DNA barcoding reveals the presence of Whitson's grenadier, Macrourus whitsoni, in sub-Antarctic waters of South Georgia, Southern Ocean

Macrourid species constitute the main bycatch in Southern Ocean toothfish longline fisheries. We report the first confirmed record of Whitson's grenadier, Macrourus whitsoni, in the South Georgia toothfish fishery. Mitochondrial cox1 DNA barcoding confirmed its presence in bycatch samples collected around South Georgia and the northern South Sandwich Islands, with approximately 1% divergence from its congener, M. caml. Haplotype network analysis revealed a single dominant haplotype and two peripheral haplotypes, indicating a well-connected Southern Ocean stock. These findings highlight the need for accurate species-level identification to inform effective fisheries management.