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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: Desert Pupfish

Taxonomy: available through www.itis.gov

Identification: Minckley (1973); Moyle (1976a); Page and Burr (1991); two subspecies in the United States, a Colorado River form C. m. macularius and a Quitobaquito form C. m. eremus. A third undescribed subspecies occurs in Mexico (U.S. Fish and Wildlife Service 1993b).

Size: 7.2 cm.

Native Range: This species occurs in the lower Colorado River drainage, including the Gila River system and south through southern Arizona and California (including the Salton Sea) into northern Mexico (Page and Burr 1991). The Colorado River form exists naturally in California in two streams tributary to, and a few shoreline pools and irrigation drainages of, the Salton Sea, and on the Colorado River Delta, and in the Laguna Salada basin. The Quitobaquito form exists only in a single modified spring at Organ Pipe Cactus National Monument, Pima County, Arizona. The Mexican subspecies is found at scattered localities along the Rio Sonoyta (U.S. Fish and Wildlife Service 1993b; Echelle, personal communication).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

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

Means of Introduction: Most introductions were for the purpose of establishing refuge populations of this imperiled species. Hendrickson and Varela-Romero (1989) reported on the spread of one population via artificial canals. Miller (1968) reported that six individuals escaped from a trap into Dos Palmas Spring, near the northeastern corner of the Salton Sea, in May 1939. Based on the distribution map for this species in Lee et al. (1980 et seq.), the spring site is apparently in or near its native range. The stocking of a least one site in California was part of a series of experiments to test the effects of changed environment on meristic and morphometric characters (Miller 1968).

Status: Established in Arizona and California.

Impact of Introduction: Unknown. Walters and Legner (1980) looked at the diets of desert pupfish in experimental ponds. Desert Pupfish ate mostly benthos, especially chironomid midge larvae, detritus, aquatic vegetation, and snails. Pupfish also ate zooplankters in weedy or benthic habitats. Walters and Legner (1980) concluded that, in the Southwest, pupfish may be a better alternative for mosquito control than stocking mosquitofish because they are less piscivorous than mosquitofish.

Remarks: The Desert Pupfish was listed as a federally endangered species in 1986 (Minckley et al. 1991; U.S. Fish and Wildlife Service 1993a). Populations within parts of its native range have declined partly as a result of introduction of nonindigenous fishes, especially tilapias (Schoenherr 1988; Minckley et al. 1991; Swift et al. 1993). The recovery plan for this species lists all known populations and transplants (i.e., U.S. Fish and Wildlife Service 1993b). Several authors (Schoenherr 1988: Hendrickson and Varela-Romero 1989; Minckley et al. 1991) reviewed the distribution and introduction of the desert pupfish; unfortunately, these authors did not always clearly distinguish between introductions made to sites outside the species range and transplant of one subspecies into the natural range of another C. macularius subspecies. Many introduced populations may be genetically contaminated because of mixing between subspecies (Minckley et al. 1991; U.S. Fish and Wildlife Service 1993b). In addition to the many spring and pond refugia, Desert Pupfish also are being held in captivity at various institutions (Hendrickson and Varela-Romero 1989; U.S. Fish and Wildlife Service 1993b).

References: (click for full references)

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.

Swift, C. C., T. R. Haglund, M. Ruiz, and R. N. Fisher. 1993. The status and distribution of the freshwater fishes of southern California. Bulletin of the Southern California Academy of Science 92(3):101-167.

U.S. Fish and Wildlife Service. 1993b. Desert pupfish recovery plan. U.S. Fish and Wildlife Service, Phoenix, AZ. 67 pp.

Williams, J. E., D. W. Sada, C. D. Williams, and other members of the Western Division of Endangered Species Committee. 1988. American Fisheries Society guidelines for introductions of threatened and endangered fishes. Fisheries 13(5):5-11.

Other Resources:

Author: Pam Fuller, and Leo Nico

Peer Review Date: 12/2/1999

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.