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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Online Access: | http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7244801/ http://www.ncbi.nlm.nih.gov/pubmed/32489635 https://doi.org/10.1002/ece3.6182 |
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ftpubmed:oai:pubmedcentral.nih.gov:7244801 2023-05-15T17:03:39+02:00 Isotopic niche differs between seal and fish‐eating killer whales (Orcinus orca) in northern Norway Jourdain, Eve Andvik, Clare Karoliussen, Richard Ruus, Anders Vongraven, Dag Borgå, Katrine 2020-04-08 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7244801/ http://www.ncbi.nlm.nih.gov/pubmed/32489635 https://doi.org/10.1002/ece3.6182 en eng John Wiley and Sons Inc. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7244801/ http://www.ncbi.nlm.nih.gov/pubmed/32489635 http://dx.doi.org/10.1002/ece3.6182 © 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. CC-BY Ecol Evol Original Research Text 2020 ftpubmed https://doi.org/10.1002/ece3.6182 2020-06-07T00:37:49Z 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 (δ(15)N: (15)N/(14)N) and carbon (δ(13)C: (13)C/(12)C) 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 δ(15)N 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 δ(15)N 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 δ(15)N values in the seal‐eaters, compared to that of whales that would eat solely seals (δ(N‐measured) = 12.6 vs. δ(N‐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. Text Killer Whale North Atlantic Northern Norway Orca Orcinus orca Killer whale PubMed Central (PMC) Norway Ecology and Evolution 10 9 4115 4127 |
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Original Research Jourdain, Eve Andvik, Clare Karoliussen, Richard Ruus, Anders Vongraven, Dag Borgå, Katrine Isotopic niche differs between seal and fish‐eating killer whales (Orcinus orca) in northern Norway |
topic_facet |
Original Research |
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 (δ(15)N: (15)N/(14)N) and carbon (δ(13)C: (13)C/(12)C) 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 δ(15)N 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 δ(15)N 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 δ(15)N values in the seal‐eaters, compared to that of whales that would eat solely seals (δ(N‐measured) = 12.6 vs. δ(N‐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. |
format |
Text |
author |
Jourdain, Eve Andvik, Clare Karoliussen, Richard Ruus, Anders Vongraven, Dag Borgå, Katrine |
author_facet |
Jourdain, Eve Andvik, Clare 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 |
John Wiley and Sons Inc. |
publishDate |
2020 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7244801/ http://www.ncbi.nlm.nih.gov/pubmed/32489635 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 |
Ecol Evol |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7244801/ http://www.ncbi.nlm.nih.gov/pubmed/32489635 http://dx.doi.org/10.1002/ece3.6182 |
op_rights |
© 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1002/ece3.6182 |
container_title |
Ecology and Evolution |
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10 |
container_issue |
9 |
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4115 |
op_container_end_page |
4127 |
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1766057554193940480 |