Tilt angle distribution and swimming speed of overwintering Norwegian spring spawning herring
When plankton production in the feeding areas decreases in the fall, adult Norwegian spring-spawning herring migrate into two fjords in northern Norway. In these wintering areas the herring occupy deeper water. Lacking the ability to refill the swimbladder they are constantly negatively buoyant. Thi...
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1996
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fthighwire:oai:open-archive.highwire.org:icesjms:53/5/863 2023-05-15T17:43:31+02:00 Tilt angle distribution and swimming speed of overwintering Norwegian spring spawning herring Huse, Ingvar Ona, Egil 1996-10-01 00:00:00.0 text/html http://icesjms.oxfordjournals.org/cgi/content/short/53/5/863 https://doi.org/10.1006/jmsc.1996.9999 en eng Oxford University Press http://icesjms.oxfordjournals.org/cgi/content/short/53/5/863 http://dx.doi.org/10.1006/jmsc.1996.9999 Copyright (C) 1996, International Council for the Exploration of the Sea/Conseil International pour l'Exploration de la Mer Articles TEXT 1996 fthighwire https://doi.org/10.1006/jmsc.1996.9999 2013-05-26T13:04:48Z When plankton production in the feeding areas decreases in the fall, adult Norwegian spring-spawning herring migrate into two fjords in northern Norway. In these wintering areas the herring occupy deeper water. Lacking the ability to refill the swimbladder they are constantly negatively buoyant. This leads to different adaptive behaviour during the day and at night, behaviour which is reflected in swimming angle. Split-beam tracking methods and still-frame photography have been used to study the herring behaviour inside the dense wintering schools. Negative buoyancy seems to be controlled through constant swimming at speeds between 0.25–0.42 ms−1 because these are sufficiently high to generate lift when the pectoral fins are used as spoilers. During the day, when the layers aggregate, the average swimming angle is close to horizontal while positive average swimming angles of up to 40° were recorded at night. A bimodal distribution of tilt angles, with one positive and one negative component, indicating a “rise and glide” swimming strategy was also observed at night. Vertically undulating split beam tracks confirmed this particular type of swimming behaviour. As adult herring are directional targets at the echo-sounder frequency used for acoustic assessment of the stock, the possible impact of the observed tilt angles on average acoustic target strength is discussed. Text Northern Norway HighWire Press (Stanford University) Norway ICES Journal of Marine Science 53 5 863 873 |
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English |
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Articles |
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Articles Huse, Ingvar Ona, Egil Tilt angle distribution and swimming speed of overwintering Norwegian spring spawning herring |
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Articles |
description |
When plankton production in the feeding areas decreases in the fall, adult Norwegian spring-spawning herring migrate into two fjords in northern Norway. In these wintering areas the herring occupy deeper water. Lacking the ability to refill the swimbladder they are constantly negatively buoyant. This leads to different adaptive behaviour during the day and at night, behaviour which is reflected in swimming angle. Split-beam tracking methods and still-frame photography have been used to study the herring behaviour inside the dense wintering schools. Negative buoyancy seems to be controlled through constant swimming at speeds between 0.25–0.42 ms−1 because these are sufficiently high to generate lift when the pectoral fins are used as spoilers. During the day, when the layers aggregate, the average swimming angle is close to horizontal while positive average swimming angles of up to 40° were recorded at night. A bimodal distribution of tilt angles, with one positive and one negative component, indicating a “rise and glide” swimming strategy was also observed at night. Vertically undulating split beam tracks confirmed this particular type of swimming behaviour. As adult herring are directional targets at the echo-sounder frequency used for acoustic assessment of the stock, the possible impact of the observed tilt angles on average acoustic target strength is discussed. |
format |
Text |
author |
Huse, Ingvar Ona, Egil |
author_facet |
Huse, Ingvar Ona, Egil |
author_sort |
Huse, Ingvar |
title |
Tilt angle distribution and swimming speed of overwintering Norwegian spring spawning herring |
title_short |
Tilt angle distribution and swimming speed of overwintering Norwegian spring spawning herring |
title_full |
Tilt angle distribution and swimming speed of overwintering Norwegian spring spawning herring |
title_fullStr |
Tilt angle distribution and swimming speed of overwintering Norwegian spring spawning herring |
title_full_unstemmed |
Tilt angle distribution and swimming speed of overwintering Norwegian spring spawning herring |
title_sort |
tilt angle distribution and swimming speed of overwintering norwegian spring spawning herring |
publisher |
Oxford University Press |
publishDate |
1996 |
url |
http://icesjms.oxfordjournals.org/cgi/content/short/53/5/863 https://doi.org/10.1006/jmsc.1996.9999 |
geographic |
Norway |
geographic_facet |
Norway |
genre |
Northern Norway |
genre_facet |
Northern Norway |
op_relation |
http://icesjms.oxfordjournals.org/cgi/content/short/53/5/863 http://dx.doi.org/10.1006/jmsc.1996.9999 |
op_rights |
Copyright (C) 1996, International Council for the Exploration of the Sea/Conseil International pour l'Exploration de la Mer |
op_doi |
https://doi.org/10.1006/jmsc.1996.9999 |
container_title |
ICES Journal of Marine Science |
container_volume |
53 |
container_issue |
5 |
container_start_page |
863 |
op_container_end_page |
873 |
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1766145608710619136 |