The minimum total breeding seabird biomass in the Australian Antarctic Territory was estimated to be 9,971.1 t, dominated by Emperor Penguins, 3,863 t (38.7%) and Adélie Penguins, 5,825 t (58.4%). The 5° sector between 75°E and 80°E, in south-east Prydz Bay, held 35% of the total AAT seabird biomass. Prydz Bay has been shown to be an area of high productivity, and the concentration of seabird biomass in this area reflects the high biomass of prey species and the availability of nesting habitat in the Vestfold Hills, a large ice-free area adjacent to Prydz Bay. Activities associated With research stations are believed to be the only factors that have impacted on breeding seabird populations to date, but minerals activities, tourism and support facilities, and a Krill fishery, are future conservation issues that will have an impact on this major concentration of seabird biomass in East Antarctica.