Data from: Atlantic mackerel population structure does not support genetically distinct spawning components

The Atlantic mackerel, Scomber scombrus (Linnaeus, 1758) is a commercially valuable migratory pelagic fish inhabiting the northern Atlantic Ocean and the Mediterranean Sea. Given its highly migratory behaviour for feeding and spawning, several studies have been conducted to identify populations, assess differentiation among spawning components and define species connectivity, as well as to understand possible adaptation linked to recent range expansion northwards. However, the resulting findings did not resolve questions about the presence of genetically distinct spawning components for the species in the northern Atlantic. The increasing use of reference genomes in population genetics studies has proven fundamental to investigate genomic markers/regions potentially linked to differences at finer scale. Here, we sequenced and annotated a high-quality genome of S. scombrus, for a final assembly of 741 Mb in size, which we have used to map Restriction-site-associated sequencing (RAD-seq) reads for SNP discovery and genotyping. Our results based on thousands of SNP markers show that the Atlantic mackerel consist of three previously known genetically separated units (Northwest Atlantic, Northeast Atlantic, Mediterranean), and provide no evidence for genetically distinct spawning components within, nor for further differentiation that could be used to redefine management boundaries.