All hail Chainsaw: the big guy with the jagged dorsal fin who, together with his fellow Bigg’s killer whales, has already racked up a record number of sightings of the orcas for 2023.
Bigg’s are “The Other Killer Whale” – not the salmon-eating endangered southern resident killer whales, but the orcas thriving in Seattle-area waters by feasting on marine mammals. There were 1,270 unique sightings of Bigg’s killer whales in the Salish Sea as of Oct. 31, surpassing the previous annual record of 1,220 set last year.
It’s the ninth year in the past 10 of record sightings, with 2020 being the exception. And that was probably because of fewer people out on the water looking, according to the Pacific Whale Watch Association, the trade association of whale watch tours, and the Orca Behavior Institute, a science nonprofit group, that released the news of the record sightings this week.
The OBI compiles sighting reports from professional whale watchers, scientists and others throughout the Salish Sea.
With their swagger and stealthy kills, the Bigg’s have become a favorite of whale watch tours, said Erin Gless, executive director of the PWWA. “Chainsaw of course, just because he is so distinct, any time he is in the neighborhood they get super excited,” she said of the orca named for sawblade-like notches in his dorsal.
At the root of all this action is prey, and more fundamentally, enactment of the Marine Mammal Protection Act in 1972. That allowed whales to rebuild in numbers – and the seals, sea lions, porpoises and whale calves that are the center of the plate for Bigg’s.
With so much to eat, Bigg’s are not only here so often, but they stay for so long – as much as a month at a time – that they no longer fit their other name of “transient” killer whales, said Monika Wieland Shields, director of OBI.
The flip side of the happy news of all those Bigg’s living large in the Salish Sea is the urgent need for more salmon for the southern residents. “People see both sides of this story and they are confused, these are separate, but connected stories,” Shields said. “These whales all share the same environment. The difference is prey.”
The southern residents are an endangered species hunting a threatened one – Puget Sound Chinook, today struggling in lower numbers than when they were listed for protection under the Endangered Species Act in 1999.
The three main threats to the southern resident orcas’ survival are lack of adequate food, especially their favorite, Chinook; vessel and boat noise, which makes it harder for them to hear underwater to hunt their food; and pollution in their food, which affects their immune system and ability to reproduce. Inbreeding is also taking a toll.
Today there are only 75 southern residents in the J, K and L pods. By contrast, about 370 orcas are in the subpopulation of Bigg’s hunting the Salish Sea, Shields said. Their numbers are growing at about 4% per year over the last 20 years, as the southern residents battle extinction.
“It’s mixed for sure,” Shields said of the news of record Bigg’s sightings yet again this year. “It sure is exciting to see this one population of killer whales thriving in an environment that is so urban, they are dealing with the same challenges of southern resident killer whales, but they are giving birth like crazy, growing in numbers, and spending more time here.”
Having so much to eat also helps protect the Bigg’s killer whales from pollution in their food – which they absorb at even higher doses, eating higher on the food chain. Because they are well fed, they don’t burn their fat as hungry southern resident orcas do, where pollutants are stored.
The two types of orcas may look alike to the casual whale watcher. But they behave differently, and have subtle differences in their appearance.
The Bigg’s – named for the late Canadian whale scientist Michael Bigg – have a pointier dorsal, a more solid white saddle patch, and tend to move in smaller packs. The southern residents have an open saddle patch, with more black showing, a rounder-tipped dorsal and are usually seen in bigger, noisier, splashier groups with a lot of socializing at the surface.
As Puget Sound and B.C.’s Fraser River Chinook have declined, the southern residents also now are spending more time foraging on the outer coast. This year so far has seen the second-lowest number of sightings in the Salish Sea in a decade, Shields noted.
Because they are less frequently seen, Gless said she worries the southern residents will slip from people’s awareness just as they need help more than ever.
“I do worry about that,” Gless said. “It can be out of sight out of mind.”