The Spatial Overlap Analysis (SOA, previously Risk Assessment) forms part of the three-part management approach endorsed by CCAMLR in 2019. The purpose of the SOA includes the spatial and temporal allocation of a catch limit amongst management units and seasons. We have implemented the SOA for the 2024 Harmonisation Symposium’s “preferred option” for spatial management in subarea 48.1 (a combination of management units, Seasonal Protection Zones which are closed to fishing for part of the year, and General Protection Zones which are closed to fishing year-round). Depending on the parameterisation, between 30% and 62% of the catch is allocated to the Gerlache Strait management unit. Elephant Island, Bransfield Strait, and Drake Passage are also each allocated more than 10% of the catch under “baseline” scenarios.
We provide further information about the 2024 Harmonisation Symposium’s “preferred option” for catch limits in subarea 48.1 which are based on two separate processes that made contrasting assumptions about the spatial distribution of krill biomass and which may assign a higher krill catch to the “core” management units than intended under the revised krill fishery management approach. Our results include further sensitivity analyses and emphasise the influence of input assumptions on the SOA outputs. We summarise the limitations and caveats identified in previous contributions to SC-CAMLR and its working groups and we suggest that further consideration of inputs and limitations is a pre-requisite for future application of the SOA.