McKeown Niall J, Lebigre Christophe, van der Kooij Jeroen, Huret Martin
Department of Life Sciences Aberystwyth University Aberystwyth Ceredigion, Wales UK.
DECOD (ecosystems and sustainability), Institut Agro, IFREMER INRAE Plouzané France.
Evol Appl. 2025 Apr 1;18(4):e70080. doi: 10.1111/eva.70080. eCollection 2025 Apr.
The European sardine () sustains some of the most important East Atlantic fisheries and is exhibiting pronounced phenotypic and distributional changes linked to environmental changes. The application of high-resolution genomic methods is recommended to provide insights into population demographics and patterns of ecological and evolutionary diversification. This study performed genome wide SNP analysis of samples collected across understudied NE Atlantic waters as well as geographical outgroup samples from Morocco and the Western Mediterranean. The data revealed pronounced differentiation of three regional groups (NE Atlantic, Morocco, and Western Mediterranean) that can be linked to glacial vicariance and contemporary dispersal limitations. Structuring was also apparent at outlier loci adding to evidence that genome architecture and non-neutral processes are influencing sardine populations at various spatial scales. The highly resolved Morocco group may be a previously undescribed and localized lineage and confirms complex stock structure along the North African coast. Among the NE Atlantic samples, genome wide patterns confirm restricted gene flow between Biscay and North Sea sardine with signatures of isolation by distance. , individual assignment, and introgression tail analyses of outlier loci revealed further structuring and identify a North Sea-Eastern Channel group distinct from a Bay of Biscay-Celtic Sea-Western Channel group. This pattern contradicts current management boundaries and indicates that increasing sardine numbers in the North Sea reflect an expansion of an eastern English Channel-North Sea fringe population. While this confirms the ability of the species' northern peripheral populations to expand in response to changing conditions, the genetically differentiated southern populations may differ in this regard. Overall, this study adds to a developing genetic framework for understanding sardine biocomplexity and provides resources for management.
欧洲沙丁鱼支撑着东大西洋一些最重要的渔业，并且正呈现出与环境变化相关的显著表型和分布变化。建议应用高分辨率基因组方法来深入了解种群统计学以及生态和进化多样化模式。本研究对在研究较少的东北大西洋水域采集的样本以及来自摩洛哥和西地中海的地理外群样本进行了全基因组SNP分析。数据揭示了三个区域组（东北大西洋、摩洛哥和西地中海）的显著分化，这可能与冰川隔离和当代扩散限制有关。在异常位点也出现了结构分化，这进一步证明基因组结构和非中性过程正在不同空间尺度上影响沙丁鱼种群。高度分化的摩洛哥组可能是一个此前未被描述的局部谱系，并证实了沿北非海岸复杂的种群结构。在东北大西洋样本中，全基因组模式证实了比斯开湾和北海沙丁鱼之间基因流受限，存在距离隔离的特征。此外，异常位点的个体分配和基因渗入尾部分析揭示了进一步的结构分化，并识别出一个与比斯开湾 - 凯尔特海 - 西海峡组不同的北海 - 东海峡组。这种模式与当前的管理边界相矛盾，表明北海沙丁鱼数量的增加反映了英吉利海峡东部 - 北海边缘种群的扩张。虽然这证实了该物种北部边缘种群有能力响应变化的条件而扩张，但遗传上有差异的南部种群在这方面可能有所不同。总体而言，本研究为理解沙丁鱼生物复杂性增添了一个不断发展的遗传框架，并为管理提供了资源。
