WG-SAM-2023

The review of the available gear selectivity studies in the krill fishery in context of standard ICES methods was undertaken.  Some methodical aspects of selectivity estimates were considered.  According to the authors, currently, the data sets used to estimate the gear selectivity does not adequately describe the krill fishing process.

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Submitted By:
Dr Svetlana Kasatkina (Russian Federation)

Approved By:
Dr Svetlana Kasatkina (Russian Federation)

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This is the third year continuation of the on-going three-year plan from 2021/22 to 2023/24. There is no significant change from the endorsed proposal (WG-FSA-2021/38). South Africa will not be participating in the research fishing in 2023/24 season due to unavailability of the fishing vessel. However, South Africa will participate in the lab and analytical work Read More
Submitted By:
Dr Takehiro Okuda (Japan)

Approved By:
Dr Takehiro Okuda (Japan)

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The Ross Sea shelf survey has been conducted annually since 2012, with the most recent revised proposal presented in 2023 and spanning three years (2023–2025). This paper:

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  Submitted By:
  Mr Nathan Walker (New Zealand)
  
  Approved By:
  Mr Nathan Walker (New Zealand)
  
  Request Meeting Document

Exploratory fishing for Antarctic toothfish (Dissostichus mawsoni) in East Antarctica (Divisions 58.4.1 and 58.4.2) began in 2003. While preliminary integrated stock assessments have been developed for these Divisions, robust estimates of stock biomass and precautionary catch limits according to CCAMLR decision rules remain to be determined. Read More
Submitted By:
Dr Philippe Ziegler (Australia)

Approved By:
Dr Philippe Ziegler (Australia)

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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:
Mr Jeongseok Park (Korea, Republic of)

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(CM). The current Patagonian toothfish (Dissostichus eleginoides) and Antarctic toothfish (Dissostichus mawsoni) fisheries have been monitored consistently across Subareas 48.2, 48.3 and 48.4 during the last years, producing scientific data for making progress towards an estimate of the toothfish fishery potential yield and productivity. This document Read More
Submitted By:
Dr César Cárdenas (Chile)

Approved By:
Dr César Cárdenas (Chile)

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Mackerel icefish (Champsocephalus gunnari) is one of the most common and widespread species of Antarctic fish. Ukraine proposes to continue a local acoustic-trawl survey of Champsocephalus gunnari in the statistical Subarea 48.2 for 2024 and 2025. The main objective of the research is to Read More
Submitted By:
Dr Kostiantyn Demianenko (Ukraine)

Approved By:
Dr Kostiantyn Demianenko (Ukraine)

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Notificación de intención de participar en la pesquería exploratoria de Dissostichus spp. en la subárea 48.6 de la CCRVMA durante la temporada 2023/24.

Plan de Operaciones Pesqueras (MC 21-02, párrafos 6(ii)(a) a 6(ii)(f)).

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Submitted By:
Mr Alberto Tabaré Lozano Junca

Approved By:
Ambassador Gustavo Miguel Vanerio Balbela

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In 2022, Casal2 was endorsed by CCAMLR at Scientific Committee for use for integrated statistical catch-at-age toothfish stock assessments. As a part of the recommendations, the Scientific Committee encouraged further research on parameter transformations within the Casal2 stock assessment models to improve stability and Markov Chain Monte Carlo (MCMC) convergence. Read More
Submitted By:
Mr Nathan Walker (New Zealand)

Approved By:
Mr Nathan Walker (New Zealand)

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Initial and ongoing tag loss rates were updated using double tagged Antarctic toothfish (Dissostichus mawsoni) released between 2005 and 2021 that were recaptured with at least one tag. Different tag loss models were explored, including assessing the effect of increasing the maximum time at liberty included in the analysis to those tags recaptured beyond 6 years at Read More
Submitted By:
Ms Helene Attrill

Approved By:
Ms Helene Attrill

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We investigated alternative parameterisations of the tag loss rate function and the effect of including tag recapture observations with greater time at liberty in the Ross Sea region (RSR) Antarctic toothfish (Dissostichus mawsoni) assessment using Casal2. The analyses used the Casal2 implementation of the 2021 CASAL assessment model that was used Read More
Submitted By:
Mr Nathan Walker (New Zealand)

Approved By:
Mr Nathan Walker (New Zealand)

Request Meeting Document

Using length-based observations in age-based population dynamics models can lead to uncertainty and / or bias due to the conversion from ages to lengths within the model. Thus, the CCAMLR Independent Stock Assessment Review for Toothfish in 2018 recommended that the use of age-length keys be investigated to estimate the age composition of tagged fish and recaptured fish as inputs Read More
Submitted By:
Ms Helene Attrill

Approved By:
Ms Helene Attrill

Request Meeting Document

In 2018, CCAMLR undertook an Independent Stock Assessment Review for Toothfish (ISART). The review was considered by the Scientific Committee in 2018, and its recommendations were summarised in the 2018 Report of the Scientific Committee. The Scientific Committee also provided a review of progress of the recommendations summarised across all the stocks that had integrated stock Read More
Submitted By:
Mr Nathan Walker (New Zealand)

Approved By:
Mr Nathan Walker (New Zealand)

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The Scientific Committee identified skates (along with macrourids) as “priority bycatch taxa for which assessments of status are required”. Catch data from the Ross Sea region show that most (~90%) of the skate catch consists of Amblyraja georgiana and that this species is the only one with enough mark-recapture data to estimate local biomass. We present methods for Read More
Submitted By:
Mr Nathan Walker (New Zealand)

Approved By:
Mr Nathan Walker (New Zealand)

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In this paper, we present a generalised additive mixed modelling (GAMM) framework to determine the probability of that a sampled macrourid is either Macrourus caml or M. whitsoni in the Ross Sea region (RSR). This GAMM was used to underpin recent vector autoregressive spatio-temporal (VAST) modelling analyses presented to WG-SAM-2022 Read More
Submitted By:
Mr Nathan Walker (New Zealand)

Approved By:
Mr Nathan Walker (New Zealand)

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This paper provides a comparison of methods to estimate von Bertalanffy growth parameters for Patagonian toothfish (Dissostichus eleginoides) in Subarea 48.3. Here, we have extended growth estimation methods presented in previous studies (Marsh et al. 2022a, b) to fit and compare a series of growth models with the aim to determine a method appropriate for these Read More
Submitted By:
Ms Helene Attrill

Approved By:
Ms Helene Attrill

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Preliminary biomass estimates for research blocks in data-limited toothfish fisheries and the resulting preliminary catch limits for the 2024 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.

Following the Scientific Committee recommendation in 2022 (SC-CAMLR-41, paragraph 3.119) to develop a management strategy evaluation of the trend analysis, this document introduces a proposed framework for the construction of an Agent-Based Model (ABM), one of the three elements of the planned operating model (WG-FSA-2022/53). The intent of this document is to describe a basic structure, coded Read More
Submitted By:
Dr Stéphane Thanassekos (CCAMLR Secretariat)

Approved By:
Dr David Agnew (CCAMLR Secretariat)

Request Meeting Document

The formula to calculate the tag overlap statistic is specified in footnote 3 of CM 41-01 Annex C. This formula is used to compare the length frequency distribution of tagged fish to that of caught fish. However, observers do not measure the lengths of all caught and retained fish which complicates the calculation of this similarity indicator. Here we describe the rationale Read More
Submitted By:
Mr Daphnis De Pooter (CCAMLR Secretariat)

Approved By:
Dr David Agnew (CCAMLR Secretariat)

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In this paper, continuing the topic of gear selectivity in relation to krill, the authors discuss the issues of collecting biometric information, paying attention to the specifics of biometrics from krill biology and the impact of krill biometrics on gear selectivity in the context of its scientific and practical significance for current CCAMLR topics Read More
Submitted By:
Dr Svetlana Kasatkina (Russian Federation)

Approved By:
Dr Svetlana Kasatkina (Russian Federation)

Request Meeting Document

This paper compares key parameters and outputs for the 2021 Patagonian toothfish (Dissostichus eleginoides) fishery at Heard Island and McDonald Islands (HIMI) in CCAMLR Division 58.5.2 using both CASAL and Casal2.  Parameterisation, weightings and settings used in the Casal2 assessment were extracted from CASAL output files produced by the 2021 CASAL stock Read More
Submitted By:
Dr Cara Masere (Australia)

Approved By:
Dr Philippe Ziegler (Australia)

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The exploratory longline fishery for Antarctic toothfish (Dissostichus mawsoni) in Subarea 48.6 began as a new fishery in 1997 and was reclassified as an exploratory fishery in 2000. R Read More
Submitted By:
Dr Sangdeok Chung (Korea, Republic of)

Approved By:
Mr Jeongseok Park (Korea, Republic of)

Request Meeting Document

In the February 2023 Ukrainian fishing vessel "MORE SODRUZHESTVA" has conducted a local acoustic-trawl survey of Champsocephalus gunnari in the statistical Subarea 48.2. Progress report of this survey are presented here.

The scientific research fishing was conducted by the Greenstar (KOR) and Marigolds (UKR) in in Subarea 88.3 following the survey design (WG-FSA- Read More
Submitted By:
Mr Illia Slypko (Ukraine)

Approved By:
Dr Kostiantyn Demianenko (Ukraine)

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An analysis of the Sea Ice Concentration (SIC), Sea Surface Temperature (SST) and winds in Research Blocks (RBs) 48.6_5 and 48.6_4 is presented. The SICs in RB5 from mid-Feb to end Mar 2023 were the lowest in the 2016-2023 period.

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Submitted By:
Mr Roberto Sarralde Vizuete (Spain)

Approved By:
Mr Roberto Sarralde Vizuete (Spain)

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Preliminary results from an integrated Casal2 assessment of Antarctic krill around the northern Antarctic Peninsula (in the area historically surveyed by the U.S. AMLR Program) and covering the years 1976-2021 are reported here. The assessment includes a 20-year forward projection. Data supplied to the model were fishery catches (1976-2021), acoustic biomass surveys (1996- Read More
Submitted By:
Dr Doug Kinzey (United States of America)

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

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