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The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

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Common name: Largespring Gambusia

Taxonomy: available through www.itis.gov

Identification: Hubbs et al. (1991); Page and Burr (1991).

Size: 4.4 cm.

Native Range: Springs in the San Marcos and Guadalupe River systems, central Texas (Lee et al. 1980 et seq.; Hubbs et al. 1991; Page and Burr 1991).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Native range data for this species provided in part by NatureServe

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Means of Introduction: Stocks from San Marcos, Texas, were introduced into Comanche Springs and Balmorhea area in 1937 and 1956, respectively (U.S. Fish and Wildlife Service 1982). Dates of other introductions are not known. Introductions into the springs at Balmorhea were separate introductions as the springs are not connected (Hubbs, personal communication). Hendrickson and Brooks (1991) indicated that G. geiseri was stocked into at least one site for conservation purposes, but the authors did not provide details or information on the locality.

Status: Locally established in Texas in the Balmorhea area springs. Extirpated at Comanche Springs which periodically becomes dry (Hubbs, personal communication).

Impact of Introduction: This species reportedly competes with another spring-dwelling species, the endangered Pecos gambusia G. nobilis and is considered a potential threat to that species' existence (U.S. Fish and Wildlife Service 1982).

References: (click for full references)

Hendrickson, D. A., and J. E. Brooks. 1991. Transplanting short-lived fishes in North American deserts: review, assessment, and recommendations. Pages 283-298 in W. L. Minckley and J. E. Deacon, editors. Battle against extinction: native fish management in the American West. University of Arizona Press, Tucson, AZ.

Hubbs, C., R. J. Edwards, and G. P. Garrett. 1991. An annotated checklist of freshwater fishes of Texas, with key to identification of species. Texas Journal of Science, Supplement 43(4):1-56.

Lee, D. S., C. R. Gilbert, C. H. Hocutt, R. E. Jenkins, D. E. McAllister, and J. R. Stauffer, Jr. 1980 et seq. Atlas of North American freshwater fishes. North Carolina State Museum of Natural History, Raleigh, NC.

Page, L. M., and B. M. Burr. 1991. A field guide to freshwater fishes of North America north of Mexico. The Peterson Field Guide Series, volume 42. Houghton Mifflin Company, Boston, MA.

U.S. Fish and Wildlife Service. 1982. Pecos gambusia (Gambusia nobilis) recovery plan. U.S. Fish and Wildlife Service, Albuquerque, NM. iii + 41 pp.

Other Resources:
Texas Freshwater Fishes - Texas State University San Marcos

US Fish and Wildlife Service Ecological Risk Screening Summary for Gambusia geiseri

Author: Leo Nico, and Pam Fuller

Peer Review Date: 8/24/2011

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.