Half of Canada’s chinook salmon are endangered, with nearly all other populations in precarious decline, according to a new report, confirming fears that prospects for the species remain dire.

The report by the Committee on the Status of Endangered Wildlife in Canada concluded that eight of the country’s 16 populations are considered endangered, four are threatened, one is of special concern and the health of two remain unknown.

Only one population, which spawns on the Thompson river in British Columbia, is believed to be stable.

“For those of us who have been working on recovering chinook salmon runs in British Columbia, we knew they were in terrible, terrible shape for quite a while now,” said Aaron Hill of Watershed Watch, an organisation that monitors ecosystem health. “It was actually good to see it finally recognised by this federally mandated science body, because this hopefully initiates more serious protection efforts from the government.”

Watershed Watch has renewed calls for chinook to be listed under federal legislation which would afford the ailing populations more robust government protection. But similar calls were made last year, when the same committee of scientists found that one-third of sockeye salmon are endangered, and the federal government has yet to take action.

“There are some [rivers] where there are thought to be fewer than 200 fish still remaining,” committee member and biologist John Neilson, told the Canadian Press. “At that level, there would be concern about those stocks. That’s why we’re sounding the alarm.”

Chinook salmon have long been a critical part of the ecosystem in British Columbia. During spawning periods, millions of fish can travel up waterways, providing a critical source of food for eagles, bears, seals and sea lions.

No single culprit has been identified for the decline. Some blame a surge in populations of seal and sea lion, which feast on salmon, while others fear ocean temperatures are warming too much for the highly sensitive fish.

“The really big overarching stressor is climate change,” said Hill. “That’s creating less favourable conditions for our fish in the ocean and the freshwater – and that’s exacerbated by all these other stressors.”

Chinook salmon are also a critical source of food for the endangered south resident killer whale, which the federal government has spent millions of dollars attempting to protect.

“We need to look after the region in its entirety, from headwaters to the ocean,” said Megan Leslie of the World Wildlife Fund Canada. “We need to act quickly to reduce threats to wildlife, and prioritise actions that have the best chance of success.”