Effective herding of flatfish by cables with minimal seafloor contact
Otter trawls are very effective at capturing flatfish, but they can affect the seaf loor ecosystems where they are used. Alaska f latf ish trawlers have very long cables (called sweeps) between doors and net to herd fish into the path of the trawl. These sweeps, which ride on and can disturb the sea...
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ftaquaticcommons:oai:generic.eprints.org:8752 2023-05-15T13:09:25+02:00 Effective herding of flatfish by cables with minimal seafloor contact Rose, Craig S. Gauvin, John R. Hammond, Carwyn F. 2010 application/pdf http://aquaticcommons.org/8752/ http://fishbull.noaa.gov/1082/rose.pdf http://aquaticcommons.org/8752/1/rose_Fish_Bull_2010.pdf en eng http://aquaticcommons.org/8752/1/rose_Fish_Bull_2010.pdf Rose, Craig S. and Gauvin, John R. and Hammond, Carwyn F. (2010) Effective herding of flatfish by cables with minimal seafloor contact. Fishery Bulletin, 108(2), pp. 136-144. Biology Ecology Fisheries Article PeerReviewed 2010 ftaquaticcommons 2020-02-27T09:23:14Z Otter trawls are very effective at capturing flatfish, but they can affect the seaf loor ecosystems where they are used. Alaska f latf ish trawlers have very long cables (called sweeps) between doors and net to herd fish into the path of the trawl. These sweeps, which ride on and can disturb the seaf loor, account for most of the area affected by these trawls and hence a large proportion of the potential for damage to seaf loor organisms. We examined modifications to otter trawls, such that disk clusters were installed at 9-m intervals to raise trawl sweeps small distances above the seafloor, greatly reducing the area of direct seafloor contact. A critical consideration was whether flatfish would still be herded effectively by these sweeps. We compared conventional and modified sweeps using a twin trawl system and analyzed the volume and composition of the resulting catches. We tested sweeps raised 5, 7.5, and 10 cm and observed no significant losses of flatfish catch until sweeps were raised 10 cm, and those losses were relatively small (5–10%). No size composition changes were detected in the flatfish catches. Alaska pollock (Theragra chalcogramma) were captured at higher rates with two versions of the modified sweeps. Sonar observations of the sweeps in operation and the seaf loor after passage confirmed that the area of direct seafloor contact was greatly reduced by the modified sweep Article in Journal/Newspaper alaska pollock Theragra chalcogramma Alaska International Association of Aquatic and Marine Science Libraries and Information Centers (IAMSLIC): Aquatic Commons |
institution |
Open Polar |
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International Association of Aquatic and Marine Science Libraries and Information Centers (IAMSLIC): Aquatic Commons |
op_collection_id |
ftaquaticcommons |
language |
English |
topic |
Biology Ecology Fisheries |
spellingShingle |
Biology Ecology Fisheries Rose, Craig S. Gauvin, John R. Hammond, Carwyn F. Effective herding of flatfish by cables with minimal seafloor contact |
topic_facet |
Biology Ecology Fisheries |
description |
Otter trawls are very effective at capturing flatfish, but they can affect the seaf loor ecosystems where they are used. Alaska f latf ish trawlers have very long cables (called sweeps) between doors and net to herd fish into the path of the trawl. These sweeps, which ride on and can disturb the seaf loor, account for most of the area affected by these trawls and hence a large proportion of the potential for damage to seaf loor organisms. We examined modifications to otter trawls, such that disk clusters were installed at 9-m intervals to raise trawl sweeps small distances above the seafloor, greatly reducing the area of direct seafloor contact. A critical consideration was whether flatfish would still be herded effectively by these sweeps. We compared conventional and modified sweeps using a twin trawl system and analyzed the volume and composition of the resulting catches. We tested sweeps raised 5, 7.5, and 10 cm and observed no significant losses of flatfish catch until sweeps were raised 10 cm, and those losses were relatively small (5–10%). No size composition changes were detected in the flatfish catches. Alaska pollock (Theragra chalcogramma) were captured at higher rates with two versions of the modified sweeps. Sonar observations of the sweeps in operation and the seaf loor after passage confirmed that the area of direct seafloor contact was greatly reduced by the modified sweep |
format |
Article in Journal/Newspaper |
author |
Rose, Craig S. Gauvin, John R. Hammond, Carwyn F. |
author_facet |
Rose, Craig S. Gauvin, John R. Hammond, Carwyn F. |
author_sort |
Rose, Craig S. |
title |
Effective herding of flatfish by cables with minimal seafloor contact |
title_short |
Effective herding of flatfish by cables with minimal seafloor contact |
title_full |
Effective herding of flatfish by cables with minimal seafloor contact |
title_fullStr |
Effective herding of flatfish by cables with minimal seafloor contact |
title_full_unstemmed |
Effective herding of flatfish by cables with minimal seafloor contact |
title_sort |
effective herding of flatfish by cables with minimal seafloor contact |
publishDate |
2010 |
url |
http://aquaticcommons.org/8752/ http://fishbull.noaa.gov/1082/rose.pdf http://aquaticcommons.org/8752/1/rose_Fish_Bull_2010.pdf |
genre |
alaska pollock Theragra chalcogramma Alaska |
genre_facet |
alaska pollock Theragra chalcogramma Alaska |
op_relation |
http://aquaticcommons.org/8752/1/rose_Fish_Bull_2010.pdf Rose, Craig S. and Gauvin, John R. and Hammond, Carwyn F. (2010) Effective herding of flatfish by cables with minimal seafloor contact. Fishery Bulletin, 108(2), pp. 136-144. |
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1766175874598567936 |