A pod of southwestern Australia killer whales travelling across the Bremer Sub-basin. Photo: Rebecca Wellard (Project Orca).
Scientists have now mapped the best habitats for Orcas in Australian waters, and found they fall into two distinct populations.
While well documented in the Northern Hemisphere and Antarctica, much less has been known about killer whales (Orcinus orca) in Australia.
However, orcas are sighted year-round in all coastal states and territories, and a new Flinders University study has now mapped this across three key regions.
The paper published in the journal Ecology and Evolution collates 1310 sightings of killer whales around the country from the past four decades.
Species distribution modelling pinpoints places of high habitat suitability – notably the Bonney Upwelling (South Australia / Victoria), Bremer Sub-basin (Western Australia), and Ningaloo Reef (WA).
Lead author Marissa Hutchings said work greatly increased our understanding of killer whales in Australian waters and identified areas of biological importance for management and monitoring.
“Not only now do we have a nationwide picture, but our findings also support the idea that at least two ecologically distinct forms of killer whales exist in Australia — a temperate and a tropical form,” she said.
“The research calls for stronger conservation measures to protect these unique populations.”
Ms Hutchings said this was particularly important given their role as apex predators in the marine ecosystem and the fact that some of their most important habitats were only partially protected by legislation.
“More research will be vital in ensuring that this species can be adequately managed in a changing environment,” she said.
“This will only be made possible by collaboration between researchers, citizen scientists, and marine users to improve the size and accessibility of datasets on both killer whales and their prey.”
