Policy differences amongst CCAMLR Members are increasingly affecting decision-making with regards to management of Southern Ocean fisheries. Major differences reflect differing interpretations of the Convention’s primary objective: the conservation of marine living resources, where conservation includes rational use. The best available science historically informed decisions, but policy objectives are increasingly coming to the fore. Resolving how scientific evidence is used in decision-making is essential, given this has consequences for all management topics. In the southwest Atlantic, scientific evidence and how it is used is central to the controlled development of the Antarctic krill fishery. Much work has already been undertaken to allow catches to increase, but more is needed, including ensuring that, as yet untested, management procedures work as intended. Precautionary development should therefore now focus upon ensuring ecosystem resilience is not compromised. Generally, the area managed by CCAMLR experiences relatively light human pressures, yet with newly proposed krill catch limits, this is set to change. Before catches increase, appropriate ecosystem monitoring is needed, and spatial management tools agreed to ensure that biodiversity is adequately maintained, especially given regional climate change. Without such constraints, the krill fishery should not expand. An integrated programme could help CCAMLR adapt. In implementing this, CCAMLR should focus upon areas where economic interests are most intense, that is, over shelf areas and areas of elevated bathymetry. Large-scale remote areas with little economic interest should be set aside as closed areas, until such future time that CCAMLR has agreed appropriate ecological impact assessments and monitoring for these largely unexploited areas.