Extensive avoidance behaviour of krill from predators and nets
Abstract We used echosounders to assess krill (Meganyctiphanes norvegica) responses to sampling gear and predators. Towing pelagic trawls above autonomous submerged, upward-looking echosounders revealed instantaneous diving by the krill during daytime but not at night. The krill dived at 10–30 cm s−...
Published in: | ICES Journal of Marine Science |
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Format: | Article in Journal/Newspaper |
Language: | English |
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Oxford University Press (OUP)
2024
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Online Access: | http://dx.doi.org/10.1093/icesjms/fsae123 https://academic.oup.com/icesjms/advance-article-pdf/doi/10.1093/icesjms/fsae123/59029537/fsae123.pdf |
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croxfordunivpr:10.1093/icesjms/fsae123 2024-09-30T14:38:24+00:00 Extensive avoidance behaviour of krill from predators and nets Christiansen, Svenja Bråthen, Mabel Pernille Moksnes, Fredrik Lund Schmedling, Charlotte Aurora Thorsby, Sara Jegstad Titelman, Josefin Kaartvedt, Stein Fields, David EU 2024 http://dx.doi.org/10.1093/icesjms/fsae123 https://academic.oup.com/icesjms/advance-article-pdf/doi/10.1093/icesjms/fsae123/59029537/fsae123.pdf en eng Oxford University Press (OUP) https://creativecommons.org/licenses/by/4.0/ ICES Journal of Marine Science ISSN 1054-3139 1095-9289 journal-article 2024 croxfordunivpr https://doi.org/10.1093/icesjms/fsae123 2024-09-10T04:12:51Z Abstract We used echosounders to assess krill (Meganyctiphanes norvegica) responses to sampling gear and predators. Towing pelagic trawls above autonomous submerged, upward-looking echosounders revealed instantaneous diving by the krill during daytime but not at night. The krill dived at 10–30 cm s−1 with a near-simultaneous response throughout the krill layer below the gear (>10 m). Traversing the paths of the previous sampling revealed long-lasting voids in the krill distribution during the daytime. Such voids were less apparent at night. Backscatter increased in the wake of the gear during nocturnal sampling, possibly due to changes in individual backscatter related to variation in swimming behaviour. During daytime, krill responded to fish schools with instantaneous coherent diving, spanning tens of meters at speeds of 10–27 cm s−1. Coordinated and far-ranging responses indicate that even loose krill aggregations may facilitate predator avoidance by enabling efficient signal transmission between individuals. The krill antipredator behaviour instigated marked daytime krill patchiness. Krill patchiness will vary relative to the predator regime and reflect recent encounters. Article in Journal/Newspaper Meganyctiphanes norvegica Oxford University Press ICES Journal of Marine Science |
institution |
Open Polar |
collection |
Oxford University Press |
op_collection_id |
croxfordunivpr |
language |
English |
description |
Abstract We used echosounders to assess krill (Meganyctiphanes norvegica) responses to sampling gear and predators. Towing pelagic trawls above autonomous submerged, upward-looking echosounders revealed instantaneous diving by the krill during daytime but not at night. The krill dived at 10–30 cm s−1 with a near-simultaneous response throughout the krill layer below the gear (>10 m). Traversing the paths of the previous sampling revealed long-lasting voids in the krill distribution during the daytime. Such voids were less apparent at night. Backscatter increased in the wake of the gear during nocturnal sampling, possibly due to changes in individual backscatter related to variation in swimming behaviour. During daytime, krill responded to fish schools with instantaneous coherent diving, spanning tens of meters at speeds of 10–27 cm s−1. Coordinated and far-ranging responses indicate that even loose krill aggregations may facilitate predator avoidance by enabling efficient signal transmission between individuals. The krill antipredator behaviour instigated marked daytime krill patchiness. Krill patchiness will vary relative to the predator regime and reflect recent encounters. |
author2 |
Fields, David EU |
format |
Article in Journal/Newspaper |
author |
Christiansen, Svenja Bråthen, Mabel Pernille Moksnes, Fredrik Lund Schmedling, Charlotte Aurora Thorsby, Sara Jegstad Titelman, Josefin Kaartvedt, Stein |
spellingShingle |
Christiansen, Svenja Bråthen, Mabel Pernille Moksnes, Fredrik Lund Schmedling, Charlotte Aurora Thorsby, Sara Jegstad Titelman, Josefin Kaartvedt, Stein Extensive avoidance behaviour of krill from predators and nets |
author_facet |
Christiansen, Svenja Bråthen, Mabel Pernille Moksnes, Fredrik Lund Schmedling, Charlotte Aurora Thorsby, Sara Jegstad Titelman, Josefin Kaartvedt, Stein |
author_sort |
Christiansen, Svenja |
title |
Extensive avoidance behaviour of krill from predators and nets |
title_short |
Extensive avoidance behaviour of krill from predators and nets |
title_full |
Extensive avoidance behaviour of krill from predators and nets |
title_fullStr |
Extensive avoidance behaviour of krill from predators and nets |
title_full_unstemmed |
Extensive avoidance behaviour of krill from predators and nets |
title_sort |
extensive avoidance behaviour of krill from predators and nets |
publisher |
Oxford University Press (OUP) |
publishDate |
2024 |
url |
http://dx.doi.org/10.1093/icesjms/fsae123 https://academic.oup.com/icesjms/advance-article-pdf/doi/10.1093/icesjms/fsae123/59029537/fsae123.pdf |
genre |
Meganyctiphanes norvegica |
genre_facet |
Meganyctiphanes norvegica |
op_source |
ICES Journal of Marine Science ISSN 1054-3139 1095-9289 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1093/icesjms/fsae123 |
container_title |
ICES Journal of Marine Science |
_version_ |
1811641059295363072 |