River Lamprey redirects here. See Lamprey River for the river in New HampshireThe European river lamprey, also known as the river lamprey or lampern, is
a jawless lamprey, scientific name Lampetra fluviatilis. It is found in coastal waters around almost all of Europe from the north-west Mediterranean Sea up to the lakes of Finland, Scotland, Norway (Lake Mjosa), Wales (Cors Caron) and Russia, including rivers in the Alps. It feeds as ectoparasites and parasites of fish. It has a reproduction cycle similar to that of salmon. River lampreys belong to the same genus as brook lamprey and are thought to be very closely related. Current thinking suggests that European brook and river lampreys are a paired species, which means the river lamprey represents the anadromous (sea going) form of the resident brook lamprey. However, this is an area that is still being actively researched.
River lampreys migrate upstream from the sea to spawning grounds in autumn/winter. Spawning activity is greatest in the springtime (like brook lamprey) and river lamprey ammocoetes also spend several years in soft sediment before migrating to sea as adults. It is not currently known how long these animals spend in marine habitats before making the return trip to spawn.
Statistics
As ammocoetes, because of their close similarity to brook lamprey, it is very difficult to identify these animals beyond genus level (Lampetra). They average 30 cm in length as adults but some may be considerably smaller (20 cm) but in each case they are distinctly larger than adult brook lamprey (12–14 cm). They are generally 150 g in mass, and their maximum life span is roughly 10 years
