These jawless fish are as interesting as they are ugly.
Pacific lamprey, an eel-like species, will be released into the Yakima River by the Yakama Nation Fisheries at a public event in Prosser on Sunday.
Lamprey, which are older than the dinosaurs, are native to the Pacific Northwest.
The endangered lamprey are important to the ecosystem of Mid-Columbia rivers and streams and also are culturally important to Columbia River tribes.
From 2 to 4 p.m. at Farrand Park, 900 Sheridan Ave., Prosser, fish biologists and technicians will staff stations with information about lamprey and also will provide entertainment, including rapping about lamprey.
The event will conclude with the release of adult lamprey, a hands-on experience for participants.