Poor feeding opportunities and reduced condition factor for salmon post-smolts in the Northeast Atlantic Ocean
Abstract During the last few decades, many wild Atlantic salmon populations have declined dramatically. One possible contributing factor for the decline is reduced prey availability at sea. Here, we examine post-smolt diet and investigate if post-smolts show signs of selective feeding based on 2546...
Published in: | ICES Journal of Marine Science |
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Language: | English |
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Oxford University Press (OUP)
2021
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Online Access: | http://dx.doi.org/10.1093/icesjms/fsab163 https://academic.oup.com/icesjms/article-pdf/78/8/2844/42162377/fsab163.pdf |
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croxfordunivpr:10.1093/icesjms/fsab163 2024-06-23T07:51:23+00:00 Poor feeding opportunities and reduced condition factor for salmon post-smolts in the Northeast Atlantic Ocean Utne, Kjell Rong Pauli, Beatriz Diaz Haugland, Monika Jacobsen, Jan Arge Maoileidigh, Niall Melle, Webjørn Broms, Cecilie Thorsen Nøttestad, Leif Holm, Marianne Thomas, Katie Wennevik, Vidar Secor, David Research Council of Norway 2021 http://dx.doi.org/10.1093/icesjms/fsab163 https://academic.oup.com/icesjms/article-pdf/78/8/2844/42162377/fsab163.pdf en eng Oxford University Press (OUP) https://creativecommons.org/licenses/by/4.0/ ICES Journal of Marine Science volume 78, issue 8, page 2844-2857 ISSN 1054-3139 1095-9289 journal-article 2021 croxfordunivpr https://doi.org/10.1093/icesjms/fsab163 2024-06-11T04:19:25Z Abstract During the last few decades, many wild Atlantic salmon populations have declined dramatically. One possible contributing factor for the decline is reduced prey availability at sea. Here, we examine post-smolt diet and investigate if post-smolts show signs of selective feeding based on 2546 post-smolts sampled from west of Ireland to the northern Norwegian Sea over a 25-year period. We also test for changes over time in stomach fullness, diet, condition factor and body length. There was a clear reduction in condition factor for post-smolts sampled in the Norwegian Sea in the period 2003–2012. The post-smolt stomach fullness was also reduced in the same period. The reduction in condition factor is partly explained by reduced stomach fullness, including a reduction of highly energetic fish larvae and Amphipoda in the diet. Feeding on other prey, such as meso-zooplankton and insects, cannot substitute the high-quality fish larvae and Amphipoda in the post-smolt diet. This is the first study to document how salmon post-smolts feeding in the Norwegian Sea are affected by reduced feeding conditions. Possible causes for the observed changes in post-smolt feeding are ocean warming, decreased primary productivity, and reduced recruitment of important fish larvae. Article in Journal/Newspaper Atlantic salmon Northeast Atlantic Norwegian Sea Oxford University Press Norwegian Sea ICES Journal of Marine Science |
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Open Polar |
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Oxford University Press |
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croxfordunivpr |
language |
English |
description |
Abstract During the last few decades, many wild Atlantic salmon populations have declined dramatically. One possible contributing factor for the decline is reduced prey availability at sea. Here, we examine post-smolt diet and investigate if post-smolts show signs of selective feeding based on 2546 post-smolts sampled from west of Ireland to the northern Norwegian Sea over a 25-year period. We also test for changes over time in stomach fullness, diet, condition factor and body length. There was a clear reduction in condition factor for post-smolts sampled in the Norwegian Sea in the period 2003–2012. The post-smolt stomach fullness was also reduced in the same period. The reduction in condition factor is partly explained by reduced stomach fullness, including a reduction of highly energetic fish larvae and Amphipoda in the diet. Feeding on other prey, such as meso-zooplankton and insects, cannot substitute the high-quality fish larvae and Amphipoda in the post-smolt diet. This is the first study to document how salmon post-smolts feeding in the Norwegian Sea are affected by reduced feeding conditions. Possible causes for the observed changes in post-smolt feeding are ocean warming, decreased primary productivity, and reduced recruitment of important fish larvae. |
author2 |
Secor, David Research Council of Norway |
format |
Article in Journal/Newspaper |
author |
Utne, Kjell Rong Pauli, Beatriz Diaz Haugland, Monika Jacobsen, Jan Arge Maoileidigh, Niall Melle, Webjørn Broms, Cecilie Thorsen Nøttestad, Leif Holm, Marianne Thomas, Katie Wennevik, Vidar |
spellingShingle |
Utne, Kjell Rong Pauli, Beatriz Diaz Haugland, Monika Jacobsen, Jan Arge Maoileidigh, Niall Melle, Webjørn Broms, Cecilie Thorsen Nøttestad, Leif Holm, Marianne Thomas, Katie Wennevik, Vidar Poor feeding opportunities and reduced condition factor for salmon post-smolts in the Northeast Atlantic Ocean |
author_facet |
Utne, Kjell Rong Pauli, Beatriz Diaz Haugland, Monika Jacobsen, Jan Arge Maoileidigh, Niall Melle, Webjørn Broms, Cecilie Thorsen Nøttestad, Leif Holm, Marianne Thomas, Katie Wennevik, Vidar |
author_sort |
Utne, Kjell Rong |
title |
Poor feeding opportunities and reduced condition factor for salmon post-smolts in the Northeast Atlantic Ocean |
title_short |
Poor feeding opportunities and reduced condition factor for salmon post-smolts in the Northeast Atlantic Ocean |
title_full |
Poor feeding opportunities and reduced condition factor for salmon post-smolts in the Northeast Atlantic Ocean |
title_fullStr |
Poor feeding opportunities and reduced condition factor for salmon post-smolts in the Northeast Atlantic Ocean |
title_full_unstemmed |
Poor feeding opportunities and reduced condition factor for salmon post-smolts in the Northeast Atlantic Ocean |
title_sort |
poor feeding opportunities and reduced condition factor for salmon post-smolts in the northeast atlantic ocean |
publisher |
Oxford University Press (OUP) |
publishDate |
2021 |
url |
http://dx.doi.org/10.1093/icesjms/fsab163 https://academic.oup.com/icesjms/article-pdf/78/8/2844/42162377/fsab163.pdf |
geographic |
Norwegian Sea |
geographic_facet |
Norwegian Sea |
genre |
Atlantic salmon Northeast Atlantic Norwegian Sea |
genre_facet |
Atlantic salmon Northeast Atlantic Norwegian Sea |
op_source |
ICES Journal of Marine Science volume 78, issue 8, page 2844-2857 ISSN 1054-3139 1095-9289 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1093/icesjms/fsab163 |
container_title |
ICES Journal of Marine Science |
_version_ |
1802642478533181440 |