Rio Grande darter
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Devils River near junction with Rio Grande, Val Verde County, Texas (Girard 1859).
Etymology/Derivation of Scientific Name
Etheostoma, from the Greek etheo, “to strain,” and stoma, mouth” (Pflieger 1997); grahami – specimen collected by John H. Clark, under Col. J.D. Graham (Girard 1859).
Oligocephalus grahami Girard 1859:102.
Maximum size: 60 mm TL (Page and Burr 1991).
Coloration: Throat red in males, but this color is lost in preservation; 10-12 body bars (Hubbs et al. 2008). Many small red (on male) or black (on female) spots on side; red 1st dorsal fin (faint on female); male has red 2nd dorsal, anal, and pelvic fins, also yellow caudal and pectoral fins; olive above, 8-10 dark saddles; often dusky blotches along side; white to yellow below; faint teardrop present (Page and Burr 1991). Strawn (1955) described color of aquarium raised fish: dorsal fins of male whitish lavender with orange dots. Sides have faint green vertical bands and small dark orange dots on scales. Anterior part of pelvic fin orange and posterior part faint green. Anal fin orange. Female has a light and dark pattern with indistinct khaki green vertical bands on the side (Strawn 1955).
Counts: Fewer than 50 lateral line scales; 2 anal fin spines; more than 6 pored lateral line scales (Hubbs et al. 2008).
Body shape: Deep-bodied (Page and Burr 1991). Body cross section oval; body depth contained in standard length less than 5 times; pectoral fin shorter than head, not reaching anus; head profile rounded, profile in front of eye less than 45 degrees; upper jaw not extending as far as to below middle of eye (Hubbs et al. 2008).
External morphology: Opercle heavily scaled; infraorbital canal interrupted below eye; gill membranes hardly connected; lateral line straight; scales on belly normal (a narrow naked band may be present on midline); preopercle smooth or weakly serrated (Hubbs et al. 2008).
Distribution (Native and Introduced)
U.S. distribution: Rio Grande drainage in the U.S. (Hubbs et al. 2008); headwaters of Rio San Juan and Rio Salado in Mexico.
Texas distribution: Essentially restricted to the mainstream and spring-fed tributaries of the Rio Grande and the lower Pecos River downstream to the Devils River and Dolan, San Felipe and Sycamore creeks (Hubbs et al. 2008).
Abundance/Conservation status (Federal, State, NGO)
State Threatened (Texas; Hubbs et al. 2008). Listed as Threatened by the American Fisheries Society due to present or threatened destruction, modification, or reduction of habitat or range (Jelks et al. 2008). Bonner et al. (2005) assessed relative abundance of Etheostoma grahami from three collection periods (1952-1968, 1974-1994, and 2001-2002) in Independence Creek, Texas; this species was taken during each collection period; data indicated that it was relatively uncommon but persistent in the area. Hoagstrom (2003) reported status of this species as Tenuous (few collections from 1991-1999) in the lower Pecos River. E. grahami common in the Devils River, Texas, and locally common but sporadic elsewhere (Page 1983). Platania (1990) reported collection of this species, in February 1990, from three locations between Laredo and Del Rio; at the most upstream locality (approximately 10 km below Amistad Reservoir) E. grahami was the most abundant fish with 33 specimens collected and released; further, many additional specimens could have been collected at this site but were not in order to avoid disrupting spawning activities. Cantu and Winemiller (1997) found E. grahami to rank among the 8 most abundant species in the Devils River study area. Garrett et al (1992), Rhodes and Hubbs (1992) and Harrell (1978) found E. grahami to rank among those species least abundant in surveys of the Devils River. Linam and Kleinsasser (1996) reported collection of 3 specimens from Independence Creek (Texas), in October 1987. Robinson (1959) reported collection of specimens from three stations San Felipe Creek.
Macrohabitat: Creeks, small rivers (Page and Burr 1991). Spring-fed tributaries (Hubbs 1954; Strawn 1955; Page 1983).
Mesohabitat: Gravel and rubble riffles (Strawn 1955; Page 1983; Page and Burr 1991). In collections from Independence Creek, Texas, species was most abundant in riffle habitats (Bonner et al. 2005). Species was strongly associated with riffles in the Devils River, Texas (Robertson and Winemiller 2003). According to Platania (1990), species collected in most abundantly from a site (in the mainstem of the Rio Grande downstream from Amistad Reservoir) described as main channel run, riffles, and shorelines with clean cobble substrate having a small amount of attached macrophytes; channel width ranged from 20-50 m; maximum depth 1.5 m. Strawn (1955) noted that the native spring runs of this species contain clear water and are frequently heavily vegetated. In San Felipe Springs at Del Rio, Texas, species flourishes in water having a hardness of 213-215; pH of these hard waters ranges from about 7.2-8.0 (Strawn 1955).
Spawning season: Late March to early June (Harrell 1980).
Spawning behavior: Attachers (Page 1983); eggs laid on vegetation and on the tops or undersides of rocks, at 20-25°C (Strawn 1956; Page 1983). If temperature is within an acceptable range, female will spawn every 4-10 days (in laboratory; Strawn and Hubbs 1956). In aquaria, spawns took place mainly during the morning and primarily on plants rather than on stones (Aguilera et al. 1999). In Texas, eggs laid on plants or plant debris (Clark Hubbs, pers. comm. in: Winn 1958).
Fecundity: In aquaria, mean number of eggs/spawn per female was 5.8 ± 2.9; eggs were spherical and translucent, averaged 1.7 ± 0.11 mm in diameter, and contained a single oil droplet; eggs were demersal and adhesive; the chorion was unsculptured and unpigmented (Aguilera et al. 1999).
Age at maturation:
Growth and Population structure: Achieves maximum biomass by October and declines slightly until breeding season begins (Harrell 1980).
Phylogeny and morphologically similar fishes
Subgenus Oligocephalus (Harrell 1980; Page 1983). Etheostoma grahami most similar to allopatric cogener E. lepidum, the greenthroat darter (Harrell 1980). Hubbs et al. (2008) noted differences between E. grahami and E. lepidum: E. grahami has heavily scaled opercle, fewer than 50 lateral line scales, and males have a red throat; in E. lepidum, the opercle is naked or with only a few scales, more than 50 lateral line scales are present, and males have a blue or green throat. E. grahami differs from the orangethroat darter (E. spectabile) in having 10-12 body bars (versus 8-9), and in males the throat is red (versus orange; Hubbs et al. 2008).
See Aguilera et al. (1999) for description of Etheostoma grahami eggs and larval characteristics.
Hybridization has been examined: Etheostoma grahami and E. lepidum produce fully viable and fertile offspring (Strawn 1961; Hubbs 1967). E. spectabile – E. grahami pairs produce viable offspring and females of these crosses are fully fertile, yet males appear to be sterile (Hubbs 1967).
Commercial or Environmental Importance
Garrett and Edwards (2001) noted that efforts to protect the Devils River minnow (Dionda diaboli) should also benefit Etheostoma grahami. Matthew et al. (2006) noted that this species has been used successfully in experimental stream units. Strawn (1955) noted that individuals maintained in an aquarium were hardy and readily consumed ground meat and other wet prepared foods.
[Additional literature noting collection of this species from Texas locations includes, but is not limited to the following: Hubbs (1957); Strawn (1957); The Nature Conservancy (2004).]
Aguilera, C., R. Mendoza, J. Montemayor, and G. Hernandez. 1999. Eggs, larvae, and early juveniles of Etheostoma grahami (Teleostei: Percidae). The Southwestern Naturalist 44(2):214-217.
Bonner, T.H., C. Thomas, C.S. Williams, and J.P. Karges. 2005. Temporal assessment of a west Texas stream fish assemblage. The Southwestern Naturalist 50(1):74-106.
Cantu, N.E.V., and K.O. Winemiller. 1997. Structure and habitat associations of Devils River fish assemblages. Southwestern Naturalist 42(3):265-278.
Garrett, G.P., and R.J. Edwards. 2001. Regional ecology and environmental issues in west Texas. Chapter 5, pp. 56-65 in: R.E. Mace, W.F. Mullican, III, and E.S. Angle. Aquifers of West Texas. Texas Water Development Board.
Garrett, G.P., R.J. Edwards, A.H. Price. 1992. Distribution and status of the Devils River minnow, Dionda diaboli. The Southwestern Naturalist 37(3):259-267.
Girard, C. 1859. Ichthyological notices. Proc. Acad. Nat. Sci. Phila. 11:100-104.
Harrell, H.L. 1978. Response of the Devil's River (Texas) Fish community to flooding. Copeia 1978(1):60-68.
Harrell, H.L. 1980. Etheostoma grahami (Girard), Rio Grande darter. pp. 652 in D. S. Lee et al., Atlas of North American Freshwater Fishes. N. C. State Mus. Nat. Hist., Raleigh, i-r+854 pp.
Hoagstrom, C.W. 2003. Historical and recent fish fauna of the lower Pecos River. pp 91-110 in: G.P. Garrett, and N.L. Allan (eds.) 33rd Annual Symposium of the Desert Fishes Council, Sul Ross University, Alpine, Texas. Vol. 42. Museum of Texas Tech University.
Hubbs, C. 1954. Corrected distributional records for Texas fresh-water fishes. Texas Journal of Science 1954(3):277-291.
Hubbs, C. 1957. Distributional patterns of Texas fresh-water fishes. The Southwestern Naturalist 2(2/3):89-104.
Hubbs, C. 1967. Geographic variations in survival of hybrids between Etheostomatine fishes. Bulletin of the Texas Memorial Museum 13:1-72.
Hubbs, C., R.J. Edwards, and G.P. Garrett. 2008. An annotated checklist of the freshwater fishes of Texas, with keys to identification of species. Texas Journal of Science, Supplement, 2nd edition 43(4):1-87.
Jelks, H.L., S.J. Walsh, N.M. Burkhead, S. Contreras-Balderas, E. Diaz-Pardo, D.A. Hendrickson, J. Lyons, N.E. Mandrak, F. McCormick, J.S. Nelson, S.P. Platania, B.A. Porter, C.B. Renaud, J.J. Schmitter-Soto, E.B. Taylor, and M.L. Warren, Jr. 2008. Conservation status of imperiled North American freshwater and diadromous fishes. Fisheries 33(8):372-407.
Linam, G.W., and L.J. Kleinsasser. 1996. Relationship between fishes and water quality in the Pecos River, Texas. Texas Parks and Wildlife Department, Austin. 11 pp.
Matthews, W.J., K.B. Gido, G.P. Garrett, F.P. Gelwick, J.G. Stewart, and J. Schaefer. 2006. Modular experimental riffle-pool stream system. Transactions of the American Fisheries Society 135(6):1559-1566.
Nature Conservancy, The. 2004. A biodiversity and conservation assessment of the Edwards Plateau ecoregion. The Nature Conservancy, San Antonio, Texas. 30 pp.
Page, L.M. 1983. Handbook of Darters. TFH Publications, Inc. Ltd., Neptune City, New Jersey. 271 pp.
Page, L. M., and B. M. Burr. 1991. A field guide to freshwater fishes of North America north of Mexico. Houghton Mifflin Company, Boston, Massachusetts. 432 pp.
Pflieger, W.L. 1997. The Fishes of Missouri. Missouri Department of Conservation, Jefferson City, Missouri. 372 pp.
Platania, S.P. 1990. The ichthyofauna of the Rio Grande drainage, Texas and Mexico, from Boquillas to San Ygnacio. U.S. Fish and Wildlife Service. 100 pp.
Rhodes, K., and C. Hubbs. 1992. Recovery of Pecos River fishes from a red tide fish kill. The Southwestern Naturalist 37(2):178-187.
Robertson, M.S., and K.O. Winemiller. 2003. Habitat Associations of fishes in the Devil's River, Texas. Journal of Freshwater Ecology 18(1):115-127.
Strawn, K. 1955. A method of breeding and raising three Texas darters. Part 1. Aquarium J. 26:408-412.
Strawn, K. 1956. A method of breeding and raising three Texas darters. Part 2. Aquarium Journal 27(1):11-32.
Strawn, K. 1957. The influence of environment on the meristic counts of the fishes Etheostoma grahami and Etheostoma lepidum. PhD. Dissertation, University of Texas at Austin. 124 pp.
Strawn, K. 1961. A comparison of meristic means and variances of wild and laboratory-raised samples of the fishes, Etheostoma grahami and E. lepidum (Percidae) Texas Journal of Science 13:127-159.
Strawn, K., and C. Hubbs. 1956. Observation on stripping small fishes for experimental purposes. Copeia 1956(2):114-116.
Winn, H.E. 1958. Comparative reproductive behavior and ecology of fourteen species of darters (Pisces-Percidae). Ecological Monographs 28(2):155-191.