WG-SAM-2021

A research plan for Subarea 88.3 was commenced by Korea in 2016 under CM 24-01, New Zealand joined the proposal in 2017. The joint research proposal was for 3 years covering the period 2017/18, 2018/19 and 2019/20. It was designed to build on Korea’s previous research by continuing to focus on research blocks where tagged fish have previously been released on the slope, while also prospecting Read More
Submitted By:
Dr Sangdeok Chung (Korea, Republic of)

Approved By:
Dr Seok-Gwan Choi (Korea, Republic of)

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The Ross Sea shelf survey has been conducted annually since 2012, with the most recent revised proposal presented in 2017 and spanning five years (2018–2022). This paper:

• serves as notification for the 2022 survey under CM 24-01 following the survey design proposed in WG-SAM-17/39, and annual notifications in WG-FSA-18/41, WG-SAM-19/03, SC-CAMLR-39-BG-03.
• fulfils the Read More
  Submitted By:
  Mr Nathan Walker (New Zealand)
  
  Approved By:
  Ms Doro Forck (CCAMLR Secretariat)
  
  Request Meeting Document

Recommendations

(1) That this research plan with a revised sampling design within six existing research blocks in Division 58.4.1 and one existing research block in Division 58.4.2 be adopted.

(2) If directed fishing was not allowed in Division 58.4.1 in 2021/22, that this research plan for the exploratory fishery in Division 58.4.2 with one existing and one new research block be Read More
Submitted By:
Dr Philippe Ziegler (Australia)

Approved By:
Dr Philippe Ziegler (Australia)

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A collaborative research program has been undertaken by Japan and South Africa since 2013 to enhance data collection and analysis in the subarea 48.6 under CM 21-02. Spain joined the proposal starting from 2018/19 fishing season in order to contribute to the data acquisition and to speed up the integrated assessments of the Antarctic toothfish (Dissostichus mawsoni) stock in this Read More
Submitted By:
Dr Yumiko Osawa

Approved By:
Ms Mako Iioka (Japan)

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Mackerel icefish (Champsocephalus gunnari) is one of the most common and widespread species of Antarctic fish. Ukraine proposes to conduct a survey of Champsocephalus gunnari in the statistical Subarea 48.2 by the midwater trawl. The main objective of the research is to determine the distribution and the abundance of Champsocephalus gunnari in the Read More
Submitted By:
Dr Kostiantyn Demianenko (Ukraine)

Approved By:
Mr Artem Ogorodnik (Ukraine)

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Preliminary biomass estimates for research blocks in data-limited fisheries and the resulting preliminary catch limits for the 2022 season have been determined using the trend analysis decision rules. The resulting preliminary catch limits are for illustrative purposes only and do not constitute recommendations.

As part of the revision of the krill management approach, the Secretariat was tasked to estimate proportional recruitment indices in Subareas 48.1, 48.2 and 48.3 using the SISO (i.e., observer) krill length data collected onboard fishing vessels. This document summarizes the steps taken to estimate the mean and standard deviation of proportional recruitment in each Subarea, for Read More
Submitted By:
Dr Stephane Thanassekos (CCAMLR Secretariat)

Approved By:
Dr David Agnew (CCAMLR Secretariat)

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Recommendations

That WG-SAM note these preliminary explorations of alternative decision rules for managing toothfish fisheries, which indicate that an approach based on a harvest rate H:

• Would be consistent with the CCAMLR decision rule and its objective, and;
• Could provide a higher level of predictability and certainty about the likely changes in future Read More
  Submitted By:
  Dr Philippe Ziegler (Australia)
  
  Approved By:
  Dr Philippe Ziegler (Australia)
  
  Request Meeting Document

Recommendations

For GYM assessments with proportional recruitment, we recommend to use:

• Formula-based methods for low variance in proportional recruitment;

• Simulation modelling for high variance in proportional recruitment to accurately reproduce mean and standard deviation;

as described in this paper and implemented in the Grym ( Read More
Submitted By:
Mr Dale Maschette (Australia)

Approved By:
Dr Philippe Ziegler (Australia)

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Recommendations

When modelling multiple fleets in a GYM assessment, we recommend the use of the presented extension to the Grym package based on its shown capacity to model more complex fisheries and fishing practices with a high degree of consistency in results.

Abstract

Grym is an implementation of the Generalized Yield Model in R that provides greater transparency and Read More
Submitted By:
Mr Dale Maschette (Australia)

Approved By:
Dr Philippe Ziegler (Australia)

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This paper examines fishery data collected by Russian scientific observers on longline vessels that fished toothfish using Spanish longline and trotlines in CCAMLR and adjacent Atlantic waters during the 2002-2017 fishing seasons. The factors influencing the longline fishing impact zone    are discussed in this paper.  It is shown that the existing approach to the Read More
Submitted By:
Dr Svetlana Kasatkina (Russian Federation)

Approved By:
Dr Svetlana Kasatkina (Russian Federation)

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As part of the revision of the krill management approach, an updated set of parameter values is required for the Grym to perform projections in Subareas 48.1, 48.2 and 48.3. Where applicable, Subarea-specific values are set to account for the different dynamics in each Subarea. Given the scope of the task, some parameter values are found in the scientific literature while others correspond to Read More
Submitted By:
Dr Stephane Thanassekos (CCAMLR Secretariat)

Approved By:
Dr David Agnew (CCAMLR Secretariat)

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We update the Bayesian sex- and age-structured integrated stock assessment model for Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea region (Subareas 88.1 and Small-Scale Research Units (SSRUs) 88.2A-B) using the most recent available data for the Antarctic toothfish fishery. The assessment model employs reported catch for 1998–2021, tag-release data for 2001–2019 and Read More
Submitted By:
Mr Nathan Walker (New Zealand)

Approved By:
Ms Doro Forck (CCAMLR Secretariat)

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Here, we provide diagnostic plots for the 2021 assessment model for Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea region presented in Grüss et al. (2021a), following the recommendations of WG-SAM-2015 (SC-CAMLR-XXXIV 2015 Annex 5). The stock assessment model is described in Grüss et al. (2021a), and a detailed description of the stock area, stock assessment methods and Read More
Submitted By:
Mr Nathan Walker (New Zealand)

Approved By:
Ms Doro Forck (CCAMLR Secretariat)

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Stock Annex for the 2021 assessment of the Antarctic toothfish (Dissostichus mawsoni) population of the Ross Sea region, including stock structure and definition, fishery information, catch data, biological information, abundance information, and stock assessments.

The problem of differences more than 10% between vessel catch reporting form (C2) and landed Dissostichus catch (DCD) on Ukrainian fishing vessels Simeiz, Koreiz and Calipso was raised  by the CCAMLR Secretariat in 2018, and the data from these Ukrainian fishing vessels for the period 2014-2018 has been quarantined. There is proposed to include these data, revised by Ukraine, Read More
Submitted By:
Dr Kostiantyn Demianenko (Ukraine)

Approved By:
Ms Doro Forck (CCAMLR Secretariat)

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Ukrainian vessel CALIPSO (Fig. 1) (shipowner FC NEPTUNO LLC, Ukraine) performed the research survey in the statistical subarea 48.1 according to the research plan SC-CAMLR-39/BG/08 and management advices of the WG-FSA-2020 and SC-CAMLR-39 in the second part of February 2021. The survey was carried out partly and stopped in advance due to the exhaustion of the limit (a total of 6.56 Read More
Submitted By:
Dr Kostiantyn Demianenko (Ukraine)

Approved By:
Ms Doro Forck (CCAMLR Secretariat)

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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 researches on Dissostichus spp.  in the East Antarctic region (Divisions 58.4.1 and 58.4.2) carried out in the seasons 2011/12 - 2017/18 Read More
Submitted By:
Dr Svetlana Kasatkina (Russian Federation)

Approved By:
Dr Svetlana Kasatkina (Russian Federation)

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Data  from catches of research trawl  were obtained in Subareas 48.1 and 48.2  during cruise  RV Atlantida  in 2020.  The number of krill measured (length, weight) from 179 trawl catches was about 20,000. The length ranges smaller 36 mm were used to define the proportional recruitment. Variability of krill length frequency distributions and Read More
Submitted By:
Dr Svetlana Kasatkina (Russian Federation)

Approved By:
Dr Svetlana Kasatkina (Russian Federation)

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This document summarizes several papers submitted to the Grym e-group and other working groups during 2020 and 2021 on proportional recruitment (R.mean, R.var inputs to the Grym: the square of SD of proportional recruitment is the 'R.var' input) from research surveys and the fishery; and biomass variability (B0logsd input to Grym) from research surveys in Subarea 48. Two different length Read More
Submitted By:
Dr Doug Kinzey

Approved By:
Dr George Watters (United States of America)

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In RB5, the SICs in Feb. 2021 were the highest and the SSTs were the lowest for the years 2016-202.  In Mar.  2021, the highest SICs decreased to nearly the long-term average while the SST increased accordingly. In the same year, the SICs and SSTs had two peaks in Feb. and Mar. respectively.  In RB4, the SICs during Jan.- Feb (Austral summer) in 2021 were also the highest since Read More
Submitted By:
Mr Roberto Sarralde Vizuete (Spain)

Approved By:
Ms Doro Forck (CCAMLR Secretariat)

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Spatial scale is the common ground of all of the three components (Biomass estimation, stock assessment and risk assessment) for the new krill management strategy. The pros and cons of the potential choices of biomass estimate at various spatial scales were discussed to facilitate the deliberation on Krill Stock Assessment at the WG-SAM-2021 meeting. Considerations were also given on the Read More
Submitted By:
Dr Yi-Ping Ying (China)

Approved By:
Dr Xianyong Zhao (China)

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