‘Salmon Cannon’ That Launches Fish Over Dams Sparks Twitter Frenzy


It’s an unfortunate reality: Humans have ruined aquatic migratory patterns. But Whooshh Innovations has designed a solution—gargantuan fish cannons that can shoot salmon over dams in seconds.

The fish-firing device has been propelling species over river obstructions since 2014—John Oliver did a segment on it then—but the tubes have just recently captured Twitter’s imagination. People have become fascinated with why it exists, how it works, whether it’s safe, and the like.

A diagram of the pressure differential within the salmon cannons
A diagram of the pressure differential within the salmon cannons Courtesy Image

Contrary to what you might think, the tubes aren’t full of water, Jim Otten, Whooshh’s VP of engineering, explains. Instead, fish are transported using pressure differentials. Higher pressure behind the fish, rather than in front of it, causes easy passage through the cannon.

There’s still water in the tunnel for lubrication and to keep fish a little wet around the gills. It’s injected into the tube every 5 feet via a high-pressure mist. This allows the fish to quickly shoot through the chute. The construction emphasizes low-friction movement, so the salmon doesn’t get hurt.

Not every tunnel requires human loading, either. Whooshh’s software takes care of that. When anything wants to access the tube, it first enters a fish airlock. A computer scans the fish—determining morphometrics, color, pattern, and size—to determine whether it’s a species that’s been approved to go through the cannon.

Unapproved fish, including hatchery varieties, are put back in the river. If a fish gets the green light, the pressure equalizes, the main tube opens, and when the pressure differential hits, the fish is off, spirited away toward the firmament at anywhere from 11 to 18 mph. Only five fish are permitted in the tube at any given time (though larger tubes may hold more).

 

“The accelerator can handle up to 60 fish per minute, so 3,600 per hour,” says Otten. Theoretically, the cannon can transfer entire migration runs within hours without needing a second tube.

At the end of the fish’s seconds-long trek, a speed trap decelerates the fish and deposits it safely on the other end, hopefully not into the waiting maw of a grizzly bear. Tests have determined the travel to be completely safe and stress-free for the fish involved.

Maintaining this affordable, low-maintenance, low-water system is not only more environmentally friendly than fish steps and ladders, but it also renders them obsolete. The company says it’s ready to put a fish tube at every dam in the country—and that, hopefully, fish populations can recover from man’s interference in their waterways.

 

As you can imagine, this cannon-waterslide mashup has birthed some fantastic memes:





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