Tilt angle and target strength: target tracking of Atlantic cod (Gadus morhua) during trawling
Abstract Vertical orientation (tilt angle) is known to affect the target strength (TS) of ensonified fish and is a large component of the variability inherent in acoustic-biomass estimates. To measure the effects of changes in tilt angle on TS during diel vertical migrations, a concentration of migr...
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Online Access: | http://dx.doi.org/10.1016/s1054-3139(03)000390 http://academic.oup.com/icesjms/article-pdf/60/3/575/29119785/60-3-575.pdf |
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croxfordunivpr:10.1016/s1054-3139(03)000390 2024-05-12T08:00:56+00:00 Tilt angle and target strength: target tracking of Atlantic cod (Gadus morhua) during trawling McQuinn, Ian H Winger, Paul D 2003 http://dx.doi.org/10.1016/s1054-3139(03)000390 http://academic.oup.com/icesjms/article-pdf/60/3/575/29119785/60-3-575.pdf en eng Oxford University Press (OUP) ICES Journal of Marine Science volume 60, issue 3, page 575-583 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)000390 2024-04-18T08:16:18Z Abstract Vertical orientation (tilt angle) is known to affect the target strength (TS) of ensonified fish and is a large component of the variability inherent in acoustic-biomass estimates. To measure the effects of changes in tilt angle on TS during diel vertical migrations, a concentration of migrating Atlantic cod (Gadus morhua) was observed acoustically from a research vessel over several days. Single-target data were collected from a split-beam echosounder and were subsequently tracked, corrected for vessel orientation and movement, and analysed for 3-dimensional displacement (speed and direction). The results revealed a large variability in TS and several patterns of swimming behaviour from random to directed orientation and movement, with changes in both vertical and horizontal displacements and inferred orientation. These behavioural patterns and their affects on TS were analysed as a function of “time-since-sunset”. Regular diel orientation patterns were observed as cod rose from the ocean bottom in the evening, increasing their tilt angle, and descended at sunrise to regain the ocean floor. Standardized TS (B20) was found to be highly correlated with tilt angle. This relationship can be used to correct for the diel changes in the TS of these migrating cod as a function of the in situ-measured tilt angle and thus to improve the accuracy of acoustic-biomass estimation. Article in Journal/Newspaper atlantic cod Gadus morhua Oxford University Press ICES Journal of Marine Science 60 3 575 583 |
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Open Polar |
collection |
Oxford University Press |
op_collection_id |
croxfordunivpr |
language |
English |
topic |
Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics Oceanography |
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Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics Oceanography McQuinn, Ian H Winger, Paul D Tilt angle and target strength: target tracking of Atlantic cod (Gadus morhua) during trawling |
topic_facet |
Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics Oceanography |
description |
Abstract Vertical orientation (tilt angle) is known to affect the target strength (TS) of ensonified fish and is a large component of the variability inherent in acoustic-biomass estimates. To measure the effects of changes in tilt angle on TS during diel vertical migrations, a concentration of migrating Atlantic cod (Gadus morhua) was observed acoustically from a research vessel over several days. Single-target data were collected from a split-beam echosounder and were subsequently tracked, corrected for vessel orientation and movement, and analysed for 3-dimensional displacement (speed and direction). The results revealed a large variability in TS and several patterns of swimming behaviour from random to directed orientation and movement, with changes in both vertical and horizontal displacements and inferred orientation. These behavioural patterns and their affects on TS were analysed as a function of “time-since-sunset”. Regular diel orientation patterns were observed as cod rose from the ocean bottom in the evening, increasing their tilt angle, and descended at sunrise to regain the ocean floor. Standardized TS (B20) was found to be highly correlated with tilt angle. This relationship can be used to correct for the diel changes in the TS of these migrating cod as a function of the in situ-measured tilt angle and thus to improve the accuracy of acoustic-biomass estimation. |
format |
Article in Journal/Newspaper |
author |
McQuinn, Ian H Winger, Paul D |
author_facet |
McQuinn, Ian H Winger, Paul D |
author_sort |
McQuinn, Ian H |
title |
Tilt angle and target strength: target tracking of Atlantic cod (Gadus morhua) during trawling |
title_short |
Tilt angle and target strength: target tracking of Atlantic cod (Gadus morhua) during trawling |
title_full |
Tilt angle and target strength: target tracking of Atlantic cod (Gadus morhua) during trawling |
title_fullStr |
Tilt angle and target strength: target tracking of Atlantic cod (Gadus morhua) during trawling |
title_full_unstemmed |
Tilt angle and target strength: target tracking of Atlantic cod (Gadus morhua) during trawling |
title_sort |
tilt angle and target strength: target tracking of atlantic cod (gadus morhua) during trawling |
publisher |
Oxford University Press (OUP) |
publishDate |
2003 |
url |
http://dx.doi.org/10.1016/s1054-3139(03)000390 http://academic.oup.com/icesjms/article-pdf/60/3/575/29119785/60-3-575.pdf |
genre |
atlantic cod Gadus morhua |
genre_facet |
atlantic cod Gadus morhua |
op_source |
ICES Journal of Marine Science volume 60, issue 3, page 575-583 ISSN 1095-9289 1054-3139 |
op_doi |
https://doi.org/10.1016/s1054-3139(03)000390 |
container_title |
ICES Journal of Marine Science |
container_volume |
60 |
container_issue |
3 |
container_start_page |
575 |
op_container_end_page |
583 |
_version_ |
1798842989119799296 |