The grey rockcod (Lepidonotothen squamifrons) was fished to commercial extinction on the Kerguelen Plateau by unregulated fishing during the 1970s/80s. Since the mid-1990s little work has been performed to assess the status of this species within the Heard Island and McDonald Island region (CCAMLR Division 58.5.2). This study has updated a range of biological parameters such as growth, maturity, condition, selectivity and age structure. Using otoliths, maximum age estimates have increased by 5 years to 24. Through the mapping of abundances the presence of three distinct geographical populations were elucidated for the first time.