We provide an update of the Bayesian sex and age structured population stock assessment for Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea region (Subareas 88.1 and SSRUs 88.2A–B), using catch, catch-at-age, and tag-recapture data from 1998 to 2017 and including the results from the Ross Sea Shelf survey from 2012 to 2017. The model estimates of unfished biomass and current status were higher than that from the 2015 assessment. This was likely driven by the revised estimates of the effective tagging survival and tag detection rates, both of which have decreased in the recent years. Sensitivity runs showed that the results were relatively insensitive to the use of a logistic ogive rather than a domed ogive for fishing selectivity.

Model runs showed that the data from the Ross Sea Shelf survey were required to reliably estimate relative year class strengths. Year class strengths were estimated from 2003 to 2011 and showed two strong year classes and two weak year classes.

Overall, model fits to the data were adequate, and, as in previous assessments, the mark-recapture data provided the most information on stock abundance. Markov chain Monte-Carlo (MCMC) diagnostics suggested no evidence of non-convergence in the key biomass parameters.

The precautionary yield, using the CCAMLR decision rules and two potential catch splits between the Shelf, Slope, and North areas of the Ross Sea region consistent with previous fishing activities and with the Ross Sea region MPA, was either 3234 t or 3258 t. This yield is higher than that specified for 2018 in CM 91-05, which states that “the total catch limit shall be fixed at a level within the range of 2583 to 3157 tonnes per fishing season, based on advice from the Scientific Committee in 2017, 2018 and 2019” (CM 91-05 paragraph 28 (i)).

As the precautionary yield estimate is higher than the range specified in CM 91-05 for 2018, we therefore recommend that the catch limit be set at 3 157 tonnes for the 2018 and 2019 fishing seasons as per CM 91-05.

Utilising the data collated by the United Nations Food and Agriculture Organisation’s GLOBEFISH unit, an analysis was conducted for the five -year period of 2012–2016 on the global trends of the toothfish trade and to assess the extent to which the Catch Documentation Scheme (CDS) for Dissostichus spp. Captures the global trade of toothfish.

The analysis showed that over this five-year period quantity of imports globally have seen an increase of 16.08% and exports have seen an increase in 15.54%. The average global unit value price of toothfish products has also shown an increase with imports increasing by 19.68% and exports by 24.58%. The United States of America (USA) were the largest importers accounting for 44.42% of the quantity. France were the largest exporters accounting for 16.63% of the quantity, closely followed by Chile (15.41%) and Mauritius (14.87%).

The application of the MPP methodology allowed for an estimation of global trade through utilising reported trade relationships. The MPP methodology estimated the USA as still the largest importer of quantity (29.72%), but a prevalence of imports in Southeast Asia with Viet Nam (10.82%) and Singapore (10.32%) making the top three importers. The largest exporters were estimated to be Australia (13.85%), Chile (13.62%) and Mauritius (9.45%).

This analysis demonstrated that over the five-year period the quantity of toothfish reported to the CDS is 2.70% higher then what States reported importing and 4.60% higher then what they reported to export. However, there are differences in the trade patterns between the two datasets so while the quantities may be similar, this is simply an artefact of the analysis as it is clear that there are differences between the two datasets.

This analysis contributes to the ongoing work of the Commission to improve the effectiveness of the CDS and detect, deter and eliminate IUU fishing. 

Following discussion at the Scientific Committee in 2016, we propose a process for independent review of CCAMLR integrated toothfish stock assessments based on the process used by the Center for Independent Experts (CIE, NOAA), and the benchmarking process used by ICES.

The Southern Ocean Observing System (SOOS) has developed a number of networks and products of importance to the work of CCAMLR. Through this paper, SOOS seeks to update SC-CCAMLR on this progress and invite collaboration towards delivery of networks and tools that will benefit both communities. SOOS encourages CCAMLR delegates to communicate with, and be involved in the SOOS regional networks that are coordinating and enhancing observational data collection and delivery. SOOS invites CCAMLR to contribute directly to the Database of Upcoming Expeditions to the Southern Ocean to facilitate international scientific collaboration. Further, SOOS requests input from SC-CCAMLR on the “SOOSmap” data discovery tool, including discussions on key data layers of interest to, and potentially provided by CCAMLR. These requests will form the foundation for discussions at the proposed joint workshop between SOOS and SC-CCAMLR (SC-CAMLR-XXXVI/BG/15).