Quantifying the performance of selective devices by combining analysis of catch data and fish behaviour observations: methodology and case study on a flatfish excluder
Abstract This article describes a method for the quantitative analysis of fish behaviour relative to selection devices in trawl gears. Based on video observations, the method estimates probabilities for a given event to happen and establishes behavioural tree diagrams representing and quantifying be...
Published in: | ICES Journal of Marine Science |
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Language: | English |
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Oxford University Press (OUP)
2020
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Online Access: | http://dx.doi.org/10.1093/icesjms/fsaa155 http://academic.oup.com/icesjms/article-pdf/77/7-8/2840/35589072/fsaa155.pdf |
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croxfordunivpr:10.1093/icesjms/fsaa155 2024-10-13T14:07:23+00:00 Quantifying the performance of selective devices by combining analysis of catch data and fish behaviour observations: methodology and case study on a flatfish excluder Santos, Juan Herrmann, Bent Stepputtis, Daniel Kraak, Sarah B M Gökçe, Gökhan Mieske, Bernd Zhou, Shijie 2020 http://dx.doi.org/10.1093/icesjms/fsaa155 http://academic.oup.com/icesjms/article-pdf/77/7-8/2840/35589072/fsaa155.pdf en eng Oxford University Press (OUP) https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model ICES Journal of Marine Science volume 77, issue 7-8, page 2840-2856 ISSN 1095-9289 journal-article 2020 croxfordunivpr https://doi.org/10.1093/icesjms/fsaa155 2024-09-17T04:29:42Z Abstract This article describes a method for the quantitative analysis of fish behaviour relative to selection devices in trawl gears. Based on video observations, the method estimates probabilities for a given event to happen and establishes behavioural tree diagrams representing and quantifying behavioural patterns in relation to the selection device under assessment. Double bootstrapping is used to account for the uncertainty originating from a limited number of fish observations and the natural variation in fish behaviour. The method is used here to supplement standard analysis of catch data for the performance assessment of a flatfish excluder (FLEX). The Baltic Sea trawl fishery targeting cod (Gadus morhua) provides the pilot case. Results obtained by comparing catches with and without FLEX installed revealed that >75% of bycaught flatfish individuals escaped through the device, while no evidence was found that catches of cod in the targeted sizes were reduced. The behavioural analysis produced values of escape efficiency comparable to those obtained in the catch analysis. Furthermore, it revealed that ∼80% of the flatfish went calmly into the excluder, while most of the roundfish displayed avoidance swimming reactions. The method provides quantitative information of fish behaviour that can be relevant for developing and optimizing selection devices. Article in Journal/Newspaper Gadus morhua Oxford University Press ICES Journal of Marine Science 77 7-8 2840 2856 |
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Open Polar |
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Oxford University Press |
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croxfordunivpr |
language |
English |
description |
Abstract This article describes a method for the quantitative analysis of fish behaviour relative to selection devices in trawl gears. Based on video observations, the method estimates probabilities for a given event to happen and establishes behavioural tree diagrams representing and quantifying behavioural patterns in relation to the selection device under assessment. Double bootstrapping is used to account for the uncertainty originating from a limited number of fish observations and the natural variation in fish behaviour. The method is used here to supplement standard analysis of catch data for the performance assessment of a flatfish excluder (FLEX). The Baltic Sea trawl fishery targeting cod (Gadus morhua) provides the pilot case. Results obtained by comparing catches with and without FLEX installed revealed that >75% of bycaught flatfish individuals escaped through the device, while no evidence was found that catches of cod in the targeted sizes were reduced. The behavioural analysis produced values of escape efficiency comparable to those obtained in the catch analysis. Furthermore, it revealed that ∼80% of the flatfish went calmly into the excluder, while most of the roundfish displayed avoidance swimming reactions. The method provides quantitative information of fish behaviour that can be relevant for developing and optimizing selection devices. |
author2 |
Zhou, Shijie |
format |
Article in Journal/Newspaper |
author |
Santos, Juan Herrmann, Bent Stepputtis, Daniel Kraak, Sarah B M Gökçe, Gökhan Mieske, Bernd |
spellingShingle |
Santos, Juan Herrmann, Bent Stepputtis, Daniel Kraak, Sarah B M Gökçe, Gökhan Mieske, Bernd Quantifying the performance of selective devices by combining analysis of catch data and fish behaviour observations: methodology and case study on a flatfish excluder |
author_facet |
Santos, Juan Herrmann, Bent Stepputtis, Daniel Kraak, Sarah B M Gökçe, Gökhan Mieske, Bernd |
author_sort |
Santos, Juan |
title |
Quantifying the performance of selective devices by combining analysis of catch data and fish behaviour observations: methodology and case study on a flatfish excluder |
title_short |
Quantifying the performance of selective devices by combining analysis of catch data and fish behaviour observations: methodology and case study on a flatfish excluder |
title_full |
Quantifying the performance of selective devices by combining analysis of catch data and fish behaviour observations: methodology and case study on a flatfish excluder |
title_fullStr |
Quantifying the performance of selective devices by combining analysis of catch data and fish behaviour observations: methodology and case study on a flatfish excluder |
title_full_unstemmed |
Quantifying the performance of selective devices by combining analysis of catch data and fish behaviour observations: methodology and case study on a flatfish excluder |
title_sort |
quantifying the performance of selective devices by combining analysis of catch data and fish behaviour observations: methodology and case study on a flatfish excluder |
publisher |
Oxford University Press (OUP) |
publishDate |
2020 |
url |
http://dx.doi.org/10.1093/icesjms/fsaa155 http://academic.oup.com/icesjms/article-pdf/77/7-8/2840/35589072/fsaa155.pdf |
genre |
Gadus morhua |
genre_facet |
Gadus morhua |
op_source |
ICES Journal of Marine Science volume 77, issue 7-8, page 2840-2856 ISSN 1095-9289 |
op_rights |
https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model |
op_doi |
https://doi.org/10.1093/icesjms/fsaa155 |
container_title |
ICES Journal of Marine Science |
container_volume |
77 |
container_issue |
7-8 |
container_start_page |
2840 |
op_container_end_page |
2856 |
_version_ |
1812813652183482368 |