Diurnal variations in bottom trawl catch rates of cod and haddock and their influence on abundance indices
Analyses of sampling data from Norwegian bottom trawl surveys for cod and haddock in the Barents Sea and the Svalbard area show that the trawl catches do not provide a representative sample of small fish in the area. In this paper, catch rates of cod and haddock from six different experiments carrie...
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1992
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fthighwire:oai:open-archive.highwire.org:icesjms:49/1/89 2023-05-15T15:38:52+02:00 Diurnal variations in bottom trawl catch rates of cod and haddock and their influence on abundance indices Engås, Arill Soldal, Aud Void 1992-02-01 00:00:00.0 text/html http://icesjms.oxfordjournals.org/cgi/content/short/49/1/89 https://doi.org/10.1093/icesjms/49.1.89 en eng Oxford University Press http://icesjms.oxfordjournals.org/cgi/content/short/49/1/89 http://dx.doi.org/10.1093/icesjms/49.1.89 Copyright (C) 1992, International Council for the Exploration of the Sea/Conseil International pour l'Exploration de la Mer Articles TEXT 1992 fthighwire https://doi.org/10.1093/icesjms/49.1.89 2013-05-27T17:55:09Z Analyses of sampling data from Norwegian bottom trawl surveys for cod and haddock in the Barents Sea and the Svalbard area show that the trawl catches do not provide a representative sample of small fish in the area. In this paper, catch rates of cod and haddock from six different experiments carried out within a limited area of the same survey strata were examined according to time of day. Catch rates of cod and haddock were higher by day. Diurnal differences were also observed in species composition and length-frequency distribution. It is concluded that the trawl catch rates cannot be relied upon to provide a truly representative estimate of the entire length range of the species in question. Effects of the observed diurnal differences on bottom trawl index estimates and on the conversion of acoustic abundance to absolute fish density are discussed. Text Barents Sea Svalbard HighWire Press (Stanford University) Svalbard Barents Sea ICES Journal of Marine Science 49 1 89 95 |
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English |
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Articles Engås, Arill Soldal, Aud Void Diurnal variations in bottom trawl catch rates of cod and haddock and their influence on abundance indices |
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Articles |
description |
Analyses of sampling data from Norwegian bottom trawl surveys for cod and haddock in the Barents Sea and the Svalbard area show that the trawl catches do not provide a representative sample of small fish in the area. In this paper, catch rates of cod and haddock from six different experiments carried out within a limited area of the same survey strata were examined according to time of day. Catch rates of cod and haddock were higher by day. Diurnal differences were also observed in species composition and length-frequency distribution. It is concluded that the trawl catch rates cannot be relied upon to provide a truly representative estimate of the entire length range of the species in question. Effects of the observed diurnal differences on bottom trawl index estimates and on the conversion of acoustic abundance to absolute fish density are discussed. |
format |
Text |
author |
Engås, Arill Soldal, Aud Void |
author_facet |
Engås, Arill Soldal, Aud Void |
author_sort |
Engås, Arill |
title |
Diurnal variations in bottom trawl catch rates of cod and haddock and their influence on abundance indices |
title_short |
Diurnal variations in bottom trawl catch rates of cod and haddock and their influence on abundance indices |
title_full |
Diurnal variations in bottom trawl catch rates of cod and haddock and their influence on abundance indices |
title_fullStr |
Diurnal variations in bottom trawl catch rates of cod and haddock and their influence on abundance indices |
title_full_unstemmed |
Diurnal variations in bottom trawl catch rates of cod and haddock and their influence on abundance indices |
title_sort |
diurnal variations in bottom trawl catch rates of cod and haddock and their influence on abundance indices |
publisher |
Oxford University Press |
publishDate |
1992 |
url |
http://icesjms.oxfordjournals.org/cgi/content/short/49/1/89 https://doi.org/10.1093/icesjms/49.1.89 |
geographic |
Svalbard Barents Sea |
geographic_facet |
Svalbard Barents Sea |
genre |
Barents Sea Svalbard |
genre_facet |
Barents Sea Svalbard |
op_relation |
http://icesjms.oxfordjournals.org/cgi/content/short/49/1/89 http://dx.doi.org/10.1093/icesjms/49.1.89 |
op_rights |
Copyright (C) 1992, International Council for the Exploration of the Sea/Conseil International pour l'Exploration de la Mer |
op_doi |
https://doi.org/10.1093/icesjms/49.1.89 |
container_title |
ICES Journal of Marine Science |
container_volume |
49 |
container_issue |
1 |
container_start_page |
89 |
op_container_end_page |
95 |
_version_ |
1766370269638688768 |