Abstract The assessment of postovulatory follicles (POFs) is of considerable importance when applying the Daily Egg Production Method (DEPM) since it is used to estimate both spawning frequency (S) and batch fecundity (FB), provided that daily cohorts of POFs are discernible. Atlantic sardine (Sardina pilchardus) and Atlantic mackerel (Scomber scombrus), two commercially valuable pelagic species with different spawning dynamics were investigated principally to evaluate the appropriateness of the POF method to properly reflect S and FB. For appropriate quantification, both the Weibel and the postovulatory follicles packing density (POFPD) method, the latter described in this paper, were applied and compared. In sardine, not only was the existence of one single daily POF cohort confirmed but also the estimated number of POFs in the cohort matched gravimetric FB results. Furthermore, the Weibel method and POFPD led to similar results. However, several daily POF cohorts co-occurred in the mackerel ovary. Therefore, POF-based estimation of FB only works for species such as sardine with a single, daily POF cohort. Likewise, in relation to estimation of S, the occurrence of single versus multiple POF cohorts makes the histological assignment of spawners to daily spawning classes either straightforward or difficult for species comparable to sardine or mackerel, respectively. In the latter case we suggest focusing in the largest, thus newest, POFs which correspond to the latest spawning event. Therefore, the appropriateness of the POF method in applications of the DEPM should be judged based on the spawning dynamics of the assessed species.

中文翻译：

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对比不同产卵动态的鱼类排卵后卵泡的产生

摘要 在应用每日产蛋方法 (DEPM) 时，排卵后卵泡 (POF) 的评估非常重要，因为它用于估计产卵频率 (S) 和分批繁殖力 (FB)，前提是 POF 的每日队列是可辨别的. 大西洋沙丁鱼 (Sardina pilchardus) 和大西洋鲭鱼 (Scomber scombrus) 是两种具有不同产卵动态的具有商业价值的远洋物种，主要是为了评估 POF 方法是否适合正确反映 S 和 FB。为了进行适当的量化，应用并比较了 Weibel 和排卵后卵泡堆积密度 (POFPD) 方法（本文中描述的后者）。在沙丁鱼中，不仅证实了一个每日 POF 队列的存在，而且还证实了队列中 POF 的估计数量与重量法 FB 结果相匹配。此外，Weibel 方法和 POFPD 导致了类似的结果。然而，在鲭鱼卵巢中同时发生了几个每日 POF 队列。因此，基于 POF 的 FB 估计仅适用于具有单个每日 POF 队列的沙丁鱼等物种。同样，关于 S 的估计，单个和多个 POF 队列的出现使得将产卵者的组织学分配到日常产卵类别对于分别与沙丁鱼或鲭鱼相当的物种而言，要么直接要么困难。在后一种情况下，我们建议关注与最新产卵事件相对应的最大、最新的 POF。所以，