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dc.contributor.authorJourdain, Eve
dc.contributor.authorGoh, Tiffany
dc.contributor.authorKuningas, Sanna
dc.contributor.authorSimilä, Tiu
dc.contributor.authorVongraven, Dag
dc.contributor.authorKaroliussen, Richard
dc.contributor.authorBisther, Anna
dc.contributor.authorHammond, Philip S.
dc.identifier.citationJourdain , E , Goh , T , Kuningas , S , Similä , T , Vongraven , D , Karoliussen , R , Bisther , A & Hammond , P S 2021 , ' Killer whale ( Orcinus orca ) population dynamics in response to a period of rapid ecosystem change in the eastern North Atlantic ' , Ecology and Evolution , vol. Early View .
dc.identifier.otherPURE: 276751019
dc.identifier.otherPURE UUID: cd9a13bb-3f3b-4ad2-a2cf-c6c7018ab40d
dc.identifier.otherRIS: urn:7F976E8333E98038B151C3F518D994B0
dc.identifier.otherORCID: /0000-0002-2381-8302/work/103510838
dc.identifier.otherScopus: 85119200351
dc.identifier.otherWOS: 000719798700001
dc.descriptionFieldwork and study conducted by SK received financial support by the University of St Andrews studentship, SMRU Ltd., the Russell Trust Award and from the Finnish-Norwegian Cultural Foundation.en
dc.description.abstractThis study investigates survival and abundance of killer whales (Orcinus orca) in Norway in 1988-2019 using capture-recapture models of photo-identification data. We merged two datasets collected in a restricted fjord system in 1988-2008 (Period 1) with a third, collected after their preferred herring prey shifted its wintering grounds to more exposed coastal waters in 2012-2019 (Period 2), and investigated any differences between these two periods. The resulting dataset, spanning 32 years, comprised 3284 captures of 1236 whales, including 148 individuals seen in both periods. The best-supported models of survival included the effects of sex and time period, and the presence of transients (whales seen only once). Period 2 had a much larger percentage of transients compared to Period 1 (mean = 30% vs. 5%) and the identification of two groups of whales with different residency patterns revealed heterogeneity in recapture probabilities. This caused estimates of survival rates to be biased downward (females: 0.955 ± 0.027 SE, males: 0.864 ± 0.038 SE) compared to Period 1 (females: 0.998 ± 0.002 SE, males: 0.985 ± 0.009 SE). Accounting for this heterogeneity resulted in estimates of apparent survival close to unity for regularly seen whales in Period 2. A robust design model for Period 2 further supported random temporary emigration at an estimated annual probability of 0.148 (± 0.095 SE). This same model estimated a peak in annual abundance in 2015 at 1061 individuals (95% CI 999-1127), compared to a maximum of 731 (95% CI 505-1059) previously estimated in Period 1, and dropped to 513 (95% CI 488-540) in 2018. Our results indicate variations in the proportion of killer whales present of an undefined population (or populations) in a larger geographical region. Killer whales have adjusted their distribution to shifts in key prey resources, indicating potential to adapt to rapidly changing marine ecosystems.
dc.relation.ispartofEcology and Evolutionen
dc.rightsCopyright © 2021 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.en
dc.subjectApparent survivalen
dc.subjectCapture heterogeneityen
dc.subjectKiller whaleen
dc.subjectPopulation dynamicsen
dc.subjectGC Oceanographyen
dc.subjectGE Environmental Sciencesen
dc.subjectQH301 Biologyen
dc.subjectSDG 10 - Reduced Inequalitiesen
dc.subjectSDG 14 - Life Below Wateren
dc.titleKiller whale (Orcinus orca) population dynamics in response to a period of rapid ecosystem change in the eastern North Atlanticen
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. School of Biologyen
dc.contributor.institutionUniversity of St Andrews. Sea Mammal Research Uniten
dc.contributor.institutionUniversity of St Andrews. Scottish Oceans Instituteen
dc.contributor.institutionUniversity of St Andrews. Centre for Research into Ecological & Environmental Modellingen
dc.contributor.institutionUniversity of St Andrews. Marine Alliance for Science & Technology Scotlanden
dc.description.statusPeer revieweden

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