The survival of wild salmon runs is an important and sometimes controversial issue in the Pacific Northwest. Hydro-electric dams, pollution, overfishing and loss of habitat are some of the man-made problems confronting salmon as they struggle to complete their life cycle. This film was made in 1975; salmon runs have continued to decline since the making of this movie.
Salmon of the Columbia River & the Bonneville Dam
Historically, average annual salmon runs returning to the Columbia River Basin above the Bonneville Dam were estimated in the range of 5 - 15 million fish. Today, Columbia River salmon runs have declined by over 90 percent, and many species (there are five types of salmon native to the Pacific Northwest) are listed as endangered or threatened. See Endangered and Threatened Species chart.
Bonneville Dam is a major obstacle to salmon returning to the upper Columbia River Basin to spawn. As you can see from this stock footage, the force of the water going through the dam (to create electricity) is very strong.
Fish ladders have been built alongside the turbines to help the salmon get over the dam.
Salmon leaping up the fish ladder at Bonneville Dam
Fish Counter/Viewing Window at Bonneville Dam (underwater view)
Lamprey at Bonneville Dam
Salmon aren't the only migratory fish in the Columbia River! Lamprey are the oldest fish species alive today, with fossils dating back 500 million years. Just like salmon, they hatch from eggs in fresh water, then travel to the ocean where they live for 2 -3 years before returning to their place of birth to spawn. Lamprey attach to a host fish or marine mammal and feed on the host's blood, a lot like a big leech! You can see their teeth in the video below. Maybe a bit gross, but also fascinating!