When fish meet a trawling vessel: examining the behaviour of gadoids using a free-floating buoy and acoustic split-beam tracking
The reaction of individual gadoids to a bottom-trawling vessel has been observed in situ in the Barents Sea using a free-floating buoy and acoustic target-tracking methods. More than 20 000 tracks were analysed in terms of velocity changes in vertical, athwarthship, and alongship direction relative...
Published in: | Canadian Journal of Fisheries and Aquatic Sciences |
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Format: | Article in Journal/Newspaper |
Language: | English |
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NRC Research Press
2005
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Online Access: | http://hdl.handle.net/11250/108691 https://doi.org/10.1139/F05-131 |
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ftimr:oai:imr.brage.unit.no:11250/108691 2023-05-15T15:38:57+02:00 When fish meet a trawling vessel: examining the behaviour of gadoids using a free-floating buoy and acoustic split-beam tracking Handegard, Nils Olav Tjøstheim, Dag 2005 647003 bytes application/pdf http://hdl.handle.net/11250/108691 https://doi.org/10.1139/F05-131 eng eng NRC Research Press urn:issn:0706-652X http://hdl.handle.net/11250/108691 http://dx.doi.org/10.1139/F05-131 2409-2422 62 Canadian Journal of Fisheries and Aquatic Sciences 10 cod torsk trawling tråling Journal article Peer reviewed 2005 ftimr https://doi.org/10.1139/F05-131 2021-09-23T20:14:32Z The reaction of individual gadoids to a bottom-trawling vessel has been observed in situ in the Barents Sea using a free-floating buoy and acoustic target-tracking methods. More than 20 000 tracks were analysed in terms of velocity changes in vertical, athwarthship, and alongship direction relative to the vessel, the warps, and the trawl, respectively. The fish starts diving about 15 min before vessel passing. This coincides with the time the trawl is running and not with the gradual increase in vessel noise caused by the approaching vessel. The change in horizontal movement is more gradual and is directed away from the vessel in the alongship direction, but towards the vessel in the athwarthship direction. The strongest and sharpest response is related to the trawl warps. A strong herding in front of the warps is seen. Closer to the bottom, an athwarthship herding reaction is seen away from the trawl doors or possibly the lower parts of the warps. There were only minor differences when grouping the tracks according to light level, fish size, and fish density. Article in Journal/Newspaper Barents Sea Institute for Marine Research: Brage IMR Barents Sea Canadian Journal of Fisheries and Aquatic Sciences 62 10 2409 2422 |
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Open Polar |
collection |
Institute for Marine Research: Brage IMR |
op_collection_id |
ftimr |
language |
English |
topic |
cod torsk trawling tråling |
spellingShingle |
cod torsk trawling tråling Handegard, Nils Olav Tjøstheim, Dag When fish meet a trawling vessel: examining the behaviour of gadoids using a free-floating buoy and acoustic split-beam tracking |
topic_facet |
cod torsk trawling tråling |
description |
The reaction of individual gadoids to a bottom-trawling vessel has been observed in situ in the Barents Sea using a free-floating buoy and acoustic target-tracking methods. More than 20 000 tracks were analysed in terms of velocity changes in vertical, athwarthship, and alongship direction relative to the vessel, the warps, and the trawl, respectively. The fish starts diving about 15 min before vessel passing. This coincides with the time the trawl is running and not with the gradual increase in vessel noise caused by the approaching vessel. The change in horizontal movement is more gradual and is directed away from the vessel in the alongship direction, but towards the vessel in the athwarthship direction. The strongest and sharpest response is related to the trawl warps. A strong herding in front of the warps is seen. Closer to the bottom, an athwarthship herding reaction is seen away from the trawl doors or possibly the lower parts of the warps. There were only minor differences when grouping the tracks according to light level, fish size, and fish density. |
format |
Article in Journal/Newspaper |
author |
Handegard, Nils Olav Tjøstheim, Dag |
author_facet |
Handegard, Nils Olav Tjøstheim, Dag |
author_sort |
Handegard, Nils Olav |
title |
When fish meet a trawling vessel: examining the behaviour of gadoids using a free-floating buoy and acoustic split-beam tracking |
title_short |
When fish meet a trawling vessel: examining the behaviour of gadoids using a free-floating buoy and acoustic split-beam tracking |
title_full |
When fish meet a trawling vessel: examining the behaviour of gadoids using a free-floating buoy and acoustic split-beam tracking |
title_fullStr |
When fish meet a trawling vessel: examining the behaviour of gadoids using a free-floating buoy and acoustic split-beam tracking |
title_full_unstemmed |
When fish meet a trawling vessel: examining the behaviour of gadoids using a free-floating buoy and acoustic split-beam tracking |
title_sort |
when fish meet a trawling vessel: examining the behaviour of gadoids using a free-floating buoy and acoustic split-beam tracking |
publisher |
NRC Research Press |
publishDate |
2005 |
url |
http://hdl.handle.net/11250/108691 https://doi.org/10.1139/F05-131 |
geographic |
Barents Sea |
geographic_facet |
Barents Sea |
genre |
Barents Sea |
genre_facet |
Barents Sea |
op_source |
2409-2422 62 Canadian Journal of Fisheries and Aquatic Sciences 10 |
op_relation |
urn:issn:0706-652X http://hdl.handle.net/11250/108691 http://dx.doi.org/10.1139/F05-131 |
op_doi |
https://doi.org/10.1139/F05-131 |
container_title |
Canadian Journal of Fisheries and Aquatic Sciences |
container_volume |
62 |
container_issue |
10 |
container_start_page |
2409 |
op_container_end_page |
2422 |
_version_ |
1766370378854170624 |