Predator–prey overlap in three dimensions: cod benefit from capelin coming near the seafloor
Spatial overlap between predator and prey is a prerequisite for predation, but the degree of overlap is not necessarily proportional to prey consumption. This is because many of the behavioural processes that precede ingestion are non-linear and depend on local prey densities. In aquatic environment...
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Online Access: | https://hdl.handle.net/11250/2757520 https://doi.org/10.1111/ecog.05473 |
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ftimr:oai:imr.brage.unit.no:11250/2757520 2023-05-15T15:27:48+02:00 Predator–prey overlap in three dimensions: cod benefit from capelin coming near the seafloor Fall, Johanna Jennifer Elisabeth Johannesen, Edda Englund, Göran Johansen, Geir Odd Fiksen, Øyvind 2021 application/pdf https://hdl.handle.net/11250/2757520 https://doi.org/10.1111/ecog.05473 eng eng Norges forskningsråd: 243676 urn:issn:0906-7590 https://hdl.handle.net/11250/2757520 https://doi.org/10.1111/ecog.05473 cristin:1892474 Ecography Peer reviewed Journal article 2021 ftimr https://doi.org/10.1111/ecog.05473 2021-09-23T20:16:04Z Spatial overlap between predator and prey is a prerequisite for predation, but the degree of overlap is not necessarily proportional to prey consumption. This is because many of the behavioural processes that precede ingestion are non-linear and depend on local prey densities. In aquatic environments, predators and prey distribute not only across a surface, but also vertically in the water column, adding another dimension to the interaction. Integrating and simplifying behavioural processes across space and time can lead to systematic biases in our inference about interaction strength. To recognise situations when this may occur, we must first understand processes underlying variation in prey consumption by individuals. Here we analysed the diet of a major predator in the Barents Sea, the Atlantic cod Gadus morhua, aiming to understand drivers of variation in cod's feeding on its main prey capelin Mallotus villosus. Cod and capelin only partly share habitats, as cod mainly reside near the seafloor and capelin inhabit the free water masses. We used data on stomach contents from ~2000 cod individuals and their surrounding environment collected over 12 years, testing hypotheses on biological and physical drivers of variation in cod's consumption of capelin, using generalized additive models. Specifically, effects of capelin abundance, capelin depth distribution, bottom depth and cod abundance on capelin consumption were evaluated at a resolution scale of 2 km. We found no indication of food competition as cod abundance had no effect on capelin consumption. Capelin abundance had small effects on consumption, while capelin depth distribution was important. Cod fed more intensively on capelin when capelin came close to the seafloor, especially at shallow banks and bank edges. Spatial overlap as an indicator for interaction strength needs to be evaluated in three dimensions instead of the conventional two when species are partly separated in the water column. publishedVersion Article in Journal/Newspaper atlantic cod Barents Sea Gadus morhua Institute for Marine Research: Brage IMR Barents Sea Ecography 44 5 802 815 |
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Open Polar |
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Institute for Marine Research: Brage IMR |
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ftimr |
language |
English |
description |
Spatial overlap between predator and prey is a prerequisite for predation, but the degree of overlap is not necessarily proportional to prey consumption. This is because many of the behavioural processes that precede ingestion are non-linear and depend on local prey densities. In aquatic environments, predators and prey distribute not only across a surface, but also vertically in the water column, adding another dimension to the interaction. Integrating and simplifying behavioural processes across space and time can lead to systematic biases in our inference about interaction strength. To recognise situations when this may occur, we must first understand processes underlying variation in prey consumption by individuals. Here we analysed the diet of a major predator in the Barents Sea, the Atlantic cod Gadus morhua, aiming to understand drivers of variation in cod's feeding on its main prey capelin Mallotus villosus. Cod and capelin only partly share habitats, as cod mainly reside near the seafloor and capelin inhabit the free water masses. We used data on stomach contents from ~2000 cod individuals and their surrounding environment collected over 12 years, testing hypotheses on biological and physical drivers of variation in cod's consumption of capelin, using generalized additive models. Specifically, effects of capelin abundance, capelin depth distribution, bottom depth and cod abundance on capelin consumption were evaluated at a resolution scale of 2 km. We found no indication of food competition as cod abundance had no effect on capelin consumption. Capelin abundance had small effects on consumption, while capelin depth distribution was important. Cod fed more intensively on capelin when capelin came close to the seafloor, especially at shallow banks and bank edges. Spatial overlap as an indicator for interaction strength needs to be evaluated in three dimensions instead of the conventional two when species are partly separated in the water column. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Fall, Johanna Jennifer Elisabeth Johannesen, Edda Englund, Göran Johansen, Geir Odd Fiksen, Øyvind |
spellingShingle |
Fall, Johanna Jennifer Elisabeth Johannesen, Edda Englund, Göran Johansen, Geir Odd Fiksen, Øyvind Predator–prey overlap in three dimensions: cod benefit from capelin coming near the seafloor |
author_facet |
Fall, Johanna Jennifer Elisabeth Johannesen, Edda Englund, Göran Johansen, Geir Odd Fiksen, Øyvind |
author_sort |
Fall, Johanna Jennifer Elisabeth |
title |
Predator–prey overlap in three dimensions: cod benefit from capelin coming near the seafloor |
title_short |
Predator–prey overlap in three dimensions: cod benefit from capelin coming near the seafloor |
title_full |
Predator–prey overlap in three dimensions: cod benefit from capelin coming near the seafloor |
title_fullStr |
Predator–prey overlap in three dimensions: cod benefit from capelin coming near the seafloor |
title_full_unstemmed |
Predator–prey overlap in three dimensions: cod benefit from capelin coming near the seafloor |
title_sort |
predator–prey overlap in three dimensions: cod benefit from capelin coming near the seafloor |
publishDate |
2021 |
url |
https://hdl.handle.net/11250/2757520 https://doi.org/10.1111/ecog.05473 |
geographic |
Barents Sea |
geographic_facet |
Barents Sea |
genre |
atlantic cod Barents Sea Gadus morhua |
genre_facet |
atlantic cod Barents Sea Gadus morhua |
op_source |
Ecography |
op_relation |
Norges forskningsråd: 243676 urn:issn:0906-7590 https://hdl.handle.net/11250/2757520 https://doi.org/10.1111/ecog.05473 cristin:1892474 |
op_doi |
https://doi.org/10.1111/ecog.05473 |
container_title |
Ecography |
container_volume |
44 |
container_issue |
5 |
container_start_page |
802 |
op_container_end_page |
815 |
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1766358203563507712 |