Pacific Southern Resident Orca
The Southern Resident population of iconic black-and-white Orcas has always been small. But higher mortality rates and a recent decline are ominous signs. Is this “slow-motion extinction”? What is causing it and what can be done?
The footage was unforgettable — a killer whale named Tahlequah
was filmed carrying her dead newborn on her head for 17 days last summer, an image of grief that struck an emotional chord worldwide. That loss, plus the death of a three-year-old orca named Scarlet a few months later, focused renewed attention on the increasingly dire plight of the southern residents, a close-knit group of killer whales that ranges from the southern British Columbia coast all the way south to California but that spends much of the year hunting salmon in the Salish Sea near Vancouver.
Data that extends back to the 1960s reveals that the southern resident population has always been small, fluctuating from a low of 66 in 1972, when they were being captured for display in aquariums, to a high of 99 in the mid-1990s. But the decline in recent years seems especially ominous. In the past two decades, 40 southern residents have been born into the group, while 72 have perished. This high mortality rate has cut their numbers from 98 to 74. Ten years ago, calves were being born at a rate of four or five a year, but since November 2015, not a single calf has survived, a trend that has caused some biologists to describe this as “a slow-motion extinction.”
What’s behind this downward slide? Without performing necropsies, scientists can’t determine the cause of death for each individual orca, but most biologists cite three key factors: a decline in chinook salmon, their preferred prey, noise and physical interference from recreational and commercial vessels, and the presence of toxins in their blubber.
Misty Macduffee, a biologist with the Raincoast Conservation Foundation, believes the three factors work in concert to harm the southern residents. “These whales need an abundance of chinook to thrive, and they need to be able to access it. The growing din of ship traffic and the close proximity of vessels has reduced the effectiveness of their hunting.” Lack of food causes the orcas to lose weight and become stressed, which compels them to use their fat reserves, explains Macduffee. But this mobilizes toxins stored in their blubber, which damages their immune systems and the development of their young.
As apex predators, orcas are the most contaminated cetaceans on the planet — they carry 30 times more pollutants than humans on an equal weight basis, including high concentrations of polychlorinated biphenyls (PCBS), industrial chemicals that were banned 40 years ago.
Mysteriously, however, the northern resident orcas, which range from northern Vancouver Island to Alaska, are equally contaminated and eat the same food, yet they are doing better (although still officially listed as threatened). Since the 1970s, their population has increased from 170 to 309. The two other ecotypes that inhabit the North Pacific — the transient and offshore killer whales — are also doing better.
It may be that the northern residents are faring better because they live primarily in cleaner and quieter northern waters, where they also have a more diverse array of salmon runs from which to choose, including Fraser River chinook, which northern residents can pick off on the salmons’ return to the spawning grounds before the southern residents get their chance.
But this remains an open question. Although these resident orcas are the world’s most intensely studied marine mammals, there is still much that biologists do not know. “They’re difficult to study because they spend 95 per cent of their lives underwater. For example, we don’t know to what extent they feed at night,” says John Ford, former head of the Marine Mammal Research Program at the Pacific Biological Station and one of the pioneer researchers of killer whales.
“It is also unclear exactly how sound affects them,” says Ford. The assumption is that the sound of ship motors interferes with the whales’ echolocation, clicking sounds they use like sonar to build an accurate picture of their surroundings. But this conclusion is not backed by hard science. “There is a lot of inference and guessing about noise and its effects,” he says.
Much of the scientific data on killer whales was obtained by studying them in captivity, a population that was drawn largely from the southern residents in the late 1960s and 1970s. The trainability, striking appearance, playfulness and sheer size of orcas made them a popular attraction at aquariums, and this exposure radically altered public perception. “Keeping whales in captivity, something we now feel very uncomfortable about, was a driving force in changing the view of killer whales from a big, black monster with jagged teeth that scared the bejesus out of us to an animal that we now treasure,” says Jason Colby, a history professor at the University of Victoria and author of the 2018 book Orca: How We Came to Know and Love the Ocean’s Greatest Predator.
Indeed, until the 1970s when the first orcas were displayed at aquariums, they were viewed as vicious predators and shot on sight. In 1961, the Department of Fisheries went so far as to mount a machine gun on a lookout above Seymour Narrows, near Campbell River, to slaughter orcas as they passed. In the end, the gun was never used, as officials decided that stray bullets might ricochet off the water and harm humans.
Today the once-despised orcas are the stars of a whale-watching industry that attracts 500,000 tourists to the Pacific Northwest each year, and their image appears on posters, coffee mugs, beer labels, Indigenous art and the logo of the Vancouver Canucks NHL team. They have become a symbol of shifting environmental values, and people on B.C.’S coast have developed a genuine affection for them.
The Canadian government appears to be taking the orcas’ plight seriously. In December 2018, Fisheries and Oceans Minister Jonathan Wilkinson pledged $61.5 million in funding to support research, enforcement and education to protect the southern residents. That’s on
top of an earlier investment of $167.4 million over five years aimed at improving prey availability and reducing disturbance from whale-watching boats and underwater noise.
Even so, critics claim the measures don’t go far enough. Several environmental groups have called for a total ban on whale-watching and a closure of the entire chinook fishery. They also warn that by pushing ahead with plans to build the Trans Mountain Pipeline, which will carry oil from Alberta to the B.C. coast, the government is adding a major threat to the killer whales.
The pipeline would boost the number of oil tankers entering the Port of Vancouver from 50 to about 400 per year. In its environmental review, the National Energy Board concluded that the marine shipping aspect of the project would have “significant adverse effects” on the species and that an oil spill would be “potentially catastrophic.”
As the stakes rise, some scientists have voiced concerns about the vast amount of money and effort being spent on a small group of whales that make up less than one per cent of the world’s killer whale population and that may be destined to disappear. These funds, they argue, could be better used to protect other endangered but less charismatic animals.
It’s a legitimate issue, but then again, as naturalist David Attenborough once noted, “No one will protect what they don’t care about.” Jason Colby believes we owe these orcas a better ending. “We have created the toxic stew they now have to live in. Given everything we have taken away from them, I believe we have a moral obligation to try to save them,” he says. “Our own culture would be diminished by the loss of these majestic creatures.”a