WG-ASAM-2021

WG-ASAM is invited to provide recommendations on improving the repository of acoustic data collected by fishing vessels maintained by the Secretariat and to provide advice on:

• Whether the surveys listed in Annex 1 correspond to what is expected to be included in this repository.
• Whether the metadata provided in Annex 2 meet metadata requirements.
• Responsibility Read More
  Soumis par:
  Daphnis De Pooter (Secrétariat de la CCAMLR)
  
  Approuvé par:
  David Agnew (Secrétariat de la CCAMLR)
  
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We provide estimates of krill biomass density in three survey strata defined by the U.S. AMLR Program: Elephant Island (EI), the West Shelf (WA), and the Bransfield Strait (or South Area (SA)). We include density estimates from U.S. AMLR research vessel surveys conducted from 1996 to 2011 and from gliders deployed in 2018-19. We also include density estimates from fishery-independent surveys Read More
Soumis par:
Christian Reiss

Approuvé par:
George Watters

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The authors have analyzed the krill size composition in the catches taken by fishing vessels and the RV Atlantida in the local fishing ground within several day to exclude  any influence of krill drift on results obtained. The fishing ground was located in Subarea 48.2 (SSMU SOW). This comparative analysis  clearly demonstrate both the differences in the krill length Read More
Soumis par:
Svetlana Kasatkina (Fédération de Russie)

Approuvé par:
Svetlana Kasatkina (Fédération de Russie)

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The Russian krill research in Subarea 48.1 and 48.2 were carried out by  RV “Atlantida”  in the period January-March 2020  including acoustic surveys, accompanied by a wide range of ecosystem studies on the biology of  krill and its habitat (hydrometeorological, oceanological and hydrochemical data)  bio-productivity indices  (chlorophyll, primary Read More
Soumis par:
Svetlana Kasatkina (Fédération de Russie)

Approuvé par:
Svetlana Kasatkina (Fédération de Russie)

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Authors present the acoustic data obtained on the R/V Atlantida cruise in 2020 to examine spatial and temporal variability of krill distribution. These data were collected in Subareas 48.1 and 48.2 using the repeated  transect system, including: local survey in Bransfield Strait and two mesoscale reference transects  (one is in the Elephant Island stratum and one is in the Read More
Soumis par:
Svetlana Kasatkina (Fédération de Russie)

Approuvé par:
Svetlana Kasatkina (Fédération de Russie)

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A multidisciplinary ecosystem survey in the eastern Indian sector of the Antarctic (CCAMLR Division 58.4.1) with a focus on Antarctic krill was carried out by Japanese survey vessel, Kaiyo-maru, during the 2018/19 season. A revised biomass (B₀) of Antarctic krill was estimated using the survey data applying Echoview template, EchoviewR and R code for the random Read More
Soumis par:
Hiroto Murase (Japon)

Approuvé par:
Mako Iioka (Japon)

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A maximum threshold setting in the noise removal part of the Echoview template used for acoustic krill biomass estimation can remove significant amounts of krill backscatter. A revised threshold setting is proposed and applied to the 2019 International Synoptic Krill survey in Area 48, resulting in a 16% increase in the biomass estimate.

This working group paper presents ideas and experiences regarding the use of unmanned surface vehicles (USVs) to monitor krill density in a fishing hotspot. While USVs have the advantage of reduced survey costs, reduced risk for personnel and higher data resolution in time and space, they sometimes struggle to follow straight transects and to withstand the rough weather and sea ice conditions Read More
Soumis par:
Sebastian Menze

Approuvé par:
Bjørn Krafft (Norvège)

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Acoustic data on Antarctic krill in Subarea 48.1 are available in several spatial scales that are relevant to the work of WG-ASAM-2021. The various spatial scales (or areas with different size and shape) available from CCAMLR that could be considered by WG-ASAM-2021 to provide biomass estimates of Antarctic krill in Subarea 48.1, together with the US AMLR survey strata and the Chinese fishing Read More
Soumis par:
Xinliang Wang

Approuvé par:
Xianyong Zhao (Chine)

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Length frequency distribution (or length PDF) of Antarctic krill is an important input for converting the acoustic density to biomass estimate. For the 2019 Area 48 multi-national krill survey, various sources of length data were combined to provide the krill PDF for biomass estimation, and its potential effect was also discussed. To address this issue further, the potential effect of krill Read More
Soumis par:
Xinliang Wang

Approuvé par:
Xianyong Zhao (Chine)

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With the recent development of techniques and protocols for the acquisition and processing of acoustic data collected aboard krill fishing vessels, a large volume of acoustic data accumulated by fishing vessels become usable. The acoustic data collected in a main fishing ground (or hotspot) in the Bransfield strait by one of the Chinese krill fishing vessel, namely F/V Fu Rong Hai, is Read More
Soumis par:
Xinliang Wang

Approuvé par:
Xianyong Zhao (Chine)

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In February and March 2021 an acoustic-trawl survey was carried out to estimate the biomass of Antarctic krill (Euphausia superba) in the eastern sector of the CCAMLR Division 58.4.2 (area = 775,732 km².) The survey was run from the Australian Research Vessel RV Investigator operating a calibrated EK80 scientific echosounder and an RMT-8 + 1 net. Krill were Read More
Soumis par:
Martin Cox

Approuvé par:
Philippe Ziegler (Australia)

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Time series of annual biomass estimates of Antarctic krill around the South Shetland Islands during the period of 2013 to 2019 is provided to aid the discussion on biomass estimation in Subarea 48.1. The estimates were based on data described in the working document ASAM-2019-04r1, which presented the time series of krill density estimates resulting from the annual acoustic surveys conducted Read More
Soumis par:
Xinliang Wang

Approuvé par:
Xianyong Zhao (Chine)

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In this paper we present krill density biomass estimates for Subareas 48.1, 48.2, 48.3 and 48.4 and for current fished areas, using post-hoc stratification of krill density estimates from the 2019 International Krill Survey. We highlight the importance of survey strata design for the differing areas, with implications for management. Each level of stratification requires different Read More
Soumis par:
Phil Trathan

Approuvé par:
Chris Darby

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We compare estimates of krill density derived from gliders to those from contemporaneous and previous ship-based surveys. Our comparisons cover several temporal and spatial scales within two strata around the northern Antarctic Peninsula (off Cape Shirreff on the north side of Livingston Island and in the Bransfield Strait). Our objective is to explore the feasibility of using gliders to Read More
Soumis par:
Christian Reiss

Approuvé par:
George Watters

Publication:
Frontiers in Marine Science, 8 (2021): 1–18, doi: 10.3389/fmars.2021.604043

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