The demography of Canadian Arctic killer whales

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dc.contributor.authorLefort, Kyle John
dc.contributor.examiningcommitteeRoth, James (Biological Sciences)en_US
dc.contributor.examiningcommitteeMuthukumarana, Saman (Statistics)en_US
dc.contributor.supervisorFerguson, Steven (Biological Sciences) Garroway, Colin (Biological Sciences)en_US
dc.date.accessioned2020-09-07T22:22:06Z
dc.date.available2020-09-07T22:22:06Z
dc.date.copyright2020-05-20
dc.date.issued2020en_US
dc.date.submitted2020-05-21T04:43:51Zen_US
dc.degree.disciplineBiological Sciencesen_US
dc.degree.levelMaster of Science (M.Sc.)en_US
dc.description.abstractThe ecosystem-level consequences of climate change-related range expansions are largely unexplored. In the Canadian Arctic, killer whale (Orcinus orca) occurrence is ice-restricted, and diminishing sea-ice cover has purportedly led to increased killer whale presence during the open-water season. However, the effects of increased predator presence on this Arctic marine ecosystem remain mostly unknown. In this thesis, I explore the consequences of such climate change-related predator range expansions. In chapter one, I review Canadian Arctic killer whale ecology and identify research priorities in the Canadian Arctic, two of which I address in chapters two and three. In chapter two, I whole-genome sequence twenty-nine western North Atlantic killer whales and describe two genetically distinct populations in Canadian waters: Canadian High Arctic and Canadian Low Arctic killer whales. Comparison with previously published genomes revealed Canadian High Arctic whales share a marginally significant excess of derived alleles with whales sampled in Newfoundland and Brazil, while Canadian Low Arctic whales share a significant excess of derived alleles with whales sampled in Greenland, Norway, and Iceland. In chapter three, I use photographs of sixty-three individually identifiable Canadian Arctic killer whales to estimate abundance in a capture-mark-recapture framework. The best-fitting model produced an estimate of 163±27, a number of killer whales which I determine could consume >1000 narwhal (Monodon monoceros) during their seasonal residency in Arctic waters. Collectively, these findings provide insight into the origins of Canadian Arctic killer whales and illustrate the magnitude of ecosystem-level modification that can occur with climate change-related shifts in predator distributions.en_US
dc.description.noteOctober 2020en_US
dc.identifier.citationLefort KJ, Matthews CJD, Higdon JW, Petersen SD, Westdal KH, Garroway CJ, and Ferguson SH. 2020. A review of Canadian Arctic killer whale (Orcinus orca) ecology. Canadian Journal of Zoology 98: 245–253. doi:10.1139/cjz-2019-0207.en_US
dc.identifier.citationLefort KJ, Garroway CJ, and Ferguson SH. In Press. Killer whale abundance and predicted narwhal consumption in the Canadian Arctic. Global Change Biology. doi:10.1111/gcb.15152.en_US
dc.identifier.urihttp://hdl.handle.net/1993/34964
dc.language.isoengen_US
dc.rightsopen accessen_US
dc.subjectBioenergeticsen_US
dc.subjectCapture-recaptureen_US
dc.subjectGeographic expansionen_US
dc.subjectPhotographic identificationen_US
dc.subjectPredationen_US
dc.subjectTrophic cascadeen_US
dc.subjectWhole-genome sequencingen_US
dc.titleThe demography of Canadian Arctic killer whalesen_US
dc.typemaster thesisen_US
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