Guadalupe Darter
The Guadalupe Darter is a freshwater fish that is endemic to the Blanco, Comal, Guadalupe, and San Marcos river drainages of the Guadalupe River Basin. The species was first described as a subspecies of the Dusky Darter (Percina sciera) in 1954 (Hubbs & Hubbs), but was demonstrated to be a separate species in 2007 (Robins & Page). The Guadalupe Darter common name was formally recognized by the American Fisheries Society in 2013. The species has been described as Imperiled by the Texas Parks and Wildlife Department (TPWD) and is protected as a State Threatened species under Texas law. TPWD designates species as imperiled if it determines that they are very vulnerable to extirpation in the state due to restricted ranges, limited populations or other factors. This species occupies a similar range of habitat to the False Spike and Guadalupe Orb freshwater mussel species designated for coverage under the Guadalupe River Habitat Conservation Plan.
Common Name:
Guadalupe Darter
Scientific Name:
Percina apristis
USFWS Endangered Species Act Status:
No Status
TPWD Species Conservation Status:
Threatened
NatureServe Global Status:
(G4) – Apparently Secure
Size:
≤100 mm (3.9 inches)
Physical Description:
Guadalupe Darter is an olive colored fish with 7 blocks of black pigment along its midline that are connected to 8 gray pigmented saddles that wrap around the dorsal surface. The dark midline blocks are notably longer and narrower than those of the Dusky Darter with fewer connecting lines. The tail has three dark spots at its base near the top, bottom and midline. A darkly pigmented line passes horizontally through the middle of the eye. The species has a downturned inferior and oblique mouth, suited to eating food from the bottom of riffles. Some of the primary morphological differences that distinguish it from similar darters are a small number (0-6) of tiny serrae protuberances on the preopercle, pectoral fins with 13-14 rays and anal fins with 10 rays (Hubbs & Hubbs 1954).
Life History:
Guadalupe Darters live up to 4 years and reach sexual maturity at around 1 year of age. Sexual maturity can occur in males of least 46 mm and females of 53 mm in length. They have an extended reproductive period that covers 9 consecutive months from December through June, when water temperatures are <23.5°C on the San Marcos River (Folb 2010). Their adhesive eggs are broadcasted onto gravel or sand riffles, where they hatch after a few days.
Distribution:
The Guadalupe Darter, is found in 9 counties of the Guadalupe River basin, including Kerr, Kendall, Comal, Hays, Caldwell, Guadalupe, Gonzales, Dewitt, and Victoria. Verified historical records have been documented on the main stem of the Guadalupe river east of Kerrville in Kerr County to downstream of the Coleto Creek confluence in Victoria county. It is also found in the Blanco river, Comal river, San Marcos river, and Plum creek drainages. (fishesoftexas.org 2023). Populations in the lower Guadalupe river seem to be declining, while the San Marcos river population appears stable. No specimens have been collected from the Upper Guadalupe river above Canyon Lake since 1963 (Perkin 2009).
Habitat and Diet:
The Guadalupe Darter occupies the gravelly riffle habitat of perennial rivers and streams, where it is commonly found on the streambed under 10 to 12-inch (25 – 305 mm) stones. It is not found near clear headwater springs such as the Guadalupe river west of Kerrville or the Upper Blanco river and appears to prefer the swift moving moderate to highly turbid water of flowing runs (Hubbs 1954).
Guadalupe Darter diet primarily consists of larval insects such as mayflies, caddisflies and dragonflies. Food consumption is seasonal with mayfly intake increasing during the fall and winter, while caddisfly intake consumption increases during the spring and summer (Folb 2010).
References:
Photo: Clinton & Charles Robertson, 2009. CC BY 2.0
Fishes of Texas Website A Virtual Museum on the State’s Fish Biodiversity. https://www.fishesoftexas.org/taxa/percina-apristis. Accessed on 10/06/2023.
Folb, C. E. 2010. Reproductive seasons and life histories of three Texas Percina (Actinopterygii). Master’s Thesis. Texas State University. San Marcos, Texas.
Hubbs, C.L., and C. Hubbs. 1954. Hadropterus scierus apristis. In Hubbs, C., A new Texas subspecies, apristis, of the Percina apristis darter Hadropterus scierus, with a discussion of variation within the species. The American Midland Naturalist. 52: 211-220
Perkin, J. S. and T. H. Bonner. 2011. Long-term changes in flow regime and fish assemblage composition in the Guadalupe and San Marcos rivers of Texas. Rivers Research and Application. 27: 566-579
Robins, R. H. and L. M. Page. 2007. Taxonomic status of the Guadalupe darter, Percina apristis (Teleostei: Percidae). Zootaxa 1618 : 51-60.
