Ray Ellenwood peered into a dark green perforated garbage can filled with water and a churning mass of Pacific lamprey. The dark, slender, two-foot-long fish gripped the sides of the container with their mouths, bodies undulating in the center, looking a bit like wet, wagging dog tails. Ellenwood, a fisheries technician for the Nez Perce Tribe, scooped about 20 of the fish, or He’esu in the Nez Perce language, into a smaller white bucket, and tipped its net-shrouded end into the Wallowa River. “The net lets them find their way out into the river slowly and helps them find something to hold onto,” he said.
Pacific lamprey are native to Wallowa County streams. Like salmon, they are anadramous, spawning in freshwater, migrating to the ocean, and then returning. During their marine life they are parasitic, feeding by attaching to fish, and sometimes gray, fin, or sperm whales. But unlike the invasive Great Lakes sea lamprey, Pacific lamprey rarely diminish the health of their hosts. And they are certainly no threat to fish, fowls, or humans here in Wallowa County. He’esu do not feed at all from the time they begin their migration upstream until they spawn and die.
Pacific lamprey were once abundant. They were observed as a “wriggling mass” at Willamette Falls in the 1920s. Even in the 1960s, as many as 380,000 lamprey were counted annually at Bonneville Dam. But in 2010, Bonneville counted only 5,735. Their populations have plummeted along the entire U.S. West Coast largely due to dams, as Pacific lamprey have great difficulty climbing fish ladders, and the applications of poisons intended to eliminate the lamprey as a “trash fish.” Additional factors include destruction of spawning and rearing habitat, and variations in ocean food sources and conditions.
“We target the streams where they have been extirpated,” Nez Perce Fisheries biologist Tod Sween said. “We’ll come back later in the year and electrofish for juveniles to confirm the population. We now have them in the Wallowa, Minam, Joseph Creek and the Imnhana.” This spring, Nez Perce Fisheries technician Joe McCormack found lamprey larvae flourishing in the Imnaha River. “It was kind of a surprise, but I was really happy to see them,” McCormack said. “They were kind of wiggly. They almost looked like really big worms.” McCormack placed them gently back into their wet, sandy riverbank home.
“We see these ancient fish every year in the Imnaha,” said Jim Harbeck, manager of the Nez Perce fisheries facility in Joseph. “It is one of the few streams in the Snake River Basin that still has a remnant population without being supplemented. We translocate adult lamprey into the Minam, Wallowa and Joseph Creek where we have since seen evidence of successful natural reproduction. But we have never released adults in the Imnaha and it is still producing juveniles.”
Last week, Sween and Ellenwood released 80 Pacific lamprey in Joseph Creek, 77 in the Wallowa River, and 78 in the Minam. The release program also includes Asotin Creek, and many tributaries along the Clearwater River. Tribal and other programs to restore Pacific lamprey in Washington, California, and elsewhere in Oregon are ongoing.
Why restore their populations now? He’esu, also called simply “Eel” by the Nez Perce, has always been a key source of tribal subsistence, medicinal and ceremonial food, providing a rich source of healthy fats. And Pacific lamprey are ecologically important as well.
“They act as a buffer for salmon both coming upstream and going down,” Sween said. “When there’s abundant lamprey, sea lions preferentially eat on them. The lamprey have five times as much fat. They’re essentially swimming sausages. And the juvenile lamprey are a buffer for young salmon migrating downstream. Any self-respecting bass would rather eat a juicy ammocete or macrophyte (juvenile lamprey) than a salmon smolt.”
He’esu’s other ecological roles include transporting marine nutrients to freshwater landscapes, providing food for birds and mammals, and, in their larval stage, filtering stream waters.
Nez Perce fisheries have been translocating Pacific lamprey back into their native Wallowa County habitat since 2006. The “Eels” are collected in June through August at Bonneville, The Dalles, and John Day dams as they struggle to make their way upstream. The fish are held in special tanks at the Nez Perce lamprey facility on the Clearwater River, and when they are close to spawning, transported to rivers that once hosted thriving populations of these elongate ancient fish.
Unlike salmon, Pacific lamprey do not need to return to their specific natal stream. They can be placed in any suitable spawning habitat where lamprey once flourished “Lamprey can scent their larvae’s bile and pheromone-like chemicals,” Sween said. “That scent tells them that this stream is going to be a good place to spawn, even if it’s not the stream they came from. They can follow the scents all the way from the ocean, which is amazing considering the dilution. The fact that they don’t spawn in the same place they grew up helps keep the genetics mixed.”
The adults that Ellenwood and Sween released this week sported radio tags and PIT tags. Ellenwood and Sween will be able to track them to their spawning redds, and check for their offspring in the future. Things are looking promising, although restoration of lamprey to harvestable levels will take a long, long time. “A lot of the places where we out planted we find larvae — stream-sides, we find the larva now — you can dig them up with your hands in sandy silty areas right off the bank,” Sween said. “The Pacific lamprey can make comeback. They are “Eels”, and they are always going to do their thing.”