Practical "Salmon Cannon" throws fish over dam gates

In 2014, for the first time, there were reports of a so-called "fish cannon" that helped salmon going upstream to spawn to overcome obstacles. Today, its more advanced version has several technical advantages.

The Salmon Cannon was created in Seattle by Whooshh Innovations. It is a plastic tube connected to a mechanical air pump that "pumps" fish over obstacles upstream.

At first, it was used to load fish onto trucks or to process them in a special hatchery. The fish was manually loaded at the bottom of the lower pressure system, where it was sucked into the inside of the pipe and transported up to the opposite end. The travel speed ranged from 5 to 10 m / s.

The main disadvantage of the system was the need to manually load fish into it. The company's specialists decided to "interest" the fish so that it could do it by itself. For this, a special gutter was installed in the lower part of the apparatus, from which water continuously flows out, imitating a river. The fish going to spawn instinctively rushes towards it and rises up the chute.

Once inside, the fish passes by the FishL recognition scanner, which is equipped with cameras that take 18 pictures per second. The resulting images are instantly analyzed by a computer system that records the species, size and other characteristics of each fish.

This not only allows biologists to track which fish species are in the river, but also enables the system to “deny entry” to foreign species. If found, they are simply transported through special gates back into the river below the dam.