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Silver Lamprey

Silver Lamprey. Photo Credit: Ellen Edmonson

Silver Lamprey. Photo Credit: Ellen Edmonson

Ichthyomyzon unicuspis

Species at Risk Status

Federal Government status: Special Concern

Provincial Government status: Special Concern


  • Eel-shaped adults are 9-39 cm in length and are dull brown in colour. This colour changes to silvery-bluish when spawning.
  • They have seven pairs of gill openings and a single dorsal fin.
  • Larvae appear to be worm-like and lack eyes or mouth parts.

Habits and Reproduction

  • Larvae are filter feeders until age 4-7 when they begin to develop eyes and teeth and start their parasitic life stage. A variety of fish species including catfish, pike, suckers, and sturgeon are host species. After 12-20 months, they cease feeding and reach sexual maturity in the spring.
  • At age 6-8, the adults migrate in May or June to spawn in the shallow riffle areas of small to moderate sized streams. They excavate a nest in the stream bed by moving sand and gravel with their mouth to form a shallow depression. They die shortly after spawning.


  • The larvae burrow into the mud at the bottom of streams. Juveniles may live within the stream or move to larger bodies of water where they grow to adult size.


  • Application of non-selective chemicals to control sea lamprey likely led to their decline.

Range Map

Distribution of Silver Lamprey (Great Lakes - Upper St Lawrence populations) in Canada.

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