Diel vertical movements determine spatial interactions between cod, pelagic fish and krill on an Arctic shelf bank
Predator-prey spatial interactions are essential to understand ecosystem processes like predation rates and trophic interaction strength. In marine systems, such spatial interactions are highly dynamic and difficult to observe, as predators, prey and resources are mobile and responsive to each other...
Published in: | Marine Ecology Progress Series |
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Language: | English |
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2020
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Online Access: | https://hdl.handle.net/11250/2722931 https://doi.org/10.3354/meps13254 |
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ftimr:oai:imr.brage.unit.no:11250/2722931 2024-09-15T17:57:59+00:00 Diel vertical movements determine spatial interactions between cod, pelagic fish and krill on an Arctic shelf bank Skaret, Georg Johansen, Geir Odd Johnsen, Espen Fall, Johanna Jennifer Elisabeth Fiksen, Øyvind Englund, Gøran Fauchald, Per Gjøsæter, Harald Macaulay, Gavin Johannesen, Edda 2020 application/pdf https://hdl.handle.net/11250/2722931 https://doi.org/10.3354/meps13254 eng eng Norges forskningsråd: 243676 Marine Ecology Progress Series. 2020, 638 13-23. urn:issn:0171-8630 https://hdl.handle.net/11250/2722931 https://doi.org/10.3354/meps13254 cristin:1802976 13-23 638 Marine Ecology Progress Series Peer reviewed Journal article 2020 ftimr https://doi.org/10.3354/meps13254 2024-07-31T03:37:25Z Predator-prey spatial interactions are essential to understand ecosystem processes like predation rates and trophic interaction strength. In marine systems, such spatial interactions are highly dynamic and difficult to observe, as predators, prey and resources are mobile and responsive to each other, and also since shifting vertical light gradients strongly affect the space use of visual predators and their prey. We visited a bank area in the northern Barents Sea with cold bottom waters (~1°C), and combined conventional trawl and acoustic sampling with broadband hydroacoustics to obtain long-range, fine-scale observations of interactions between cod, their planktivore prey (capelin and polar cod) and krill. We caught cod in demersal trawl hauls but could not detect them with the vessel acoustics. However, broadband acoustics mounted on a submersible probe allowed us to track individual cod, revealing that they remained mostly within 10 m of the bottom throughout the diel cycle. In the morning, cod lifted slightly from the seabed indicating feeding activity, which corresponded with more fresh prey in cod stomachs in the morning. During daylight, krill pushed towards the bottom, sharing habitat with cod, while the planktivores aggregated in pelagic schools at the cost of lost feeding opportunities, overlapping with their krill prey only during twilight hours. The diel light cycle was an important driver of the spatial movements and aggregations, and krill appear to hide from capelin among the cod near bottom, while cod take advantage of descending pelagic fish after dawn to feed with a minimum of effort. submittedVersion Article in Journal/Newspaper Barents Sea polar cod Institute for Marine Research: Brage IMR Marine Ecology Progress Series 638 13 23 |
institution |
Open Polar |
collection |
Institute for Marine Research: Brage IMR |
op_collection_id |
ftimr |
language |
English |
description |
Predator-prey spatial interactions are essential to understand ecosystem processes like predation rates and trophic interaction strength. In marine systems, such spatial interactions are highly dynamic and difficult to observe, as predators, prey and resources are mobile and responsive to each other, and also since shifting vertical light gradients strongly affect the space use of visual predators and their prey. We visited a bank area in the northern Barents Sea with cold bottom waters (~1°C), and combined conventional trawl and acoustic sampling with broadband hydroacoustics to obtain long-range, fine-scale observations of interactions between cod, their planktivore prey (capelin and polar cod) and krill. We caught cod in demersal trawl hauls but could not detect them with the vessel acoustics. However, broadband acoustics mounted on a submersible probe allowed us to track individual cod, revealing that they remained mostly within 10 m of the bottom throughout the diel cycle. In the morning, cod lifted slightly from the seabed indicating feeding activity, which corresponded with more fresh prey in cod stomachs in the morning. During daylight, krill pushed towards the bottom, sharing habitat with cod, while the planktivores aggregated in pelagic schools at the cost of lost feeding opportunities, overlapping with their krill prey only during twilight hours. The diel light cycle was an important driver of the spatial movements and aggregations, and krill appear to hide from capelin among the cod near bottom, while cod take advantage of descending pelagic fish after dawn to feed with a minimum of effort. submittedVersion |
format |
Article in Journal/Newspaper |
author |
Skaret, Georg Johansen, Geir Odd Johnsen, Espen Fall, Johanna Jennifer Elisabeth Fiksen, Øyvind Englund, Gøran Fauchald, Per Gjøsæter, Harald Macaulay, Gavin Johannesen, Edda |
spellingShingle |
Skaret, Georg Johansen, Geir Odd Johnsen, Espen Fall, Johanna Jennifer Elisabeth Fiksen, Øyvind Englund, Gøran Fauchald, Per Gjøsæter, Harald Macaulay, Gavin Johannesen, Edda Diel vertical movements determine spatial interactions between cod, pelagic fish and krill on an Arctic shelf bank |
author_facet |
Skaret, Georg Johansen, Geir Odd Johnsen, Espen Fall, Johanna Jennifer Elisabeth Fiksen, Øyvind Englund, Gøran Fauchald, Per Gjøsæter, Harald Macaulay, Gavin Johannesen, Edda |
author_sort |
Skaret, Georg |
title |
Diel vertical movements determine spatial interactions between cod, pelagic fish and krill on an Arctic shelf bank |
title_short |
Diel vertical movements determine spatial interactions between cod, pelagic fish and krill on an Arctic shelf bank |
title_full |
Diel vertical movements determine spatial interactions between cod, pelagic fish and krill on an Arctic shelf bank |
title_fullStr |
Diel vertical movements determine spatial interactions between cod, pelagic fish and krill on an Arctic shelf bank |
title_full_unstemmed |
Diel vertical movements determine spatial interactions between cod, pelagic fish and krill on an Arctic shelf bank |
title_sort |
diel vertical movements determine spatial interactions between cod, pelagic fish and krill on an arctic shelf bank |
publishDate |
2020 |
url |
https://hdl.handle.net/11250/2722931 https://doi.org/10.3354/meps13254 |
genre |
Barents Sea polar cod |
genre_facet |
Barents Sea polar cod |
op_source |
13-23 638 Marine Ecology Progress Series |
op_relation |
Norges forskningsråd: 243676 Marine Ecology Progress Series. 2020, 638 13-23. urn:issn:0171-8630 https://hdl.handle.net/11250/2722931 https://doi.org/10.3354/meps13254 cristin:1802976 |
op_doi |
https://doi.org/10.3354/meps13254 |
container_title |
Marine Ecology Progress Series |
container_volume |
638 |
container_start_page |
13 |
op_container_end_page |
23 |
_version_ |
1810434192607019008 |