The present study used mitochondrial DNA control region to investigate the genetic stock structure and phylogenetic relationship of 38 samples of Narrow-barred Spanish mackerel Scomberomorus commerson (Lacépède, 1800) from two sites (Dar es Salaam and Pangani) located along the northern Tanzanian coastal waters. The study revealed that the Narrow-barred Spanish mackerel were characterized by high levels of mitochondrial DNA genetic diversity, at both haplotypes and nucleotide levels which is indicative of a large population size. The Analysis of Molecular Variance (AMOVA) test gave a significantly low ${\mathit{F}}_{ST}$ value (${\mathit{F}}_{ST}=0$.0011), suggestive of a lack of genetic differentiation between the fish populations of the two investigated sites ($p=0.925$). Furthermore, AMOVA analysis showed that 99.50% of the total molecular variance was distributed within the populations, while only 0.5% was distributed between the populations. The Median-Joining network revealed a star-like median network, suggesting that the collected samples had similar evolutionary history and characterized by a recent historical population expansion. The present study recommends a single stock model for management of Narrow-barred Spanish mackerel in the northern coastal waters of Tanzania. However, due to the migratory nature of the species, a co-management initiative between coastal states within the Western Indian Ocean (WIO) region along with further studies focused on acquiring detailed information on the genetic stock structure covering the entire area is being recommended.

本研究使用线粒体 DNA 控制区来调查位于坦桑尼亚北部沿海水域的两个地点（达累斯萨拉姆和 Pangani）的 38 个窄条鲭鱼Scomberomorus commerson（Lacépède，1800）样本的遗传种群结构和系统发育关系. 该研究表明，窄条鲭鱼的特点是线粒体 DNA 遗传多样性在单倍型和核苷酸水平上都很高，这表明种群规模很大。分子方差分析 (AMOVA) 测试给出了显着低的${\mathit{F}}_{秒吨}$ 价值 （${\mathit{F}}_{秒吨}=0$.0011），表明两个调查地点的鱼类种群之间缺乏遗传差异（$磷=0.925$）。此外，AMOVA 分析表明，总分子方差的 99.50% 分布在种群内，而仅 0.5% 分布在种群之间。Median-Joining 网络揭示了一个星状的中位数网络，表明收集的样本具有相似的进化历史，并以最近的历史人口扩张为特征。本研究建议采用单一种群模型来管理坦桑尼亚北部沿海水域的窄条鲭鱼。然而，由于该物种的迁徙性质，建议在西印度洋 (WIO) 区域内的沿海国之间采取共同管理举措，并进一步研究侧重于获取覆盖整个地区的遗传种群结构的详细信息。