The latest survey of endangered southern resident killer whales confirms their plateau and gradual slide toward disappearance in the absence of stronger measures to protect them, a director with the Center for Whale Research says.

Michael Weiss says declining chinook salmon, pollutants and noise from cruise ships, tankers and freighters in the orcas' habitat off the coast of Washington state and southern British Columbia are among the factors driving the decline.

"We're not talking about southern residents going extinct in the next five years, but we are talking about a fairly good chance of at least one of the (three) pods being gone within the next 50 years," Weiss told The Canadian Press.

The long-term work of restoring chinook habitat, particularly freshwater spawning grounds, along with adjusting fisheries, would be key to the orcas' recovery, says Weiss.

His remarks come with the release on Monday of an annual survey by the organization based in Washington state, offering a snapshot of the population of southern residents as of July 1.

This year's survey found the overall population was 74, up by one from last year.

During the census period, researchers documented four births among all three distinct pods of southern residents, but only two calves survived, it says.

An adult male from K pod, known as K26, also went missing in late summer 2024.

Weiss calls it a "huge loss" for the southern residents, which are suffering from a lack of genetic diversity as their numbers plateau and shrink.

"The population is very inbred, very low genetic diversity, which is probably causing some issues for survival and resilience towards disease," Weiss says.

There is a strong correlation between age and reproduction in males, with greater success among older members of the population, he says.

The survey found 27 males of reproductive age, meaning older than 10. But Weiss says fewer males are actually breeding at any given time and the youngest male confirmed to have reproduced among the southern residents was 15.

Weiss says he considers the prime reproductive age for southern resident males to be in the early 20s and just 12 males are currently at least 20 years old.

The male that is presumed dead, K26, was the oldest of its pod and was one of the few adult males confirmed to have successfully reproduced at some point.

At the same time, females are reproducing at a rate that's roughly half that of their neighbours, the northern resident killer whales, and mortality among calves is high -- about 50 per cent in the first year of life among southern residents, Weiss says.

If those trends continue, the population will slowly decline, he says.

Weiss says K pod is in a particularly bad state, numbering just 14 members and tied for the lowest number across the survey's 50-year history.

"What's really concerning about K pod is they're just not reproducing," Weiss says.

A female member of K pod last gave birth in 2022, and prior to that it had been about a decade since the last successful birth in the pod, he says.

"The only pod that's growing is J pod," he says. "They've had a low mortality rate for adults in the last few years, but that could change very quickly."

The survey also revealed just 11 immature whales younger than 10, representing just 15 per cent of the southern residents' population.

By comparison, immature orcas make up 47 per cent of the northern resident population, which is growing and faring far better, Weiss says.

While the two populations bear similarities, he says the southern residents rely on a specific salmon species, chinook, which has itself been declining.

The southern residents often get the "last crack" at chinook that largely migrate from northern waters to rivers along the Pacific coast, Weiss adds.

"These salmon are going through, you know, fishing fleets and ... other killer whale populations and it's the southern residents that are kind of getting the last bit of it."

Restoring salmon habitat and moving chinook fisheries away from ocean waters and estuaries are two levers governments could pull to help the orcas, Weiss says.

"If you're fishing out in the ocean where everything's mixed up, it's really hard ... to avoid taking fish from these declining populations," he says.

The southern residents' urbanized habitat is another factor in their struggle.

"They're trying to hunt in these areas where cruise ships and freighters are coming through every day," Weiss says. "It's trying to find food on a highway."

This report by The Canadian Press was first published Oct. 13, 2025.

Brenna Owen, The Canadian Press

Southern resident killer whales show signs of slow decline toward disappearance