Identification of Southern Ocean acoustic targets using aggregation backscatter and shape characteristics
Abstract 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 o...
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Language: | English |
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2003
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Online Access: | http://dx.doi.org/10.1016/s1054-3139(03)00062-6 http://academic.oup.com/icesjms/article-pdf/60/3/641/29119461/60-3-641.pdf |
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croxfordunivpr:10.1016/s1054-3139(03)00062-6 2023-12-31T10:01:08+01:00 Identification of Southern Ocean acoustic targets using aggregation backscatter and shape characteristics Woodd-Walker, Rachel S Watkins, Jonathan L Brierley, Andrew S 2003 http://dx.doi.org/10.1016/s1054-3139(03)00062-6 http://academic.oup.com/icesjms/article-pdf/60/3/641/29119461/60-3-641.pdf en eng Oxford University Press (OUP) ICES Journal of Marine Science volume 60, issue 3, page 641-649 ISSN 1095-9289 1054-3139 Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics Oceanography journal-article 2003 croxfordunivpr https://doi.org/10.1016/s1054-3139(03)00062-6 2023-12-06T08:41:21Z Abstract 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 Oxford University Press (via Crossref) ICES Journal of Marine Science 60 3 641 649 |
institution |
Open Polar |
collection |
Oxford University Press (via Crossref) |
op_collection_id |
croxfordunivpr |
language |
English |
topic |
Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics Oceanography |
spellingShingle |
Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics Oceanography Woodd-Walker, Rachel S Watkins, Jonathan L Brierley, Andrew S Identification of Southern Ocean acoustic targets using aggregation backscatter and shape characteristics |
topic_facet |
Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics Oceanography |
description |
Abstract 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 |
Oxford University Press (OUP) |
publishDate |
2003 |
url |
http://dx.doi.org/10.1016/s1054-3139(03)00062-6 http://academic.oup.com/icesjms/article-pdf/60/3/641/29119461/60-3-641.pdf |
genre |
Antarc* Antarctic Antarctic Krill Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Krill Southern Ocean |
op_source |
ICES Journal of Marine Science volume 60, issue 3, page 641-649 ISSN 1095-9289 1054-3139 |
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_ |
1786795748880285696 |