At its annual meeting in 2016, WG-EMM recalled its obligation to review and advise on Conservation Measure 51-07, which is due to lapse at the end of the 2015/16 fishing season, and presented its discussions on this subject in paragraphs 2.201 to 2.244 of its WG report. WG-EMM recommended that work be undertaken to further develop a risk assessment approach to spatially subdivide the trigger level through an e-group and to deliver these outputs to Scientific Committee. The risk assessment approach for subdividing the trigger level in CM 51-07 aims to minimise the risk to predator populations, in particular land-based predators, of being inadvertently or disproportionally affected by the krill fishery. It also takes account of the desirability of different areas to the fishery and for management. The overall risk of localised effects on predators can also be calculated for a known or nominated distribution of catches across the region. It can be used to compare alternative fishing patterns in order to help minimise risk. For example, the overall risk could be reduced by spreading the fishery further, creating buffer zones or having seasonal closures to minimise overlap between predators and the fishery at critical times. This paper provides the first part of a contribution to the required review of CM51-07 in 2016 and provides a risk assessment method for distributing the trigger level to reduce the risk of disproportionate effects on predators in local areas. It also provides the data to be used in the risk assessment. The assessment and results are presented in a second paper.