It took 50 million years for salmon to evolve and only about 50 years to nearly wipe them out. Now, Washington’s native salmon and steelhead populations are getting a reprieve—one stream at a time. It took 50 million years for salmon to evolve and only about 50 years to nearly wipe them out. Now, Washington’s native salmon and steelhead populations are getting a reprieve—one stream at a time. Ecology Phys.org – latest science and technology news stories