Abstract
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.