Orcas Spotted in Northeastern Pacific Ocean Could Be New Population

Orca whales are familiar residents of West Coast waters. The black and white marine mammals are often seen swimming in groups, diving and slapping their tails against the water’s surface.

Researchers from the University of British Columbia (UBC) believe that a group of 49 killer whales seen hunting sperm whales and other marine animals in the ocean off the coasts of Oregon and California may be a separate population, a press release from UBC said.

The researchers said the orcas could be a unique oceanic population or part of a transient killer whale subpopulation.

“The open ocean is the largest habitat on our planet and observations of killer whales in the high seas are rare,” said Josh McInnes, lead author of the study and a UBC masters student at the Institute for the Oceans and Fisheries (IOF), in the press release. “In this case, we’re beginning to get a sense of killer whale movements in the open ocean and how their ecology and behaviour differs from populations inhabiting coastal areas.”

There are three killer whale ecotypes living in waters off the Oregon and California coasts — “offshores,” “residents” and “transients.”

According to the researchers, the unidentified orcas have been seen previously. The study puts together information gathered during nine encounters from 1997 to 2021.

“It’s pretty unique to find a new population. It takes a long time to gather photos and observations to recognize that there’s something different about these killer whales,” said study co-author Dr. Andrew Trites, a professor at IOF, in the press release.

Descriptions and photos did not match any of the group of 49 with known orcas.

“In one of the first encounters researchers had with a pod of these oceanic killer whales, they were observed taking on a herd of nine adult female sperm whales, eventually making off with one. It is the first time killer whales have been reported to attack sperm whales on the west coast,” McInnes said in the press release. “Other encounters include an attack on a pygmy sperm whale, predation on a northern elephant seal and Risso’s dolphin, and what appeared to be a post-meal lull after scavenging a leatherback turtle.”

Based on shark bite scars seen on nearly all the orcas in the new group, the research team believes they mostly live in the deep ocean far from the coast.

“The presence of cookiecutter shark wounds provides indirect evidence that these unknown killer whales had spent time in warmer oceanic waters,” the study said, as The Canadian Press reported.

The killer whales are also physically distinct from the three principal ecotypes in their white or grey patches next to the fin — known as “saddle patches” — and their dorsal fins.

“While the sizes and shapes of the dorsal fins and saddle patches are similar to transient and offshore ecotypes, the shape of their fins varied, from pointed like transients to rounded like offshore killer whales,” McInnes said in the press release. “Their saddle patch patterns also differed, with some having large uniformly gray saddle patches and others having smooth narrow saddle patches similar to those seen in killer whales in tropical regions.”

The study, “Evidence for an Oceanic Population of Killer Whales (Orcinus orca) in Offshore Waters of California and Oregon,” was published in the journal Aquatic Mammals.

Trites said birding and whale watching expedition passengers, as well as fishers, gave them additional observations of the unidentified whales.

The research team hopes to document acoustic data, genetic information and more sightings to continue their investigation into the differences between these whales and known populations.

“We’re just kind of at the tip of the iceberg of what these whales are doing. I mean, are they all one population? Are they multiple? We don’t know. So, I feel like this is kind of the big start of the next steps in our research, and to maybe get more sightings and more information,” said McInnes, as reported by The Canadian Press.