Genome-wide analyses indicate a lack of population structure in Antarctic toothfish (Dissostichus mawsoni) in the Atlantic Sector of the Southern Ocean (CCAMLR Subarea 48.6).

The Antarctic toothfish (Dissostichus mawsoni), a notothenioid, is endemic to the Southern Ocean and supports economically important long line fisheries. Stock discrimination is a central component of fisheries management which embraces the recognition of self-sustaining components within natural populations. The stock structure of Dissostichus mawsoni in CCAMLR subarea 48.6 is not known and thus presents an impediment to its fisheries management. This study employs a genotyping-by-sequencing approach to examine population genetic structure among samples of D. mawsoni taken from within the CCAMLR subarea 48.6 region. 5020 Single Nucleotide Polymorphisms (SNPs) were genotyped across samples from 87 individual fish, with no evidence for genetic structure  consistent with a signal of panmixia inferring ongoing gene flow across the region. The results are discussed with recourse to whether the patterns indicate common spawning areas but then demographic separation in adults.