An expert on British Columbia害羞草研究所檚 salmon populations says the massive landslide that blocked off part of Canada害羞草研究所檚 largest sockeye salmon run has created an unprecedented situation potentially putting the already struggling fish at even more risk.

Scott Hinch, the associate dean at the University of British Columbia害羞草研究所檚 Pacific Salmon Ecology and Conservation Laboratory, said the debris piled 30 metres high and 600 metres long blocking the Chilcotin River could cause problems for chinook and sockeye populations both while the water is being held back, and when it eventually bursts free.

害羞草研究所淭hese are natural events, but what害羞草研究所檚 unusual about this event is it害羞草研究所檚 occurring at a time when the rivers are way warmer than they used to be,害羞草研究所� he said in an interview Thursday.

害羞草研究所淎nd that creates this unprecedented lack of understanding of what害羞草研究所檚 going to happen to these fish.害羞草研究所�

The sockeye are on their way to Chilko Lake, where they will spawn. But to get there, they have to get through Farwell Canyon, close to where the dam of rock and mud is in the way.

害羞草研究所淭hey would be starting to trickle through naturally now and then in about a week and a half, 10 days or so, the peak of that run will be into the Chilcotin,害羞草研究所� he said.

害羞草研究所淭hey害羞草研究所檙e coming up the Fraser right now, these fish.害羞草研究所�

The Chilcotin is a tributary of the Fraser River and officials with the province and Cariboo Regional District say it害羞草研究所檚 uncertain if the lake building behind the dam will burst or if it will top over the debris. The B.C. government said a release could swell the Fraser River for hundreds of kilometres, potentially setting off dozens of emergency evacuations and alerts.

Hinch said the warmer Fraser River is already nearly lethal for the salmon, and if the fish get held back from entering cooler glacier-fed waters, that could be dangerous.

害羞草研究所淪o, what害羞草研究所檚 happening right now is, with the reduced water flow downstream, that water is going to be warmer as a start. It害羞草研究所檚 also going to possibly be less accessible. So, these fish are going to be holding in warmer water and low flows, either in the Chilcotin system or in the Fraser system, he said.

Williams Lake First Nation Chief Willie Sellars said the situation with the salmon run is 害羞草研究所渋ncredibly concerning.害羞草研究所�

He said the First Nation is worried about what will happen to the fish after the large lake pooling behind the landslide breaks loose.

害羞草研究所淲hat is that going to do to every single one of those sockeye and chinook that are swimming up the Fraser River looking to spawn in those other tributaries?害羞草研究所� he said.

Hinch said one of the problems is that there害羞草研究所檚 no way to know how the debris sent flowing down the rivers will eventually settle.

害羞草研究所淚f not full barriers, it could create partial barriers, it could create areas where it害羞草研究所檚 more difficult for the fish to get around,害羞草研究所� Hinch said.

害羞草研究所淜eep in mind that these fish have all stopped feeding about a month ago. And so, they害羞草研究所檙e migrating up on reserves.害羞草研究所�

There害羞草研究所檚 also a risk that new rock and debris in the water could affect the salmon害羞草研究所檚 ability to navigate using their sense of smell, a skill imprinted on them as fry.

害羞草研究所淭hey are imprinted on unique chemicals that are in their home watershed. That chemical composition is disrupted by landslides, because you now have other organic chemicals coming into the river, at high concentrations, that aren害羞草研究所檛 part of their home stream smell,害羞草研究所� he said.

Sellars said this year was already anticipated to be a low run year.

害羞草研究所淢aybe it害羞草研究所檚 better that something like this happened on the low year, but then it害羞草研究所檚 also pretty devastating to that run that害羞草研究所檚 going to be heading up the Chilcotin and four years from now, there is going to be no fish,害羞草研究所� he said.

At a news conference Thursday, Nathan Cullen, the minister of water, land and resource stewardship, said the government knows that the water is critical spawning habitat for salmon and other fish and that the sockeye are on their way.

He said the government was 害羞草研究所渋nitiating early plans as to what we can do to make sure that those stocks remain intact.害羞草研究所�

Hinch said there害羞草研究所檚 not much that can be done prior to the dam breaking.

害羞草研究所淎ll we can do is hope that the temperatures that these fish are holding in isn害羞草研究所檛 doing irreparable damage to them for too long of a period of time. And that the fish get into the Chilcotin once the river is amenable for migration.害羞草研究所�

In 2019, a landslide partially blocked the Fraser River and created an impassable barrier to key salmon populations that spawn in the Upper Fraser watershed.

Rescue efforts to get the trapped salmon beyond that slide included shooting them through a so-called salmon cannon, capturing the salmon, then transporting them on a truck or helicopter past the site and finally creating a permanent fishway to help them get past the slide.

Ashley Joannou, The Canadian Press