The Amundsen Sea region toothfish fishery has been operating since 2003. In 2015, a research plan was developed to estimate the toothfish biomass the area, particularly in the South.

The biological characterisation of the fishery shows a truncation of the right-hand limb of the age distribution between 2004 and 2014. No age data are currently available after 2014. We recommend that further ageing of toothfish in the ASR be made a priority to develop annual age-length keys and age frequencies. We further recommend that catch limits in the ASR be calculated following the trend analysis rules developed by WG-FSA for research blocks (CAMLR-XXXVI 2017, Annex 7, paragraph 4.33). However, the calculations are slightly different as the effective tag release and recaptures (to account for different levels of tag survival and tag detection by individual vessels) can be applied:

• 882H: 177 t based on a one-year Chapman estimate using effective tagging survival and tag detection rates and allowing a maximum of 20% change in the catch limit from 200 t.
• Research block 882_1: 240 t based on CPUE by seabed area and allowing a maximum of 20% change in the catch limit from 200 t.
• Research block 882_2: 240 t based on a one-year Chapman estimate using effective tagging survival and tag detection rates and allowing a maximum of 20% change in the catch limit from 200 t.
• Research block 882_3: 160 t based on CPUE by seabed area and allowing a maximum of 20% change in the catch limit from 200 t.
• Research block 882_4: 214 t based on CPUE by seabed area and allowing a maximum of 20% change in the catch limit from 200 t.

We note that research blocks 882_1, 3 and 4 use CPUE by seabed area analogy and can also be calculated by CCAMLR Secretariat using the agreed method for research blocks in other areas. As 882H and research blocks 882_2 use effective tagging survival and effective tag detection rates, we have presented Chapman estimates for these research blocks.

We note that consideration of the spatial overlap of tag releases and subsequent effort to recapture tagged fish remains an issue for tag-based estimations of biomass and we note that improved analytical methods need to be developed. Individual research block catch limits (rather than an overall catch limit for all southern research blocks) should improve the ability for information to be obtained from these research blocks, especially blocks 1 and 4, where sea ice dynamics can prevent access early in the season.

This report summarises the toothfish fishery in the Ross Sea region (Subarea 88.1 and SSRUs 88.2AB) together with biological characteristics of the catch of Antarctic toothfish through the 2018 season. Despite 2018 being the first year of implementation of the Ross Sea region Marine Protected Area, most of fishing effort was carried out in the historically fished areas. There was a small amount of effort in the northern area of SSRU 88.2A, which was opened to the exploratory fishery with the introduction of the Ross Sea region MPA. A small amount of the catch historically taken from areas bounded by the SRZ and the area inside the General Protection Zone of the Ross Sea region MPA was taken in the slope area outside the MPA and south of 70°S.

The median and 90^th percentile scaled length distributions showed no trend over time in the shelf, slope or northern areas. Patterns in the age frequency of the catch showed no consistent pattern of trend through time, but showed interannual variability. This was likely driven by spatial variability in the locations of fishing effort, most likely driven by ice conditions and vessel choice of locations. The ratio of males to females showed some suggestion of a weak trend with a small increase in the proportion of males over time in all three areas. The number of fish recaptured in 2018 was similar to that recaptured in previous years, with some fish recaptured after 14 years at liberty.

Total numbers of Antarctic toothfish collected in the CCAMLR Conservation Zone were 600 fish which consist of 306 fish from the 58 area and 294 fish from the 88 area during February through March, 2016. Female ratios were found to be 0.49 in both areas, showing higher female occurrence with higher total length. The ratio of female among the 857 specimens of Antarctic toothfish collected from the 58.4.1 area and 88.3 area within the CCAMLR Conservation Zone during December, 2016 to March, 2017 was found to be 0.53, and displayed the tendency of increase with increase in the total length 140 cm. The type of ovarian development of Antarctic toothfish was group-synchronous type. The results in 2016 are as follows. The average gonadosomatic index of the fish was found to be 2.16, with 2.57 for female and 1.77 for male. Frequency of ovarian development stages of Antarctic toothfish showed the highest proportion with 41.9% at the mature stage, and followed by the growing stage with 40.6% and ripe stage with 17.5%. The group maturity in accordance with the total length (TL) categories of Antarctic toothfish displayed 50% for female in larger than TL 120.1 cm categories and almost 100% for male in larger than TL 180 cm categories. And the results in 2017 are as follows. The average gonadosomatic index of the fish was found to be 3.88, with 4.18 for female and 3.53 for male. Frequency of ovarian development stages of Antarctic toothfish showed the highest proportion with 62.7% at the mature stage, and followed by the ripe stage with 19.9% and growing stage with 17.5%. The group maturity in accordance with the total length (TL) categories of Antarctic toothfish displayed 50% for female in larger than TL 130.1 cm categories and almost 100% for male in larger than TL 170 cm categories. The main spawning season is estimated after May.

The paper provides a brief history and review of the CCEP as well as outlining the flow of the procedure. The paper highlights current implementational practice, historical work in development, and evolution of CM 10-10 since adoption.

The CDS was effectively implemented in 2018 by 21 Member States, 3 Acceding States and 1 NCP. CDS reports of catches outside the Convention Area have increased in 2018. The Secretariat contacted 9 NCPs to seek their engagement in the CDS in 2018.

A collaborative research program is being undertaken by Japan and South Africa since 2013 to enhance data collection and analysis in the Subarea 48.6. In the last WG-SAM Spain has proposed to join the former proposal in order to contribute to the data acquisition and to speed up the integrated assessments of the D.mawsoni stock in this subarea.

The Working Group recommended that Spain should coordinate its research efforts with Japan and South Africa and encouraged the submission of a multi-Member proposal for consideration at WG-FSA (pargraph 6.29).

The three-member research proposal for 2018/19 season is presented to ensure continuity of previous research activities. Data and investigations about the population structure and various demographic parameters of Antarctic toothfish (Dissostichus mawsoni) using trotline (JPN and ZAF) and Spanish longline (ESP) gears, established tagging techniques, pop-up tags and genetic analysis will provide the basis for the development of spatial population models and assessments in support of management advice. An Integrated Stock Assessment (ISA) of this species is expected to be done by 2021/22.

Additional outcomes of the research include documenting relative abundance of Antarctic and Patagonian toothfish, tagging toothfish for biomass estimation and for stock linkage studies, and collecting information on distribution, and life history of bycatch and Vulnerable Marine Ecosystems (VMEs).

Efforts to engage NCPs have so far met with modest success. The Secretariat proposes to work with Members on a new approach in 2019, targeting NCPs that are important in toothfish trade with Members, and working with those Members to approach the NCPs.