Our study aims to assess the population connectivity, evolutionary history, and conservation status of the short-beaked common dolphin in the Black Sea and Turkish Straits System (TSS). We also include DNA sequences from the Atlantic Ocean and the Mediterranean Sea to provide a regional perspective to our localized study. Analysis of 366 base pairs of mitochondrial DNA D-loop fragments from 37 samples collected from short-beaked common dolphins in the Black Sea, TSS, and Aegean Sea revealed 13 haplotypes, eight of which have not been previously reported. While analysis of samples archived on GenBank revealed 89 different haplotypes across the region. The haplotype network contains two main peripheral groups that include individuals from all locations. Haplotypes from the Atlantic Ocean are scattered across the network and no obvious population separation was detected. Some shared haplotypes potentially indicate multi-directional colonization events of the Mediterranean Sea from the eastern Atlantic Ocean. Moreover, some less widely distributed haplotypes suggest some level of more recent genetic connectivity through the Strait of Gibraltar and the TSS and point out the importance of these straits in the dispersal of short-beaked common dolphins. The haplotype and nucleotide diversity values were lower in the Black Sea, TSS, and western Mediterranean Sea when compared to the Atlantic Ocean, supporting the expansion of Atlantic populations into the Mediterranean and the Black Seas. Differentiation was observed between the Atlantic Ocean, and the Mediterranean Sea, TSS and the Black Sea based on Фst but not between Mediterranean and the Black Seas. For common dolphins, which have high dispersal potential, the protection of open seas and narrow seaways to enhance connectivity may be crucial.

我们的研究旨在评估黑海和土耳其海峡系统（TSS）中短喙普通海豚的种群连通性，进化历史和保护状况。我们还包括了来自大西洋和地中海的DNA序列，为我们的本地化研究提供了区域视角。从黑海，TSS和爱琴海的短喙普通海豚收集的37个样品中，分析了366个碱基对的线粒体DNA D环片段，揭示了13个单倍型，其中8个以前没有报道。在对GenBank上存档的样本进行分析时，发现该地区有89种不同的单倍型。单体型网络包含两个主要的外围群体，包括来自所有位置的个体。来自大西洋的单倍型散布在整个网络中，没有发现明显的种群分离。一些共有的单倍型可能表明从东大西洋到地中海的多方向殖民化事件。此外，一些分布较不广泛的单倍型表明通过直布罗陀海峡和TSS进行某种程度的较新的遗传连通性，并指出这些海峡在散发短喙普通海豚中的重要性。与大西洋相比，黑海，TSS和地中海西部的单倍型和核苷酸多样性值较低，这支持了大西洋人口向地中海和黑海的扩展。在大西洋和地中海之间发现了差异，TSS和黑海基于Фst，但不在地中海和黑海之间。对于具有高扩散潜力的普通海豚而言，保护公海和狭窄海道以增强连通性可能至关重要。