Entosphenus minimus (Bond & Kan, 1973)
Miller Lake lamprey
photo by FAO

Family:  Petromyzontidae (Northern lampreys), subfamily: Lampetrinae
Max. size:  14.5 cm TL (male/unsexed); max. reported age: 3 years
Environment:  demersal; freshwater, non-migratory
Distribution:  North America: Miller Lake in USA.
Diagnosis:  Adults: 7.2-14.5 cm TL; body proportions, as percentage of TL (based on 58 specimens 8.0-14.5 cm TL): 11.0-17.0 prebranchial length, 8.9-12.2 branchial length, 40.3-49.1 trunk length, 27.0-34.6 tail length, 2.1-3.3 eye length and 5.0-8.6 disc length; height of the second dorsal fin, as a percentage of TL, is significantly greater in mature (4.4-6.1) versus immature adults (2.2-4.2); urogenital papilla length (percentage of branchial length in 12 spawning males 7.8-10.0 cm TL): 10.0-18.8; trunk myomeres, 59-66. Adult dentition: supraoral lamina, 2-3 unicuspid teeth, usually 3, the median one smaller than the lateral ones; infraoral lamina, 5 unicuspid teeth; 4 endolaterals on each side; endolateral formula, typically 2-3-3-2; 2 rows of anterials; first row of anterials, 3 unicuspid teeth; exolaterals absent; single row of posterials, 11-19, usually with the outermost 1-3 posterials on either side bicuspid and the internal ones unicuspid, however, 0-16 can be bicuspid; transverse lingual lamina, 17-29 unicuspid teeth, the median one slightly enlarged; longitudinal lingual laminae each with 18-25 unicuspid teeth. Velar tentacles in adults, 5-9, without tubercles; wings consisting of a single short tentacle on either side; median tentacle shorter than the lateral ones immediately next to it; body coloration (preserved) in adults darker on the upper surface and paler on the lower surface with immature adults being yellowish brown, and with mature and spent adults being brownish purple; lateral line neuromasts unpigmented; extent of caudal fin pigmentation, 25% to <75%; caudal fin shape, spade-like or rounded; oral fimbriae, 86-101; oral papillae, 7-17 (Ref. 89241).
Biology:  Freshwater; in the upper reaches of rivers at an elevation of 1,402-2,134 m. Ammocoetes are associated with substrates of organic detritus at water depths up to 1 m. Spawning has been observed both in lake and in stream habitats. Life span approximately 36 months; about 30 months as an ammocoete and 6 months as an adult. Metamorphosis occurs in the fall. Adults parasitic on fishes (native Gila bicolor, Rhinichthys osculus klamathensis, and introduced Salvelinus fontinalis, Salmo trutta) usually measuring much less than 15 cm TL. Because of the small size of the hosts and the deep nature of the wounds inflicted, most attacks likely result in the death of the fish being attacked. Also reported to be scavengers and cannibals. Adults apparently do not feed more than a few months. Spawning migration is very limited. Adults build redds about 10 cm wide by 3 cm deep, at a water depth of about 30 cm. The redds consist of gravel and sand. Spawning period between 17 July and 20 August in Miller Lake and 10 June in Sycan River; in the latter case, spawning occurred during mid-morning at a water temperature of 12 °C. Fecundity, 503-727 eggs/female. Adults die after spawning. The species was extirpated from Miller Lake through poisoning in 1958 because of its parasitism of planted trout fingerlings.
IUCN Red List Status: Vulnerable (VU); Date assessed: 22 February 2012 (D2) Ref. (123251)
Threat to humans:  harmless
Country info:   
 

Entered by: Froese, Rainer - 01.05.91
Modified by: Luna, Susan M. - 23.09.16
Checked by: Torres, Armi G. - 02.09.94

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