While human-created dams generate useful, green energy, they disrupt a river’s natural flow, also disrupting the natural spawning runs of the indigenous salmon. Written reports of rough fishways date to 17th-century France, where bundles of branches were used to make steps in steep channels to bypass obstructions.
Salmon Cannons
Though the strange salmon cannon has suddenly caught fire, it turns out the quick process of spitting fish through tubes to hurdle over obstacles in water has been a focus of wildlife experts for years.