Do beaver dams prevent salmon from moving upstream?
Beavers and salmon have naturally co-existed in the Pacific Northwest for thousands of years. Beaver dams that prevent salmon from migrating are rare. In most cases, salmon will wait at the bottom of a dam until a heavy rain. When the flow of water over the top of the dam is higher, the fish will jump over the dam. Even juvenile trout and salmon just a few inches long can go over most beaver dams. Water flows over the top of the dam and across the sticks in the face of the dam, creating a fish ladder effect. Four inch long salmon have been observed scaling dams as high as six feet in this manner!
Related Questions
- Salmon and trout can reach even the most remote spawning grounds so surely Beaver dams would not be a real problem for them?
- Do the Snake River dams block salmon access to pristine high-elevation spawning habitat in Idaho and Oregon?
- Salmon and Sea-trout can jump over waterfalls – surely they can get over Beaver dams?
