Lethenteron japonicum

Author: (Martens, 1868)

Lethenteron japonicum (Martens, 1868)

Status in World Register of Marine Species:
Accepted name: Lampetra camtschatica (Tilesius, 1811) (updated 2009-06-25)

Diagnosis: in addition to the characteristics given in the key, the average diameter of the sucking-disc (sexes combined) is equal to 62.5% of the branchial region and 6.1% of the total length. The number of trunk myomeres ranges from 65 to 73. Size: the maximum length obtained is 625 mm, while the common lengths of metamorphosed specimens in different areas vary from 130 to 460 mm.

Habitat: it is typically an anadromous species but in some areas of North America and Asia there are present land-locked populations. Berg (1931a) recognized three forms of L. japonicum, which differ, in addition to their distribution, by their sizes. The largest form is found along the Pacific coasts. The lack of comparative material prevents our further consideration of these forms.
Food: all populations of L. japonicum parasitize different types of fish in salt- and freshwater habitats. Reproduction: the number of eggs varies according to the size of the female from 80,000 to 107,000. The egg diameter is approximately 1 mm.

Distribution: in the area, from East Finnmark (River Pasvik) through the Barents Sea to Novaya Zemlya. In the White and Barents Seas, it is taken commercially. Abundant in the Arctic Ocean, along the Siberian coast, eastward to Kamchatka and the Bering Sea, south to Japan and Korea. On the North American mainland from the Kenai Peninsula, east along the Arctic Ocean drainages as far as the Anderson River. Formerly very abundant in the Yukon River and up the Mackenzie River to the Great Slave and Artillery Lakes and to Fort Smith on the Slave River.
In addition to parasitic L. japonicum in North America and Asia there are found several non-parasitic (satellite) species belonging to the same genus (Vladykov and Kott, 1978).

Spawning. Heard, 1966: 332-339.
Eggs, larvae and young stages. Okada, 1955: 4 | Morozova, 1956: 154-155 | Tambs-Lyche, 1963: 24 | Heard, 1966: 338.