Modern management of fish stocks is based on integrating the precautionary approach with the maximum sustainable yield framework. It relies on accurate estimation of precautionary limits, defined as levels of spawning biomass where a stock has reduced reproductive capacity, and harvesting targets aimed to maximise future yields. Therefore, it is heavily depending on productivity assumptions. Most fish stocks are managed assuming that productivity will increase as the stock size decreases (i.e., density dependent compensatory stock and recruitment relationship). However, several biological and ecological processes will result in a decreased productivity below a certain population size, referred to as the Allee effect or depensation. Through a meta‐analysis of 81 Northeast Atlantic fish stocks, we investigated the impact of assuming compensatory recruitment in the presence of depensation in fisheries management. Across life histories, depensation results in a 22% reduction of the fishing mortality rate leading to extinction. On average, the maximum reproductive rate per spawning biomass was found at 35% of BMSY, which was also the biomass where stocks have a 5% risk of extinction without fishing. Finally, the presence of depensation resulted in increased rebuilding times when stock spawning biomass falls below the limit reference point. When depensatory effects are present, assuming increasing productivity at low biomass will generally result in over‐optimistic perceptions of rebuilding and stock status at biomass below 25% and 45% of BMSY in general, and for pelagic stocks respectively. When not accounted for, depensation will potentially lead to unsustainable harvesting practices of marine living resources.

中文翻译：

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补偿和补偿补充下的重建和参考点：东北大西洋鱼类种群的荟萃分析


鱼类种群的现代管理基于将预防方法与最大可持续产量框架相结合。它依赖于对预防限值的准确估计，预防限值定义为种群繁殖能力降低的产卵生物量水平，以及旨在最大限度地提高未来产量的收获目标。因此，它在很大程度上依赖于生产力假设。大多数鱼类种群的管理假设生产力会随着种群规模的减少而增加（即，密度依赖性补偿种群和补充关系）。然而，一些生物和生态过程将导致低于一定种群规模的生产力下降，称为 Allee 效应或 depensation。通过对 81 个东北大西洋鱼类种群的荟萃分析，我们调查了在渔业管理中存在补偿性补充的影响。在生活史中，捕捞导致渔业死亡率降低 22%，从而导致灭绝。平均而言，每个产卵生物量的最大繁殖率为 BMSY 的 35%，这也是种群如果不捕鱼就有 5% 灭绝风险的生物量。最后，当种群产卵生物量低于极限参考点时，沉积的存在导致重建时间增加。当存在依赖效应时，假设在低生物量下提高生产力通常会导致对生物量低于 BMSY 的 25% 和 45% 的生物量以及中上层种群的重建和种群状况过于乐观的看法。如果不考虑，收集可能会导致不可持续的海洋生物资源捕捞做法。