Head to head
River Lamprey vs Sea Lamprey
River Lamprey
VS Sea Lamprey
The river lamprey and the sea lamprey are both parasitic, jawless fish that spend their adult feeding years in the sea and return to rivers to spawn, but they differ greatly in size and range.
| River Lamprey | Sea Lamprey | |
|---|---|---|
| Scientific name | Lampetra fluviatilis | Petromyzon marinus |
| Relationship | A fellow jawless lamprey with a parasitic, sea-going life | A fellow jawless lamprey with a parasitic, sea-going life |
| Adult size | Reaches around 25 to 40 cm in length | Adults reach 60 to 120 cm in length |
| Mouth | A round, sucker-like mouth ringed with horny teeth | A funnel-shaped oral disc with concentric rows of yellowish teeth and a toothed, piston-like tongue that bores through skin and scales |
| Prey | Feeds on fish in estuaries and coastal waters for a year or two | Attaches to living fish, and occasionally to whales and basking sharks, feeding on blood and tissue fluids |
| Larval life | Several years as a blind larva buried in silt | Spends 3 to 7 years, and up to 10 or more, as a blind, burrowing, filter-feeding larva |
| Range | Rivers, estuaries, and coastal waters of north-western and northern Europe | Coasts and rivers on both sides of the North Atlantic, and a landlocked invasive population in the Great Lakes |
| Conservation status | Least Concern, and protected under European Union law, but affected by dams and pollution | Least Concern, though a pest that is controlled in the Great Lakes by poisons, barriers, and sterile-male release |
River Lamprey vs Sea Lamprey: common questions
Which lamprey is larger?
The sea lamprey, which reaches 60 to 120 cm, while the river lamprey reaches around 25 to 40 cm.
Are both parasites?
Yes, as adults both fasten onto fish with their sucker mouths and feed on their blood and tissues, before returning to rivers to spawn.
Which one invaded the Great Lakes?
The sea lamprey, which reached the Great Lakes through shipping canals in the early twentieth century and helped collapse the lake trout and whitefish fisheries.