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Pacific Lamprey Biology

Entosphenus tridentatus

The Pacific lamprey is distributed throughout the Pacific Rim from Japan to Mexico. Lampreys belong to a primitive group of fishes that are eel-like in form but lack the jaws and paired fins of true fishes. It is from this resemblance that they are sometimes called eels. (Click here to learn the differences between lamprey and eels.) Lamprey have a round sucker-like mouth, no scales, and breathing holes instead of gills. The Pacific lamprey is ancient fish that has survived ice ages, mass extinctions, and shifting continental plates for hundreds of millions of years. Now, in less than a century, they have declined to the point where their very existence is in peril. The tribes of the Columbia Basin, honor-bound to protect them, are working to restore this important part of the ecosystem and tribal culture.

Pacific lamprey are one of the 40 members of the lamprey family still found on earth. The lamprey family is one of the oldest of all the vertebrates and is the only living representative of this ancient line. Lamprey have been on earth between 400 and 450 million years (compared to 200 million for sturgeon, 6 million years for salmon, and a minuscule 100,000 years for humans). They appeared during the same era as insects and seed-bearing plants.

Lamprey Lifecycle

After hatching from eggs, lamprey young, called ammocoetes, burrow in the mud and sand of freshwater streams. They are toothless and have only rudimentary eyes. The ammocoetes filter feed on microorganisms from five to seven years, after which they undergo a radical metamorphosis into adult lamprey. This metamorphosis includes rearranging the internal organs and the development of eyes and their characteristic toothed sucking disc. The adult lamprey then migrate to the ocean where they spend one to two years feeding before returning to fresh water to spawn. As adults in the marine environment, Pacific lamprey are parasitic and feed on a variety of prey. After spending one to three years in the marine environment, they cease feeding and migrate to freshwater in the spring. They are thought to overwinter and remain in freshwater habitat for at least a year before spawning the following summer. There is much that science does not know about these ancient creatures. Often treated as a “trash fish,” they have never been a priority for research. This has been changing, particularly due to the efforts of tribal scientists who are focusing their efforts and research on them in an effort to increase our understanding of the Pacific lamprey and give us as much information about them as possible in order to create appropriate and effective restoration plans to rescue this threatened species.

My great aunt was a medicine woman, and she would collect the fat that would drip off an eel as it was cooking over a fire. She would store the fat in a small bottle and use it for oil in lamps and for medicines.

Horace Axtell

Nez Perce


A Part of Our Ecosystem

The late Elmer Crow, Nez Perce, who dedicated the final years of his life to helping restore his “eels.” Here, he is showing a net full of Pacific lamprey at the Nez Perce Tribal Hatchery awaiting outplanting into the wild streams and rivers in Idaho.

Role of Lamprey in the Ecosystem

Due to their unique life history, the Pacific lamprey is an important component to the ecosystem both as a predator and prey. As a predator, Pacific lamprey has coevolved with native fish assemblages in the Pacific Ocean and freshwater ecosystems. As prey, lamprey is important to many species of fish, birds, and mammals, including humans. Like other anadromous fish species, they transport nutrients from the ocean to the freshwater environment.

Lamprey Harvest

Lamprey are usually caught by hand at places on the river where rapids and waterfalls force the lamprey to attach themselves to rocks to rest before attempting to move further upstream.

A Cultural Resource

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