Biomass limit reference points are widely used in fisheries management and define the biomass threshold (BT) below which stock productivity (i.e. recruitment) is likely to be impaired. Scientifically sound and transparent methods for estimating BTs are therefore needed together with ways of quantifying uncertainties. The main focus of the study was placed on two methods currently applied to several small‐bodied pelagic species in the Northeast Atlantic. These methods have not formerly been described in the scientific literature and are in the present study being compared with some already described methods, of which one is broadly applied outside the Northeast Atlantic. Using a combination of data simulations and data from 51 small‐bodied pelagic fish stocks, we analysed the sensitivity of estimated BTs to (a) the choice of method, (b) time‐series length and (c) stock development (e.g. rebuilding or declining). It was demonstrated that estimated BTs are associated with considerable uncertainty not previously quantified. Furthermore, the level of the estimated threshold and the amount of uncertainty depended on choice of method, time‐series length and stock development trends. Hence, this study contributes to improving the quality of future biomass limit reference points by providing guidance regarding choice of method and how to demonstrate stock‐specific uncertainties.

中文翻译：

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生物质极限参考点对估算方法，时间序列长度和种群发展敏感

生物量极限参考点已广泛用于渔业管理中，并定义了生物量阈值（BT），低于该阈值可能会损害种群生产力（即募集）。因此，需要科学合理且透明的估算BT的方法以及量化不确定性的方法。该研究的主要重点放在目前应用于东北大西洋几种中上层鱼类的两种方法上。这些方法以前没有在科学文献中描述过，并且在本研究中与已经描述的一些方法进行了比较，其中一种方法广泛应用于东北大西洋以外。结合数据模拟和来自51种中上层鱼类种群的数据，我们分析了估计的BTs对（a）方法选择的敏感性，（b）时间序列长度和（c）库存发展（例如重建或下降）。结果表明，估计的BT与先前未量化的相当大的不确定性有关。此外，估计阈值的水平和不确定性的数量取决于方法的选择，时间序列的长度和种群发展趋势。因此，本研究通过提供有关方法选择以及如何证明特定于种群的不确定性的指导，有助于提高未来生物量极限参考点的质量。时间序列长度和库存发展趋势。因此，本研究通过提供有关方法选择以及如何证明特定于种群的不确定性的指导，有助于提高未来生物量极限参考点的质量。时间序列长度和库存发展趋势。因此，本研究通过提供有关方法选择以及如何证明特定于种群的不确定性的指导，有助于提高未来生物量极限参考点的质量。