The genetic structure of Cerastoderma edulis suggests two separated populations between the southwestern (Iberian and Scottish) and northern (North Sea and Scandinavian) groups of populations in the NE Atlantic. 
However, another study revealed the existence of significant genetic structure in the southern groups; all but one locality from the Iberian Peninsula were genetically homogeneous, while more remote localities from France, The Netherlands, and Scotland were significantly different from all other localities (Krakau et al. 2012)(Martínez et al. 2013). An Irish management unit is here considered as no assessment is known to exist.