Teleostei (teleosts) > Cypriniformes
(Carps) > Leuciscidae
(Minnows) > Plagopterinae
Etymology: Couesius: From the American ornithologist Eliot Coues of the US Army Medical Coprs (Ref. 45335).
More on author: Agassiz.
Environment: milieu / climate zone / depth range / distribution range
Freshwater; demersal; pH range: 6.5 - 7.8; non-migratory. Temperate; 4°C - 25°C (Ref. 12468); 66°N - 40°N
North America: Alaska (Yukon River drainage); throughout most of Canada and northern USA; south to Delaware River in New York, south end of Lake Michigan, Illinois, Platte River system in Colorado, and Columbia River drainage in Washington, USA. Relict population in Mississippi River basin in Iowa, USA. Sometimes hybridizes with Rhinichthys cataractae in Lake Superior (Ref. 4564).
Length at first maturity / Size / Weight / Age
Maturity: Lm 8.6  range ? - ? cm
Max length : 23.0 cm TL male/unsexed; (Ref. 86798); common length : 10.5 cm TL male/unsexed; (Ref. 12193); max. reported age: 5 years (Ref. 12193)
soft rays: 7 - 9;
Vertebrae: 39 - 44. Couesius plumbeus is distinguished by having the following characters: barbel at corner of large, barely subterminal mouth; moderately pointed snout; large eye; head flattened above and below; dorsal fin origin over or slightly behind pelvic fin origin; complete lateral line, 53-70 lateral scales; 8 anal rays, and pharyngeal teeth 2,4-4,2 (Ref. 86798). Spineless fins, normal jaws, and tiny barbel at the corner of the mouth (Ref. 27547). Body moderately compressed and slender, coloration include brown to green above, dark stripe along silver gray side, darkest on young and large male, sometimes black specks on side and belly, dusky caudal spot. Large male may have red at pectoral and pelvic fin origins, corners of mouth (Ref. 86797). In some populations, breeding males develop bright orange-red patches on sides of head and at bases of pectoral fins, but the presence of this color varies from place to place (Ref. 27547).
Inhabits virtually any body of water, standing or flowing, large or small (Ref. 5723, 86798). Common in gravel-bottomed pools and runs of streams and along rocky lake margins (Ref. 86798). Mostly found in shallow water, but may move to deeper parts of lakes during hot weather (Ref. 27547). Feeds on zooplankton, algae, terrestrial and aquatic insects, and small fishes (Ref. 1998).
Spawning individuals form schools that move from lakes or deeper parts of streams to shallower water (Ref. 27547). Also Ref. 10280.
Page, L.M. and B.M. Burr, 2011. A field guide to freshwater fishes of North America north of Mexico. Boston : Houghton Mifflin Harcourt, 663p. (Ref. 86798)
IUCN Red List Status (Ref. 126983)
Threat to humans
Aquarium: public aquariums; bait: occasionally
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82804
= 1.0000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01023 (0.00546 - 0.01916), b=3.01 (2.84 - 3.18), in cm total length, based on LWR estimates for this species & (Sub)family-body (Ref. 93245
Trophic level (Ref. 69278
): 3.4 ±0.43 se; based on food items.
Generation time: 3.1 ( na - na) years. Estimated as median ln(3)/K based on 1 growth studies.
Resilience (Ref. 120179
): Medium, minimum population doubling time 1.4 - 4.4 years (tm=2-4; tmax=5; K=0.36).
Fishing Vulnerability (Ref. 59153
): Low to moderate vulnerability (31 of 100).