Norwegian killer whale movements reflect their different prey types
Norwegian killer whales (Orcinus orca) are thought to be generalists that feed primarily on fish, but some individuals have been observed targeting pinnipeds. In the study reported here, field observations of foraging behaviours formed the basis of a priori classification as either seal-eaters or fi...
Published in: | Polar Research |
---|---|
Main Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2024
|
Subjects: | |
Online Access: | https://hdl.handle.net/11250/3143810 https://doi.org/10.33265/polar.v43.9840 |
id |
ftimr:oai:imr.brage.unit.no:11250/3143810 |
---|---|
record_format |
openpolar |
spelling |
ftimr:oai:imr.brage.unit.no:11250/3143810 2024-09-15T18:10:46+00:00 Norwegian killer whale movements reflect their different prey types Vogel, Emma Frances Rikardsen, Audun H. Blanchet, Marie-Anne Blévin, Pierre Biuw, Martin 2024 application/pdf https://hdl.handle.net/11250/3143810 https://doi.org/10.33265/polar.v43.9840 eng eng Polar Research. 2024, 43 . urn:issn:0800-0395 https://hdl.handle.net/11250/3143810 https://doi.org/10.33265/polar.v43.9840 cristin:2263948 0 43 Polar Research Peer reviewed Journal article 2024 ftimr https://doi.org/10.33265/polar.v43.9840 2024-08-06T23:35:33Z Norwegian killer whales (Orcinus orca) are thought to be generalists that feed primarily on fish, but some individuals have been observed targeting pinnipeds. In the study reported here, field observations of foraging behaviours formed the basis of a priori classification as either seal-eaters or fish-eaters. Concurrent collection of photographic identification and biopsies for stable isotope analysis were used to validate prey choice classification. We found through satellite tracking that whales classified as seal-eaters took different paths south after leaving the northern fjords seemingly optimized for pinniped predation. Specifically, we found that seal-eaters took paths that tightly followed the coastline, remaining on average 6.9 ± 10.7 km (mean ± SD, n = 315) from the coast, whereas fish-eaters moved offshore along the continental shelf, travelling on average 45.1 ± 30.2 km (n = 1534) from the coast. We also found that, compared to fish-eaters, seal-eaters displayed more movements directed towards harbour seal haul-outs (p = 0.001). As expected, our data suggest that the fish-eaters feed primarily on fish, whilst seal-eaters appear to opportunistically use diverse foraging strategies optimized for either fish or seals based on availability and preference. Our findings demonstrate that tracking data can elucidate Norwegian killer whale movements associated with different prey types and selection. publishedVersion Article in Journal/Newspaper harbour seal Killer Whale Orca Orcinus orca Polar Research Killer whale Institute for Marine Research: Brage IMR Polar Research 43 |
institution |
Open Polar |
collection |
Institute for Marine Research: Brage IMR |
op_collection_id |
ftimr |
language |
English |
description |
Norwegian killer whales (Orcinus orca) are thought to be generalists that feed primarily on fish, but some individuals have been observed targeting pinnipeds. In the study reported here, field observations of foraging behaviours formed the basis of a priori classification as either seal-eaters or fish-eaters. Concurrent collection of photographic identification and biopsies for stable isotope analysis were used to validate prey choice classification. We found through satellite tracking that whales classified as seal-eaters took different paths south after leaving the northern fjords seemingly optimized for pinniped predation. Specifically, we found that seal-eaters took paths that tightly followed the coastline, remaining on average 6.9 ± 10.7 km (mean ± SD, n = 315) from the coast, whereas fish-eaters moved offshore along the continental shelf, travelling on average 45.1 ± 30.2 km (n = 1534) from the coast. We also found that, compared to fish-eaters, seal-eaters displayed more movements directed towards harbour seal haul-outs (p = 0.001). As expected, our data suggest that the fish-eaters feed primarily on fish, whilst seal-eaters appear to opportunistically use diverse foraging strategies optimized for either fish or seals based on availability and preference. Our findings demonstrate that tracking data can elucidate Norwegian killer whale movements associated with different prey types and selection. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Vogel, Emma Frances Rikardsen, Audun H. Blanchet, Marie-Anne Blévin, Pierre Biuw, Martin |
spellingShingle |
Vogel, Emma Frances Rikardsen, Audun H. Blanchet, Marie-Anne Blévin, Pierre Biuw, Martin Norwegian killer whale movements reflect their different prey types |
author_facet |
Vogel, Emma Frances Rikardsen, Audun H. Blanchet, Marie-Anne Blévin, Pierre Biuw, Martin |
author_sort |
Vogel, Emma Frances |
title |
Norwegian killer whale movements reflect their different prey types |
title_short |
Norwegian killer whale movements reflect their different prey types |
title_full |
Norwegian killer whale movements reflect their different prey types |
title_fullStr |
Norwegian killer whale movements reflect their different prey types |
title_full_unstemmed |
Norwegian killer whale movements reflect their different prey types |
title_sort |
norwegian killer whale movements reflect their different prey types |
publishDate |
2024 |
url |
https://hdl.handle.net/11250/3143810 https://doi.org/10.33265/polar.v43.9840 |
genre |
harbour seal Killer Whale Orca Orcinus orca Polar Research Killer whale |
genre_facet |
harbour seal Killer Whale Orca Orcinus orca Polar Research Killer whale |
op_source |
0 43 Polar Research |
op_relation |
Polar Research. 2024, 43 . urn:issn:0800-0395 https://hdl.handle.net/11250/3143810 https://doi.org/10.33265/polar.v43.9840 cristin:2263948 |
op_doi |
https://doi.org/10.33265/polar.v43.9840 |
container_title |
Polar Research |
container_volume |
43 |
_version_ |
1810448340574273536 |