©Andi Hartl

Sea lamprey

D-Meerneunauge; GB-Sea lamprey, great sea lamprey, green sea lamprey; DK-Havlempret; PL-Minóg morski; LT-Upinė nėgė; LV-Jūras nēģis; EST-Merisutt; RU-Минога морская; FIN-Merinahkiainen; S-Havsnejonöga

Characters

1) Mouth disc with several small, keratinous teeth.
●) Seven gill openings per side and a single nostril.
●) No paired fins.
●) Body usually clearly marbled.
Length usually 70 to 90 cm, rarely up to 120 cm; about 5 cm in diameter.

Similar species

River lamprey - three pairs of large ceratinous teeth along mouth opening; uniform body colouration; body in cross section about as deep as a thumb.

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

Mature adults migrate upstream. They breed only once in their live. Larvae, the so called Ammocoetes, live 3 to 5 years buried in mud and filter-feeding on smallest particles. After metamorphosis into adults they migrate back to the sea, where they live for about three to four years until their sexual maturity.

Diet

Lampreys suck with their mouth disc on prey fish feeding so on blood and tissue which they rasp away. Sometimes smaller fish are also eaten completely.

Importance

Appreciated food fish; commercially of little use because of small stock.

Endangerment

Endangered due to obstruction of river courses, e.g. by hydro-electric power plants, and because of water pollution.