Pacific Lamprey

Pacific Lamprey, US Fish & Wildlife Service Photo Credit

Description: This eel-like species is believed to be part of an ancient group of fish dating back a few hundred million years. They have long slender bodies, are brown in color, have a round sucker-like mouth, no scales and breathe through holes instead of gills. As juveniles they develop eyes, teeth and become free-swimming. Generally grow to 15 – 25 inches.

Diet: Lamprey are parasitic and feed primarily on salmon, flatfish, rockfish and pollock. They are preyed upon by sharks, sea lions and other marine mammals.

Habitat: Similar to salmon, they prefer gravel-bottomed streams, particularly towards the upstream end of riffle habitat. As an anadromous species, they are well adapted to both fresh and saltwater habitat.

Range: Historically found throughout the Pacific Rim, from Alaska south to Mexico and along major river systems along the Pacific coastline where there were large concentrations of salmon and steelhead. Historically found in robust numbers throughout the Columbia, lower Snake, upper Snake and Clearwater River Basins. Previously found in tributaries throughout the Clearwater, including in places like Lolo Creek.

Reproduction: Spawning occurs between March – July. Both sexes construct nests by moving rocks (gravel) with their mouths. Adults die within 36 days of spawning. Ammocoetes (larval lamprey) hatch and drift downstream to areas of low velocity and fine substrates where they will burrow, feed on algae and grow for the next seven years. As juveniles they then migrate to the ocean, where they can spend another 1-3 years maturing before they cease feeding and migrate back (at night) to freshwater bodies to spawn. Species is thought to overwinter for one year before spawning.

Threats: The dam building frenzy of the 20th Century has greatly reduced Pacific Lamprey populations. The species no longer thrives in ecosystems above dams. Culverts, water diversions, tide gates, dredging, poor water quality, changing ocean conditions and predation by non-native fish have also taken a great toll on this ancient species.

Legal Status: Despite the species being imperiled, Lamprey’s currently do not receive protection under the Endangered Species Act. They are instead listed as a Species of Concern. The Columbia River Inter-Tribal Fish Commission has a lamprey conservation plan for the Columbia River Basin. Learn more.

Miscellaneous: Pacific lamprey provided an important food source for tribes of the Columbia River Basin and were prized for their rich, oily meat. The fish were generally served alongside salmon during feasts and celebrations. The late Elmer Crow of the Nez Perce Tribe fiercely advocated for the recovery of this important species until his tragic death in 2013.

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