Killer whales in the Southern Ocean
Distribution, relative abundance, migration patterns and foraging ecology of three ecotypes of killer whales in the Southern Ocean
There are three ecotypes of killer whales described from Antarctic waters comprising at least three separate species. Little is known about these ecotypes and it is important to understand these populations as killer whales play a key role in the Antarctic marine ecosystem. This is especially true with respect to the impacts that they have on prey populations including marine mammals, fish and penguins.
Researchers involved in this theme are investigating the factors relative to the ecosystem impact of three species killer whales that occur in Antarctic and adjacent waters, by focusing on their systematic relationships, abundance, distribution, movement patterns and prey preferences. Collaborators are from USA, Brazil, France and Canada.
The theme leaders are Dr Luciano Dalla Rosa and Dr Giancarlo Lauriano.
Foraging range of sub-Antarctic killer whales
Marion Island provides one of the few platforms for dedicated research on killer whales within the sub-Antarctic zone. Killer whales return predictably to the island during much of the year, with specific peak occurrences during September to December and April to May, associated with prey species presence.
Land-based research on killer whales was consolidated within a dedicated killer whale programme in 2006. Field personnel are based permanently on Marion Island and conduct consistent structured observations, genetic- and photo-identification, and photogrammetry of killer whales.These observations have delivered published insights into social structure, abundance, diet and preliminary assessments of ecological role.
Since 2011, satellite tagging has been conducted. Results suggest that killer whale movements are localised during spring and autumn, but range more widely during late winter and summer, with some individuals heading north of the island towards the South African south-east coast.
The project leader is Dr PJ Nico de Bruyn.
Co-researcher: Ryan R Reisinger.
Publications
Papers from this IWC-SORP project submitted to the International Whaling Commission can be found at our IWC papers and reports page.
‘Killer whale ecotypes: is there a global model?’ (2013) Biological Reviews, DOI: 10.1111/j.1469-185X.2012.00239.x.
‘Killer whale predation on subantarctic fur seals at Prince Edward Island, Southern Indian Ocean’ (2012) Polar Biology, DOI: 10.1007/s00300-012-1216-1.
‘Predatory impact of killer whales on pinniped and penguin populations at the subantarctic Prince Edward Islands: fact and fiction’ (2011) Journal of Zoology, DOI: 10.1111/j.1469-7998.2011.00815.x.
‘Abundance estimates of killer whales at subantarctic Marion Island’ (2011) Aquatic Biology, DOI: 10.3354/ab00340.
‘Prey and seasonal abundance of killer whales at subantarctic Marion Island’ (2011) African Journal of Marine Science, DOI: 10.2989/1814232X.2011.572356.
Dr Pitman guest edits this edition of Whalewatcher – 'Killer whale: the top, top predator' [PDF].
Killer whale identification poster: Orcinus orca, Killer whale ecotypes and forms [PDF]
