VANCOUVER — Parts of a pneumatic fish pump dubbed the salmon cannon have arrived at the site of a massive landslide along British Columbia’s Fraser River, where Fisheries and Oceans Canada expects some salmon to begin arriving soon.
Gwil Roberts, director of the department’s landslide response team, says six 160-metre tubes of different sizes are being suspended along the canyon wall above the river.
A fish ladder that Roberts says is nearly complete would attract salmon, guiding them into a holding pond before they enter the fish pump and tube system that will take them up river to their spawning grounds.
The system is leased from a Seattle-based company and includes a scanner that measures the size of the salmon in order to send them into the appropriate tube.
Roberts says the largest tube is about 25 centimetres in diameter and the system is more gentle than the “salmon cannon” label suggests.
He says a deceleration mechanism would slow the salmon down and deposit them gently upstream after the fish have travelled about 20 metres per second for 20 seconds.
Roberts says the pump and other measures underway at the site, including a series of boulders arranged to create pools where salmon can rest, are designed to minimize the need to handle the fish.
He says the primary contractor is preparing the site where the pump will be installed shortly.
The slide was discovered last June after it sent 75,000 cubic metres of boulders and debris into the Fraser River north of Lillooet, creating a waterfall and obstacle for salmon returning to their spawning grounds.
“Mortality last year was extremely high. This year we have the plan in place to move the salmon to ensure they can get across the slide site and we are very hopeful we will have very, very low mortality,” says Roberts.
This report by The Canadian Press was first published May 25, 2020.
The Canadian Press