In a recently released catalog, researchers from the University of British Columbia examined 13 years of photo identification data and more than 100,000 photographs taken off North America's west coasts. What they encountered was a group of what they referred to as the massive Western whales, which rarely traveled to California's coast and hunt outer elephant seals or sea lions.
What we did with this catalog is report 150 killer whales that seem to be different from other groups of killer whales, said Andrew Trites, director of the Marine Mammal Research Unit at the University of British Columbia, who co-authored the study.
According to Trites, there are different species of killer whales in the Pacific: residents, which eat fish; offshores, which consume sharks; and transients, which specialize in eating marine mammals. Trites noted how it has been known there are two populations of resident killer whales, northern and southern, which have been extensively studied since they live very close to shore.
We've got some evidence suggesting that the small whale population should be considered two distinct populations and the one we're seeing most frequently in California, we suspect they may specialize in eating elephant seals and transients, said Trites.
Trites told CNN around Monterey Bay the continental shelf - The edge of a continent that lies under the ocean - comes very close to land, where the population of coastal whales has been primarily seen. Yet the researchers encountered a group of mammal-eating outer coast whales that rarely travel to the coast, preferring deeper water and living near canyon systems.
Most of the whales were spotted in the sea waters between Oregon and central California from 2006 to 2019, but 26 were found near Vancouver Island. Outer coast whales also exhibit a way of communicating with each other outside of California waters, separate from other transient whales in coastal waters of the Pacific Northwest.
In the same way that when the distinction between Northern and Southern Resident Killer Whales, that shaped the understanding of their needs in terms of conservation or threats they faced, Trites said. If there are two distinct populations of the tawnai's killer whales, they are presently having different needs as well. Brad Hanson, a wildlife biologist at NOAA's Northwest Fisheries Science Center who has researched Southern Resident killer whales, commented many of the whales had not been previously matched to existing photo ID catalogs until the new findings. Now, with more individual whales cataloged, researchers can start to learn more about their ecology.
This research is a significant contribution in my mind because these image ID catalogues are essentially the foundation of virtually all work that we do on killer whales, Hanson told CNN.
Jenny Atkinson, executive director of The Whale Museum in Friday Harbor, Washington, told CNN there have been discussions over whether fish-eating and marine mammal-eating populations are different species, because right now they are all classified as killer whales.
We didn't really see transients before, we didn’t see them in these numbers, said Atkinson. We didn't know how they were related. We always thought it was this rogue group of killer whales who got together for successful hunting strategies and they traveled up and down the coast looking for marine mammals to predate on. The more encounters you have, the more you can add a point or information to your long term research. According Tokinson, in 2010 researchers used to say that transients come in groups of three or four and were not necessarily associated. By 2011, however, they began seeing groups of 20 to 25 that come into the waters, and now transients come back year after year with their offspring as a family group.
Although Atkinson is not a researcher, she told CNN that as far back as 10 years ago, transients were recorded entering into inland waters and predating on adult gray whales right in front of whale-watching boats. She believes the new catalogue will aid in furthering research into diverse transient whale behaviors.
They are starting to sense association and relationships and starting to see whether or not these different, for lack of a better term we'll call subpods or groups, are associating as an Acoustic Plan or developing hunting strategies, she said. What's cool are they trying to make sense of all this amazing data, they've looked at everything in a way that we've never been able to make up prior to using it. The catalog also pointed to another astonishing discovery: an unknown group of killer whales that resembled offshores but eat sharks like transients.
Trites said a few whales were found dead on shore dead that were not previously known, and their teeth were deepening almost to the gum line. This suggested there must have been something very abrasive which ground their teeth down.
What is more abrasive than the skin of a shark? Trites asked.
The whales looked like circular animals and had cookie-cutter bite marks or transient scars on the body of the whale. These could have been caused by killer whales living offshore, which may point to where parasitic sharks live.
According to Trites the next step is to continue updating the catalog, since there are still many more varieties of whales to be discovered. In addition to their efforts for sightings and acoustics research, scientists will continue to find out about killer whales and better understand how transients establish themselves as the top predators of the oceans.