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Lamprey at Winchester Dam

Lamprey passing through the fish ladder at Winchester Dam.

On the Ground: The Oregon Conservation Strategy at Work

April 2011

The Pacific lamprey is an Oregon State sensitive species, a federal Species of Concern and a Strategy species. Its life history intrigues many people; its rapid decline has the attention of conservationists.


The Pacific Lamprey: One Good Fish Story
Pacific Lamprey in the North Umpqua River Get a Closer Look
What’s next for Umpqua Basin Lamprey?
The Historic Winchester Dam


The Pacific Lamprey is an old, old fish—one that dates back 500 million years, and while biologists will be the first to tell you what they don’t know about the prehistoric fish, what they do know is fascinating.

An Oregon native, the Pacific lamprey, is long and eel-like. It is classified as a fish but has no jaws or fins. Its disk-shaped mouth is dominated by three large and many smaller teeth, and its life history is jam-packed with more intriguing events than a soap opera.

Pacific Lamprey life stages

Pacific lamprey life stages. Ralph Lampman photos. Click on photo to enlarge.

It hatches from an egg in two to three weeks as larvae, called ammocoete. For the next three to seven—yes seven!—years, it lives burrowed in the muck of stream and river beds. During one summer, the ammocoete goes through a slow metamorphosis and becomes a juvenile lamprey, developing eyes and a mouth. On winter flows, it migrates to the ocean, becoming an adult. Once in the ocean, and after years of feeding on algae, it cuts its new teeth by becoming parasitic to larger fish. After a couple of years, it leaves the ocean and returns to freshwater. Then, there is nest building, courtship, spawning and death. What’s not to find fascinating?


Sam Moyers, Oregon Department of Fish and Wildlife biologist, first encountered Pacific lamprey in his work with salmon and steelhead in the Umpqua Basin and has been intrigued with them for many years. “The more you know about them, the more you want to know,” he said.

He is especially concerned about their rapid decline. “We figure we had about forty to sixty thousand in the North Umpqua in the 1960s. Today, we have about 50 to 100 individuals.”

Reasons for the decline in the northwest are numerous: dams, water flows, chemicals, poor water quality, dredging, stream degradation, ocean conditions and other factors all contribute.

That’s a lot of criteria to look at, so Moyers and team focused their questions and in 2009 began working with an Oregon State University master’s degree candidate, Ralph Lampman, on a research project centered at Winchester Dam near Roseburg.

“We wanted to know how lampreys were navigating past the dam during the spring and summer upriver migration and, once past the dam, what habitat they used before they spawned,” said Moyers.

Fish are videographed as they pass through a fish ladder at the dam and then counted by ODFW fish biologists, but there is no data on what percent of lampreys use the ladder.

Lampman, with technical support from ODFW Roseburg staff Moyers, Kirk Haskett and Fabian Carr, began the research project in March 2009 and will wrap it up next month. During the 2010 migration, 45 lampreys were caught and radio tagged in the lower Umpqua. Two-thirds of them were released below Winchester Dam to determine if and how they passed the dam; one-third of them were released above the dam to learn about habitat preference.

Ralph Lampman and Reed Janke

Ralph Lampman, foreground, and Reed Janke, use a receiver and underwater antenna to track lampreys holding inside the dam timber crib structures. Ralph Lampman photo. Click on photo to enlarge.

Results show that during the 2009 migration, only eight percent of the lampreys successfully passed the dam. In 2010, 18 percent were successful. Interestingly, about two-thirds of the lampreys that approached the dam, but did not cross it, ended up using the dam as overwintering habitat. According to Lampman, this is not typically observed in other rivers with hydro dams. He believes the fish may be taking refuge in colder water at the dam’s base. Of the lampreys who successfully achieved dam passage, few used the fish ladder—the vast majority found ways to get through the log and stone dam.

Lampreys that were either released upstream of the dam or passed through the dam distributed themselves widely between one and 30 miles upstream of the dam where they held over the winter, moving to nearby gravel beds in the spring and summer to spawn. Lampman found the habitat they selected for holding was in deep, swift and well-covered water.

Currently, ODFW staff are working on a lamprey ramp at the dam that will aid in passage. It is expected to be complete this spring.

Other partners in the project include the Oregon Watershed Enhancement Bureau. U.S. Fish and Wildlife Service, the Bureau of Land Management, Partnership for the Umpqua Rivers and Oregon State University.


Amy Amoroso, Natural Resources Director for the Cow Creek Band of Umpqua Tribe of Indians, works to bring attention to the health of lamprey populations. The fish is culturally important to many Native American tribes. In 2008, she worked with ODFW and USFWS staffs to convene a Western Oregon Lamprey workshop to share research and expand knowledge of the species.

“We are very concerned about the decline of the species in the drainage. Tribal members who swam in the river as children tell of an abundance of lampreys,” she said. “Clearly there has been a change in the system, and we have to wonder what this says about its overall health.”

Pacific Lamprey

Pacific lamprey. Photo Jeremy Monroe, Freshwaters Illustrated, USFWS. Click on photo to enlarge.

Both the tribes and ODFW want to do additional research in the area. Amoroso is building capacity to undertake projects. ODFW staff want to learn more about species distribution, and Lampman would like to look at how invasive species, specifically small mouth bass, affect lamprey populations. 



The Winchester Dam is about 118 river miles from the Pacific Ocean, near the town of Roseburg on the North Umpqua River. It was built in November 1890 and is in the National Register of Historical Places. Constructed from large timber cribs, the dam was originally four feet high. In1907, it was raised to sixteen feet.

ODFW maintains a fish counting station and fish ladder at the dam, which provides a viewing opportunity for steelhead and salmon as they migrate upstream. It is free and open to the public.

Biologists use the fish counts to monitor populations, make management decisions and recommend angling regulations. A video camera records fish passage, and a technician views the tapes to record species and size, fin clips and any predator marks.

In addition to summer and winter steelhead, spring chinook and coho salmon, cutthroat trout also pass the dam in small numbers. The primary non-salmonid species are large-scale suckers, Pacific lamprey and northern pike minnow. To visit the Winchester Dam viewing area, take exit 129 from I-5.

winchester dam

Winchester Dam.
-- ODFW Photo --


Learn more about Oregon’s lampreys. In addition to Pacific lamprey, several other species are on the decline including western brook, river and Kern brook lamprey. Miller Lake lamprey, long thought to be extinct from the lake, were reintroduced in 2010. The world’s smallest predatory lamprey, they are about four inches long. Miller Lake Lamprey Conservation Plan.


On the Ground newsletter archives


The Oregon Conservation Strategy provides a blueprint and action plan for the long-term conservation of Oregon’s native fish and wildlife and their habitats through a voluntary, statewide approach to conservation. It was developed by ODFW with the help of a diverse coalition of Oregonians including scientists, conservation groups, landowners, extension services, anglers, hunters, and representatives from agriculture, forestry and rangelands.


Meg Kenagy
Oregon Conservation Strategy Communications coordinator
(503) 947-6021

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