- 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.