The Oregon Health Authority issued a health advisory Wednesday to warn people about toxic contaminants found in lamprey, a snake-like fish that is eaten by Indigenous people as a cultural and ceremonial food.
The advisory sets limits for the first time on how many lamprey people can safely eat from the Columbia River and its tributaries in Oregon.
State testing of lamprey tissue found the toxic industrial chemical polychlorinated biphenyls, known as PCBs, at levels of concern. It also detected the toxic metal mercury at levels of concern to vulnerable people, including children, people who are pregnant and nursing parents.
Over time, eating too many fish contaminated with PCBs or mercury can damage people’s organs and cause learning and behavioral problems. Both toxins can be passed along to babies during pregnancy or in breast milk.
To protect people’s health, OHA is recommending a meal limit of four lampreys per month for adults and two per month for vulnerable people, including children under 6, people who are or may become pregnant and nursing parents.
Aja DeCoteau, executive director of the Columbia River Inter-Tribal Fish Commission, said tribal members have led the effort to restore lamprey in the Columbia River Basin to protect their role in the ecosystem and to preserve tribal access to an important cultural food.
“As Oregon’s largest consumers of lamprey, this consumption advisory will impact tribal people most of all,” DeCoteau said. “Lamprey have been an important part of the cultures, diets and ceremonies of Columbia Basin tribes since time immemorial.”
DeCoteau said limiting consumption should only be a temporary solution.
“The tribes believe that the long-term solution to this problem isn’t keeping people from eating contaminated fish — it’s keeping fish from being contaminated in the first place,” she said.
David Farrer, a toxicologist with OHA, said the toxins in the fish are likely coming from the ocean, where lamprey spend the majority of their time.
“They start out as little tiny things, and they go out to sea and they grow big out there,” he said. “When they come back up the river, they don’t eat at all.”
Farrer said salmon also spend the majority of their lives in the ocean and generally have low contaminant levels. Lamprey might be different because they are parasites that feed on larger predators that often accumulate more toxins in their bodies.
Lamprey tissue collected by the Columbia River Inter-Tribal Fish Commission in 2009 did not originally meet state standards for issuing a health advisory, Farrer said, but a new analysis of the same tissue examined cumulative health risks from multiple contaminants.
“We hadn’t done that earlier,” Farrer said. “We took a new look at it using more current methods. That new method made the difference. This is definitely a very important species for tribes, so we thought it was important to take a new look at these data.”
Additional information about harvesting lamprey and fish advisories limiting consumption of contaminated fish is available on OHA’s website.