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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: Porthole Livebearer

Taxonomy: available through www.itis.gov

Identification: A few distinguishing characteristics provided by Rosen and Bailey (1963), Page and Burr (1991), and Wischnath (1993). Generally resembles mosquitofish (Gambusia), but can be distinguished from co-occurring poecilids by 4-8 black spots along the side (Mearns 1975). For photographs of species see Dawes (1991) and Wischnath (1993).

Size: Females 5 cm SL; males 4 cm SL

Native Range: Southern Mexico to Honduras on Atlantic and Pacific slopes (Rosen and Bailey 1963; Page and Burr 1991).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

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

Means of Introduction: Probably due to an aquarium release or escape from a local fish farm (Mearns 1975; Lee et al. 1980 et seq.).

Status: Population in Riverside County, California, was locally established (Mearns 1975; Shapovalov et al. 1981); however, it may no longer exist. Canal reportedly filled in as of 1987 (Courtenay, personal communication). Current status unknown.

Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. It does, however, mean that research is required to evaluate effects before conclusions can be made.

Remarks: Courtenay et al. (1984) and Swift et al. (1993), incorrectly citing Mearns (1975), mistakenly reported that the species was first found in California in 1965. Mearns (1975) sampled the area reguarly between 1964-1974 and did not collect this species, suggesting that the introduction happened early in 1974. This species exhibits a broad range in body build and coloration, especially in terms of spotting pattern (Wischnath 1993).

Voucher specimens: California (SIO 74-126).

References: (click for full references)

Courtenay, W. - Florida Atlantic University, Boca Raton.

Courtenay, W. R., Jr., D. A. Hensley, J. N. Taylor, and J. A. McCann. 1984. Distribution of exotic fishes in the continental United States. Pages 41-77 in W. R. Courtenay, Jr., and J. R. Stauffer, Jr., editors. Distribution, biology and management of exotic fishes. Johns Hopkins University Press, Baltimore, MD.

Courtenay, W. R., Jr., D. P. Jennings, and J. D. Williams. 1991. Appendix 2: exotic fishes. Pages 97-107 in Robins, C. R., R. M. Bailey, C. E. Bond, J. R. Brooker, E. A. Lachner, R. N. Lea, and W. B. Scott. Common and scientific names of fishes from the United States and Canada, 5th edition. American Fisheries Society Special Publication 20. American Fisheries Society, Bethesda, MD.

Dawes, J.A. 1991. Livebearing fishes. A guide to their aquarium care, biology and classification. Blandforn, London, England.

Hubbs, C. L., W. I. Follett, and L. J. Dempster. 1979. List of the fishes of California. California Academy Science Occasional Papers 133. 51 pp.

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

Mearns, A. J. 1975. Poeciliopsis gracilis (Heckel), a newly introduced poeciliid fish in California. California Fish and Game 61(4):251-253.

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.

Rosen, D. E., and R. M. Bailey. 1963. The poeciliid fishes (Cyprinodontiformes), their structure, zoogeography, and systematics. Bulletin of the American Museum of Natural History 126:1-176.

Shapovalov, L., A. J. Cordone, and W. A. Dill. 1981. A list of freshwater and anadromous fishes of California. California Fish and Game 67(1):4-38.

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.

Wischnath, L. 1993. Atlas of livebearers of the world. TFH Publications, Inc., Neptune, NJ.

Other Resources:
US Fish and Wildlife Service Ecological Risk Screening Summary for Poeciliopsis gracilis

Author: Leo Nico, and Matt Neilson

Peer Review Date: 8/30/2011

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.