Classification / Names
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Petromyzontiformes (Lampreys) >
Petromyzontidae (Northern lampreys) > Lampetrinae
Etymology: Lampetra: lambo (L.), to lick; petra (Gr.), rock or stone, referring to their suctorial behavior (adults attach to rocks during nest building and mating) (See ETYFish); richardsoni: In honor of surgeon-naturalist John Richardson (1787-1865), “author of several important works on fishes from North America” (See ETYFish).
Eponymy: Sir John Richardson (1787–1865) was a Scottish naval surgeon, naturalist and Arctic explorer. [...] (Ref. 128868), visit book page.
Issue
This species is a synonym of Occidentis ayresii (Günther, 1870) (Carim et al. 2023: Ref: 133110). The species accounts will be merged.
Environment: milieu / climate zone / profondeur / distribution range
Écologie
; eau douce démersal; non migrateur. Temperate; 57°N - 43°N
North America: Pacific slope from McDonald Lake, southeastern Alaska to Umpqua River drainage in Oregon, USA.
Taille / Poids / Âge
Maturité: Lm ? range ? - ? cm
Max length : 17.3 cm TL mâle / non sexé; (Ref. 43939)
Distinguished by the very blunt teeth, the lack of a distinct median tooth on the tongue and the lack of posterial teeth (Ref. 27547). Anterior dorsal fin lower than the posterior, arising well back on body; caudal fin joined to both dorsal and anal fins; anal fin small, represented in males by a low ridge (Ref. 27547). Females with a pointed 2nd dorsal fin and a conspicuous anal lobe (Ref. 1998). Back and sides dark gray to brown, ventral side of body whitish (Ref. 27547); fins translucent olive-green and the caudal fin with diffuse black pigment (Ref. 1998). Oral disc narrower than head; usually 58-67 trunk myomeres; caudal fin with dark spot (Ref. 86798). Other adult diagnostic features: 8.0-15.4 cm TL. Body proportions, as percentage of TL (based on 45 specimens measuring 10.1-15.4 cm TL): prebranchial length, 10.4-14.0; branchial length, 8.3-10.8; trunk length, 44.7-53.1; tail length, 25.2-30.4; eye length, 2.0-2.7; disc length, 4.1-7.9. Urogenital papilla length, as a percentage of branchial length, in 26 spawning males measuring 12.2-15.1 cm TL, 17.6-30.8. Trunk myomeres, 60-67. Dentition: supraoral lamina, 2 unicuspid teeth; infraoral lamina, 7-10, usually 7 unicuspid teeth; 3 endolaterals on each side; endolateral formula, typically 1-2-1 (15 cases), 2-2-1 (12), or 2-2-2 (10), and rarely 2-3-2 (5) and 2-3-1 (1); 2 rows of anterials; first row of anterials, 4-6 unicuspid teeth; exolaterals absent; posterials usually absent; transverse lingual lamina, 5-11 unicuspid teeth, the median one enlarged or only the median enlarged tooth is present; longitudinal lingual laminae cusps too small to count. Velar tentacles, 5-6, with tubercles. Body coloration (preserved), dorsal and lateral aspects grayish, ventral surface whitish. Lateral line neuromasts unpigmented. Extent of caudal fin pigmentation, 75% or more. Fleshy tissues around the lingual laminae unpigmented. Caudal fin shape, rounded or spade-like. Oral fimbriae, 93 (Ref. 89241).
Body shape (shape guide): eel-like.
Inhabits gravel riffles and runs of clear, cool streams (Ref. 5723). Ammocoetes occur in muddy and sandy backwaters and pools of streams (Ref. 5723). Ammocoete feed mostly on diatoms but also on other microscopic plant and animal matter (Ref. 1998). Transformed lampreys do not feed at all (Ref. 1998). Nonparasitic (Ref. 5723, 89241). Spawning period in early May in British Columbia as evidenced by spent females being collected on 8 May. Spawning occurs in redds and fertilized eggs collected on 8 May hatched in about 28 days at water temperatures between 10-12 °C. Eggs are greenish. In the state of Washington, in the early 1900s, ammocoetes were sold at $1.50 to $1.75 US per dozen to use as bait for sportfishes (Ref. 89241).
Nest mostly made by males; may be shared by 6 pairs at a time; occupied by different groups at different times. Male carries out 'sliding-feeling' courtship by sliding up the body of the female with the disc gently touching her body. The male then attaches itself to her head and coils around her. The pair vibrates when the eggs and sperms are released.
Page, L.M. and B.M. Burr, 1991. A field guide to freshwater fishes of North America north of Mexico. Houghton Mifflin Company, Boston. 432 p. (Ref. 5723)
Statut dans la liste rouge de l'IUCN (Ref. 130435: Version 2025-1)
Menace pour l'homme
Harmless
Utilisations par l'homme
Pêcheries: sans intérêt; appât: usually
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Sources Internet
Estimates based on models
Phylogenetic diversity index (Réf.
82804): PD
50 = 0.5010 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00138 (0.00062 - 0.00310), b=2.97 (2.78 - 3.16), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref.
93245).
Niveau trophique (Réf.
69278): 2.4 ±0.23 se; based on food items.
Résilience (Réf.
120179): Faible, temps minimum de doublement de population : 4,5 à 14 années (Semelparous species, assuming tm (= tmax) > 4).
Fishing Vulnerability (Ref.
59153): Low vulnerability (10 of 100).
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