We summarise fishing catch and fishing effort in the Ross Sea region (Subarea 88.1 and Small-Scale Research Units 88.2A-B) together with biological characteristics of the catch of Antarctic toothfish (Dissostichus mawsoni) through the 2024–25 fishing season. The Ross Sea fishery has been in operation since 1997. Over that time, well over 800 000 toothfish have been measured, 200 000 toothfish otoliths collected, and 30 000 otoliths aged. Over 78 800 toothfish were tagged and over 5000 recaptured.
The implementation of the Ross Sea region Marine Protected Area (RSrMPA) from 1st December 2017 has concentrated subsequent fishing on the continental slope south of 70° S, with recent fishing effort extending in SSRUs 88.2A-B. The Ross Sea fishery in 2025 was characterised by a continued increase in the number of vessels taking part in the fishery. This increase, combined with the introduction of the RSrMPA has resulted in the following patterns.
The N70 fishery in recent years was not only characterised by an increase in the number of vessel fishing but also by a continued expansion east where higher catch rates could be achieved. As a result, the N70 fishery in 2025 was only a few days long and the catch limit was exceeded by over 50%. The expansion east into higher catch rate areas also resulted in a strong increase in the CPUE in recent years and a reduction in the tag recapture rates, which are not deemed to represent the underlying biomass.
The S70 fishery has been characterised by an increase in the density of effort, tag recapture rates, duration of the fishery and a reduction in the CPUE and tag-based Chapman estimates of abundance over time. These patterns are consistent with higher localised exploitation rate of this area, which was a predicted outcome of the RSrMPA but are unlikely to represent the underlying population as they only represent a small portion of the likely extent of toothfish in the Ross Sea.
The tag recapture rate of toothfish in the SRZ has dropped to below 1% since the inception of the RSrMPA, consistent with its aims of reducing fishing intensity in this area (CM-91-05 paragraph 5 iii).
These results indicate the importance of continuing the spatial and temporal investigation of this fishery. Fully spatio-temporal CPUE standardisation models will be developed to that effect.
Age frequencies and population modelling have shown periods of strong recruitment over the duration of the fishery, and the 2025 Ross Sea shelf survey has indicated that another period of strong recruitment has likely begun.