Columbia River Gorge DemoWhooshhInnovations

How do quickly transport a load of live fish from one body of water, to another body of water 200 metres away that's up a big hill? With a fish cannon, of course.

A company called Whooshh has developed a system that can gently transport fish across distances of up to 200 metres at a rate of 40 fish per second, travelling at around 36 kilometre per hour. Whoosh indeed!

The technology used by Whooshh was actually developed for transporting ripe fruit and vegetables: tubes that can carry the food items from A to B without causing any bruising to the produce. The system has been reappropriated for transporting fish -- particularly salmon -- at high speed without causing any damage to the creatures' scales or eyes. It's kind of like a waterslide for fish, but going uphill instead of down.

Fish can be fed into the system either automatically or manually, and a seal is created around the fish, thanks to many partial membranes that are positioned at regular intervals inside the tubes. The membranes extend from the perimeter of the tube towards the centre, leaving a flexible hole in the middle. Fish (or any other products) can be fed through one end, and the pressure differential between one end of the tube and the other allows it to move rapidly through the system, out the other side and back into the water.

Whooshh doesn't actually pump the water through the tube -- the fish are transported through air (with a light mist introduced for lubrication) for their brief journey. In taking this approach, the fish cannon uses much less pressure and energy than other systems that rely on pumping lots of water from one place to another.

Why do fish need to be transported in across distances like this in the first place? Well, because humans build dams, which can block fish migration. Juvenile fish that live downstream need to migrate upstream. As it stands, many get killed by dams even if there are fish passage systems. A number of technologies can get round this issue, including fish ladders, lifts, locks and trapping and hauling them in trucks. The fish cannon is an alternative.

Whooshh's system can handle fish that weigh up to 15kg. It's been tested in a number of locations in the US, including the Columbia River Gorge, Roza Dam and Kalama Falls. The Verge has an interview with the guys who built the system, in which they describe the transportation system as a "salmon cannon". That is all.


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