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Helping Migrating Salmon­­-By Shooting Them Out of a Cannon

Author Nicholas Derenzo Illustration Jameson Simpson

brightideas

Hydroelectric power may be renowned as a clean, renewable resource, but for salmon, it’s proving to be a dam problem. Conservationists have devised several plans to help the fish clear dams and finish their spawning trips upstream—fish ladders, elevator-like fish lifts, even trap-and-haul programs using helicopters—but they’re all rather inefficient and expensive. This summer, though, a Bellevue, Washington–based company, aptly named Whooshh Innovations, debuted a method that, well, sucks. Dubbed the “salmon cannon,” the simple system—adapted from vacuum tubes used to transport fruit without bruising it—sucks a fish into a tube and shoots it through the air, over a barrier, at high speed. At worst, it sounds barbaric. At best, like a punchline. But the cannon is efficient and cheap, and it transports the fish safely and stress-free. Here’s how they’ll get from A to B in one piece.

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1. Once a fish enters the soft and flexible sleeve— either by being fed into the system by hand or by swimming in by itself—a seal forms around the body, creating a vacuum. Interestingly, the interior remains almost completely dry, with just a thin mist of water for lubrication; pumping water through would require higher pressure and thus use more energy. Inside, the pressure remains only 1 to 2 PSI, gentle enough not to damage the fish’s fragile eyes and scales.

2. The salmon is then shot through the cannon much like a canister in a bank’s pneumatic tube system. For the duration of the trip, the fish travels at speeds of 11 to 22 mph. Currently, the system can handle about 40 salmon per minute, depending on the length of the trip.

3. In June, Whooshh began testing the technology at Washington’s Roza Dam, with a course that lifted salmon over a 15-foot obstacle through a 230-foot-long tube at a 45-degree angle. Whooshh says the cannon will eventually be able to extend some 2,000 feet, reaching 1,000 vertical feet at an impressive 90-degree angle—handily clearing most dam hurdles you can throw in its way.

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