Egg surveys are used worldwide for the estimation of spawning stock biomass (SSB) of small pelagic fish species, requiring detailed knowledge about their reproductive biology. In the present study, we revisit the current conceptual framework of teleost fecundity types using Northeast Atlantic (NEA) mackerel (Scomber scombrus) as case study due to conflicting views across different assessment methods. We hypothesized that the herein presented unique time series on protein and lipid content for this stock would help in resolving the long-lasting, intrinsic fecundity type problem. First, we document that the body surplus energy has varied substantially over time, with a significant drop to historically low levels following a stock increase from 2005 to 2015. This fluctuating pattern is in stark contrast to the stable relative fecundity (oocyte g⁻¹ females) measured in connection with the egg surveys. Second, we show that the feeding levels are at the highest during the spawning season. These findings are consistent with an indeterminate fecundity type as opposed to the presently accepted determinate-type classification dating back to the 1990s. Furthermore, we quantify the batch fecundity and find it to be largely constant. Hence, the main reproductive output regulator that is driven by the bioenergetic status should therefore be the number of batches shed. Based on this novel framework for an indeterminate spawner, we provide alternative estimates of relative realized fecundity, which significantly change the egg survey-based SSB indices, reduces the contrast to the other data sources in the mackerel stock assessment (1990–2019), improves the assessment model fit and reduces the uncertainty of the stock size estimate. The presented algorithms and lines of thinking are applicable to other teleosts and may improve the precision and accuracy of the estimation in cases where the annual egg production method is used to assess stock size.

鸡蛋调查在世界范围内用于估计小型远洋鱼类的产卵种群生物量 (SSB)，需要详细了解它们的生殖生物学。在本研究中，我们使用东北大西洋 (NEA) 鲭鱼 ( Scomber scombrus) 作为案例研究，因为不同评估方法的观点存在冲突。我们假设本文提出的关于该种群蛋白质和脂质含量的独特时间序列将有助于解决长期存在的内在繁殖力类型问题。首先，我们记录到身体剩余能量随着时间的推移发生了很大变化，在 2005 年至 2015 年库存增加后显着下降至历史低位。这种波动模式与稳定的相对繁殖力（卵母细胞 g ^-1雌性）与鸡蛋调查有关。其次，我们表明产卵季节的摄食水平最高。这些发现与不确定的繁殖力类型一致，而不是目前公认的可追溯到 1990 年代的确定型分类。此外，我们量化了批次繁殖力，发现它在很大程度上是恒定的。因此，受生物能量状态驱动的主要生殖输出调节器应该是批次数棚。基于这种不确定产卵者的新框架，我们提供了相对实际繁殖力的替代估计，这显着改变了基于鸡蛋调查的 SSB 指数，减少了与鲭鱼种群评估（1990-2019）中其他数据源的对比，提高了评估模型拟合并降低了库存规模估计的不确定性。所提出的算法和思路适用于其他硬骨鱼，并且在使用年度产蛋方法评估种群规模的情况下可以提高估计的精度和准确性。