Antarctic Toothfish (Dissostichus mawsoni) is one of the target species that CCAMLR sets catch limits in the Southern Ocean. Due to their broad distribution relating to their life cycle and difficulties of in situ observations, life cycle with their spatial and temporal distribution is yet to be fully understood. Especially in early life stage, the process of successful egg/larval transport pattern from spawning ground to nursery ground is poorly known in the East Antarctic region. This project investigates the transport pattern of egg/larvae of toothfish using particle tracking scheme uses more than 10 years unique satellite product data and ocean model output data. This work examines not only passive particle drift but also the effects of multiple physical and biological factors (such as eddy, sea ice, egg buoyancy and swimming activity of larvae) on their distributions. Using this sensitivity analysis, we explore possible transport process of egg/larvae in the East Antarctic region and it will contribute to developing CCAMLR’s stable management of Antarctic Toothfish.

To achieve the milestone “Updating biological parameters for the population, suitable for inclusion in CASAL: Age Length Key (ALK), growth curves, maturity ogives” (SC-CAMLR-37 Report, para 3.130), this paper represents the updated length-weight relationship, growth curve, ALK, and maturity ogives as biological parameters of Dissostichus mawsoni at Subarea 48.6 up to the 2017/18 fishing season collected from a collaborative research program among Japan, South Africa, and Spain.

Due to the lack of sufficient aging data, it is not possible at present to calculate annual and sex-specific growth curve, ALK, and maturity ogive. Continuing both data collection and otolith aging will lead to the implementation of CASAL stock assessment with rich biological information.

The Scientific Committee considered the assessment of Dissostichus spp. in data-poor fisheries to be of a high priority (SC-CAMLR-XXIX, paragraphs 3.125 to 3.145). The use of different gear types for the implementation of a multi-Member research on   Dissostichus spp.  in East Antarctica (Divisions 58.4.1 and 58.4.2) carried out in the seasons 2011/12 - 2017/18  is a critical factor for their   efficiency and reliability. In the context of the discussion of the Scientific Committee (SC-CAMLR-XXXVII p.3.338-3.144) related to the methodical  problems and analysis issues of  the above said research   we propose the research program on Dissostichus spp by the  multi-vessels  in Divisions 58.4.1 and 58.4.2 for seasons 2019/20-2021/22 based on standardization of sampling longline gear  and survey design.

Russian program provides proposals to continue investigations of the species composition, biology, life cycle, distribution and structure of craboids stock (Anomura, Decapoda) and assess their resource potential in the Bellingshausen Sea (Subarea 88.3) and Amundsen Sea (Subarea 88.2). Russian pilot research program of craboids (Anomura, Decapoda) in the Antarctic Pacific (Subareas 88.2 and 88.3) were carried out in March 2019 (vessel Volk Arctic) in full compliance with the Russian program (WGSAM-18/06; WGFSA-18/32 Rev.1) and recommendations of the Scientific Committee (SC-CAMLR –XXXVII, paragraph 4.3 (i-viii)).

Russian Federation is going to continue investigation  of life –cycle and resource potential for Dissostichus spp. in Ross Sea. This paper presents the   research program in the frame of the Research and Monitoring Plan for RSRMOR. 

The research program shall be conducted in the Special Research Zone during 2019 - 2027 or the first reference period for existence of the RSRMPA.   This program provides possibility   for collaborative investigations in the Special Research Zone by Russian vessels and vessel from other CCAMLR members.

The Oceanographic study of the Subarea 48.6 on the SST, SIC, PST, current and wind vector was conducted. The lower SST corresponded to the higher SIC and vice versa. The PST  indicates  the  mixed  layer  depths  in  research  block5.  The  currents  around the research block 4 and 5 were indicated. It is found out that there is a relationship between the SST and the wind. The CTD vertical profile data collected by Tronio should contribute  to  developing  this  oceanographic  study.

An Analysis of the sea ice concentration (SIC) in research blocks 2,3,4, and 5 of subarea 48.6, with sea surface temperature(SST) and statistical models is presented. 

For research block 4, the SIC in 2019 was the highest for the last 4 years (2016-2019). For research block 5, the SIC in 2019 was also as high as in 2016 but around the west of block 5 the SIC in 2019 was much lower than in 2016. The lower SST anomalies corresponds to the higher SICs in 2019 both in research blocks 4 and 5 and vice versa. The chart of the SIC as per HYCOM corresponds well to the SIC derived from data by the University of Bremen(AMSR2). Repeated Accessibility(RA) in research blocks 4 and 5 with statistical models, where the limit of navigability for fishing vessels is set at 20 % SIC, was calculated. It should become possible to predict the accessibility to research blocks 4 and 5 with the model in cooperation with HYCOM.

The toothfish catch estimation on board of fishing vessels at the CCAMLR area is being done often in a difficult weather conditions at sea, which can cause a negative impact on the measurement equipment. Besides, until today the “green weight” of the toothfish catch on fishing vessels was not estimated directly, but by calculation, based on the weight of the production using appropriate conversion factors (coefficients) determined experimentally. These circumstances, together with mistakes in the informational communication on board of fishing vessels, can lead to a significant distortion of fishing catches in operational statistical reports. The document analyzes the significance of all the critical factors and offers recommendations on how to minimize the distortions in catch estimation on board of fishing vessels.

Catch rates or catch per unit of effort (CPUE) are used for data-poor exploratory fisheries without integrated assessments in the CPUE by seabed area method to estimate stock biomass in the interim of collecting sufficient tag recaptures. Here, we address the two questions: (1) which unit of effort should be used for catch rates in mixed longline fisheries, and (2) how do different parameters such as gear type, vessel, fishing season, month, bait, fishing depth and area affect estimates of trend and magnitude of catch rates.

Using data from the Ross Sea Antarctic toothfish fishery, we compared effort units including length of line (km), total number of hooks per line, and a combination of total number of hooks per line for autoline and Spanish line and total number of clusters for trotline (hooks/cluster) with Generalised Linear Models (GLMs). The model with total hook numbers was preferred with the lowest Akaike’s Information Criterion (AIC), however standardised catch rates over the fishing season differed little between the models with the three effort units, so the effect of the choice of effort unit on the estimated standardised catch rates is small.

The parameters with the largest effects in the catch rate models were vessel, gear and bait, with vessels showing by far the largest effect size. This confirms previous advice that research fishing is conducted with a high level of spatial and temporal overlap between vessels and gear types to allow for a meaningful standardisation of variables such as catch rates.

To assist in future quality checking of data, we also recommend a new reporting field in the C2 form for the number of droplines per line deployed.

Robust stock assessments and catch limits for Dissostichus mawsoni according to CCAMLR decision rules remain to be determined for Divisions 58.4.1 and 58.4.2, and precautionary management arrangements are in place as set out in Conservation Measures 41-11 and 41-05. WG-FSA-16/29 and WG-FSA-18/59 outlined the multi-member toothfish exploratory fishery research plans for these Divisions, including research objectives, methods and milestones in accordance with ANNEX 24-01/A.

In this paper we report on exploratory fishing activities undertaken by Australia, France, Japan, Republic of Korea and Spain between the 2011/12 and 2018/19 fishing seasons, including the quantity of data and samples collected, as per Milestone 1.1 of WG-FSA-18/59. Reports relating to other research milestones for 2019 will be submitted to WG-FSA-19. The summaries provided herein were generated using an R-Markdown document which is available to Members to facilitate reporting on data collection in CCAMLR's Exploratory Fisheries.