In 2016, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) adopted what was then the world’s largest marine protected area (MPA), the Ross Sea region marine protected area (RSrMPA). One fishery currently operates in the Ross Sea region (RSr) and targets Antarctic toothfish (Dissostichus mawsoni), which has an ontogenically-segregated life-history spanning both the RSrMPA and areas fully open to fishing.
We evaluate the impacts of the RSrMPA for the species using the Spatial Population Model (SPM), a spatially-explicit population model for RSr Antarctic toothfish. We considered six alternative scenarios that consisted of the combination of two spatial management scenarios (MPA versus no-MPA situations) and three different spatial patterns of future fishing. The same CCAMLR decision rules were employed to determine a total catch limit in each case.
Our results indicate that access to productive fishing grounds continues to exist, the total catch limit and fishery catch rates were not impacted, and the RsrMPA specific objectives relating to Antarctic toothfish are being met. The no-take fraction of the RSrMPA (the “General Protection Zones”) protects areas of ecological importance for the species (juvenile settlement areas, migration corridors for maturing individuals, and adult feeding areas), while the partial-take fraction of the MPA (the “Special Research Zone”) allows for the continuity and integrity of a critical tagging program.
Our modelling framework provides valuable information to inform resource management at CCAMLR and could be employed to explore other proposed large-scale MPAs in the Southern Ocean.
We recommend that future studies update the environmental layers that drive fish movement in the SPM. In particular, we recommend that future studies refine the bottom depth and hill habitat data that are used in the SPM, specifically in the northern area where the spatial scale makes the depth approximation inaccurate.