Actinopteri (ray-finned fishes) > Cypriniformes
(Carps) > Leuciscidae
(Minnows) > Plagopterinae
Etymology: Semotilus: Greek, sema = banner (dorsal fin) + Greek, tilos = spotted; used by Rafinesque (Ref. 45335); atromaculatus: From the words ater, meaning black; and maculatus, spotted (Ref. 10294) More on author: Mitchill.
Environment: milieu / climate zone / depth range / distribution range
Freshwater; demersal; depth range - m (Ref. ), usually - m (Ref. ). Temperate; 0°C - 30°C (Ref. 35682); 55°N - 31°N
North America: most of east USA and southeast Canada in Atlantic, Great Lakes, Hudson Bay, Mississippi, and Gulf basins as far west as Saskatchewan, Wyoming, and Brazos River in Texas, but absent from Florida and south Georgia; isolated population in the upper Pecos and Canadian River systems, New Mexico. Introduced elsewhere in USA.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 30.3 cm TL male/unsexed; (Ref. 10294); common length : 19.1 cm TL male/unsexed; (Ref. 12193); max. reported age: 8 years (Ref. 12193)
(total): 8. Semotilus atromaculatus is distinguished by having the following characters: body barely compressed at front, compressed at caudal peduncle; mouth pointed; 47-65 scales on lateral line; dorsal fin with 8 rays; large black spot at front of dorsal fin base, black caudal spot (not distinct in large individuals); large terminal mouth reaching past front of eye. Coloration consists of gray-brown above, dark stripe along back; herringbone lines on upper side in young; dusky black stripe (darkest on young) along olive-silver side, around snout and onto upper lip; black bar along back of gill cover; and orange at dorsal base, orange lower fins, blue on side of head, pink on lower half of head and body, and 6-12 large tubercles on head in breeding males (Ref. 86798).
Inhabits rocky and sandy pools of headwaters, creeks and small rivers (Ref. 5723, 86798). Mostly found in tiny, intermittent streams. Young feed on small aquatic invertebrates while adults consume small fish, crayfish and other large invertebrates (Ref. 10294). One of the most common fishes in eastern North America (Ref. 86798).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Male digs a pit in the stream bottom by removing mouthful of gravel, guards the pit and attempts to attract females. Spawning occurs over the pit. Male guards the nest from intruders. As eggs are deposited in the pit, the male covers them with stones and excavates another pit immediately downstream. As spawning continues and the male covers the eggs, a long ridge of gravel develops.
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. 124695)
Threat to humans
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82805
= 0.5625 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00617 (0.00258 - 0.01473), b=3.05 (2.83 - 3.27), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245
Trophic level (Ref. 69278
): 4.0 ±0.5 se; based on diet studies.
Resilience (Ref. 120179
): Medium, minimum population doubling time 1.4 - 4.4 years (tmax=8; tm=2.5; K=0.41; Fec=2,225).
Vulnerability (Ref. 59153
): Moderate vulnerability (38 of 100) .