E-Fauna BC: Electronic Atlas of the Fauna of BC (Mobile Atlas Page)

Lampetra ayresii (Günther, 1870)
American River Lamprey; River Lamprey
Family: Petromyzontidae

Distinguished by 2 large teeth on the supraoral bar, a large middle tooth on the tongue, 3 points (rarely 2) on each central lateral tooth plate, and the absence of posterial teeth (Ref. 27547). Anterior dorsal fin being lower than posterior, the fins separate in nonbreeding individuals but coming into contact at spawning; caudal fin lobes about equal, lower lobe joined to anal fin; anal fin virtually absent in males (Ref. 27547). Dark brown or brownish gray on sides and back; belly yellowish, silvery around head, gill openings and lower sides; caudal fin has a band of dark pigment inside its margins, symmetrical on each lobe (Ref. 27547).

Source: FishBase. Page, L.M. and B.M. Burr 1991 A field guide to freshwater fishes of North America north of Mexico. Houghton Mifflin Company, Boston. 432 p.

Species Biology

Parasitic adults are found in estuaries and the ocean, migrating to clear gravel riffles of streams to spawn (Ref. 5723). Ammocoetes burrow into the mud where they live for an unknown period and migrate to the sea only after transformation (Ref. 1998). Adults feed by ripping flesh from other fishes (Ref. 2850), ammocoetes feed on microscopic plants and animals just like other members of this family (Ref. 1998). Parasitism can take place at a length of 16.2 cm TL (Ref. 1998). Preyed upon by a number of fishes, e.g. lingcod, and birds (Ref. 1998).

Source: FishBase. Page, L.M. and B.M. Burr 1991 A field guide to freshwater fishes of North America north of Mexico. Houghton Mifflin Company, Boston. 432 p.

BC Distribution and Notes

The relationship between this species (river lamprey) and the western brook lamprey is unclear. They may be anadromous and non-migratory forms of the same species (not unlike the anadromous and freshwater-resident forms of threespine sticklebacks). If the river lamprey is a separate species, its spawning sites are unknown.

Source: Information provided by Don McPhail for E-Fauna BC.

Global Distribution

Eastern Pacific: Tee Harbor, Alaska to Sacramento-San Joaquin drainage in California, USA. Freshwater resident population in Morrison Creek, Vancouver Island, British Columbia (Ref. 12269).

Source: FishBase. Page, L.M. and B.M. Burr 1991 A field guide to freshwater fishes of North America north of Mexico. Houghton Mifflin Company, Boston. 432 p.

Origin Status	Provincial Status	BC List (Red Blue List)	COSEWIC
Native	S4	Yellow	Not Listed

BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

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