An expert in salmon migration says the landslide that occurred on B.C.’s Chilcotin River in the Central Interior is catastrophic for residents, property and fish.
Scott Hinch, a professor and associate dean in the University of British Columbia’s faculty of forestry, with expertise in salmon migration, ecology and physiology, told Global News it was devastating to see the slide.
“For the fish that require the river for both their habitat and as a migration corridor to get to where they need to go, it’s just another sad tale in the life of Pacific salmon trying to get to their spawning grounds over the last five to 10 years,” he said.
Hinch added that the Big Bar landslide that occurred north of Lillooet in 2019, coupled with record-high river temperatures, has affected the salmon run in B.C. over the years.
“I’m terribly distraught over what’s happening again for the humans and the people and the fish,” he said.
Hinch said the peak of the sockeye run is expected in a week-and-a-half but they are not the only fish using the migration route.
Chinook salmon and steelhead also swim up the Chilcotin River. Hinch said if the Big Bar landslide was any indication, it took a few years to make that passage feasible for the fish to pass through.
“In terms of sockeye salmon, this is the largest run of sockeye salmon in Canada, and certainly the largest one we have in the Fraser watershed,” Hinch said.
“And it’s been at fairly high levels over the last several years, despite what’s happening with other populations and other stocks. It’s kind of one that we always look up to in terms of being a strong population, in terms of their return. And this is going to potentially have catastrophic effects on their return because these fish are getting the peak, are now getting close to, if not already in, the Chilko Lake system or in the Fraser and getting into the Chilcotin.”
He added that when the landslide lets loose it will be devastating for the fish due to the physical damage and the change in the olfaction scent cues that they need to navigate.
Margo Wagner, chair of the Cariboo Regional District, said in an update on Thursday morning that the timeline of the breach is unknown but that a breach is expected.
“We don’t know exactly when this landslide is going to give way,” she said, “but we have heard it could be between the next 24 to 48 hours.”
Hinch said they know the fish are coming up the river and they only have a few weeks to get to their spawning grounds. The longer the fish are holding in the warm water, the more energy reserves will be used and mortality rates will rise.
“I can tell you that the ramifications of this are dire,” he added.
“And again, we need to be hearing a lot about the people and the property and people’s safety at the moment. But soon we’ll be thinking about the fish.
“Just the fact that many of these fish aren’t going to get there, to one of the last few strongholds we had for sockeye salmon in the Fraser and areas where chinook and steelhead were struggling but still existing.”