CCAMLR’s Scientific Committee and its working groups are developing a revised management approach for the Antarctic krill fishery in Subareas 48.1 to 48.4. A critical phase is the development of an interim approach that can be applied to Subarea 48.1 to update the measures within CM-51-07, which expires before the next (2022/23) krill fishing season. Progress has been made in terms of defining potential spatial management units, establishing biomass estimates for these units and identifying potential proportional catch allocations between them. Additional progress has been made in updating the Generalised Yield Model, which is used to compute precautionary harvest rates (i.e. the proportion of the krill biomass that can be harvested). However, agreement has not yet been reached on parameterisation of this model and so there is a need to make progress in the absence of formally agreed precautionary harvest rates.
Interim management options for Subarea 48.1 have already been proposed and it is possible to evaluate such options in terms of the implied harvest rates. This is possible because the proposed interim management options define catch limits (or allocations of a total catch limit) at the same spatial scale for which WG-ASAM has produced timeseries of biomass density estimates. The evaluation approach uses retrospective analysis to calculate the probability that harvest rates would exceed candidate precautionary levels. We demonstrate this approach and use it to evaluate two illustrative management options.