Although sockeye salmon have managed to avoid obstacles caused by the Chilcotin River landslide, their migration is forecast to be much slower than average.
In late July, a landslide on the Chilcotin River in Farwell Canyon, about 176 miles north of Vancouver, blocked the flow of water. More than a week later, debris and a flood of water poured over the landslide and flowed down the Chilcotin and Fraser rivers.
Currently, only a fraction of the average sockeye salmon run occurs outside the landslide area.
A report by the Pacific Salmon Commission says warmer than average temperatures and landslide disruptions are hampering salmon migration up the Fraser and Chilcotin rivers.
This year, the sockeye salmon population is lower than usual, even before it reaches the Chilcotin River.
About 456,800 sockeye salmon crossed the Fraser River near Mission, B.C., the commission said, the second-lowest total on record. 2020 saw the lowest salmon count of 396,000 sockeye salmon.
Some salmon pass through the landslide area on their way to Chilko Lake, where they spawn. A Sept. 6 report from the federal Department of Fisheries and Oceans (DFO) said scientists counted 552 salmon passing a monitoring site on the Chilko River.
In the report, DFO states that the data is not updated and extrapolated during the season. However, the number is still significantly lower than in previous years. In 2020, DFO estimates that more than 10,000 sockeye salmon passed through the area during the same time period that year.
According to DFO data, as of early September 2021, more than 100,000 sockeye salmon have been caught at this location.
Chief Joe Alphonse, chairman of the Tŝilhqot’in National Government, said that despite improvements in the river, fish numbers are simply not increasing.
Alphonse said that normally nearly a million fish pass through the Chilcotin River system to spawn. This year, the Tŝilhqot’in Nations expected to see several hundred thousand fish. Now, Alphonse says he’ll be lucky if 10,000 sockeye salmon pass through in time to spawn.
“It’s really late in the year. They should be spawning now,” Alphonse said. “If they’re just passing through the landslide area, it looks like they have little chance of making it to Chilko Lake.”
For Alphonse, the fate of the sockeye is a matter of survival. The people of the Tŝilhqot’in Nations rely on sockeye as a significant source of food. This year, the nations have halted fishing for sockeye and chinook to allow the population to recover.
But recovery will take time. In an email to CBC News, DFO spokeswoman Lara Sloan said the long-term effects of the landslide on salmon populations won’t be seen for eight years.
In four years, the current generation of sockeye salmon will attempt to reach Lake Chilko. Alphonse says it will take several generations for the fish to return to their previous numbers.
“We’re not trying to build this just for our own benefit,” he said. “If Chilko Lake is healthy, it benefits everyone downstream.”
