‘High risk’ many salmon species threatened by Big Bar landslide won’t be rescued, DFO says

Click to play video: 'Big Bar landslide could mean extinction for B.C. salmon runs'
Big Bar landslide could mean extinction for B.C. salmon runs
WATCH: A landslide that came down last year on the Fraser River continues to block a critical fish migration route and experts are now warning that some salmon runs could disappear. Julia Foy reports – Nov 30, 2019

Government officials overseeing the response to a massive landslide in B.C.’s Fraser River say there’s a “high risk” they won’t be successful in rescuing several salmon species being impacted by the rocks.

In a progress update Wednesday, Sarah Murdoch of the Department of Fisheries and Oceans (DFO) said water levels are beginning to drop, presenting the only opportunity for crews to remove tonnes of rock blocking a critical migration route.

But with crews facing difficult winter conditions in the remote area northwest of Kamloops, Murdoch said it’s unclear if enough rock can be removed by mid-March when spring and summer salmon runs arrive.

“Unless sufficient rock debris is removed to reduce the flow rate before the water levels increase again, we’re expecting Fraser salmon populations that migrate before late August could be significantly affected,” she said.

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The federal government issued an open request for information to the private sector on Nov. 26 seeking input on best methods to clear the slide, with submissions being accepted until Friday.

When asked why the request was posted so late in the year, Murdoch said various levels of government have been working on solutions throughout the year.

Between that work and earlier consultations with the private sector, she said the government already has “a good approach on how to go forward” but still wants to hear more suggestions.

Click to play video: 'More than 2 million salmon at risk due to Big Bar landslide'
More than 2 million salmon at risk due to Big Bar landslide

“We have not seen a slide of this scale that impacts the salmon since the Hell’s Gate slide back in the early 1900s,” she said.

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“We want to make sure that we’re being as efficient and as effective as possible with the limited amount of time we have.”

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The discovery of the slide this past June sparked a massive response from federal, provincial and First Nations officials, who transported more than 60,000 fish up the river with helicopters and trucks.

The slide, which is believed to have come down between October and November last year, created a five-metre waterfall that made it nearly impossible for millions of salmon to make it to their natural spawning grounds upstream.

After months spent stabilizing slopes to prevent future slides, officials transitioned into longer-term planning in September, creating contingency plans while anticipating the drop in water levels.

But Murdoch again stressed the unpredictable conditions posed by Mother Nature, warning crews have only “one shot” to make progress in removing the rock.

“There is a high risk we will not be fully successful,” she said. “We may be at this for a couple of winters.”

DFO scientists have said at least three salmon runs are at risk of extinction, with three more facing “considerable risk” depending on how operations to clear the slide play out in 2020.

Click to play video: 'Rockslide causing concern for the future of salmon stock'
Rockslide causing concern for the future of salmon stock

Murdoch said around 275,000 salmon were able to make it through the waterfall as of mid-October, the majority of which — over 245,000 — made their way through narrow passages created by crews.

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But just like the DFO scientists said in their October presentation to the Pacific Salmon Commission, Murdoch said a majority of those fish that made it through were stressed and refused to spawn.

Estimates on the mortality rates of those that were transported by helicopter were not available, but Murdoch said further information would be released around the turn of the year.

In September, the federal department adjusted the number of returning Fraser River sockeye expected this year to a little more than 600,000, down from an earlier projection of nearly five million.

Murdoch said at least two salmon species, the spring and summer 52 groups, were over 80 per cent affected by the slide, while early Stuart sockeye were 100 per cent impacted.

Other groups were more than 50 per cent impacted, including summer and early summer sockeye.

An emergency measure to transport some of the Stuart sockeye to a hatchery at Cultus Lake is proving promising, and all 28,000 eggs hatched seem to be doing well, says Murdoch.

Similar measures could be taken next season.

— With files from the Canadian Press


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