|Scientific Name:||Gambusia georgei|
|Species Authority:||Hubbs & Peden, 1969|
|Red List Category & Criteria:||Extinct ver 3.1|
|Reviewer/s:||Smith, K. & Darwall, W.R.T.|
|Facilitator/s:||Hammerson, G.A. & Ormes, M.|
This species is listed as Extinct because no genetically pure individuals have been found since 1983.
|Range Description:||Its historical range included the San Marcos Spring and upper few kilometres of the San Marcos River, Texas (Hubbs and Peden 1969, Page and Burr 2011).|
Regionally extinct:United States (Texas)
|Range Map:||Click here to open the map viewer and explore range.|
No occurrences are extant.
Population in 1969 was estimated at less than 1,000 individuals; genetically pure individuals have not been collected since 1983 (Johnson and Hubbs 1989); presumed extinct (Miller et al. 1989, USFWS 1990).
|Habitat and Ecology:||Historical habitat included a large vegetated spring and its effluent (Page and Burr 2011); shallow, quiet, mud-bottomed, shoreline areas without dense vegetation in the thermally constant main channel. Formerly this species was common under the shade of bridges. Primary habitat requirements appear to be clean, clear water of a relatively stable temperature (Matthews and Moseley 1990).|
|Major Threat(s):||Decline was due to reduced spring flows and pollution, including herbicide spraying along the river; introduced fishes; spread of an ornamental plant (Elephant Ears, Colocasia esculenta); and, as it became rare, hybridization with Gambusia affinis (Miller et al. 1989).|
|Conservation Actions:||This species is extinct and does not require protection or management, monitoring, or research action.|
Campbell, L. 1995. Endangered and Threatened Animals of Texas: Their Life History and Management. Texas Parks and Wildlife Department, Endangered Resources Branch, Austin, Texas.
IUCN. 2013. IUCN Red List of Threatened Species (ver. 2013.1). Available at: http://www.iucnredlist.org. (Accessed: 12 June 2013).
Lee, D.S., Gilbert, C.R., Hocutt, C.H., Jenkins, R.E., McAllister, D.E. and Stauffer, J.R., Jr. 1980. Atlas of North American freshwater fishes. North Carolina State Museum of Natural History, Raleigh, North Carolina.
Matthews, J.R. and Moseley, C.J. (eds). 1990. The Official World Wildlife Fund Guide to Endangered Species of North America. Volume 1. Plants, Mammals. xxiii + pp 1-560 + 33 pp. appendix + 6 pp. glossary + 16 pp. index, pp. 1180. Beacham Publications, Inc., Washington, D.C.
Meffe, G.K. and Snelson, F.F., Jr. (eds). 1989. Ecology and evolution of livebearing fishes (Poeciliidae). pp. 453. Prentice Hall, Englewood Cliffs, New Jersey.
Miller, R.R., Williams, J.D. and Williams, J.E. 1989. Extinctions of North American fishes during the past century. Fisheries 14(6): 22-38.
Minckley, W.L., Meffe, G.K. and Soltz, D.L. 1991. Conservation and management of short-lived fishes: the cyprinodontoids. In: W.L. Minckley and J.E. Deacon (eds), Battle Against Extinction: Native Fish Management in the American West, pp. 247-282. University of Arizona Press, Tucson, Arizona.
Nelson, J.S., Crossman, E.J., Espinosa-Perez, H., Findley, L.T., Gilbert, C.R., Lea, R.N. and Williams, J.D. 2004. Common and scientific names of fishes from the United States, Canada, and Mexico. American Fisheries Society, Bethesda, Maryland.
Page, L.M. and Burr, B.M. 1991. A field guide to freshwater fishes: North America north of Mexico. Houghton Mifflin Company, Boston, Massachusetts.
Page, L.M. and Burr, B.M. 2011. Peterson field guide to freshwater fishes of North America north of Mexico. Houghton Mifflin Harcourt, Boston, Massachusetts.
Rauchenberger, M. 1989. Systematics and biogeography of the genus Gambusia (Cyprinodontiformes: Poecilidae). American Museum Novitates 2951: 1-74.
Robins, C.R., Bailey, R.M., Bond, C.E., Brooker, J.R., Lachner, E.A., Lea, R.N. and Scott, W.B. 1991. Common and scientific names of fishes from the United States and Canada. American Fisheries Society.
San Marcos Recovery Team. 1985. San Marcos recovery plan for San Marcos River endangered and threatened species (San Marcos gambusia, fountain darter, San Marcos salamander, andTexas wildrice. U.S. Fish and Wildlife Service.
U.S. Fish and Wildlife Service (USFWS). 1990. Endangered and threatened species recovery program: report to Congress.
U.S. Fish and Wildlife Service (USFWS). 1996. San Marcos and Comal springs and associated aquatic ecosystems (revised) recovery plan. USFWS, Albuquerque, New Mexico.
Williams, J.E, Johnson, J.E., Hendrickson, D.A., Contreras-Balderas, S., Williams, J.D., Navarro-Mendoza, M., McAllister, D.E. and Deacon, J.E. 1989. Fishes of North America endangered, threatened or of special concern: 1989. Fisheries 14(6): 2-20.
|Citation:||NatureServe 2013. Gambusia georgei. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 10 December 2013.|
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