Although sockeye salmon managed to overcome obstacles caused by the Chilcotin River landslide, their migration is predicted to be much below average.
In late July, a landslide across the Chilcotin River in Farwell Canyon, about 285 kilometers north of Vancouver, blocked the flow of water. More than a week later, accumulated debris and water rushed through the landslide and down the Chilcotin and Fraser rivers.
Now part of the average run of sockeye salmon is observed outside the landslide zone.
A Pacific Salmon Commission report said warmer-than-normal temperatures and obstacles caused by the landslide are making it difficult for salmon to migrate up the Fraser and Chilcotin rivers.
This year, sockeye salmon populations are already lower than usual, even before they reach the Chilcotin River.
About 456,800 sockeye passed through the Fraser River near Mission, B.C., the second-lowest total on record, the commission said. The 2020 run set a record for the lowest salmon total, with 396,000 sockeye.
Some salmon are moving through the landslide zone on their way to Chilko Lake, where they spawn. A Sept. 6 report from the federal Department of Fisheries and Oceans (DFO) said researchers counted 552 salmon passing through a monitoring site on the Chilko River.
The DFO report says the data is not populated and is extrapolated throughout the season. But the numbers are still significantly lower than in previous years. In 2020, DFO estimates more than 10,000 sockeye passed through the area by the same time of year.
According to DFO, more than 100,000 sockeye salmon were spotted in the area in early September 2021.
Chief Joe Alphonse, chairman of the Chilcotin Nation Government, said that despite the improvements in the river's health, the numbers are simply not there.
Alphonse said that typically about a million fish pass through the Chilcotin River system to spawn. This year, the Chilcotin people were expecting to see several hundred thousand fish. Now, Alphonse says he'll be lucky to see 10,000 sockeye pass through on time to spawn.
“It's really late now. They should be right in the middle of spawning,” Alphonse said. “If they're just passing through the landslide zone, it looks like they're unlikely to make it to Chilko Lake.”
For Alphonse, the fate of the sockeye salmon is a matter of survival. People in the Tŝilhqot'in Nations rely on sockeye salmon as an important food source. This year, the countries suspended fishing for sockeye and chinook salmon to allow the populations to recover.
But recovery will take time. In an email to CBC News, DFO spokesperson Lara Sloan said the long-term impact of the landslide on salmon populations won't be clear for eight years.
In another four years, the current generation of sockeye will try to break into Chilko Lake. Alphonse says it will take several generations for the fish to return to their previous size.
“We're not trying to build it just for our own benefit,” he said. “If Chilko Lake has healthy flows, it will benefit everyone downstream.”