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Etheostoma rupestre Gilbert and Swain, 1887
Rock Darter

47mm standard length Conasauga River (Coosa Basin), Bradley Co., TN 5 September 2004 Photo by Brett Albanese (Georgia DNR – Wildlife Resources) and Chris Skelton (Georgia College and State University)
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Federal Protection: No US federal protection

State Protection: Rare

Global Rank: G4

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: High Conservation Concern

Element Occurrences (EOs) in Georgia: 23

Habitat Summary for element in Georgia: Swift rocky riffles often associated with attached vegetation such as Podostemum


Description

The rock darter has a small, subterminal mouth, and a blunt (downcurved instead of pointed) snout that is connected to the upper jaw by a fleshy bridge of tissue (the frenum). It reaches about 84 mm (3⅜ inches) total length. Its large pectoral fins and six, square-shaped dorsal saddles are prominent when viewed from above. There are 6-9 markings on the sides that can be represented as either blotches or vertical bars. Dark markings are usually evident before and below the eye and on the base of the pectoral fin. Breeding males have green in all fins, as blotches along the sides, and on the underside of the head.

Similar Species

The speckled darter (Etheostoma stigmaeum) also has six dorsal saddles, but these are hour-glass shaped rather than square. The speckled darter is further differentiated by lacking a frenum and having smaller pectoral fins. Coosa darter (E. coosae) and holiday darter (E. brevirostrum) also have blunt snouts, but lack frenums and have more (8-9) dorsal saddles than the rock darter.

Habitat

As both its scientific and common names suggest, the rock darter occurs over rocky substrates in swift riffles. It is often associated with riverweed (Podostemum ceratophyllum). A study in the Etowah River found that rock darters were three times more likely to occur when riverweed is present in a single seine-sample than when it is absent. Most Georgia records are from large rivers, such as the Conasauga and Etowah River mainstems.

Diet

No diet studies have been completed for the rock darter. Like other darters, it probably preys on aquatic insects and other aquatic invertebrates.

Life History

Very little is known about the biology of this species. Breeding occurs between late March and May. Clutch size ranged from 18-94 eggs for a population studied in Alabama. Length frequency data suggests a lifespan of at least 3 years.

Survey Recommendations

Disturbing the substrate upstream of a kick-set seine is an effective technique for capturing many darter species. Backpack electrofishing upstream of a seine is also effective, but may cause mortality of the rock darter and many other protected species with which it occurs.

Range

The rock darter is endemic to the Mobile Basin in Mississippi, Alabama, Georgia, and a small portion of Tennessee. Most Georgia records are from the mainstem of the Conasauga and Etowah Rivers, but the rock darter is also known from the Coosawattee and Oostanaula River systems. Check the [Fishes of Georgia Webpage](http://fishesofgeorgia.uga.edu/index.php?page=speciespages/species_page&key=etherupe) for a watershed-level distribution map.

Threats

Non-point pollution associated with agriculture and residential development are primary threats in the Conasauga system. The Etowah population is threatened by urbanization and water supply development.

SWAP 2025 Threat Matrix

Threat 1 Threat 2 Threat 3
General Threat Pollution Residential & commercial development None
Specific Threat Garbage & solid waste Housing & urban areas None

Georgia Conservation Status

The largest populations of this species in Georgia occur in the Etowah and Conasauga mainstems. Some of the headwater streams in these systems occur on public lands.

Conservation Management Recommendations

Conserving populations of the rock darter will require a watershed-level focus. Incentive programs to help farmers implement best-management practices could improve instream habitat by decreasing sediment, nutrient, and chemical runoff and increasing riparian forest cover. Conservation groups should work cooperatively with developers and local governments to minimize the impacts from new home construction and commercial development. Additional water withdrawals and impoundments should be minimized by promoting water conservation practices and augmenting existing water storage whenever possible.


SWAP 2025 Conservation Actions:

  • Action 1: Provide technical and financial assistance to farmers/landowners to protect stream buffers and wetlands, minimize runoff of sediment and pollutants, and protect habitat from livestock trampling
  • Action 2: Minimize impacts of urbanization on aquatic SGCN and habitats
  • Action 3: Monitor upper Etowah River SGCN fishes and fish community
  • Action 4: Monitor Conasauga River SGCN fishes and fish community

References

Boschung, H. T. and R. L. Mayden. 2004. Fishes of Alabama. Smithsonian Books, Washington D.C. 736 pp.

Etnier, D.A. and W.C. Starnes. 1993. The Fishes of Tennessee. The University of Tennessee Press, Knoxville. 689 pp.

Georgia Department of Natural Resources. 1999. Protected animals of Georgia. Wildlife Resources Division, Nongame Wildlife and Natural Heritage Section, Social Circle. 247 pp.

Hagler, Megan M. 2006. Effects of natural flow variability over seven years on the occurrence of shoal-dependent fishes in the Etowah River. M.S. Thesis, University of Georgia, Athens.

Joachim, R.D., J.M. Guill, and D. C. Heins. 2003. Female reproductive life-history traits of the rock darter, Etheostoma rupestre, from Flat Creek, Alabama. American Midland Naturalist 150: 268-274.

Mettee, M. F., P. E. O'Neil, and J. M. Pierson. 1996. Fishes of Alabama and the Mobile basin. Oxmoor House, Birmingham, Alabama. 820 pp.

Ross, S.T. 2001. Inland fishes of Mississippi. University of Mississippi Press. Jackson. 624 pp.

Tsai, C. 1968. Variation and distribution of the rock darter, Etheostoma rupestre. Copeia 1968 (2): 346-353.

Skelton, C.E. and B. Albanese. 2006. Field guide to the fishes of the Conasauga River system. U.S. Forest Service, Gainesville, Georgia. 251 pp.

Authors of Account

Brett Albanese

Date Compiled or Updated

Aug-08

Talking Rock Creek, Pickens Co., GA 10 August, 2017 Peter Dimmick (Georgia DNR- Wildlife Resources)