Identification of Southern Ocean acoustic targets using aggregation backscatter and shape characteristics
Acoustic surveys for biomass estimation require accurate identification of echoes from the target species. In one objective technique for identifying Antarctic krill, the difference between mean volume-backscattering strength at two frequencies is used, but can misclassify small krill and other plan...
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2003
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Online Access: | http://nora.nerc.ac.uk/id/eprint/13078/ http://icesjms.oxfordjournals.org/content/60/3/641.full |
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ftnerc:oai:nora.nerc.ac.uk:13078 2023-05-15T13:45:11+02:00 Identification of Southern Ocean acoustic targets using aggregation backscatter and shape characteristics Woodd-Walker, Rachel S. Watkins, Jonathan L. Brierley, Andrew S. 2003 http://nora.nerc.ac.uk/id/eprint/13078/ http://icesjms.oxfordjournals.org/content/60/3/641.full unknown Academic Press LTD Woodd-Walker, Rachel S.; Watkins, Jonathan L.; Brierley, Andrew S. 2003 Identification of Southern Ocean acoustic targets using aggregation backscatter and shape characteristics. ICES Journal of Marine Science, 60 (3). 641-649. https://doi.org/10.1016/S1054-3139(03)00062-6 <https://doi.org/10.1016/S1054-3139(03)00062-6> Marine Sciences Zoology Ecology and Environment Publication - Article PeerReviewed 2003 ftnerc https://doi.org/10.1016/S1054-3139(03)00062-6 2023-02-04T19:28:22Z Acoustic surveys for biomass estimation require accurate identification of echoes from the target species. In one objective technique for identifying Antarctic krill, the difference between mean volume-backscattering strength at two frequencies is used, but can misclassify small krill and other plankton. Here, we investigate ways to improve target identification by including characteristics of backscattering energy and morphology of aggregations. To do this, multi-frequency acoustic data were collected concurrently with target fishing of Antarctic krill and other euphausiid and salp aggregations. Parameter sets for these known aggregations were collated and used to develop empirical classifications. Both linear discriminant-function analysis (DFA) and the artificial neural network technique were employed. In both cases, acoustic-backscattering energy parameters were most important for discriminating between Antarctic krill and other zooplankton. However, swarm morphology and other parameters improved the discrimination, particularly between krill and salps. Our study suggests that for krill-biomass estimates, a simple DFA based on acoustic-energy parameters is a substantial improvement over current dB-difference acoustic methods; but studies requiring the discrimination of zooplankton other than krill must still be supported by target fishing. Article in Journal/Newspaper Antarc* Antarctic Antarctic Krill Southern Ocean Natural Environment Research Council: NERC Open Research Archive Antarctic Southern Ocean ICES Journal of Marine Science 60 3 641 649 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
topic |
Marine Sciences Zoology Ecology and Environment |
spellingShingle |
Marine Sciences Zoology Ecology and Environment Woodd-Walker, Rachel S. Watkins, Jonathan L. Brierley, Andrew S. Identification of Southern Ocean acoustic targets using aggregation backscatter and shape characteristics |
topic_facet |
Marine Sciences Zoology Ecology and Environment |
description |
Acoustic surveys for biomass estimation require accurate identification of echoes from the target species. In one objective technique for identifying Antarctic krill, the difference between mean volume-backscattering strength at two frequencies is used, but can misclassify small krill and other plankton. Here, we investigate ways to improve target identification by including characteristics of backscattering energy and morphology of aggregations. To do this, multi-frequency acoustic data were collected concurrently with target fishing of Antarctic krill and other euphausiid and salp aggregations. Parameter sets for these known aggregations were collated and used to develop empirical classifications. Both linear discriminant-function analysis (DFA) and the artificial neural network technique were employed. In both cases, acoustic-backscattering energy parameters were most important for discriminating between Antarctic krill and other zooplankton. However, swarm morphology and other parameters improved the discrimination, particularly between krill and salps. Our study suggests that for krill-biomass estimates, a simple DFA based on acoustic-energy parameters is a substantial improvement over current dB-difference acoustic methods; but studies requiring the discrimination of zooplankton other than krill must still be supported by target fishing. |
format |
Article in Journal/Newspaper |
author |
Woodd-Walker, Rachel S. Watkins, Jonathan L. Brierley, Andrew S. |
author_facet |
Woodd-Walker, Rachel S. Watkins, Jonathan L. Brierley, Andrew S. |
author_sort |
Woodd-Walker, Rachel S. |
title |
Identification of Southern Ocean acoustic targets using aggregation backscatter and shape characteristics |
title_short |
Identification of Southern Ocean acoustic targets using aggregation backscatter and shape characteristics |
title_full |
Identification of Southern Ocean acoustic targets using aggregation backscatter and shape characteristics |
title_fullStr |
Identification of Southern Ocean acoustic targets using aggregation backscatter and shape characteristics |
title_full_unstemmed |
Identification of Southern Ocean acoustic targets using aggregation backscatter and shape characteristics |
title_sort |
identification of southern ocean acoustic targets using aggregation backscatter and shape characteristics |
publisher |
Academic Press LTD |
publishDate |
2003 |
url |
http://nora.nerc.ac.uk/id/eprint/13078/ http://icesjms.oxfordjournals.org/content/60/3/641.full |
geographic |
Antarctic Southern Ocean |
geographic_facet |
Antarctic Southern Ocean |
genre |
Antarc* Antarctic Antarctic Krill Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Krill Southern Ocean |
op_relation |
Woodd-Walker, Rachel S.; Watkins, Jonathan L.; Brierley, Andrew S. 2003 Identification of Southern Ocean acoustic targets using aggregation backscatter and shape characteristics. ICES Journal of Marine Science, 60 (3). 641-649. https://doi.org/10.1016/S1054-3139(03)00062-6 <https://doi.org/10.1016/S1054-3139(03)00062-6> |
op_doi |
https://doi.org/10.1016/S1054-3139(03)00062-6 |
container_title |
ICES Journal of Marine Science |
container_volume |
60 |
container_issue |
3 |
container_start_page |
641 |
op_container_end_page |
649 |
_version_ |
1766215365612797952 |