In One Ear: Lamprey ladder

Published 12:15 am Thursday, February 27, 2025

Ear: Lamprey

A news tidbit from the Portland District, U.S. Army Corps of Engineers Facebook page: “We’re rebuilding our Bonneville Dam, Washington, fish ladder for Pacific lamprey! They’re stoked, we assume.

“This ladder will have openings through its baffles (vertical walls) to give lamprey a more direct path upstream to spawn … (and) improve overall passage for our eel-like fish friends, and also decrease the amount of time it takes them to make their way through the ladder.” The new ladder will help salmon get through, too.

A bit of trivia: The Washington Department of Fish and Wildlife says female and male lampreys work together to build nests, using their sucker mouths to clear a 1- to 2-foot circle in which the eggs are laid.

Females can lay up up 200,000 eggs, which incubate for about a month. Lampreys, a jawless fish, evolved over 450 million years ago. They’re older than dinosaurs, and even trees, and are still around in spite of at least four mass extinction events.

“The fish viewing windows aren’t going anywhere,” the Facebook post added. “You can still drop on by between June and the end of October to see some of these buddies suckin’ on the windows. July and August are good months to see LOL — lots of lamprey.” (Illustration: Portland District, U.S. Army Corps of Engineers)

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