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'Salmon Cannon' Fires Fish Over Dams At 22mph
A "salmon cannon" which sucks fish out of water and fires them over barriers such as dams has been developed.
Salmon are born in freshwater before migrating to the ocean - then return to their place of birth to lay their own spawn.
But obstacles such as dams mean the fish can become disorientated, prompting a company called Whooshh Innovations to step in with a device to help ease their journey.
It is similar to a pneumatic tube and works when the fish swim into one end.
The tube's soft fabric forms a seal around the salmon, creating a vacuum which propels it through the pipe at speeds of up to 22mph.
The fish are out of water for just a few seconds before they land in the water at the other side.
Up to 40 fish every minute can be transported - and the tube can span gaps of more than 60 metres (200ft).
The team - which has tested the system at Kalama Falls, Columbia River Gorge and Roza Dam in Washington state - says the fish are happy to swim into the tube themselves.