Isotopic niche differs between seal and fish-eating killer whales (Orcinus orca) in northern Norway
Ecological diversity has been reported for killer whales (Orcinus orca) throughout the North Atlantic but patterns of prey specialization have remained poorly understood. We quantify interindividual dietary variations in killer whales (n = 38) sampled throughout the year in 2017–2018 in northern Nor...
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ftnorskinstvf:oai:niva.brage.unit.no:11250/2678254 2023-05-15T17:03:38+02:00 Isotopic niche differs between seal and fish-eating killer whales (Orcinus orca) in northern Norway Jourdain, Eve Andvik, Clare Margaret Karoliussen, Richard Ruus, Anders Vongraven, Dag Borgå, Katrine 2020 application/pdf https://hdl.handle.net/11250/2678254 https://doi.org/10.1002/ece3.6182 eng eng Wiley Ecology and Evolution. 2020, 10 (9), 4115-4127. urn:issn:2045-7758 https://hdl.handle.net/11250/2678254 https://doi.org/10.1002/ece3.6182 cristin:1827564 Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no CC-BY 4115-4127 10 Ecology and Evolution 9 Peer reviewed Journal article 2020 ftnorskinstvf https://doi.org/10.1002/ece3.6182 2023-02-21T08:46:21Z Ecological diversity has been reported for killer whales (Orcinus orca) throughout the North Atlantic but patterns of prey specialization have remained poorly understood. We quantify interindividual dietary variations in killer whales (n = 38) sampled throughout the year in 2017–2018 in northern Norway using stable isotopic nitrogen (δ15N: 15N/14N) and carbon (δ13C: 13C/12C) ratios. A Gaussian mixture model assigned sampled individuals to three differentiated clusters, characterized by disparate nonoverlapping isotopic niches, that were consistent with predatory field observations: seal‐eaters, herring‐eaters, and lumpfish‐eaters. Seal‐eaters showed higher δ15N values (mean ± SD: 12.6 ± 0.3‰, range = 12.3–13.2‰, n = 10) compared to herring‐eaters (mean ± SD: 11.7 ± 0.2‰, range = 11.4–11.9‰, n = 19) and lumpfish‐eaters (mean ± SD: 11.6 ± 0.2‰, range = 11.3–11.9, n = 9). Elevated δ15N values for seal‐eaters, regardless of sampling season, confirmed feeding at high trophic levels throughout the year. However, a wide isotopic niche and low measured δ15N values in the seal‐eaters, compared to that of whales that would eat solely seals (δN‐measured = 12.6 vs. δN‐expected = 15.5), indicated a diverse diet that includes both fish and mammal prey. A narrow niche for killer whales sampled at herring and lumpfish seasonal grounds supported seasonal prey specialization reflective of local peaks in prey abundance for the two fish‐eating groups. Our results, thus, show differences in prey specialization within this killer whale population in Norway and that the episodic observations of killer whales feeding on prey other than fish are a consistent behavior, as reflected in different isotopic niches between seal and fish‐eating individuals. publishedVersion Article in Journal/Newspaper Killer Whale North Atlantic Northern Norway Orca Orcinus orca Killer whale Norwegian Institute for Water research: NIVA Open Access Archive (Brage) Norway Ecology and Evolution 10 9 4115 4127 |
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Open Polar |
collection |
Norwegian Institute for Water research: NIVA Open Access Archive (Brage) |
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ftnorskinstvf |
language |
English |
description |
Ecological diversity has been reported for killer whales (Orcinus orca) throughout the North Atlantic but patterns of prey specialization have remained poorly understood. We quantify interindividual dietary variations in killer whales (n = 38) sampled throughout the year in 2017–2018 in northern Norway using stable isotopic nitrogen (δ15N: 15N/14N) and carbon (δ13C: 13C/12C) ratios. A Gaussian mixture model assigned sampled individuals to three differentiated clusters, characterized by disparate nonoverlapping isotopic niches, that were consistent with predatory field observations: seal‐eaters, herring‐eaters, and lumpfish‐eaters. Seal‐eaters showed higher δ15N values (mean ± SD: 12.6 ± 0.3‰, range = 12.3–13.2‰, n = 10) compared to herring‐eaters (mean ± SD: 11.7 ± 0.2‰, range = 11.4–11.9‰, n = 19) and lumpfish‐eaters (mean ± SD: 11.6 ± 0.2‰, range = 11.3–11.9, n = 9). Elevated δ15N values for seal‐eaters, regardless of sampling season, confirmed feeding at high trophic levels throughout the year. However, a wide isotopic niche and low measured δ15N values in the seal‐eaters, compared to that of whales that would eat solely seals (δN‐measured = 12.6 vs. δN‐expected = 15.5), indicated a diverse diet that includes both fish and mammal prey. A narrow niche for killer whales sampled at herring and lumpfish seasonal grounds supported seasonal prey specialization reflective of local peaks in prey abundance for the two fish‐eating groups. Our results, thus, show differences in prey specialization within this killer whale population in Norway and that the episodic observations of killer whales feeding on prey other than fish are a consistent behavior, as reflected in different isotopic niches between seal and fish‐eating individuals. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Jourdain, Eve Andvik, Clare Margaret Karoliussen, Richard Ruus, Anders Vongraven, Dag Borgå, Katrine |
spellingShingle |
Jourdain, Eve Andvik, Clare Margaret Karoliussen, Richard Ruus, Anders Vongraven, Dag Borgå, Katrine Isotopic niche differs between seal and fish-eating killer whales (Orcinus orca) in northern Norway |
author_facet |
Jourdain, Eve Andvik, Clare Margaret Karoliussen, Richard Ruus, Anders Vongraven, Dag Borgå, Katrine |
author_sort |
Jourdain, Eve |
title |
Isotopic niche differs between seal and fish-eating killer whales (Orcinus orca) in northern Norway |
title_short |
Isotopic niche differs between seal and fish-eating killer whales (Orcinus orca) in northern Norway |
title_full |
Isotopic niche differs between seal and fish-eating killer whales (Orcinus orca) in northern Norway |
title_fullStr |
Isotopic niche differs between seal and fish-eating killer whales (Orcinus orca) in northern Norway |
title_full_unstemmed |
Isotopic niche differs between seal and fish-eating killer whales (Orcinus orca) in northern Norway |
title_sort |
isotopic niche differs between seal and fish-eating killer whales (orcinus orca) in northern norway |
publisher |
Wiley |
publishDate |
2020 |
url |
https://hdl.handle.net/11250/2678254 https://doi.org/10.1002/ece3.6182 |
geographic |
Norway |
geographic_facet |
Norway |
genre |
Killer Whale North Atlantic Northern Norway Orca Orcinus orca Killer whale |
genre_facet |
Killer Whale North Atlantic Northern Norway Orca Orcinus orca Killer whale |
op_source |
4115-4127 10 Ecology and Evolution 9 |
op_relation |
Ecology and Evolution. 2020, 10 (9), 4115-4127. urn:issn:2045-7758 https://hdl.handle.net/11250/2678254 https://doi.org/10.1002/ece3.6182 cristin:1827564 |
op_rights |
Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1002/ece3.6182 |
container_title |
Ecology and Evolution |
container_volume |
10 |
container_issue |
9 |
container_start_page |
4115 |
op_container_end_page |
4127 |
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1766057544246099968 |