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BC Conservation Data Centre: Species Summary


Entosphenus tridentatus
Pacific Lamprey

 
Scientific Name: Entosphenus tridentatus (Richardson, 1836)
Scientific Name Synonyms: Lampetra tridentata
English Name: Pacific Lamprey
 
Classification / Taxonomy
Scientific Name - Concept Reference: Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. 1991. Common and scientific names of fishes from the United States and Canada. American Fisheries Society, Special Publication 20. 183 pp.
Classification Level: Species
Taxonomy Comments: April 11, 2013 - Changed from Lampetra tridentata to Entosphenus tridentatus to align with NatureServe (DDW).
Species Group: Vertebrate Animal
Species Code: F-ENTR
Kingdom Phylum Class Order Family
Animalia Craniata Petromyzontida Petromyzontiformes Petromyzontidae
   
Conservation Status / Legal Designation
Global Status: G4 (Feb 2012)
Provincial Status: S5 (Jul 2025)
BC List: Yellow
Provincial FRPA list:   
Provincial Wildlife Act:
COSEWIC Status:
SARA Schedule:
General Status Canada: 4 - Secure (2005)
   
Ecology & Life History
General Description:
Global Reproduction Comments: The timing of migration to spawning stream varies geographically, and different runs may occur in a single river system. According to Wydoski and Whitney (1979) spawning occurs in June-July in Washington. In southern California, spawning likely begins by late January in most years, and spawning may continue into April (Chase 2001). In the Santa Clara River in southern California, upstream migration began as early as mid-December or as late as mid-March; peak migration occurred in March in most years (Chase 2001). Eggs hatch in 2 or 3 weeks. Ammocoetes remain in stream, metamorphose in 4-6 years (late September-October). Form macrostoma in British Columbia: spawns May-August, probably spends 6 years as larva and 2 years as subadult-adult before reproducing; metamorphosis July-October (Beamish 1987). Oceanic phase apparently may last 3-4 years in British Columbia but may be shorter in more southern areas (Moyle 2002). Generation time is 9 years (Luzier et al. 2011).

This is the only species of lamprey in which some individuals (from Washington) are known to spawn more than once (Page and Burr 1991).

See Luzier et al. (2011) for an up-to-date review of Pacific lamprey life history.
Migration Characteristics:
(Global / Provincial)		 
    Nonmigrant:
    Local Migrant:
    Distant Migrant:
    Within Borders Migrant: 		N /
Y /
Y /
na /
Global Migration Comments: This species is mainly anadromous; newly metamorphosed individuals migrate from parent streams to the Pacific Ocean. Upstream migrations may be as long as several hundred kilometers. Land-locked populations omit the oceanic phase but migrate between lakes and spawning streams. Goose Lake, California, population migrates up to 20-30 km between the lake and tributary streams. See reproduction comments for further information.
Habitats:
(Type / Subtype / Dependence)
Global Habitat Comments: The predatory phase of the life cycle (excluding land-locked populations) occurs in the ocean, primarily near stream mouths in estuaries and in other coastal areas but sometimes far away (Moyle 2002). Freshwater-resident populations exist in several areas in British Columbia (McPhail 2007) and elsewhere.

Ammocoetes inhabit shallow backwater and eddy areas along edges of streams in mud, silt and sand (Lee et al. 1980). In southern California, adults apparently spend approximately one year in fresh water prior to spawning (Chase 2001).

Adults spawn in runs and riffles in rock-, sand-, or gravel-bottomed clear streams, in small, shallow depressions, or crude nests, at the heads of riffles (Wydoski and Whitney 1979). Water depth at spawning sites often is 30-150 cm (Moyle 2002).

Lake populations in British Columbia spawn at creek mouths or sometimes move up to a few hundred meters up creeks (Beamish 1987). The Goose Lake, California, population spawns in gravel riffles of tributary streams, far enough upstream such that there is adequate ammocoete habitat (muddy backwaters) downstream from the breeding area (Moyle et al. 1989).
Food Habits: Herbivore: Adult, Immature
Invertivore: Adult, Immature
Piscivore: Adult, Immature
Global Food Habits Comments: Adults parasitic on fishes; attach and feed on body fluids. Parasitic stage may last 20-40 months (Lee et al. 1980) (probably 1-2 years in Goose Lake, California, population: Moyle et al. 1989). Ammocoetes (larvae) are filter feeders; feed on microscopic plant and animal material.
Global Phenology:
Global Phenology Comments: Adults die soon after spawning.
Provincial Phenology:
(1st half of month/
2nd half of month)
Colonial Breeder: N
Length(cm)/width(cm)/Weight(g): 76/ /
Elevation (m) (min / max): Global: 
Provincial: 
   
 
Distribution
Endemic: N
Global Range Comment: Pacific lampreys occur in rivers around the North Pacific Ocean from Hokkaido, Japan (Yamazaki et al. 2005), to Alaska (Cape Lisburne and Norton Sound; apparently rare north of the Alaska Peninsula) and south to southern Baja California (Luzier et al. 2011). Malibu Creek, Los Angeles County, seems to be the southernmost point of regular occurrence in California; scattered distribution south of San Luis Obispo County, with regular runs in the Santa Clara River (Moyle 2002). Adults are wide-ranging in the Pacific Ocean from Japan to Baja California. Landlocked populations occur in lakes or reservoirs in British Columbia, Oregon, California, and possibly elsewhere.

At least historically, Pacific lampreys penetrated far inland in the Fraser, Columbia (to Idaho), Klamath-Trinity, Eel, and Sacramento-San Joaquin rivers. Dams now block or inhibit upstream passage in many rivers.
 
Authors / Contributors
Global Information Author: Hammerson, G.
Last Updated: Feb 23, 2012
Provincial Information Author:
Last Updated:
   
References and Related Literature
Beamish, R. J. 1987. Evidence that parasitic and nonparasitic life history types are produced by one population of lamprey. Canadian Journal of Fisheries and Aquatic Sciences 44:1779-1782.
Chase, S. D. 2001. Contributions to the life history of adult Pacific lamprey (Lampetra tridentata) in the Santa Clara River of southern California. Bulletin of the Southern California Academy of Science 100(2):74-85.
Hardisty, M. W. and I. C. Potter, eds. 1971. The Biology of Lampreys. Academic Press, London and New York. pp. 1-65.
Lee, D. S., C. R. Gilbert, C. H. Hocutt, R. E. Jenkins, D. E. McAllister, and J. R. Stauffer, Jr. 1980. Atlas of North American freshwater fishes. North Carolina State Museum of Natural History, Raleigh, North Carolina. i-x + 854 pp.
Moyle, P. B. 1976a. Inland fishes of California. University of California Press, Berkeley, California. 405 pp.
Moyle, P. B., J. E. Williams, and E. D. Wikramanayake. 1989. Fish species of special concern of California. Final report submitted to California Dept. of Fish and Game, Inland Fisheries Division, Rancho Cordova. 222 pp.
Page, L. M., and B. M. Burr. 1991. A field guide to freshwater fishes: North America north of Mexico. Houghton Mifflin Company, Boston, Massachusetts. 432 pp.
Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. 1991. Common and scientific names of fishes from the United States and Canada. American Fisheries Society, Special Publication 20. 183 pp.
Wydoski, R. S., and R. R. Whitney. 1979. Inland fishes of Washington. The University of Washington Press, Seattle. 220 pp.
 

Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.

Suggested Citation:

B.C. Conservation Data Centre. 2012. Species Summary: Entosphenus tridentatus. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 14, 2026).