Latin name

Lethenteron camtschaticum

Other name

Japanese river lamprey or Japanese lampern.

Identification

The Arctic lamprey is characterized by its eel-like body shape, the presence of two large teeth on the supra-oral plates, the presence of only two points on the central pair of lateral dental plates, and the presence of a row of hind teeth. The oral papillae are: 12–22.

This species exhibits remarkable adaptability due to extensive gene flow among populations, morphobiological flexibility in response to changing environmental conditions, and evolutionary conservation of neuropeptide Y receptors, which together ensure survival in diverse Arctic habitats.

Features of fish fins

These fish have two dorsal fins on their tail, with the rear fin being larger than the front fin. The caudal fin consists of two lobes; the lower lobe is longer than the upper lobe. The caudal fin is a continuation of the dorsal and anal fins. The anal fin of the male fish is shaped like a small ridge.

Fish colouring

The Arctic lamprey is brown, gray, or olive with a lighter belly. The receptors of the lateral line are unpigmented. The eye area is unpigmented. The second dorsal fin has a dark spot near the apex.

Distribution

This species' range extends from Lapland eastward to Kamchatka and southward to Japan and Korea. It inhabits the Arctic and Pacific waters off the coast of Alaska and northwestern Canada. Adults live in freshwater habitats near the coast, such as rivers and lakes. They can be found on rocky and sandy surfaces, as well as in shelters under vegetation.

Habitat

This is a circumpolar marine and freshwater demersal species that prefers brackish waters. Their habitat depth ranges from 0 to 50 meters, and adults inhabit coastal and estuarine waters. Larvae are found along riverbanks in muddy-silt substrates where currents are weak. They prefer areas with rocky or sandy bottoms that are shaded by coastal vegetation.

Size

This lamprey typically grows to 5.1 to 12.6 inches (13 to 32 centimeters) in length, though some specimens have been known to reach 25 inches (63 centimeters) and weigh up to 7.1 ounces (200 grams). Non-migratory individuals rarely exceed 7.1 inches (18 centimeters) in length. Males are larger than females. Migratory lamprey species tend to be distinct from their much smaller freshwater counterparts. The maximum reported age is seven years.

Behavior

Adult Arctic lampreys spawn in coastal reefs. Their larvae inhabit muddy freshwater habitats, burrowing into the mud to feed on detritus. Lampreys are usually anadromous, living in the ocean before migrating to freshwater to spawn. However, some populations are permanent freshwater inhabitants. They parasitize any suitable-sized fish species, including commercial species. Adults are not parasitized. 

Food and feeding habits

The adult form typically feeds on parasites that attach themselves to various other fish species, including salmon, lake trout, and lake whitefish. The smaller, non-migratory form is not parasitic. Juveniles feed on aquatic invertebrates, algae, and organic debris.

Reproduction

Males of both species tend to exhibit similar preferences in mate choice. Regardless of size, males prefer larger, more robust females. However, the size of freshwater males limits their ability to mate with larger females. Therefore, they must use stealthy behavior to fertilize the eggs of larger females. In contrast, passage lampreys use their larger size and more aggressive behavior to mate with passage females.

Both males and females build nests by collecting pebbles and small rocks from the creek bottom. The male sucks on the female's head. The pair arches out, and the male wraps himself around the female. Both lampreys vibrate rapidly and release eggs and sperm into the nest. Two males may mate with one female at the same time. The female mates several times before her supply of eggs runs out, typically with multiple males. Larvae spend one to two years in this stage. After metamorphosis, which occurs from fall through winter, the young descend the creek to reach the sea, lakes, or larger rivers.

Fishing

The Arctic lamprey is a commercially important fish.

Relationship with a person

Harmless. This species is farmed through aquaculture. Its meat is high quality and rich in fat.