Salmon cannon being built in BC to help fish overcome Fraser River landslide

Canada Department of Fish and Wildlife officials say that they are planning to use a pneumatic fish pump, commonly known as a salmon cannon, to help salmon migrate past a landslide on the Fraser River in British Columbia, Canada.

A ladder is being constructed to lead the fish to a holding pool, where humans or a machine will sort them by size and push them into one of two different-sized tubes. The salmon will then be shot through the cannon – a 525-foot tube – which will take them to the other side of the landslide.

Scientists believe that the Big Bar landslide on the Fraser River, where the system is to be used, occurred in November 2018. However, it wasn’t discovered until June of last year, because the area where it occurred is so remote. Scientists initially detected the landslide using satellite imagery.

Chinook salmon are expected to arrive at Big Bar later in May and sockeye are predicted to arrive beginning in July, but Gwil Roberts, who is leading the Department of Fisheries and Oceans’ response to the landslide, said that the water volume will have to drop for the cannon to be functional – and that might not be until August.

“In terms of what percentage of success we’ll have, I can’t hazard a guess,” Roberts said.

If for some reason the cannon doesn’t function as expected, a backup plan is in place to transport the salmon by truck and helicopter, as was done last year. Last July, workers from the British Columbia Ministry of Forests, Lands, and Natural Resource Operations trapped salmon in holding pools and transferred them into oxygenated aluminum tanks to be lifted by helicopter two miles past the slide site. Radio tags were inserted into the stomachs of the fish to track their migratory journey upstream.

The cannon system is being leased from Seattle, Washington, U.S.A.-based company Whooshh Innovations. The company has calculated that with a constant supply of fish, some 86,000 salmon could move through the system every day. The system can use a camera to photograph the fish, can sort wild and hatchery salmon, and can block invasive species from entering. 

Photo courtesy of Harry Beugelink/Shutterstock