CCAMLR manages the krill fishery in Area 48 using a catch limit (the trigger level) which was established in 1991 based on the maximum catches reported for each subarea. Since that time the ecosystem has undergone rapid environmental change. Several studies suggest that krill numerical density, demographic structure, distribution and availability to predators have also changed. These changes are consistent with global evidence of the ecological effects of environmental change. At the same time catches in Subarea 48.1 have increased beyond the maximum pre-1991 catch for that subarea which was used to set the trigger level. As a consequence of these major risk factors (increased catch levels in Subarea 48.1 and environmental stress on the krill stock), the need for precaution is likely to be greater now than when the trigger level was established. Ideally CCAMLR should establish a process for regularly reviewing whether its management of the krill fishery is suitably precautionary. At the very least Conservation Measure 51-07, which defines subarea catch limits and provides additional precaution, should be retained.