Zoo, partners return Pacific lamprey to the wild

Tribal-led conservation efforts continue in North Santiam River

Pacific lamprey took a jawless leap forward last week when zoo care staff, along with Tribal and agency partners, released 23 of the ancient fish above the Detroit dam on the North Santiam River. The cohort spent the past 9 months living at the Oregon Zoo, as part of a tribal-led effort to restore Pacific lamprey populations in the region.

"We've been caring for this special group of lamprey at the zoo since last year," said Jen Osburn Eliot, who oversees the zoo's northwest area. "We've learned so much in that time, and it was wonderful to work with our Tribal and agency partners to return these fish to the wild."

The 23 Pacific lamprey arrived at the zoo in June from nearby Willamette Falls, marking the first time in human care for a group of lamprey from that population. Additional lamprey collected at Willamette Falls were translocated directly to the release site, without spending time in human care. Comparing the different overwintering approaches can provide valuable information on how best to restore the species, wildlife officials say.

"We'll use DNA fingerprinting of the zoo lamprey to identify their offspring and compare their reproductive success with that of the lamprey released last year," said Jon Hess, senior fisheries geneticist for the Columbia River Inter-Tribal Fish Commission. "This sample group from the zoo will allow us to learn more about how to be most effective in restoring lamprey to their native streams."

In addition to spending time in the zoo's Great Northwest area, the lamprey also received full health checkups from the veterinary team, including lab work to monitor their maturation and CT scans to better understand their anatomy. Biologists from the Columbia River Inter-Tribal Fish Commission worked with care staff from the zoo to learn everything they could about the jawless fish before their release.

"Our Tribal partnerships are among our most meaningful in conservation, and they show what's possible when relationships are built around a shared purpose," said Shervin Hess, who manages the zoo's conservation programs. "They're working to restore this ancient species to their historic range, and we're so happy the zoo can play a role in this important effort."

The Pacific lamprey, a long fish with a jawless mouth and no scales, has survived three ice ages and five mass extinctions, but populations have declined over the past 75 years due to habitat loss and degradation, passage barriers, climate change and food scarcity. They are now considered a species of concern by the U.S. Fish & Wildlife Service as well as the Oregon and Washington state fish and wildlife agencies.

In 2019, the Columbia River Inter-Tribal Fish Commission and its member tribes partnered with the Oregon Zoo and U.S. Fish and Wildlife Service to create a new lamprey habitat celebrating this ancient, important fish. The habitat has since connected millions of guests with the story of lamprey, their cultural significance and why humans need to protect them.

Another cohort of Pacific lamprey from Willamette Falls is expected to arrive at the zoo in a few months. That group will spend 9 months at the zoo before being released back to the wild.