Description

PURPOSE: The focus of this research is on changes in the distribution of killer whales in the Canadian Arctic, which is within the field of marine biogeography and marine megafauna. Our research details change in killer whale presence and ties it to changes in sea ice coverage. These are novel results, presenting trends in the arrival and departure dates of killer whales into the eastern Canadian Arctic for the first time. We go on to discuss the impacts of these changes on other aspects of Arctic ecosystems and how increasing in killer whale presence might affect other species and the management of those species in Canada. Killer whales are a widespread species of interest, especially in the Canadian Arctic as their presence is tied to multiple aspects of a region rapidly changing from the effects of climate change. DESCRIPTION: This study examines 20 years of killer whale (Orcinus orca) sightings in the eastern Canadian Arctic, drawing from a comprehensive sighting database spanning 1850-2023. Despite inherent biases favoring data collection near communities and coastal areas, spatiotemporal analyses reveal significant shifts in killer whale distribution linked to changing sea ice conditions. We developed a clustering metric representing the mean distance to the five nearest sightings and results show that killer whales are progressively moving away from historically high-use areas and that sighting locations are becoming more dispersed over time. A significant year × sea ice interaction indicates observations occur earlier during their arrival period at lower sea ice concentrations over time, suggesting that declining sea ice concentration contributes to earlier arrival. Conversely, for departure periods, killer whales are observed farther south later in the year, likely linked to earlier freeze-up at higher latitudes, and are overall observed later into the year over time. This trend has led to a near doubling of their average presence from 26 days in 2002 to 48 days in 2023 (27 July to 13 September) reflecting an extended open-water season. These findings underscore the prolonged seasonal use of Arctic regions by killer whales, driven by diminishing sea ice and expanding openwater habitat. Such shifts highlight potential implications for Arctic marine ecosystems as killer whales increasingly overlap with endemic species.

Resources

Name	Format	Description	Link
Data_Dictionary_Dictionnaire_de_données.pdf	PDF		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/b43be740-1496-11f0-9b16-cdaf3d076dbf/attachments/Data_Dictionary_Dictionnaire_de_donn%C3%A9es.pdf
Killer whale sighting data 2002-2023.csv	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/b43be740-1496-11f0-9b16-cdaf3d076dbf/attachments/Killer%20whale%20sighting%20data%202002-2023.csv
Supplementary_Citation_List_Liste_de_citation_supplémentaire.pdf	PDF		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/b43be740-1496-11f0-9b16-cdaf3d076dbf/attachments/Supplementary_Citation_List_Liste_de_citation_suppl%C3%A9mentaire.pdf
open_data_donnees_ouvertes/killer_whale_range_presence_eastern_canada_arctic_2002_2023	Ersi REST		https://egisp.dfo-mpo.gc.ca/arcgis/rest/services/open_data_donnees_ouvertes/killer_whale_range_presence_eastern_canada_arctic_2002_2023/MapServer
open_data_donnees_ouvertes/killer_whale_range_presence_eastern_canada_arctic_2002_2023	Ersi REST		https://egisp.dfo-mpo.gc.ca/arcgis/rest/services/open_data_donnees_ouvertes/killer_whale_range_presence_eastern_canada_arctic_2002_2023/MapServer

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