及 (ii) 在符合指令要求的 6 年周期的时间范围内推断“良好环境状况”的轨迹，从而使利益相关者能够做出知情且及时的决策。我们将这些指标应用于 3 个物种来说明不同的案例研究：英吉利海峡的港湾鼠海豚 ()、比斯开湾的普通海豚 () 以及西地中海的条纹海豚 ()。我们的研究结果显着表明，渔业副渔获物仍然对短喙海豚构成巨大威胁，而且没有减弱的迹象。