| Family: |
Petromyzontidae (Northern lampreys), subfamily: Lampetrinae |
| Max. size: |
50 cm TL (male/unsexed); max.weight: 150.0 g; max. reported age: 10 years |
| Environment: |
demersal; freshwater; brackish; marine; depth range - 10 m, anadromous |
| Distribution: |
Europe: southern Norway to France, including Ireland and the British Isles. Also in the Baltic Sea and along the French and western Italian coasts of the Mediterranean Sea (Ref. 59043). Absent from Black, Caspian and Polar seas (Ref. 3161). Landlocked populations from Lake Mjosa in Norway (Ref. 12269), Lakes Ladoga and Onega, upper Volga in Russia, Loch Lomond in Scotland, some Finnish lakes and possibly in Lough Neagh in Ireland (Ref. 59043). |
| Diagnosis: |
Dorsal spines (total): 0-0; Anal spines: 0-0; Anal soft rays: 0-0. It is jawless with a round sucker-like mouth and has an outer circle of small teeth and an inner circle of large teeth (Ref. 88171). It has a typical eel-like shape with 2 dorsal fins and 7 gill openings behind the eye. It lacks paired fins. Young adults are uniformly greyish in colour. As it ages, the river lamprey becomes greenish-brown dorsally, golden yellow along the sides and white ventrally (Ref. 58137). In coastal waters of Germany, it can be confused with the sea lamprey (Petromyzon marinus), which is distinguished by having its teeth arranged in many consecutive circular rows (Ref. 88171). Other diagnostic features: Adults 8.6-49.2 cm TL. Body wet weight in individuals 18.0-49.2 cm TL, 30-150 g. Body proportions, as percentage of TL (based on 48 specimens measuring 10.8-38.6 cm TL): prebranchial length, 10.0-12.9; branchial length, 7.9-11.3; trunk length, 46.2-54.3; tail length, 24.1-30.3; eye length, 1.4-3.1; disc length, 4.6-7.0. Urogenital papilla length, as a percentage of branchial length, in 19 spawning males measuring 19.7-28.3 cm TL, 15.9-37.5. Trunk myomeres, 58-66. Dentition: marginals, 70-95; supraoral lamina, 2 unicuspid teeth; infraoral lamina, 5-9 either all unicuspid teeth or, more frequently, the lateralmost are bicuspid and the internal ones unicuspid; 3 endolaterals on each side; endolateral formula, typically 2-3-2, rarely 1-3-2 or 2-3-1; 1-2 rows of anterials; first row of anterials, 4-7 unicuspid teeth; exolaterals absent; posterials absent; transverse lingual lamina, 8-18, usually 12-14, unicuspid laminae straight or parentheses-shaped and each with 9-13 unicuspid teeth. Marginal membrane present. Velar tentacles, 4-10, with tubercles; no velar wings. Body coloration in recently metamorphosed individuals silvery; in preserved upstream migrants, bluish brown or lead gray on the dorsal aspect tending towards silvery on the lateral aspects and whitish or yellowish on ventral aspect. Early upstream spawning migrants returning from the sea have a bronze sheen. Dorsal fins of maturing individuals may have a purplish tint. Iris is golden yellow. Body coloration in the landlocked population in Lake Ladoga is completely black. Lateral line neuromasts unpigmented or darkly pigmented. Extent of caudal fin pigmentation, absent or trace in young adults and 75% or more in spawning individuals. Caudal fin shape, spade-like. Oral fimbriae, 84-112. Oral papillae, 11-20 (Ref. 89241). |
| Biology: |
In fresh waters, in rivers, brooks, and lakes. Anadromous, but some populations are permanent freshwater residents (e.g. Lough Neagh, Northern Ireland (UK); Loch Lomond, Scotland (UK); lakes Ladoga and Onega, Russian Federation) (Ref. 89241). Amphihaline species (Ref. 51442). Metamorphosis takes place at a length of about 13 cm and they migrate to the sea (Ref. 51442). Most river lampreys live 4-7 years and reach 30-35 cm length (Ref. 88187). Females grow larger than males (Ref. 58137). Adults spend 1-2 years at sea, often along the coast or in estuaries (Ref. 59043). They live on hard bottoms or attached to larger fish like cod and herring (Ref. 88174). Adults are parasitic, feeding on fishes by sucking their blood and afterwards consuming the flesh (Ref. 1998). Adults predatory on marine fishes from the end of July to October. Trematodes and cestodes have been found in the intestine of prespawning adults at sea. (Ref. 89241). In autumn, adults commonly undergo reproductive migration from the sea to shallow middle or upper reaches of rivers and streams with strong currents (1.0-2.0 m/s in British rivers) and gravel bottoms (Ref. 51442, 59043, 88171). Spawning migration upriver (Vistula and Neman rivers) begins near the end of September in the Baltic Sea Basin. In tributaries to the Gulf of Finland (Narva, Neva, and Luga rivers), upstream spawning migrations occur twice yearly; once in summer-fall and once in spring. In the upper Rhine River, the spawning season is February to April; in England (UK) from April to May; and in the lower Neva River, Russian Federation, from early June to early July (Ref. 89241). During reproductive migration and reproduction, adults do not feed but instead utilize their lipid reserves (Ref. 30578) and are known to undergo a considerable shortening of up to 27 per cent (Ref. 83507). Fecundity is highly variable and ranges from 650 to 42,500 eggs/female; 10,000-16,000 eggs/female in Lake Ladoga. Communal spawning in the same redd by L. fluviatilis and L. planeri has been reported in the River Tywi Basin, Wales (UK), in April, at a water temperature of 11 °C. Both species participated in constructing a redd about 23 cm in diameter and 5-8 cm deep, consisting of pebbles, gravel and coarse sand (Ref. 89241). Spawning takes place in pre-excavated pits in river beds, its depth between 50-100 cm; after spawning the adults die (Ref. 51442). The blind ammocoetes are filter feeders of detritus and microorganisms; they live mostly buried in sand, silt or clay sediments for up to 4.5 years, often at the edges of rivers and streams where currents are slow (Ref. 51442, 59043, 88184, 88185). Sometimes they are found in substrates with submerged vegetation and plant debris (Ref. 12285). Ammocoetes may tolerate low oxygen levels but when burrows reach near anoxic levels, the larvae need to emerge from the substrate in order to survive (Ref. 88184). Fisheries exist in England (UK), Finland, France, and the Russian Federation. In the 19th century, up to 450,000 adults yearly were used by the English fishing fleet as bait in the fisheries for Gadus morhua and Psetta maxima. In Finland, the catch in 1983 was 2.3-2.4 million individuals (about 100 t) for a value of $800,000 US. There are reports of intoxication through eating this species (Halstead 1967). The mucus and serum are poisonous and the flesh must be thoroughly washed and all the blood removed before consumption (Ref. 5504). Cooking method involves de-sliming, removal of heads and branchial regions, the rest of the body covered in sunflower flour, and cooked in sunflower oil (Ref.89241). Utilized fresh and smoked; eaten fried (Ref. 9988). |
| IUCN Red List Status: |
Least Concern (LC); Date assessed: 05 March 2010 Ref. (130435)
|
| Threat to humans: |
poisonous to eat |
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