This year’s Pacific lamprey return in the Columbia River is nearly 30 percent lower than the average run in the past 10 years, according to counts from the U.S. Army Corps of Engineers taken at Bonneville Dam.
The dismal numbers come after decades of slow and small progress in restoring populations of the important if unusual-looking fish after it was driven to the brink of local extinction in the 1990s and 2000s.
Last year’s returns were higher than the 10-year average; experts cautioned returns can vary substantially year-to-year.
The 87,365 adult eel-like fish that traversed Bonneville as of Sept. 14 make up 10 percent or less of pre-dam returns, according to lamprey biologists.
“People say they returned in the millions, and you could walk over their backs. Or, at Willamette Falls, it was like Medusa’s hair with all the fish hanging off the rocks,” Laurie Porter said of historic runs. Porter is the Lamprey Project lead at the Columbia River Inter-Tribal Fish Commission and a member of the Lac Courte Oreilles Band of Lake Superior Chippewa from Wisconsin. “They were abundant and plentiful, which they are not now.”
Life cycles interrupted
Lamprey survived 450 million years pretty much unchanged. Problems started for the foundational Columbia River Basin fish with the arrival of Euro-American settlers in the Pacific Northwest.
Native nations depended on nutrient-rich lampreys. The fish were a key part of many local nations, tribes and bands’ diets.
Dams — along with pollutants from industry, declining ocean food stocks, invasive species, rampant habitat destruction, warming river temperatures and other factors — interrupted that, said Ralph Lampman, the aptly-named lead biologist of the Yakama Nation’s Pacific Lamprey Project.
Bonneville Dam, for example, monitored how many lamprey passed during the day from its completion in 1938 until 1969. During that time, it saw daytime returns of between 50,000 to 400,000 a year, meaning total returns then could have numbered more than a million because daytime counts only capture a fraction of the fish. Just 25 percent of the lamprey that the dam counted this year came during the day.
Lampman suspects returns were two to three times more still because lamprey are so hard to count.
But the dam stopped counting in 1969 and, by the time it began again in 1994, the population had collapsed with returns varying from roughly 100,000 to fewer than 7,000 in the decades that followed.
Restoration efforts
“Some pretty scary years from a conservation standpoint, where all of us in the region, especially our tribal partners, were really concerned about the status of Pacific lamprey in the Columbia Basin,” said fish biologist Sean Tackley of that era.
He’s the fish policy and program manager with the Northwest division of the U.S. Army Corps of Engineers, the agency that operates most of the major Columbia Basin dams that lamprey must negotiate.
“Those low counts in the late ’90s and early 2000s really prompted a lot of the efforts that you’re seeing today across the basin,” he said.
Those efforts include lamprey ramps, which allow the fish to climb up a chute to an alternative passage that’s easier for them. Resting boxes, another example, are bolted to the bottom of the fish ladder and allow lamprey to take a break from the ladder’s fast currents.
Ramps, resting boxes and similar projects modify infrastructure that was originally designed for salmon to accommodate the much older, much different looking fish. Salmon are a more popular target of conservation efforts due in part to their huge comparative appeal to non-native Americans and also to being listed by the Endangered Species Act.
While studies show fish ladders enable as many as 97 percent of salmon to successfully pass each dam they attempt to cross, the number for lamprey on the Columbia River is roughly 50 percent, Tackley said.
That’s for each individual dam. Lamprey have eight to pass on the Snake River to access hundreds of miles of their historical spawning grounds. On the mainstem Columbia River, lamprey must pass nine — before arriving at the unpassable Chief Joseph Dam.
(However, data shows some appear to get the hang of it, with 2,660 passing Lower Granite Dam this year. Many fish also spawn in tributaries of the lower and mid-Columbia.)
Lampman, of the Yakama Nation’s restoration project, said that while he recognizes the variety of challenges the species faces and that the dams’ ongoing mitigation work is essential, dams are still the biggest threat to lamprey.
“There’s been a lot of effort at the facilities like Bonneville Dam to make things better. But, even with all that effort, we only brought up the passage rates by 10 percent or so in the 20 years of working,” Lampman said. “So, we can’t really call it a success.”
That reality underscores the importance of Native-run lamprey restoration efforts.
Since 2000, the Yakama Nation and other tribes have taken on a large role in lamprey restoration efforts, in particular, through translocation — trapping lamprey and releasing them into the water above the dams.
Once the Columbia River Inter-Tribal Fish Commission traps the fish, they’re held in Bonneville’s captive brood building hatchery. From there, members of the Yakama Nation, Umatilla Tribe and Nez Perce Tribe pick up the fish with giant trucks.
Some are immediately taken to spawning grounds, Lampman said, while others are kept in the nation’s own hatchery before being released later.
Different populations of the fish — those who get to spawning grounds without human help, those that receive human help and some pilot hatchery fish — are tracked through their DNA to see which methods are most effective.
While much is still unknown about Pacific lamprey, their life cycle starts when they hatch in gravelly streambeds and head to slower moving water. There, they spend the next three to seven years burrowed in the sand and silt, filter feeding — and absorbing harsh chemicals that various industries deposited in the sediment.
Juveniles then experience a metamorphosis into the iconic toothy, jawless fish we recognize, and head to the ocean where they spend one to three years using their hallmark “sucking disk” to feed on host fish. From there, they head back to rivers and streams like where they were born, spending up to two years there before mating and dying.
Future generations
In the nearly quarter of a century since the translocation programs started, tribes have trapped and transported 53,500 lamprey to ideal sites around the region. And the programs have increasingly expanded their scope and picked up steam, with just this year’s count set to add a record 17,600 to that total.
In addition to the basic program (and despite humble funding compared to salmon restoration efforts), tribes now also track the lamprey’s genetics, track the fish themselves, run hatcheries, conduct research, lend fish to the Oregon Zoo, do on-site education at Bonneville and more.
And, crucially, the translocation projects have started to succeed.
Already, in the Yakima Basin, Lampman is seeing increases in juveniles heading out to the Pacific and adults are starting to come back in higher numbers. That’s enabled the restoration project to expand to places where dams have left the species functionally extinct.
“We focus on Yakima Basin but as the numbers increased from translocation efforts, we were able to expand into other basins,” Lampman said, “like in the mid-Columbia, like Klickitat and even White Salmon and then in the upper Columbia, like Wenatchee, Methow Basin.”
That’s particularly impressive because, unlike salmon, lamprey don’t always return to their birthplace.
“It’s not a certainty that they’ll return to that particular stream, or even to the Columbia River,” said Porter, the lamprey project lead at the Columbia River Inter-Tribal Fish Coalition. “So our work supports lamprey populations throughout their range, and other folks’ work will support our fish. So everywhere that they travel it’s necessary to be doing restoration, conservation efforts.”
For her, efforts including the Yakama Nations’ can only expand until lamprey passage is fully restored.
“That’s the goal, to continue — and not ‘improving,’ that’s not the word, the tribes don’t use that word anymore, we want to use the word ‘fix’ — (to) fix passage so that the lamprey pass,” she said. “They have to pass and we want them passing at 100 percent.”
But Lampman cautioned that for Pacific lamprey to be saved, the slowly growing awareness, support and funding of the last decades has to expand.
“When it comes down to the funding and nitty-gritty, there’s still not enough support to make the restoration work,” he said. “So, yeah, there’s growing awareness, but actual work on the ground still needs a lot more attention.”
