Etheostoma segrex Norris & Minckley
Rio Salado darter, dardo del Salado
PERCIDAE - perches, pikeperches, and darters
44 mm SL as adult female, largest male 41 mm, rarely >40 mm
Considered endangered by the American Fisheries Society in 1989 (in part).
Restricted to the uppermost, mainstream Rio Salado de los Nadadores, at and near its origin from the Cuatro Cienegas basin, Coahuila, Mexico.
Common in strongly flowing, highly localized areas.
Habitat & Ecology
This species most often occupies riffles 1.5 to 3.0 m wide and 10 to 25 cm deep, of moderate turbulence over gravel/small cobble substrates. Aquatic plants (Potamogeton, Zannichellia, and Cladophora) often present. Currents estimated at 10 to 30 cm/sec. Seemingly concentrated in vegetated areas when such are present.
Essentially nothing is known of the reproductive habitats or habitats. Males in apparent breeding coloration have been taken in April, but were exceedingly rare (1 colorful male in a sample of 35 fish of mixed sexes) in an August sample.
Extraction of groundwater within the Cuatro Cienegas basin and water diversions upstream for agriculture both reduce downflow water volumes diminishing the available habitat. As with other fishes in this area, non-indigenous crayfish, molluscs, and fishes may be anticipated to result in ecosystem-level changes that undoubtedly will influence this species in the near future.
A substantial proportion of the Cuatro Cienegas basin, comprising the apparent source of water for the upper Rio Salado de los Nadadores, were set aside in 1994 as a biological preserve, which should assist in maintaining flow within this speciesU habitats. Specific conservation actions are, however, yet to be proposed or implemented.
Devise and implement conservation actions preventing further loss and change of habitat and prohibit introductions of non-indigenous organisms. Especially needed are provisions to maintain discharge volumes and prevent additional modification of local stream channels, which are seriously impacted by grazing and other human-induced activies.
- Anonymous. 1994. Descreto por el que se declara como area natural protegida, con el caracter de area de proteccion de flora y fauna, la region conocida como Cuatrocienengas, con una superficie de 84,347-47-00 hectares, municipio del mismo nombre, Coah. Diario Oficial de la Federation CCXCIV(5): 5-11. Mexico, DF.
- Miller, R. R. 1978. Composition and derivation of the native fish fauna of the Chihuahuan Desert region. Pp. 365-382, in R. H. Wauer & D. Riskind (eds.). Transactions of the Symposium of the Biological Resources of the Chihuahuan Desert Region, United States and Mexico. US Natl. Park Ser. Trans. Proc. Ser. 3(1977). US Gov. Print. Off., Wash., DC.
- Minckley, W. L. 1969. Environments of the Bolson of Cuatro Cienegas, Coahuila, Mexico, with special reference to the aquatic biota. TX Westerm Press, Univ. Texas El Paso Sci. Ser. 2: 1-65.
- ______. 1978. Endemic fishes of the Cuatro Cienegas basin, Coahuila, Mexico. Pp. 383-404, in R. H. Wauer & D. Riskind (eds.). Symposium on the Biological Resources of the Chihuahuan Desert Region, United States and M xico. US Natl. Park Ser. Trans. Proc. Ser. 3(1977). US Gov. Print. Off., Wash., DC.
- ______. 1994. A bibliography for natural history of the Cuatro Cienegas basin and environs, Coahuila, Mexico. Proc. Desert Fishes Council 25(1993): 47-64.
- Norris, S. M & W. L. Minckley. 1997. Two new species of Etheostoma (Osteichthyes: Percidae) from central Coahuila, northern Mexico. Ichthyological Explorations of freshwaters 8(2): 159-176
- Williams, J. E., J. E. Johnson, D. A. Hendrickson, S. Contreras-Balderas, J. D. Williams, M. Navarro-Mendoza, D. E. McAllister & J. E. Deacon. 1989. Fishes of North America, endangered, threatened or of special concern: 1989. Fisheries (Bethesda, Maryland) 14: 2-20..
W. L. Minckley, Department of Zoology, Arizona State University, Tempe, Arizona 85287-1501. 1 June 1998.