Thursday August 22, 2024
Northwest Public Broadcasting —
As salmon and steelhead swim upstream, they’re now facing one more challenge in fish ladders. It’s a non-native fish competing for space: the American shad.
At Lower Granite Dam on the Lower Snake River, American shad hang out in the fish ladder. A few years ago, the American shad population exploded into a horde on the Columbia and Snake rivers.
“They were introduced in the late 1800s in the Sacramento Valley, and they found the Columbia River,” said Elizabeth Holdren, lead supervisory biologist with the U.S. Army Corps of Engineers. “Just like us, it’s beautiful, and they loved it. So they became established here.”
Now, American shad are causing the most trouble for fish ladders in the region, she said.
“They kind of chill out. They don’t necessarily go all the way out of our ladder and then they spawn. They die in the ladder,” Holdren said.