Knowledge of genetic structure at the finest level is essential for the conservation of genetic resources. Despite no visible barriers limiting gene flow, significant genetic structure has been shown in marine species. The common cockle (Cerastoderma edule) is a bivalve of great commercial and ecological value inhabiting the Northeast Atlantic Ocean. Previous population genomics studies demonstrated significant structure both across the Northeast Atlantic, but also within small geographic areas, highlighting the need to investigate fine-scale structuring. Here, we analysed two geographic areas that could represent opposite models of structure for the species: (1) the SW British Isles region, highly fragmented due to biogeographic barriers, and (2) Galicia (NW Spain), a putative homogeneous region. A total of 9250 SNPs genotyped by 2b-RAD on 599 individuals from 22 natural beds were used for the analysis. The entire SNP dataset mostly confirmed previous observations related to genetic diversity and differentiation; however, neutral and divergent SNP outlier datasets enabled disentangling physical barriers from abiotic environmental factors structuring both regions. While Galicia showed a homogeneous structure, the SW British Isles region was split into four reliable genetic regions related to oceanographic features and abiotic factors, such as sea surface salinity and temperature. The information gathered supports specific management policies of cockle resources in SW British and Galician regions also considering their particular socio-economic characteristics; further, these new data will be added to those recently reported in the Northeast Atlantic to define sustainable management actions across the whole distribution range of the species.

最精细水平的遗传结构知识对于遗传资源的保护至关重要。尽管没有明显的障碍限制基因流动，但海洋物种中已经显示出重要的遗传结构。普通鸟蛤（Cerastoderma edule）是一种栖息在东北大西洋的具有巨大商业和生态价值的双壳类动物。先前的群体基因组学研究表明，在整个东北大西洋以及较小的地理区域内都存在显着的结构，这凸显了研究精细结构的必要性。在这里，我们分析了两个可以代表该物种结构相反模型的地理区域：（1）不列颠群岛西南部地区，由于生物地理障碍而高度分散，以及（2）加利西亚（西班牙西北部），一个假定的同质地区。通过 2b-RAD 对来自 22 个自然床的 599 个个体进行了基因分型的总共 9250 个 SNP 用于分析。整个SNP数据集大部分证实了之前与遗传多样性和分化相关的观察结果；然而，中性且不同的 SNP 异常数据集能够消除构成这两个区域的非生物环境因素的物理障碍。虽然加利西亚表现出同质结构，但不列颠群岛西南部地区被分为四个与海洋特征和非生物因素（例如海面盐度和温度）相关的可靠遗传区域。收集到的信息支持英国西南部和加利西亚地区的鸟蛤资源的具体管理政策，同时考虑到其特定的社会经济特征；此外，这些新数据将添加到最近在东北大西洋报告的数据中，以确定该物种整个分布范围的可持续管理行动。