{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,9]],"date-time":"2026-09-09T03:06:48Z","timestamp":1788923208004,"version":"build-2803163510"},"reference-count":74,"publisher":"Wiley","issue":"8","license":[{"start":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T00:00:00Z","timestamp":1787616000000},"content-version":"vor","delay-in-days":24,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,8,1]],"date-time":"2026-08-01T00:00:00Z","timestamp":1785542400000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"funder":[{"DOI":"10.13039\/501100005416","name":"Norges Forskningsr\u00e5d","doi-asserted-by":"publisher","award":["315392"],"award-info":[{"award-number":["315392"]}],"id":[{"id":"10.13039\/501100005416","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Ecology and Evolution"],"published-print":{"date-parts":[[2026,8]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>\n                    Amino acid\u2010specific nitrogen isotope analysis (\u03b4\n                    <jats:sup>15<\/jats:sup>\n                    N\u2010AA) is increasingly used to infer trophic ecology, yet remains poorly validated in marine predators. We analyzed bulk tissue \u03b4\n                    <jats:sup>15<\/jats:sup>\n                    N (\n                    <jats:sup>15<\/jats:sup>\n                    N\/\n                    <jats:sup>14<\/jats:sup>\n                    N) and \u03b4\n                    <jats:sup>13<\/jats:sup>\n                    C (\n                    <jats:sup>13<\/jats:sup>\n                    C\/\n                    <jats:sup>12<\/jats:sup>\n                    C), and \u03b4\n                    <jats:sup>15<\/jats:sup>\n                    N\u2010AA in 105 skin samples collected from individually identified Norwegian killer whales between 2017 and 2023. Forty\u2010two individuals with best documented diets in 2010\u20132023, based on field observations and corroborated by mercury concentrations and bulk tissue \u03b4\n                    <jats:sup>15<\/jats:sup>\n                    N values in skin, provided reference diet groups against which \u03b4\n                    <jats:sup>15<\/jats:sup>\n                    N\u2010AA\u2010derived hypotheses were tested:\n                    <jats:italic>Fish\u2010only<\/jats:italic>\n                    (100% fish prey;\n                    <jats:italic>n<\/jats:italic>\n                    \u2009=\u200915),\n                    <jats:italic>Intermediate mixed<\/jats:italic>\n                    diet (~10% mammalian prey in addition to fish;\n                    <jats:italic>n<\/jats:italic>\n                    \u2009=\u200914), and\n                    <jats:italic>Top mixed<\/jats:italic>\n                    diet (~50% mammals, 50% fish prey;\n                    <jats:italic>n<\/jats:italic>\n                    \u2009=\u200913). Univariate and multivariate approaches identified diet as the primary driver of \u03b4\n                    <jats:sup>15<\/jats:sup>\n                    N variation across individual amino acids and multivariate isotopic space, whereas sex and life stage had little effect. However, substantial inter\u2010individual variation remained unexplained and appeared to reflect metabolic processes. Metrics \u03b4\n                    <jats:sup>15<\/jats:sup>\n                    N\n                    <jats:sub>\u03a3Trophic\u2014\u03a3Source<\/jats:sub>\n                    (\u03b4\n                    <jats:sup>15<\/jats:sup>\n                    N difference between the sum of trophic amino acids and the sum of source amino acids) and isotopic difference between glutamic acid\/glutamine (Glu) and phenylalanine (Phe) (\u03b4\n                    <jats:sup>15<\/jats:sup>\n                    N\n                    <jats:sub>Glu\u2013Phe<\/jats:sub>\n                    ) successfully identified\n                    <jats:italic>Top mixed<\/jats:italic>\n                    diet whales but lacked the sensitivity to identify\n                    <jats:italic>Intermediate mixed<\/jats:italic>\n                    diet individuals, whilst \u03b4\n                    <jats:sup>15<\/jats:sup>\n                    N values of Threonine showed no relationship with trophic position. Proline (Pro) and Phe used as trophic\u2010source pair provided the first plausible \u03b4\n                    <jats:sup>15<\/jats:sup>\n                    N\u2010AA\u2010derived trophic position estimates for killer whales and performed better than bulk isotope\u2010derived trophic position when a priori knowledge was not available. Multivariate clustering of \u03b4\n                    <jats:sup>15<\/jats:sup>\n                    N\u2010AA data complemented trophic position estimates by resolving finer\u2010scale dietary variation occurring within trophic levels.\n                  <\/jats:p>","DOI":"10.1002\/ece3.74121","type":"journal-article","created":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T09:21:36Z","timestamp":1787649696000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Advancing Amino Acid Isotope\u2010Inferred Trophic Ecology in an Apex Predator: Insights From a Data\u2010Rich Killer Whale Population"],"prefix":"10.1002","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2619-7799","authenticated-orcid":false,"given":"Eve","family":"Jourdain","sequence":"first","affiliation":[{"name":"Department of Biosciences University of Oslo  Oslo Norway"},{"name":"Norwegian Orca Survey  Andenes Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8171-7534","authenticated-orcid":false,"given":"Melissa A.","family":"McKinney","sequence":"additional","affiliation":[{"name":"Department of Natural Resource Sciences McGill University  Sainte\u2010Anne\u2010de\u2010Bellevue Quebec Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5801-4670","authenticated-orcid":false,"given":"Ana\u00efs","family":"Remili","sequence":"additional","affiliation":[{"name":"Department of Natural Resource Sciences McGill University  Sainte\u2010Anne\u2010de\u2010Bellevue Quebec Canada"},{"name":"Department of Biological Sciences Simon Fraser University  Vancouver Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Clare","family":"Andvik","sequence":"additional","affiliation":[{"name":"Department of Biosciences University of Oslo  Oslo Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carl","family":"Fagerlund","sequence":"additional","affiliation":[{"name":"Department of Biosciences University of Oslo  Oslo Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Richard","family":"Karoliussen","sequence":"additional","affiliation":[{"name":"Norwegian Orca Survey  Andenes Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katrine","family":"Borg\u00e5","sequence":"additional","affiliation":[{"name":"Department of Biosciences University of Oslo  Oslo Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anders","family":"Ruus","sequence":"additional","affiliation":[{"name":"Department of Biosciences University of Oslo  Oslo Norway"},{"name":"Norwegian Institute of Water Research  Oslo Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,8,25]]},"reference":[{"key":"e_1_2_10_2_1","doi-asserted-by":"publisher","DOI":"10.3945\/jn.117.256404"},{"key":"e_1_2_10_3_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41598\u2010020\u201068659\u2010y"},{"key":"e_1_2_10_4_1","first-page":"655","article-title":"An Assessment of Killer Whale \n                     Orcinus orca\n                   Stocks Off Vancouver Island, British Columbia","volume":"32","author":"Bigg M. A.","year":"1982","journal-title":"Report of the International Whaling Commission"},{"key":"e_1_2_10_5_1","doi-asserted-by":"publisher","DOI":"10.1002\/lom3.10041"},{"key":"e_1_2_10_6_1","doi-asserted-by":"publisher","DOI":"10.3354\/meps12856"},{"key":"e_1_2_10_7_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00442\u2010006\u20100571\u20104"},{"key":"e_1_2_10_8_1","doi-asserted-by":"publisher","DOI":"10.3354\/meps342085"},{"key":"e_1_2_10_9_1","doi-asserted-by":"publisher","DOI":"10.4319\/lom.2009.7.740"},{"key":"e_1_2_10_10_1","doi-asserted-by":"publisher","DOI":"10.1002\/ece3.1491"},{"key":"e_1_2_10_11_1","first-page":"633","article-title":"Killer Whales in Norwegian Coastal Waters","volume":"32","author":"Christensen I.","year":"1982","journal-title":"Report of the International Whaling Commission"},{"key":"e_1_2_10_12_1","doi-asserted-by":"publisher","DOI":"10.1002\/lol2.10176"},{"key":"e_1_2_10_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/0016\u20107037(81)90244\u20101"},{"key":"e_1_2_10_14_1","doi-asserted-by":"publisher","DOI":"10.1080\/00364827.1997.10413643"},{"key":"e_1_2_10_15_1","unstructured":"Fagerlund C.2023.\u201cEstimating the Biomagnifying Potential of Mercury (Hg) and Chlorinated Paraffins (CPs) in a Norwegian Arctic Food Web and in Killer whale (Orcinus orca).\u201d [Master Thesis] University of Oslo."},{"key":"e_1_2_10_16_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365\u2010294X.2009.04407.x"},{"key":"e_1_2_10_17_1","volume-title":"An R Companion to Applied Regression","author":"Fox J.","year":"2011"},{"key":"e_1_2_10_18_1","doi-asserted-by":"publisher","DOI":"10.3354\/meps14699"},{"key":"e_1_2_10_19_1","doi-asserted-by":"publisher","DOI":"10.1002\/rcm.7835"},{"key":"e_1_2_10_20_1","doi-asserted-by":"publisher","DOI":"10.3354\/meps10257"},{"key":"e_1_2_10_21_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jembe.2015.11.001"},{"key":"e_1_2_10_22_1","doi-asserted-by":"publisher","DOI":"10.1007\/s10815\u2010010\u20109467\u20107"},{"key":"e_1_2_10_23_1","doi-asserted-by":"publisher","DOI":"10.1007\/s004420050865"},{"key":"e_1_2_10_24_1","doi-asserted-by":"publisher","DOI":"10.3354\/meps084009"},{"key":"e_1_2_10_25_1","unstructured":"ICES.2018.Report of the Working Group on Widely Distributed Stocks (WGWIDE) 28 August\u20133 September 2018."},{"key":"e_1_2_10_26_1","doi-asserted-by":"publisher","DOI":"10.1021\/es061263h"},{"key":"e_1_2_10_27_1","doi-asserted-by":"publisher","DOI":"10.1002\/ece3.6182"},{"key":"e_1_2_10_28_1","doi-asserted-by":"publisher","DOI":"10.1002\/ece3.8364"},{"key":"e_1_2_10_29_1","unstructured":"Jourdain E. andR.Karoliussen.2021.\u201cPhoto\u2010Identification Catalogue of Norwegian Killer Whales 2007\u20102021.\u201d [Dataset]. figshare.https:\/\/doi.org\/10.6084\/m9.figshare.4205226.v4."},{"key":"e_1_2_10_30_1","doi-asserted-by":"publisher","DOI":"10.1111\/mms.12618"},{"key":"e_1_2_10_31_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0180099"},{"key":"e_1_2_10_32_1","doi-asserted-by":"publisher","DOI":"10.18637\/jss.v025.i01"},{"key":"e_1_2_10_33_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.dsr2.2014.02.003"},{"key":"e_1_2_10_34_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00442\u2010020\u201004645\u20105"},{"key":"e_1_2_10_35_1","doi-asserted-by":"publisher","DOI":"10.1111\/mms.12931"},{"key":"e_1_2_10_36_1","doi-asserted-by":"publisher","DOI":"10.1017\/S0025315413001379"},{"key":"e_1_2_10_37_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0249641"},{"key":"e_1_2_10_38_1","doi-asserted-by":"publisher","DOI":"10.1002\/ece3.6142"},{"key":"e_1_2_10_39_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41598\u2010024\u201059307\u2010w"},{"key":"e_1_2_10_40_1","doi-asserted-by":"publisher","DOI":"10.1111\/1365\u20102656.14123"},{"key":"e_1_2_10_41_1","doi-asserted-by":"publisher","DOI":"10.1890\/0012\u20109658(2002)083[2173:TRATNI]2.0.CO;2"},{"key":"e_1_2_10_42_1","doi-asserted-by":"publisher","DOI":"10.1002\/ecs2.1511"},{"key":"e_1_2_10_43_1","doi-asserted-by":"publisher","DOI":"10.1002\/ece3.1437"},{"key":"e_1_2_10_44_1","doi-asserted-by":"publisher","DOI":"10.1002\/lno.10081"},{"key":"e_1_2_10_45_1","doi-asserted-by":"publisher","DOI":"10.1016\/0016\u20107037(84)90204\u20107"},{"key":"e_1_2_10_46_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.orggeochem.2024.104823"},{"key":"e_1_2_10_47_1","doi-asserted-by":"publisher","DOI":"10.3354\/meps07747"},{"key":"e_1_2_10_48_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00442\u2010015\u20103305\u20107"},{"key":"e_1_2_10_49_1","doi-asserted-by":"publisher","DOI":"10.1002\/ece3.4295"},{"key":"e_1_2_10_50_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00442\u2010017\u20103881\u20109"},{"key":"e_1_2_10_51_1","unstructured":"Ogle D. 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A.Remili R.Dietz et\u00a0al.2026.\u201cUsing Amino Acid \u03b415N and \u03b413C to Trace Trophic Ecology and Contaminant Accumulation in Ecologically\u2010Distinct Greenland and Norway Killer Whales.\u201dSubmitted to Marine Ecology Progress Series (Mansucript #MEPS\u20102025\u201009\u2010011).","DOI":"10.3354\/meps15301"},{"key":"e_1_2_10_58_1","doi-asserted-by":"publisher","DOI":"10.1016\/S1936-7961(07)01012-3"},{"key":"e_1_2_10_59_1","doi-asserted-by":"publisher","DOI":"10.1890\/0012\u20109658(2002)083[0703:USITET]2.0.CO;2"},{"key":"e_1_2_10_60_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00442-006-0630-x"},{"key":"e_1_2_10_61_1","volume-title":"R: A Language and Environment for Statistical Computing (Version 4.2.0) [Computer software]","author":"R Core Team","year":"2018"},{"key":"e_1_2_10_62_1","doi-asserted-by":"publisher","DOI":"10.1111\/2041\u2010210X.13678"},{"key":"e_1_2_10_63_1","doi-asserted-by":"publisher","DOI":"10.1111\/1365\u20102656.13920"},{"key":"e_1_2_10_64_1","doi-asserted-by":"publisher","DOI":"10.1111\/mms.13097"},{"key":"e_1_2_10_65_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0110355"},{"key":"e_1_2_10_66_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1752-4571.2010.00166.x"},{"key":"e_1_2_10_67_1","doi-asserted-by":"publisher","DOI":"10.1139\/f95\u2010253"},{"key":"e_1_2_10_68_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.marpol.2004.04.002"},{"key":"e_1_2_10_69_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1095\u20108649.1999.tb00834.x"},{"key":"e_1_2_10_70_1","unstructured":"Spiess A.\u2010N.2025.propagate: Propagation of Uncertainty(Version 1.0\u20107) [Computer software].https:\/\/cran.r\u2010project.org\/web\/packages\/propagate\/index.html."},{"key":"e_1_2_10_71_1","doi-asserted-by":"publisher","DOI":"10.1111\/1365\u20102656.12326"},{"key":"e_1_2_10_72_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.envres.2021.111610"},{"key":"e_1_2_10_73_1","doi-asserted-by":"publisher","DOI":"10.33265\/polar.v43.9840"},{"key":"e_1_2_10_74_1","doi-asserted-by":"publisher","DOI":"10.1017\/S0025315413001707"},{"key":"e_1_2_10_75_1","doi-asserted-by":"publisher","DOI":"10.1093\/beheco\/aru183"}],"container-title":["Ecology and Evolution"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/ece3.74121","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1002\/ece3.74121","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/ece3.74121","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,9]],"date-time":"2026-09-09T02:10:14Z","timestamp":1788919814000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/ece3.74121"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8]]},"references-count":74,"journal-issue":{"issue":"8","published-print":{"date-parts":[[2026,8]]}},"alternative-id":["10.1002\/ece3.74121"],"URL":"https:\/\/doi.org\/10.1002\/ece3.74121","archive":["Portico"],"relation":{},"ISSN":["2045-7758","2045-7758"],"issn-type":[{"value":"2045-7758","type":"print"},{"value":"2045-7758","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8]]},"assertion":[{"value":"2026-04-07","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-07-23","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-08-25","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e74121"}}