Salmon Transport Kevin Hand
It's pretty difficult to track the movements of millions of salmon. Here's how
At the turn of the 19th century, up to 16 million salmon and steelhead trout migrated up the waterways of the Columbia River Basin to spawn. Today, about one million salmon and an equal number of steelhead return, in large part because the rivers have been dammed. When fish swim from their hatching grounds to the ocean, they learn the route and return by the same course years later. If a dam blocks it, the run discontinues. Read more about delicious salmon here.