©Andi Hartl

River lamprey

D-Flussneunauge; GB-River lamprey; DK-Almindelig flodlampret; PL-Minóg rzeczny; LT-Upinė nėgė; LV-Upes nēģis; EST-Jõesilm; RU-Речная минога; FIN-Nahkiainen; S-Flodnejonöga

Characters

1) 3 big keratinous teeth on both sides of the mouth.
●) 7 external gill openings on eath side, one single nasal opening.
●) No paired fins.
●) Body without colour pattern; blue-brownish back well defined from light-coloured bottom.
Average length 30 to 40 cm, seldom 50 cm long; body diameter about thumb-thick.

Similar species

Sea lamprey - many small ceratinous teeth on sucking disc; marbeled pattern on body; much larger and thicker.

Eel - paired pectoral fins; gill cover (operculum) and a single external gill opening.

Conger - paired pectoral fins; gill cover (operculum) and a single external gill opening.

Biology

For spawning adults migrate upstream. River lampreys breed only once in their live. The larvae, so called Ammocoetes, live buried in sand or mud for up to 4 years. They feed by filtrating very small particles. After metamorphosis they live in coastal waters for about two years.

Diet

Parasitic, sucks itself with the mouth-disc on other fish and feeds on rasped tissue and blood.

Importance

Commercially important only in few areas, e.g. Latvia.

Endangerment

Migration impaired by dam construction, e.g. by hydroelectric powerplants. The long living larvae are very sensitive to water pollution.