Dams are problem
A recent letter to the editor expressed concern for the “vast number of seagulls and pelicans feasting on the salmon coming down [the Lower Snake River].”
The writer then said, “I don’t think it’s the dams causing the trouble on the Snake River but rather the predators.”
No, it is the dams causing the trouble.
The dams increase the time the small salmon take to get to the ocean from three days to up to two weeks.
The predators thus have much more time to feed on the small salmon.
The dams cause the sediment to drop out of the water.
This artificially increases the clarity of the water and makes it easier for the predators to see — and therefore catch — the small salmon.
The dams improve the habitat for predator fish such as the pike minnow and spiny rays.
This increases the numbers of predator fish to feed on the small salmon.
The dams disorient the fish as they pass through the turbines or over the dams.
This makes the small salmon easier prey for the predators that congregate below the dams.
And this is just the trouble the dams cause because of the predators.
There are many, many more reasons why the dams cause trouble for the salmon — from inundating and ruining the finest spawning grounds, to lowering the dissolved oxygen content of the water, to making the return trip for adult salmon more difficult.