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Vocal behaviour and feeding ecology of killer whales Orcinus orca around Shetland, UK

2011; Inter-Research; Volume: 13; Issue: 1 Linguagem: Inglês

10.3354/ab00353

2195-2744

Volker B. Deecke, M. Nykänen, Andrew D. Foote, Vincent M. Janik,

Arctic and Antarctic ice dynamics

AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 13:79-88 (2011) - DOI: https://doi.org/10.3354/ab00353 Vocal behaviour and feeding ecology of killer whales Orcinus orca around Shetland, UK Volker B. Deecke1,*, Milaja Nykänen1, Andrew D. Foote2,3, Vincent M. Janik1 1Sea Mammal Research Unit, Scottish Oceans Institute, University of St. Andrews, St. Andrews, KY16 8LB, UK 2Lighthouse Field Station, University of Aberdeen, Cromarty, Ross-shire, IV11 8YJ, UK 3The Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen 1350, Denmark *Email: volker.deecke@st-andrews.ac.uk ABSTRACT: Killer whales Orcinus orca are sighted regularly off Shetland, UK, but little is known about their numbers, diet and population identity. We aimed to relate vocal behaviour to diet of killer whales around Shetland in order to investigate population structure and differences in feeding strategies. Fieldwork was conducted in the summers of 2008 and 2009. We located killer whales through a sightings network and shore-based scans and collected photo-ID data, behavioural information, feeding data and acoustic recordings from a small boat. The majority of encounters (n = 14) were of small groups (1 to 15 individuals) travelling close to shore and feeding on marine mammals. Two encounters were with large groups (20+ individuals) feeding on herring Clupea harengus farther offshore. Seal-hunting groups vocalised rarely, producing pulsed calls, echolocation clicks and whistles almost exclusively when surface-active or milling after a kill. Herring-eating groups were largely silent during one encounter, but very vocal during the other. Analysis of pulsed calls identified 6 stereotyped call types for seal-hunting groups and 7 for herring-eating groups. No call types were shared between both kinds of groups. The vocal behaviour of seal-hunting groups showed striking parallels to that of Pacific marine mammal specialists and presumably evolved to decrease detection by acoustically sensitive prey. One call type produced by Shetland herring-eating killer whales matched a vocalisation that a previous study had described from Iceland and identified as a possible herding call that may function to concentrate herring during feeding. These findings point to behavioural and dietary specialisation among Shetland killer whales, which should be taken into account when making management decisions affecting these animals. KEY WORDS: Dietary specialisation . Vocal behaviour . Feeding ecology . Killer whale . North Atlantic Full text in pdf format Supplementary material PreviousNextCite this article as: Deecke VB, Nykänen M, Foote AD, Janik VM (2011) Vocal behaviour and feeding ecology of killer whales Orcinus orca around Shetland, UK. Aquat Biol 13:79-88. https://doi.org/10.3354/ab00353 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 13, No. 1. Online publication date: July 21, 2011 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2011 Inter-Research.