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Percina sciera (Swain, 1883)
Dusky Darter
Federal Protection: No US federal protection
State Protection: Rare
Global Rank: G5
State Rank: S2
Element Locations Tracked in Biotics: Yes
SWAP 2015 Species of Greatest Conservation Need (SGCN): Yes
SWAP 2025 Species of Greatest Conservation Need (SGCN): Yes
2025 SGCN Priority Tier: Data Deficient
Element Occurrences (EOs) in Georgia: 16
Habitat Summary for element in Georgia: Large creeks and rivers in moderate current associated with woody debris, undercut banks, or vegetation
A slender darter growing to a maximum total length of about 130 mm (5.1 in), the dusky darter typically is tan or gray in color, with 8-12 dark oval blotches along the sides, dorsolateral reticulations above the lateral blotches, and 7-9 vague to dark saddles on the dorsum. A fleshy bridge of tissue (i.e., a frenum) connects the snout to the upper lip. The gill membranes are moderately connected. A suborbital bar is sometimes present. The fins are speckled (or darkened in breeding males) and three spots form a vertical row at the base of the caudal fin, although the lower two spots often blend together. The dusky darter lacks bright breeding coloration.
The dusky darter is not similar to any potentially co-occurring members of the genus Percina in the Chickamauga Creek (logperch Percina caprodes, snail darter Percina tanasi) or Toccoa River systems (gilt darter Percina evides, olive darter Percina squamata, tangerine darter Percina aurantiaca) systems.
This widespread species occurs in moderate to low gradient streams and rivers. In Georgia, it is usually collected from larger streams, such as Tiger Creek, Lookout Creek, and Little Chickamauga Creek. It is typically associated with moderate current velocities in habitats ranging from rocky riffles to sand-bottomed areas with abundant woody debris.
Diet includes aquatic insect larvae, including caddisflies, black flies, midges, and mayflies.
The breeding season occurs from late spring to early summer. Dusky darters probably broadcast spawn their adhesive eggs over gravel and sand substrata. Both sexes reach sexual maturity at age 1. Females have between 80 and 196 mature eggs during a breeding season. Maximum life span is about 3 years for females and 4 years for males.
This species is vulnerable to backpack electrofishing and seining.
The dusky darter is found in Gulf Coast drainages from Texas to west Alabama, including the Mississippi River basin northward to Indiana and Ohio. In Georgia, the dusky darter has been found in the Chickamauga Creek, Lookout Creek and Toccoa River systems. Toccoa specimens are only known from Star Creek and from the Ocoee River within Tennessee. Check the [Fishes of Georgia Webpage](http://fishesofgeorgia.uga.edu/index.php?page=speciespages/species_page&key=percscie) for a watershed-level distribution map.
The dusky darter, although abundant in parts of its range, has a limited distribution in Georgia. The Georgia localities for this small, versatile darter represent populations along the Tennessee River system that have been isolated from other populations by impoundments. The principal threat to the dusky darter in Georgia is stream degradation resulting from failure to employ Best Management Practices (BMPs) for forestry and agriculture, failure to control soil erosion from construction sites and bridge crossings, and increased stormwater runoff from developing urban and industrial areas.
| Threat 1 | Threat 2 | Threat 3 | |
|---|---|---|---|
| General Threat | Pollution | Pollution | None |
| Specific Threat | Industrial & military effluents | None | None |
Although its overall range in the state is small, the dusky darter is widely distributed within the Chickamauga Creek system in northwest Georgia. Recent (i.e. early to mid 2000s) records indicate persistence within several creek systems. The dusky darter is only known from one tributary stream in the Georgia portion of the Toccoa River system, where its current status is unknown.
Conserving aquatic species restricted to Tennessee River tributaries, including the dusky darter, depends on protecting stream habitat quality in these streams by eliminating sediment runoff from land disturbing activities such as roadway and housing construction, maintaining and restoring forested buffers along stream banks, eliminating inputs of contaminants such as fertilizers and pesticides, and maintaining natural streamflow patterns. Special efforts must be taken to minimize contaminant, sediment, and stormwater runoff from urban and residential developments if stream habitat and sensitive aquatic species are to be protected.
Boschung, H. T. and R. L. Mayden. 2004. Fishes of Alabama. Smithsonian Institution, Washington D.C. 736pp.
Etnier, D. A. and W.C. Starnes. 1993. The fishes of Tennessee. Univ. Tennessee Press, Knoxville. 681pp.
Jenkins, R. E. and N. M. Burkhead. 1993. Freshwater fishes of Virginia. Am. Fish. Soc., Bethesda, Md. 1079pp.
Lee, S. L., C. R. Gilbert, C. H. Hocutt, R. E. Jenkins, D. E. McAllister, and J. R.Stauffer. 1980. Atlas of North American fishes. North Carolina State Mus. Nat. Hist. 867pp.
Miller, G. L. 1983. Trophic resource allocation between Percina sciera and P. ouachitae in the Tombigbee River, Mississippi. Am. Midl. Nat. 110: 299-313.
Page, L. M. and B. M. Burr. 1991. A field guide to freshwater fishes of North America north of Mexico. Houghton Mifflin, Boston. 432pp.
Page, L. M. and P. W. Smith. 1970. The Life History of the Dusky Darter, Percina Sciera, in the Embarras River, Illinois. Illinois Natural History Survey Biological Notes No 69.
Byron J. Freeman
B. Freeman,1999: original account
B. Albanese, Dec 2009: added similar species, conservation status, and general edits.
S. Mitchell, Feb, 2019: general update of entire account