Common name: Gila Topminnow
Synonyms and Other Names: (Gila topminnow, Yaqui topminnow).
available through www.itis.gov
Identification: Minckley (1973); Sublette et al. (1990); Page and Burr (1991). Two subspecies: P. o. occidentalis - Gila topminnow; P. o. sonoriensis - Yaqui topminnow. For a photograph of the species see Dawes (1991).
Size: Females to 5 cm SL; males to about 2.5 cm SL
Native Range: P. o. occidentalis endemic to Gila River system of Arizona, New Mexico, and northern Sonora, Mexico. P. o. sonoriensis native to Yaqui River system in southeastern Arizona and northern Mexico (U.S. Fish and Wildlife Service 1983b). Now extirpated in New Mexico and rare in Arizona (Page and Burr 1991).
Hydrologic Unit Codes (HUCs) Explained
Puerto Rico &
Interactive maps: Point Distribution Maps
Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Poeciliopsis occidentalis occidentalis are found here.
Table last updated 10/4/2018
† Populations may not be currently present.
Ecology: Prefers shallow, warm springs or slow-moving waters, but can tolerate a wide range of temperature and current regimes. Primarily omnivorous, consuming detritus, algae, amphipods, ostracods, and insect larvae. Generally only lives one year, with sexual maturity occuring as soon as two months. Viviparous, similar to other topminnows, with breeding occuring January through August (USFWS 1998).
Means of Introduction: This endangered species was intentionally stocked to create additional populations. It was introduced into Arivaca Creek in 1936. Populations were abundant by 1957, but were extirpated in less than two years by introduced mosquitofish (U.S. Fish and Wildlife Service 1983b). The species is established in Hidden Waters, where it was first stocked in 1976. It was stocked in Tule Creek in 1968, but extirpated by flooding in 1978. It was restocked in October 1981 and was still established as of 1983. The fish first was stocked at Seven Springs and Cave Creek in the late 1960s, but the population was lost to flooding several times. It was restocked in 1975, but extirpated by flooding again in 1978. It was stocked again in February 1980 and became established. It was stocked in Cow Creek in September 1981 and became established (U.S. Fish and Wildlife Service 1983b). Simons (1987) documented more than a hundred introductions of Poeciliopsis o. occidentalis into isolated Arizona waters, many of which were created for livestock watering and therefore, were historically fishless.
Status: Most stocked populations have failed or were extirpated; however, several stocked locations still have extant populations.
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.
References: (click for full references)
Dawes, J.A. 1991. Livebearing fishes. A guide to their aquarium care, biology and classification. Blandforn, London, England.
Duncan, D. - USFWS.
Johnson, J. E. 1970. A New Locality for the Gila Topminnow, Poeciliopsis Occidentalis (Poeciliidae). The Southwestern Naturalist, 14(3): 368.
Minckley, W.L. 1969. Attempted re-establishment of the Gila topminnow within its former range. Copeia 1969:193-194
Minckley W.L. 1973. Fishes of Arizona. Arizona Game and Fish Department, Phoenix, AZ.
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.
Simons, L.H. 1987. Status of the Gila topminnow (Poeciliopsis o. occidentalis) in the United States. Special report on Project E-1, title VI of the Endangered Species Act of 1973, Arizona Game and Fish Department, Phoenix, AZ.
Sublette, J.E., M.D. Hatch, and M. Sublette. 1990. The fishes of New Mexico. New Mexico Department of Game and Fish, University of New Mexico Press, Albuquerque, NM.
U.S. Fish and Wildlife Service. 1983. Gila and Yaqui topminnow recovery plan. U.S. Fish and Wildlife Service, Albuquerque, NM.
U.S. Fish and Wildlife Service. 1994. Yaqui fishes recovery plan. U.S. Fish and Wildlife Service, Albuquerque, NM.
U.S. Fish and Wildlife Service. 1998. Gila topminnow, Poeciliopsis occidentalis occidentalis, revised recovery plan. U.S. Fish and Wildlife Service, Albuquerque, NM.
Wischnath, L. 1983. Atlas of livebearers of the world. TFH Publications, Inc., Neptune, NJ.
Leo Nico, Pam Fuller, and Matt Neilson
Revision Date: 9/27/2011
Peer Review Date: 4/1/2016
Leo Nico, Pam Fuller, and Matt Neilson, 2019, Poeciliopsis occidentalis occidentalis (Baird and Girard, 1853): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=866, Revision Date: 9/27/2011, Peer Review Date: 4/1/2016, Access Date: 1/21/2019
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.