The tribes are trying to restore the Columbia River Basin population of lamprey, eel-like parasites that survive by sucking the blood from salmon and other fish.
"We would cook them over the open fire and grease would drop off and keep the fire burning," Jay Minthorn said.
"As long as I can remember, lamprey has always been an important food at the ceremonies," the 64-year-old tribal leader said.
The number of lamprey counted at Ice Harbor Dam on the Snake River dropped from 50,000 in 1963 to just 1,000 in 1996. As a part of an experimental program, tribal biologists have released nearly 600 adult lamprey at three places in the Umatilla River Basin.
"Lamprey are important to the ecosystems as well as important to our tribal culture," said David Close, a tribal member leading the research and restoration project. "They're just not glamorous."
Young lamprey spend five years as blind, toothless filter-feeders buried in river silts. They are an important food source for birds and raccoons. Adults, who return from the ocean laden with fat, are eaten by seals and other mammals. Scientists think lamprey suffer from the same problems as salmon - logging, grazing, dams and development.