The Amundsen Sea region toothfish fishery has been ongoing since 2003. It is characterised by a highly variable pattern of fishing locations between year, combined with highly aggregated catches on specific seamounts.
Despite best efforts, structured fishing has achieved tagging data that might be adequate to derive local estimates of abundance for Research Block 882_2 and Seamount 882H_1 only, with limited tag recaptures elsewhere. Even in those areas the tag recapture rates have been highly variable, which might limit the usefulness of those data. As a result, a stock assessment of toothfish in the Amundsen Sea region is currently not available.
Unstandardised catch rates have been generally stable or increasing in all areas apart from Research Block 882_2 and Seamounts 882H_9 and882H_10. These areas warrant further scrutiny, particularly since Seamount 882H_9 has been fished in the last three years as a result of the imposed structured fishing.
We recommend that the structured fishing along with the delayed start of the season in 88.2H, as is currently required by CM 41-10 (2022), be continued, to improve mark recapture data and to better index the biomass for the seamount complex.
No recent age frequencies are available for the Amundsen Sea region. We recommend that the multi-national effort to read otoliths and develop a unified dataset for this area be carried on.