Entosphenus tridentatus

Identification Tips:

• Lacks lower jaw
• Body long, tubular, eel-like
• May reach 70 cm, but more often 30-50 cm
• from the sea blue-black to greenish above, silvery to white below
• Spawning adults become reddish brown
• Three large sharp teeth on bar along top of mouth
• Three sharp points on plates along the sides of the mouth
• Dorsal fins arise far back on the body,
• Lower lobe of caudal (tail) fin larger than upper

Ammocoete Larva
• Cannot be reliably distinguished from other lamprey species
• Hood-like head and mouth
• No eyes or fins
• Body muscular and tubular in cross-section

Conservation Status:

British ColumbiaCanadaNatureserve
COSEWICSpecies at Risk Act
Not at Risk (Yellow List)Not AssessedNoneG4, S5

Information Source: BC Conservation Data Centre: http://a100.gov.bc.ca/pub/eswp/

Life History:

• Most populations spawn in rivers but live as adults in the ocean for 3 to 4 years
• Parasitic on fish and whales, attach to sides and suck body fluids
• Migrate up rivers to spawn, sometimes hundreds of kilometers
• Construct depressions in gravel or sand to spawn
• A few land-locked populations migrate between lakes and spawning streams.
• Some individuals may spawn more than once
• Larval form (ammocoetes) burrow in soft stream sediments for 4-6 years as filter-feeders
• Metamorphosis to adult form in September-October


• Adults usually found in estuaries or inshore ocean waters, especially near stream mouths, but sometimes far offshore
• Spawn in gravel riffles of streams and rivers
• Larvae burrow in mud, sand, silt or organic debris of stream bottom


British Columbia
• Coastal Rivers including Vancouver Island and Haida Gwaii

• Rivers around the North Pacific Ocean from Hokkaido, Japan to Alaska and south to southern Baja California

Primary Information Source:
McPhail, J.D. 2007. The Freshwater Fishes of British Columbia. University of Alberta Press. Edmonton, Alberta.