Scomber colias Gmelin, 1789 is of growing interest as a commercial species, making it one of the most demanding fish on the northwest coasts of Africa (NWA). However, relevant data on the stock structure and connectivity of S. colias along the NWA is scarce. The Eastern Central Atlantic Fisheries Committee (CECAF) assumes the existence of two stocks (a northern and a southern stock) between Morocco and Senegal, separated by Cap Boujdour. However, given the absence of relevant biological information on the migration and connectivity of the species, CECAF suggests a joint assessment of the two stocks. Otoliths can be used as natural tracers to study the population structure, fish movements, and habitat connectivity of fish. Otolith morphology, for instance, is a phenotypic trait with a genetic background that usually responds to environmental variables. This study used otolith shape analysis (wavelets) to investigate S. colias stock structure along the NWA, from Morocco to Senegal. Fish were collected between September and December of 2019 by a scientific survey in ten sites (Larache, Casablanca, Safi, Agadir, Tantan, Tarfaya, South of Boujdour, North of Cape Barbas, south Mauritania and Senegal) using a purse seine. The hereby results showed a highly significant regional differentiation among the sites, suggesting the existence of two population-units, with an overall correct re-classification of 91% to the two clusters. This dataset indicates the existence of an oceanographic barrier at the level of 28°N (Tarfaya), which limits the connectivity between the two stocks. Moreover, the mean otolith shape based on wavelet reconstruction for the two population-units revealed high phenotypic plasticity for S. colias otoliths. The broad variance between the two morphotypes highlights the environmental heterogeneity of the Atlantic Northwest African waters. The variation in the rostrum and anti-rostrum of S. colias otoliths is most likely due to genetic diversity or long-term isolation of the two population-units. The hereby data support the hypothesis that S. colias in the NWA is divided into two stocks with limited connectivity. In terms of fisheries management, this study recommends a fine-scale stock assessment.

Scomber colias Gmelin, 1789 作为商业品种越来越受关注，使其成为非洲西北海岸 (NWA) 需求量最大的鱼类之一。然而，关于 NWA 沿线S. colias种群结构和连通性的相关数据很少。东中大西洋渔业委员会 (CECAF) 假定摩洛哥和塞内加尔之间存在两个种群（北部种群和南部种群），中间被布支杜尔角隔开。然而，鉴于缺乏有关物种迁徙和连通性的相关生物信息，CECAF 建议对这两个种群进行联合评估。耳石可作为天然示踪剂来研究鱼类的种群结构、鱼类运动和栖息地连通性。例如，耳石形态是一种具有遗传背景的表型特征，通常会对环境变量做出反应。本研究使用耳石形状分析（小波）来研究从摩洛哥到塞内加尔的 NWA 沿线的S. colias种群结构。 2019 年 9 月至 12 月期间，使用围网对十个地点（拉腊什、卡萨布兰卡、萨菲、阿加迪尔、坦坦、塔尔法亚、布支杜尔南部、巴尔巴斯角北部、毛里塔尼亚南部和塞内加尔）进行了科学调查，收集了鱼类。由此结果显示，站点之间存在高度显着的区域差异，表明存在两个种群单元，对两个簇的总体重新分类正确率为 91%。该数据集表明在北纬 28°（塔尔法亚）水平存在海洋屏障，这限制了两个种群之间的连通性。此外，基于两个群体单元的小波重建的平均耳石形状揭示了大肠杆菌耳石的高表型可塑性。两种形态类型之间的巨大差异凸显了大西洋西北非洲水域的环境异质性。 S. colias耳石的喙部和反喙部的变异很可能是由于遗传多样性或两个种群单位的长期隔离造成的。特此数据支持这样的假设： NWA 中的大肠杆菌被分为两个连通性有限的种群。在渔业管理方面，本研究建议进行精细的种群评估。