At WG-SAM-15, it was noted that 5 members, Australia, France, Japan, Korea and Spain had notified to conduct research in the exploratory toothfish fisheries off East Antarctica, covered by CCAMLR Divisions 58.4.1 and 58.4.2. This proposal seeks to establish an arrangement whereby all notified members have a catch allocation to undertake research, thereby avoiding Olympic fishing.

Incidence of odontocete depredation, involving sperm whales (Physeter microcephalus) and orcas (Orcinus orca) has been reported in nearly all of the Patagonian toothfish (Dissostichus eleginoides) longline fisheries in the Southern Ocean (Moir Clark and Agnew 2010, Tixier et al 2010, Soeffker and Tixier 2015, Söffker et al. 2015). The first reports of odontocete depredation in the Division 58.5.2 fishery date from 2011, and incidences have been reported in every season thereafter. The majority of  reports involve sperm whales, with a single sighting of orcas to date. There is a strong seasonal pattern to sperm whale presence, with depredation events confined to the months April-July, despite longlining activity occurring April-November. Currently, all vessels mitigate depredation by hauling lines once sperm whales are sighted, and steaming over 50 nautical miles before resetting gear. A collaborative project with depredation experts from France is currently being developed to monitor depredation behaviour across the Kerguelen Plateau and explore options for long term mitigation

This paper presents an updated assessment for the Patagonian toothfish (Dissostichus eleginoides) fishery at the Heard Island and the McDonald Islands in CCAMLR Division 58.5.2 with data until end of July 2015. The updated assessment model is based on the best available estimates of model parameters, the use of abundance estimates from a random stratified trawl survey (RSTS), longline tag-release data from 2012-2014 and longline tag-recapture data from 2013-2015, and auxiliary commercial composition data to aid with the estimation of year class strength and selectivity functions of the trawl, longline and trap sub-fisheries.

Compared to the 2014 assessment that was accepted by WG-FSA-14 to be used for management advice, this assessment takes into account the recommendations of WG-FSA-2014 and WG-SAM-2015, and incorporates (a) new fishery observations up to 2015 including new ageing data from the 2014-2015 RSTS and commercial fishery from 2009-2014, (b) tag-releases from 2014 and tag-recaptures from 2014 (complete) and 2015 (partial), (c) an updated growth model, (d) changes in priors for survey catchability q, unfished spawning biomass B₀ and year class strength, and (e) a split of the trawl sub-fishery into two periods. All model runs were conducted with the CASAL version 2.30-2012-03-21 that was agreed on by WG-SAM-14.

The updated assessment model leads to a smaller estimate of the virgin spawning stock biomass B₀ than that obtained in 2014, with an MCMC estimate of 87 077 tonnes (95% CI: 78 500-97 547 tonnes). Estimated SSB status in 2015 was 0.64 (95% CI: 0.59-0.69). Using this model, a catch limit of 3405 tonnes satisfies the CCAMLR decision rules. Similarly to the 2014 assessment, the projected stock remains above the target level for the entire projection period.

CASAL files are available here.

The grey rockcod (Lepidonotothen squamifrons) was fished to commercial extinction on the Kerguelen Plateau by unregulated fishing during the 1970s/80s. Since the mid-1990s little work has been performed to assess the status of this species within the Heard Island and McDonald Island region (CCAMLR Division 58.5.2). This study has updated a range of biological parameters such as growth, maturity, condition, selectivity and age structure. Using otoliths, maximum age estimates have increased by 5 years to 24. Through the mapping of abundances the presence of three distinct geographical populations were elucidated for the first time.

The annual Random Stratified Trawl Survey was undertaken within Division 58.5.2 during May 2015. Recent work which is presented here has allowed for many of the biological parameters of Channichthys rhinoceratus to be updated from previous assessments (Constable et al. 1998) and many parameters to be calculated which were previously unknown for the area within Division 58.5.2. This paper provides both short (2 years) and long term (20 years) projections of unicorn icefish structure, abundance and yield for the area of Division 58.5.2 to the west of 79°20’ E using standard CCAMLR methods. Short term projections indicate 2208 t for the 2015/16 season and 1689 t for the 2016/17 season, while long term projections (20 year) indicate sustainable yield of 1663 t.

In New and Exploratory fisheries for toothfish, mark-recapture plays a critical role to estimate biomass in the initial stage of developing an assessment. This short paper describes the use of the R package tagr to obtain Petersen / Chapman estimates of abundance. The package implements a non-parametric bootstrap to obtain confidence intervals from single release tag-recapture data.

We recommend that WG-FSA encourage Members to provide estimates of uncertainty associated with indicative biomass estimates, as often calculated for exploratory fisheries without integrated stock assessments. We also recommend that additional functions associated with mark-recapture analysis within CCAMLR’s fisheries be developed and made available to Members.

Season extension trials occur step-wise in the longline fishery for Dissostichus eleginoides in Statistical Division 58.5.2.  This paper presents results of trial fishing season extensions for the periods between 15 and 30 April, and between 1 and 14 November, during 2013/14 and 2014/15.  Based on the results, it proposes a new step-wise trial pre-season extension of the longline fishing season to include the period between 1 and 14 April with day/night setting allowed.  It also proposes that conditions be established as the basis for a further step-wise trial post-season extension of the longline fishing season.  Subject to these conditions being met, the post-season is proposed to be extended to include the period between 15 and 30 November with day/night setting allowed.  Australia will continue to report to SC‑CAMLR each year concerning the progress and outcomes of each step-wise season extension trial.

Age determination of the Patagonian (Dissostichus eleginoides) and Antarctic toothfish (Dissostichus mawsoni) is conducted using otoliths, collected while carrying out the scientific program on board the Ukrainian vessel “Simeiz” in the Northern part of Weddell Sea (statistical Subarea 48.2) in March 2015. 124 otolith pairs of Dissostichus mawsoni and 87 otolith pairs of Dissostichus eleginoides were sampled; one otolith from each pair was used for age determination. Preliminary results of age determination of the caught fish showed that, in the studied fishing area, specimens of older age groups prevailed: their age ranged from 15 to 35 years for both species.

During March-April 2015 Ukraine began the research within statistical subarea 48.2. The research activities on the assessment of the stock state of the Dissostichus spp species in subarea 48.2 will be carried out within three years. Implementation of the tagging program in the long-term prospective will provide the indicators for the procedure of abundance assessment of the studied species in this area based on the repeatedly caught tagged fish specimens according to the CASAL methodology. The certain number of the following bottom long line surveys are proposed to be conducted during March-April 2016. Investigated area will be demarcated on two blocks - Northern and Southern. During the season of year 2016 we propose to remain the majority of surveys in the Northern Block as were conducted in year 2015 in order to repeat them in the same coordinates. In the Southern Block where relatively high quantity of tagged fish were released we propose the creation of the new research block with another conditions of the investigation. On the four sea bottom risings, which are probably enough isolated from each other, we propose to conduct 25 sets. Proposed to tag 3 fish per ton in the Southern Block, remained the ratio 5 fish per ton in the Northern Block.

The stock abundance of Antarctic toothfish in Subarea 48.4 is estimated using tag based mark-recapture analysis. During WG-FSA-14 the recommendation was made that the stock should move from the Petersen estimation method to the use of the Chapman bias corrected estimator; a correction specifically developed to reduce estimation bias in populations with low recaptures, a feature typical of the data available for this species in 48.4. During a review of assessment methodology two main issues have been identified: the appropriate application of the method when applied to estimate low tag recapture rate population abundance, and the mis-identification of species at release. This paper presents a review of assessment data and methods in order to discuss and address the issues.