Massive rock-blasting salmon rescue on way
An industrial-scale fish rescue will soon take place on the North Shore in a 40-metre-deep canyon, nearly impossible terrain and wall-hugging trees. Beginning next month, crews will lower themselves into the Seymour River Valley to blast apart a giant rock slide that threatens to wipe out thousands of wild salmon.
“Our goal is to get the fish swimming upstream,” said Sandie Hollick-Kenyon of Fisheries and Oceans Canada.
“The rock-breaking will lead to that.”
It has taken 18 months for authorities to agree on a $250,000- peryear plan to deal with 50,000 cubic metres of river-choking rubble. As part of that plan — which includes two First Nations, the Squamish and Tsleil-Waututh — a $30,000 fish-capturing system was installed near the river mouth Thursday.
The floating aluminum fence will span the river and corral spawning salmon into a side channel, where they can be caught, transported above the slide and released into dozens of spawning channels in the pristine valley.
Seymour Salmonid Society president Shaun Hollingsworth said the salmon run will likely die out if fish can’t be transported over the obstruction while a passage is being cleared.
“When these wild fish are gone, there’s no other Seymour wild fish in the world,” he said.
Seymour hatchery manager Brian Smith, who was among a handful of volunteers attaching fences to the slippery river bottom, was pleased that an 18-month process to secure governments’ approval was finally done.
“This is a monumental day for us,” he said. “It’s super-historic.”
The blasting plan was worked out carefully because homes are located several hundred metres away and adjacent trails are used by hundreds of hikers and bikers. To soothe fears about the use of explosives and falling debris, Hollick-Kenyon said a low-impact type of rock-splitting technology was chosen, which is different than traditional blasts that depend on high-impact shock waves. The technology uses a rapidly expanding volume of gas, which seeks out fissures within stones and bursts them open with a quieter thump.
“They don’t go boom in the old way. When it expands, it just pops,” Hollick-Kenyon said.
“We don’t end up with rocks flying through the air, so it’s safe.”
The rocks — several as big as houses — will be split into smaller chunks that can eventually be grad- ed into a fish-accessible waterway with the aid of high-pressure hoses. Salmonid volunteer co-ordinator Sasha Gale said crews will wait for low-flow periods in August to begin their work.
“They don’t want to take out too much at a time. They don’t want to create another wall,” she said.
Overhead trees are being assessed so “nothing will fall” on the crews, Hollick-Kenyon said.
Despite uncertainties about whether a fish-friendly passage can be created, she said the consulting company, Northwest Hydraulic, is “confident.”
“They do this kind of thing all the time,” she said.
Wild coho and steelhead populations can’t wait for the new waterway to be completed, because their numbers would begin to die out.
As a result, the society mounted a fish-rescue operation Thursday, installing a system of floats and aluminum fencing at the river mouth that will corral spawning salmon and allow thousands to be scooped up.
“It’s an opportunity to catch a good portion. Some will be dropped at the hatchery for brood stock and others will be released into natural habitats,” HollickKenyon said.