Lampreys lurk on Clackamas River
When you imagine fish swimming through the Clackamas River, you might picture a chinook or steelhead, but there's also another creature occupying the waters near Estacada.
Since 2006, Portland General Electric has been working to improve Pacific lamprey passage through the company's hydro facilities on the river. The work is part of the company's license with the Federal Energy Regulatory Commission (FERC), which allows them to operate hydroelectric projects on the Clackamas.
Every summer, PGE biologists facilitate a trap-and-haul program, which involves collecting adult lamprey at River Mill Dam and releasing them upstream of North Fork Reservoir. This year, a record 362 fish were collected through the program.
Allison Dobscha, a strategic communications officer for Portland General Electric, said that the trap-and-haul program was started in 2017 to jumpstart lamprey migration and spawning.
"The adults migrate by following the scent released by juveniles, but if there aren't juveniles to begin with, it's really hard to get that cycle going. We started the trap-and-haul program as a way to jumpstart that cycle," she explained. "We collect adult lamprey at our River Mill fish ladder, and then we transport them upstream and release them into the North Fork Reservoir. The hope is that they'll spawn up there, start producing juveniles and then that cycle will eventually be self-sustaining."
Dobscha noted that lampreys play multiple roles in the ecosystem.
"Like salmon, they carry marine nutrients back from the ocean, which in turn help nourish juvenile salmon and other wildlife. On the other hand, adult lamprey can actually attach to adult salmon and feed off them in the ocean," she said.
Back on the Clackamas River, staff at PGE are working to facilitate passage for lampreys.
"In general, lamprey swim and move differently than salmon and steelhead," Dobscha said. "Most fish ladders are designed with salmon and steelhead in mind, but lamprey, for example, have trouble swimming around sharp corners. So one of the things we've been doing at the River Mill fish ladder is rounding the corners so that (lamprey) can kind of suction on as they're moving upstream."
Lampreys also may have difficulty with fast-moving currents.
"There's a certain current stream that's conducive to salmon and steelhead movement, but that might be slightly difficult for lamprey," Dobscha said. "There's a lot of research that's in the early stages. People don't tend to think about lamprey as much as they do about salmon or steelhead because they're not as charismatic."
To learn more about lamprey behavior, PGE biologists began studying their movements at night this past summer.
"Typically, we observe all that behavior during the day, but wildlife and fish behave differently at night sometimes, so we conducted nighttime observations to see where they get stuck and how they move," Dobscha said. "It's part of this larger effort to learn as much as we can about how they're moving upstream, where the roadblocks are and what bottlenecks their passage."
During the nighttime observations, biologists noticed lampreys clinging to walls and trying to climb upward when approaching difficult passage areas. Areas on the North Fork fish ladder that create difficulty for the fish also were noted.
Portland General Electric is sharing their findings about lampreys with the Columbia River Inter-Tribal Fish Commission.
"Lampreys are really difficult to categorize and track, and one of the ways that's easier to do it is by looking at their genetics. (The Columbia River Inter-Tribal Fish Commission) is conducting region wide Columbia Basin research, and we're helping by sending them our genetic data," she said.
Dobscha described lampreys as a "historically misunderstood creature" that are culturally and ecologically significant.
"Just like salmon and steelhead, they play a really important role in the ecosystem, and they're really important to Native American tribes in this region. We think they deserve as much love and attention as salmon and steelhead. All of us researchers are helping improve their migration and improve their populations just like we do for salmon and steelhead," she said.
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