Research illuminates growing extinction threat for southern resident orcas

New research is revealing just how fragile these urban whales are, particularly in contrast with the northern residents, which live in the waters of northern Vancouver Island and Southeast Alaska.

The northern residents’ population has been increasing 2.2% a year on average since 1973, said Sheila Thornton, research scientist for the Department of Fisheries and Oceans in Canada.

The northern residents’ foraging areas are calmer and quieter, not overlapping shipping lanes, and the population is experiencing less physical and acoustic disturbance, Thornton said.

They also have first crack at bigger, fattier fish — the ones northern and southern resident orcas prefer to eat.

“There have been studies saying … there are more than enough salmon in the ocean, but they [the orcas] are discerning in which salmon they will consume,” Thornton said.

In their analysis of skin and scales collected after orcas were hunting on the west side of Vancouver Island near the mouth of the Strait of Juan de Fuca, scientists found the southern residents preferentially hunt salmon 4 to 6 years old, and 29 to 33 inches long and with a higher fat content, Thornton said.

These are the super Chinook evolved to put on the heft and the fat while they are at sea to power up to their high-elevation spawning grounds deep into the Fraser River watershed and spawning areas including the Columbia Basin. The most endangered fish — the spring and summer runs that make these epic journeys to high elevation habitat — are the most energy rich, the scientists found.

Such fatties are a rarity today, as Chinook shrink across their range to snacks by comparison. Invasive shad, not salmon, are the new kings of the Columbia.

It’s not that the orcas have nothing to eat. But they are facing gaps in their seasonal round they are not adapted to. The orcas also have to work harder to fill up when they are stuck with lower-quality salmon — essentially put on a diet.

Snake River spring-summer Chinook, for instance are in steep decline and headed to extinction because of multiple problems, including dams and climate change — yet they are of outsized importance to the whales foraging at the mouth of the Columbia in hungry months.

“We know the Columbia River runs are vital, that first surge of Columbia Chinook appear to be really important to turn them around to get the increase in body condition for the summer,” Thornton said. Orcas, she noted, are not fasting-adapted. “They end up being in this feast-or-famine nutritional circle which over time can be detrimental.”

The orcas may also be having gut trouble.

Thornton and her collaborators are pursuing findings from scat research still in the works that suggests the southern resident orcas may be suffering a condition similar to inflammatory bowel disease in humans.

That could cause trouble with absorbing nutrition from their food, Thornton said, and be indicative of less robust immune system. “It’s a really disconcerting finding that their guts don’t seem to be healthy,” Thornton said. “It leads to a lot of questions about what could be causing that.”

What should be done?

Deborah Giles, science and research director of Wild Orca, a research nonprofit, said the losses are mounting.

“We are losing important breeding-age males and females and we are having even less … babies being born and living. The southern residents can’t wait any longer, we have to figure this out, and do something massively different, even if only for a trial basis,” Giles said.

She and other orca scientists have long pushed for dam removal on the Lower Snake River to help boost Snake River salmon recovery.

Brad Hanson has studied killer whales since they were considered vermin and legally captured for aquariums, to the explosion of knowledge in the 1980s, when scientists began to understand the southern residents were a distinct population, with their own family groups, culture and language — to the revolution in investigative tools available today.

“When I look back at what we were able to do to what we can do now, it is amazing the transformation that has occurred,” said Hanson, research biologist at the Northwest Fisheries Science Center of the National Oceanic and Atmospheric Administration in Seattle. From their scat to their breath, these whales are among the most studied in the world. Yet they are not recovering.

Rob Williams, chief scientist at the research nonprofit Oceans Initiative, is the lead author on a recent paper that found the risk of extinction for the southern residents is accelerating, and other scientists advocate both short- and long-term measures to save the whales.

For one, creation of a transboundary body similar to the Northern Atlantic Right Whale Consortium could serve as a platform for scientific data sharing and be in place for decision-making, especially in times of crisis.

New approaches have got to be tried to get the whales help now, while the longer-term effort to rebuild salmon runs and the ecosystem that supports them is ongoing, said Michael Weiss, research director of the Center for Whale Research. He supports mandatory slowdowns for ships, and changing fisheries, to leave more salmon for the whales, and quiet the waters to give orcas more and better foraging time.

“We need stopgaps, Band-Aids to slow the bleeding of population decline to give us time to do the important larger work to recover the whales’ food supply,” Weiss said.

Environmental nonprofits in B.C. filed suit in Canadian federal court Jan. 27 calling on the government to issue an emergency order to better protect the southern residents. The Canadian government has found that the southern residents are at imminent risk of extinction and the possibility and nature of an emergency order is under review, according to a spokesman for Fisheries and Oceans Canada.

An order would allow enactment of policies such as mandatory ship slowdowns and fishing closures, to make more fish, especially Chinook salmon, available to the whales — and provide quieter conditions in which they could hunt, said Misty MacDuffee, conservation biologist with Raincoast Conservation Foundation, one of the groups that filed the suit.

Mandatory slowdowns are opposed by commercial shippers, who would prefer to work with technology to do real-time detection of the whales and slow down when whales are present, said Michael Moore, vice president of the Pacific Merchant Shipping Association. Voluntary slowdowns are in effect at both Puget Sound and Vancouver ports and are reducing vessel noise.

In addition, the introduction of so-called terminal fisheries could move salmon catches to the mouths of rivers, instead of trolling for them in the open ocean, leaving them to grow larger and available for the southern residents to catch. Joel Kawahara owns a 42-foot troller and has fished Washington, California and Alaskan waters and says such a change would put him out of business, with a smaller fishing area, and a fish that won’t bite once it’s that close to its home waters.

He called the proposal “simply an eye poke toward ocean fisheries that is not practical and has no merit.”

But while people have choices to make, the southern residents do not, Williams said. They evolved to do what they do, and humans have created an environment that is driving them to extinction.

“The first thing is to decide,” Williams said, “is whether we are serious about saving these whales or we are not.”