SG-ASAM-2019

SG-ASAM are invited to consider provide further recommendations for improving this fishing vessel data collection program and provide advice on

• the timing and frequency for conducting acoustic transects;
• the methods for the data transmission to the Secretariat including the use of EchoExplore to provide a meta-data catalogue of the data and
• whether to have Read More
  Soumis par:
  Doro Forck (Secrétariat de la CCAMLR)
  
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Biomass (B₀) of Antarctic krill for CCAMLR Division 58.4.1 in 2018/19 was preliminarily estimated as 4.349 million ton (CV=54.8 %) based on the swam based method using data obtained by Kaiyo-maru. The point estimate was comparable with the estimate in 1996 by BROKE (4.83 million ton with CV=17 %). However, they can not be compared directly because (1) biomass Read More
Soumis par:
Hiroto Murase (Japon)

Approuvé par:
Taro Ichii

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The density of Antarctic krill swarm inhabiting the Subarea 48.1, which includes the Elephant Island peripheries and the west and north of the South Shetland Island, was estimated using an acoustics survey. Acoustic data were collected using two frequencies with 38 and 120 kHz from March 8 to 15 in 2019. Krill were collected by the commercial midwater trawl fishing vessel. The data were Read More
Soumis par:
Sangdeok Chung (Corée, Rép. de)

Approuvé par:
Seok-Gwan Choi (Corée, Rép. de)

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Metadata for krill biomass time series obtained by Chinese krill fishing vessel in Subarea 48.1 is submitted with accompanying description of the acoustic survey and data analysis. Distribution of Antarctic krill for the 2013/14 to 2015/16 and the 2017/18 to 2018/19 fishing seasons were mapped by the Chinese F/V Fu Rong Hai to understand the interannual variations of Antarctic krill Read More
Soumis par:
Xiaotao Yu (Chine)

Approuvé par:
Xianyong Zhao (Chine)

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To address the potential effect of DVM behavior on krill biomass estimates, diel vertical distribution of krill swarms around the South Shetland Islands in Subarea 48.1 were analyzed based on data collected by the Chinese fishing vessel participating in the international 2019 Area 48 survey. Results show that more krill swarms were found in shallower depth at night than during daytime, while Read More
Soumis par:
Xinliang Wang (Chine)

Approuvé par:
Xianyong Zhao (Chine)

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To address the effect of various identification methods on krill biomass estimates, comparison on the swarm-based and dB-difference (Sv_120kHz-Sv_38kHz) identification method were made using the acoustic data collected around the South Shetland Islands in Subarea 48.1 by the Chinese fishing vessel F/V Fu Rong Hai during the 2019 Area 48 survey. Identification Read More
Soumis par:
Xiaotao Yu (Chine)

Approuvé par:
Xianyong Zhao (Chine)

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As a contribution to the joint effort on the large-scale international synoptic krill survey of Area 48 (2019 Area 48 survey), the Chinese krill fishing vessel F/V Fu Rong Hai conducted the acoustic survey around the South Shetland Islands and the Elephant Islands in the Subarea 48.1 from 5^th to 10^th February 2019. Implementation and preliminary results on the Read More
Soumis par:
Xinliang Wang (Chine)

Approuvé par:
Xianyong Zhao (Chine)

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Results from the International Synoptic Krill Survey in Area 48, 2019, are presented. This survey covered both the strata occupied during the CCAMLR 2000 acoustic survey and the strata that comprise the regular AMLR survey. Acoustic transects (10534 n.mi), oceanographic measurements (253 casts), and trawls (164) were carried out as per survey procedures developed in 2018, which were based on Read More
Soumis par:
Gavin Macaulay

Approuvé par:
Odd Aksel Bergstad (Norvège)

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We compare supervised, using the interactive software Echoview™, and unsupervised, using python,  processing  of acoustic  data  collected  during  the  UK  cruise  DY098.  The  same  data processing procedures are applied in both methods, and we show that the unsupervised method comes  up  with  a  similar Read More
Soumis par:
Sophie Fielding (Royaume-Uni)

Approuvé par:
Doro Forck (Secrétariat de la CCAMLR)

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The effect of differences in the methodology used for the CCAMLR 2000 krill acoustic survey and the 2019 synoptic survey were considered. These were 1) the effect of acoustic surveying at night, 2) differing trawl selectivity between the vessels that participated in the survey, and 3) the effect of krill discrimination method. Surveying during the day only produced a 6% increase in the Read More
Soumis par:
Gavin Macaulay

Approuvé par:
Odd Aksel Bergstad (Norvège)

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