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BC Conservation Data Centre: Species Summary


Lampetra ayresii
River Lamprey

 
Scientific Name: Lampetra ayresii (Günther, 1870)
English Name: River 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
Species Group: Vertebrate Animal
Species Code: F-LAAY
Kingdom Phylum Class Order Family
Animalia Craniata Petromyzontida Petromyzontiformes Petromyzontidae
   
Conservation Status / Legal Designation
Global Status: G5 (Dec 2017)
Provincial Status: S5? (May 2019)
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: In California, spawns late April-May. In British Columbia, spawns in winter (Beamish and Youson 1987). Adults die after spawning. Ammocoete stage lasts several years; transformation into adult stage occurs when ammocoetes reach about 12 cm TL. In British Columbia, metamorphosis begins in July and is completed in April of the following year (Beamish and Youson 1987).
Global Ecology Comments: Adults may be eaten by game fishes during spawning migrations.
Migration Characteristics:
(Global / Provincial)		 
    Nonmigrant:
    Local Migrant:
    Distant Migrant:
    Within Borders Migrant: 		N /
N /
Y /
na /
Global Migration Comments: Transformed individuals migrate to sea and return to fresh water to spawn. In British Columbia, adults migrate back into freshwater by September (Beamish and Youson 1987).
Habitats:
(Type / Subtype / Dependence)
Global Habitat Comments: Habitat includes fresh and salt water. Ammocoetes burrow in sandy-muddy backwaters of streams. Adults are anadromous, feeding in estuaries and at sea and spawning over gravel riffles in clear freshwater streams (Lee et al. 1980). In British Columbia, just prior to metamorphosis, congregates immediately upriver of salt water, enters ocean from May to July (Beamish and Youson 1987). Adults probably spend much of their life in estuaries (Moyle et al. 1989). Spawning occurs in small, clean tributary streams, over gravel riffles, probably in saucer-shaped nests, dug in sand and gravel (Wydoski and Whitney 1979).
Food Habits: Herbivore: Adult, Immature
Invertivore: Adult, Immature
Piscivore: Adult, Immature
Global Food Habits Comments: Larval lampreys feed on algae and microscopic organisms. Adults are parasitic on various fish species (e.g., Pacific herring, Pacific salmon; mainly mid-sized salmonids); will attack fish in salt or fresh water; feeds mainly on muscle tissue and usually kills host in process of feeding.
Global Phenology:
Provincial Phenology:
(1st half of month/
2nd half of month)
Colonial Breeder: N
Length(cm)/width(cm)/Weight(g): 31/ /
Elevation (m) (min / max): Global: 
Provincial: 
   
 
Distribution
Endemic: N
Global Range Comment: The river lamprey occurs as widely scattered, isolated populations (Moyle et al. 1995, Moyle 2002) along the Pacific Slope, from the Sacramento-San Joaquin drainage, California, to Tee Harbor near Juneau, Alaska (Lee et al. 1980, Page and Burr 2011).

In California, this species has been recorded from the lower Sacramento and San Joaquin rivers (especially the Stanislaus and Tuolumne rivers); the Napa River, Sonoma Creek, and Alameda Creek (tributaries to San Francisco Bay); in Salmon Creek and in tributaries to the lower Russian River (Sonoma County, where the species appears to be a regular spawner); a single adult female was captured at Cape Horn Dam in the Eel River; this species has not been adequately surveyed in most California streams (Moyle 2002).

In Oregon, river lampreys have been found in sites 182 km apart in the Columbia and Yaquina rivers (Moyle 2002). According to the Center for Biodiversity, the species has not been documented in the Columbia River or anywhere in Oregon since 1980.

Detailed distribution records are not available for Washington, but the species probably occurs in major coastal drainages (Wydoski and Whitney 2003).

In British Columbia, in the center of their range, river lampreys have been reported from the Strait of Georgia and Fraser River (Beamish and Neville 1995). A landlocked population exists in Morrison Creek, Vancouver Island, British Columbia (Renaud 1997).

In southeastern Alaska, the species has been recorded north of Juneau at Tee Harbor-Lynn canal area, Douglas Island, Taku River, and in Portland Canal (Mecklenburg et al. 2002). Probably it occurs coastally in areas south of Juneau.
 
Authors / Contributors
Global Information Author: Hammerson, G.
Last Updated: Feb 21, 2012
Provincial Information Author:
Last Updated:
   
References and Related Literature
Beamish, R. J. 1980. Adult biology of the river lamprey (Lampetra ayresi) and the Pacific lamprey (Lampetra tridentata) from the Pacific coast of Canada. Canadian Journal of Fisheries and Aquatic Sciences 37:1906-1923.
Beamish, R. J., and J. H. Youson. 1987. Life history and abundance of young adult Lampetra ayresi in the Fraser River and their possible impact on salmon and herring stocks in the Strait of Georgia. Can. J. Fish. Aqua. Sci. 44:525-537.
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.
Scott, W. B., and E. J. Crossman. 1973. Freshwater fishes of Canada. Fisheries Research Board of Canada, Bulletin 184. 966 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: Lampetra ayresii. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Apr 26, 2025).