New subpopulation of Deep Ocean Orcas Identified

Roy L Hales/ Cortes Currents - A new subpopulation of Orcas has been identified in the open ocean off the coasts of Oregon and California. UBC researchers have identified 49 individual killer whales in photographs taken between 1997 and 2021. 


According to Josh McInnes, a masters student in the UBC Institute for the Oceans and Fisheries and lead author of a new paper in Aquatic Animals, they may also be off the coast of British Columbia.


“I would not be surprised. Transient killer whales can have distributions that are quite large, over 2000 kilometres.  For instance, the transient type of killer whales that we do know about, that eats marine mammals in British Columbia,  can be seen anywhere between Glacier Bay (in southeast Alaska), all the way down to San Diego, California. They have large distributions and they move widely,” he explained.


“Killer whales in the Antarctic have been seen moving straight up into the South Atlantic, into the South Pacific, and even up to Australia.” 


Cortes Currents: Why are scientists only just beginning to realize that there is a new subpopulation?


Josh McInnes: "A lot of the issue that we're facing, with understanding killer whale movements in the open ocean, is the effort that is involved. Surveys are super expensive, the weather out there is complete garbage half the time, and it's very difficult to get out there." 


"The reason why we believe we're seeing killer whales more off California than British Columbia is the continental shelf.  This is the big stretch of underwater landmass that extends out from our continent towards what we call the continental shelf break. The break is where we separate the continental shelf from the open ocean.  It's actually quite thick.  It's quite wide off of Vancouver Island. It can go, on average, about 40 kilometers off the coast of Vancouver Island, which is a long way to get to the open ocean. Whereas in California, it's quite narrow. The open ocean comes really close to the coast.  It's sometimes within 12 kilometers.  So getting out to the open ocean is a lot easier off California and Oregon than it is off of British Columbia."