The methodology of modern trawl surveys carried out the ICES responsibility area is discussed in the context of discussion at the Scientific Committee and the CCAMLR Commission in 2018 regarding the longline survey methodology in Division 58.4.1. It is shown that the methodology of modern bottom trawl surveys requires a standardized design of the spatial location of trawl samples and standard fishing gear as a data collection tool.    Moreover, the use of standard fishing gear should be accompanied by standard procedures for trawl adjusting and monitoring of its parameters. These procedures are mandatory for all ships participating in the survey.

At the same time, methodological aspects of the multi-year international research program implemented in Subdivision 58.4.1., such as the lack of standardized design of longline settings, the use of  various  types and constructions of gears  and fishing efforts  by years and research blocks  do not allow obtaining scientific-based  data for understanding the abundance, population structure and productivity indices, toothfish distributions and dependent species in accordance with the  goals and objectives of the research program in Divisions 58.4.1 and 58.4.2.

The solution of the current methodological problems of toothfish  research in Division 58.4.1 by only  improving statistical data processing  is  unacceptable. For Division 58.4.1 and 58.4.2.  we propose a  toothfish  researches  to be carried out by the vessels   based on standardization of sampling longline gear and survey design

Scientific observation activities during Dissostichus spp. fishing for research purposes in the statistical subarea 48.1 on board of the fishing vessel “Calipso” (Fig. 1) (the shipowner LLC “Fishing Company “NEPTUNO”, Ukraine) were carried out in accordance with the research plan WG-FSA-18/20 Rev.1.

WG-FSA 2018 noted that changes in productivity parameters may impact assessment estimates and consequent management advice, and that these changes may be related to long-term environmental change. The Working Group recommended that key assessment parameters be reviewed and that changes in the fishery dynamics that would impact their estimation be explored.

The biological productivity parameters in subarea 48.3 are analysed here, particularly whether the proportion of females in the catch, maturity at length, length-weight relationships and growth rates have changed over time and how the fishery dynamics impact parameter estimates. Variation in parameter estimates is noted but no systematic trends in growth or maturity through time, after the effects of confounding factors were included in the analysis.

Russian research of craboids (Anomura, Decapoda) in the Antarctic Pacific (Subareas 88.2 and 88.3) were carried out by the  vessel “Antarctic Wolf” in March 2019 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)). Pot catches was presented by craboid Paralomis birstaini and Antarctic King crab Neolithodes yaldwini. Detailed analysis of obtained data is shown.

The fifth year survey and observations of Dissostichus spp. in statistical subarea 48.2 on board of the Ukrainian vessel SIMEIZ were conducted in accordance with the recommendations of the Scientific Committee and Commission.  The design and timing of the fifth year of research generally corresponded to the 2018 season, but significant changes were noted in the CPUE of Antarctic toothfish (Dissostichus mawsoni). Data on CPUE of target and main by-catch species, biological characteristics of toothfish, by-catch fish, results of seabirds and marine mammals observations are presented.

Ukraine proposes to continue a scientific survey of Dissostichus spp. by bottom longline in the eastern part of Subarea 48.1 in a season 2019-2020.

In order to achieve the milestone “1.1 Update biological parameters”(SC-CAMLR-37 Report, Annex12), biological parameters (length-weight relationship, growth curve, Age Length Key, and maturity ogice) of Dissostichus eleginoides for Division 58.4.4b were updated based on the data gathered up to the 2017/18 fishing season by France and Japan. Furthermore, the updated CASAL models were developed to conduct an exploration of the impact of different scenarios of depredation and IUU in order to evaluate the uncertainties associated with these factors as achievements of milestones “1.2 Updated estimation of IUU catch” and “1.5 Update CASAL model” (SC-CAMLR-37 Report, Annex12).

A single-sex age structured CASAL model was built to assess the stock of D. eleginoides at the research block 1 of Division 58.4.4b. The base model (M1) did not explicitly consider either IUU catch and depredation; those were explored within sensitivity runs in the three alternative models (M2~M4). Compared to the CASAL results previously reported in WG-FSA-15/23, the MPD profile become better under all scenarios.

Comparing the MPD profile between M1 (base model without depredation) and M2 (4.8% depredation model), depredation would not have large impact on estimated B0 at the block 1 of Division 58.4.4b. On the other hands, the degree of IUU estimation potentially has large impact on the CASAL B0 estimation. The results of MCMC indicates future predictions of toothfish biomass under current catch level (19 tonnes) with/without depredation and IUU catch.

Mackerel icefish (Champsocephalus gunnari) – one of the most common and widespread species of Antarctic fish. Ukraine proposes survey of Champsocephalus gunnari at previously scheduled stations (trawlings) points in the statistical Subarea 48.2. The main objective of the research is to determine the distribution and abundance of mackerel icefish in Subarea 48.2.

The experience of the use of methods by Ukrainian vessels to search for lost longliness in the CCAMLR Convention Area is presented.

The issues of longlines geo-referencing during the exploratory fisheries of the toothfish in the Convention Area are discussed. Cases of differences in the coordinates of settings and haulings are considered. The estimation of the maximum possible variation of the coordinates in the depths range of 550-3000 m was performed. It is shown that the differences of coordinates of settings and haulings increases in the areas with large depths and high velocities of sea currents in the high seas. The data indicate the necessity of revising the radius of risk areas around points of potential VMEs, taking into account scattering of longlines geo-referencing.