Application of an unsupervised clustering algorithm on in situ broadband acoustic data to identify different mesopelagic target types
The mesopelagic zone (200–1000 m depth) contains high fish species diversity but biomass and abundances are uncertain yet essential to understand ecosystem functioning. Hull-mounted acoustic systems (usually 38 kHz) often make assumptions on average target strength (TS) of mesopelagic fish assemblag...
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Online Access: | https://hdl.handle.net/11250/2827817 https://doi.org/10.1093/icesjms/fsab167 |
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ftimr:oai:imr.brage.unit.no:11250/2827817 2023-05-15T17:41:29+02:00 Application of an unsupervised clustering algorithm on in situ broadband acoustic data to identify different mesopelagic target types Agersted, Mette Dalgaard Khodabandeloo, Babak Liu, Yi Melle, Webjørn Raunsgård Klevjer, Thor Aleksander 2021 application/pdf https://hdl.handle.net/11250/2827817 https://doi.org/10.1093/icesjms/fsab167 eng eng Norges forskningsråd: 280 546 EC/H2020/817669 ICES Journal of Marine Science. 2021, 78 (8), 2907-2921. urn:issn:1054-3139 https://hdl.handle.net/11250/2827817 https://doi.org/10.1093/icesjms/fsab167 cristin:1934839 2907-2921 78 ICES Journal of Marine Science 8 Peer reviewed Journal article 2021 ftimr https://doi.org/10.1093/icesjms/fsab167 2021-11-10T23:36:42Z The mesopelagic zone (200–1000 m depth) contains high fish species diversity but biomass and abundances are uncertain yet essential to understand ecosystem functioning. Hull-mounted acoustic systems (usually 38 kHz) often make assumptions on average target strength (TS) of mesopelagic fish assemblages when estimating biomass/abundance. Here, an unsupervised clustering algorithm was applied on broadband acoustic data (54–78 kHz), collected by a towed instrumented platform in the central Northeast Atlantic, to identify different mesopelagic target types based on similarity of individual TS spectra. Numerical density estimates from echo-counting showed spatial differences in vertical distribution patterns of the different target types and TS spectra data suggested that >30% of the gas-bearing targets had high resonance frequencies (>60 kHz) with low scattering strength at 38 kHz. This conceptual study highlights the importance of separating targets into different target groups to obtain correct backscatter information and to account for all relevant scatterers when estimating average TS at 38 kHz, in order to achieve more accurate biomass/abundance estimates. It furthermore demonstrates the use of a towed broadband acoustic platform for fine-scale numerical density estimates as a complementary method to hull-mounted acoustic data to increase knowledge on mesopelagic ecosystem structure. publishedVersion Article in Journal/Newspaper Northeast Atlantic Institute for Marine Research: Brage IMR ICES Journal of Marine Science 78 8 2907 2921 |
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Open Polar |
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Institute for Marine Research: Brage IMR |
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ftimr |
language |
English |
description |
The mesopelagic zone (200–1000 m depth) contains high fish species diversity but biomass and abundances are uncertain yet essential to understand ecosystem functioning. Hull-mounted acoustic systems (usually 38 kHz) often make assumptions on average target strength (TS) of mesopelagic fish assemblages when estimating biomass/abundance. Here, an unsupervised clustering algorithm was applied on broadband acoustic data (54–78 kHz), collected by a towed instrumented platform in the central Northeast Atlantic, to identify different mesopelagic target types based on similarity of individual TS spectra. Numerical density estimates from echo-counting showed spatial differences in vertical distribution patterns of the different target types and TS spectra data suggested that >30% of the gas-bearing targets had high resonance frequencies (>60 kHz) with low scattering strength at 38 kHz. This conceptual study highlights the importance of separating targets into different target groups to obtain correct backscatter information and to account for all relevant scatterers when estimating average TS at 38 kHz, in order to achieve more accurate biomass/abundance estimates. It furthermore demonstrates the use of a towed broadband acoustic platform for fine-scale numerical density estimates as a complementary method to hull-mounted acoustic data to increase knowledge on mesopelagic ecosystem structure. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Agersted, Mette Dalgaard Khodabandeloo, Babak Liu, Yi Melle, Webjørn Raunsgård Klevjer, Thor Aleksander |
spellingShingle |
Agersted, Mette Dalgaard Khodabandeloo, Babak Liu, Yi Melle, Webjørn Raunsgård Klevjer, Thor Aleksander Application of an unsupervised clustering algorithm on in situ broadband acoustic data to identify different mesopelagic target types |
author_facet |
Agersted, Mette Dalgaard Khodabandeloo, Babak Liu, Yi Melle, Webjørn Raunsgård Klevjer, Thor Aleksander |
author_sort |
Agersted, Mette Dalgaard |
title |
Application of an unsupervised clustering algorithm on in situ broadband acoustic data to identify different mesopelagic target types |
title_short |
Application of an unsupervised clustering algorithm on in situ broadband acoustic data to identify different mesopelagic target types |
title_full |
Application of an unsupervised clustering algorithm on in situ broadband acoustic data to identify different mesopelagic target types |
title_fullStr |
Application of an unsupervised clustering algorithm on in situ broadband acoustic data to identify different mesopelagic target types |
title_full_unstemmed |
Application of an unsupervised clustering algorithm on in situ broadband acoustic data to identify different mesopelagic target types |
title_sort |
application of an unsupervised clustering algorithm on in situ broadband acoustic data to identify different mesopelagic target types |
publishDate |
2021 |
url |
https://hdl.handle.net/11250/2827817 https://doi.org/10.1093/icesjms/fsab167 |
genre |
Northeast Atlantic |
genre_facet |
Northeast Atlantic |
op_source |
2907-2921 78 ICES Journal of Marine Science 8 |
op_relation |
Norges forskningsråd: 280 546 EC/H2020/817669 ICES Journal of Marine Science. 2021, 78 (8), 2907-2921. urn:issn:1054-3139 https://hdl.handle.net/11250/2827817 https://doi.org/10.1093/icesjms/fsab167 cristin:1934839 |
op_doi |
https://doi.org/10.1093/icesjms/fsab167 |
container_title |
ICES Journal of Marine Science |
container_volume |
78 |
container_issue |
8 |
container_start_page |
2907 |
op_container_end_page |
2921 |
_version_ |
1766143055833858048 |