Fish & wildlife Success stories Umatilla

 
Success stories ? Umatilla River Pacific Lamprey

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When it comes to restoring anadromous fish populations in the Columbia Basin, it's salmon that comes to mind. But there is another fish that is also historically and culturally important to basin tribes: the Pacific lamprey.

Like salmon, the lamprey has experienced declines in abundance from the effects of human development and disturbances to its habitat. Although the lamprey, which is an eel-like fish, is a highly valued resource to Native Americans, both as a cultural icon and as a subsistence food by various tribes along the Pacific coast, the conservation of native lampreys has not been a fisheries management priority in the United States. Even though these primitive fish share many of the same habitats as salmonids, lampreys have received little attention.

The Pacific Lamprey Research and Restoration project, initiated in 1994, is sponsored by the Confederated Tribes of the Umatilla Indian Reservation, and has been recommended by the Council for funding by the Bonneville Power Administration to provide critical information about Pacific lampreys in the Umatilla River. The overall goal of the project is to restore the natural production of Pacific lampreys in the Umatilla River to self-sustaining and harvestable levels. The Umatilla River basin was chosen by the tribe as an initial pilot project for several reasons: The river historically produced significant numbers of lampreys for fishing opportunities; recovery efforts for salmonids in the basin may help with the overall recovery of Pacific lampreys; and the current population levels of Pacific lampreys are extremely low.

David Close, project manager, believes the research suggests that the lamprey plays an important role in the food web, and may have acted as a buffer for salmon from predators. For a predatory sea mammal, lampreys are easier to capture than adult salmon; they have a higher caloric value per unit weight than salmonids; and their migration in schools means fertile feeding patches. And lampreys, like other anadromous fish species, also bring important marine nutrients to watersheds when they return to spawn and die in streams and rivers.

?We've really learned a lot about lampreys through this project, including the importance of pheromones in the timing of their migrations,? says Close.

One of the objectives of the project is to evaluate the role of these pheromones, or bile salts, which are released by larval lampreys as a migratory cue to upstream migrating Pacific lampreys. Researchers are measuring the fish's response to bile salts during the adult spawning migration in freshwater at the Columbia River Research Laboratory through a variety of techniques. The project should also give insight into the habitat requirements for larval lampreys; researchers have found that certain habitat variables can predict the abundance of larvae.

Since 2000, the project has outplanted adult lampreys in the Umatilla River, monitoring different life history stages to determine if this technique will help in restoring the natural production of lampreys. Initial results have been encouraging: adult lampreys are successfully spawning and producing larval lampreys. These larval lampreys are beginning to distribute from the headwaters to the lower reaches of the Umatilla River. In time, researchers hope that the larvae will attract adult lampreys during their spawning migration. Other techniques include the use of surgically implanted radio-tags used to monitor the behavior of Pacific lampreys in the Columbia River. Results have shown that radio-telemetry is effective with accurately sized tags and the proper acclimation time before the fish's release back to the river.

Researchers hope to better understand the Pacific lamprey in order to restore their natural production in the Umatilla River. Their future goals include research into the role of stress steroids in the lamprey; the role of microsatellite DNA in the population structure of lamprey; and ecological studies of recently hatched larvae.