Silver Lamprey

Ichthyomyzon unicuspis

Status:

  • COSSARO – Special Concern
  • COSEWIC – Special Concern

Description:

  • 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:

  • 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.

Reproduction:

  • 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.

Habitat:

  • 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.

Threats:

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