Data from: Spatial dynamics and mixing of bluefin tuna in the Atlantic Ocean and Mediterranean Sea revealed using next generation sequencing

The Atlantic bluefin tuna is a highly migratory species emblematic of the
challenges associated with shared fisheries management. In an effort to
resolve the species’ stock dynamics, a genome-wide search for spatially
informative single nucleotide polymorphisms (SNPs) was undertaken, by way
of sequencing reduced representation libraries. An allele frequency
approach to SNP discovery was used, combining the data of 555 larvae and
young-of-the-year (LYOY) into pools representing major geographical areas
and mapping against a newly assembled genomic reference. From a set of
184,895 candidate loci, 384 were selected for validation using 167 LYOY. A
highly discriminatory genotyping panel of 95 SNPs was ultimately developed
by selecting loci with the most pronounced differences between western
Atlantic and Mediterranean Sea LYOY. The panel was evaluated by genotyping
a different set of LYOY (n= 326) and from these 77.8% and 82.1% were
correctly assigned to western Atlantic and Mediterranean Sea origins,
respectively. The panel revealed temporally persistent differentiation
among LYOY from the western Atlantic and Mediterranean Sea (FST = 0.008,
p=0.034). The composition of six mixed feeding aggregations in the
Atlantic Ocean and Mediterranean Sea was characterized using genotypes
from medium (n = 184) and large (n = 48) adults, applying population
assignment and mixture analyses. The results provide evidence of
persistent population structuring across broad geographic areas and
extensive mixing in the Atlantic Ocean, particularly in the mid-Atlantic
Bight and Gulf of St. Lawrence. The genomic reference and genotyping tools
presented here constitute novel resources useful for future research and
conservation efforts.