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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: blackfin pearlfish

Synonyms and Other Names: Cynolebias nigripinnis, (black-finned pearl fish).

Taxonomy: available through www.itis.gov

Identification: Costa (1990) provided diagnostic characters and included this species in his identification keys to the genera and species of the subfamily Cynolebiatinae. A few distinguishing characteristics were also given in Sterba (1973). Color photographs appeared in Mills and Vevers (1989), Axelrod et al. (1985), and Costa (1990).

Size: 5 cm.

Native Range: Tropical America. Lower Parana basin, around Rio de la Plata, in Argentina and Uruguay, and an area along the Rio Uruguay floodplains, South America (Costa, personal communication).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

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

Means of Introduction: Intentionally stocked to assess its ability as a mosquito control agent, especially in ricefields (Dill and Cordone 1997). These studies were with the approval of the Fish and Game Commission (Dill and Cordone 1997).

Status: Failed in California. Dill and Cordone (1997) concluded that there is no evidence that the species was ever an inhabitant of open waters (see Remarks section).

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: Like other annual killifishes, this species is capable of surviving in temporary pool habitats. The literature is fragmentary and somewhat contradictory concerning the introduction of this species in open waters of California. Dill and Cordone (1997) provided details on the history of this fish in California. They related that the species was used for experimental purposes at the Agricultural Experiment Station at the University of California at Riverside, either carried out in the laboratory or in outdoor plots. These experiments were terminated in 1965 after one year because the species did not reproduce adequately, was prone to disease, and did not tolerate cold temperatures. Dill and Cordone also reported that the Butte County Mosquito Abatement District used the blackfin pearlfish in tests at the Biggs Rice Experiment Station in Butte County, California. As part of these tests, young blackfin pearlfish were introduced to ponds and rice paddies at the Station and in an adjacent temporary pool. None of the fish survived and tests were terminated. In contrast to other authors (e.g., Courtenay et al. 1986, 1991; Williams and Jennings 1991), Dill and Cordone (1997) did not consider these California sites to be open waters. Unfortunately, the literature does not provide details on the outflow connections, if any, of the experimental ponds or of the ricefield areas where this species was used. In addition, if these sites were subject to periodic flooding from adjacent areas, then the introductions may be considered open water.

There are no known voucher specimens.

References: (click for full references)

Axelrod, H.R., W.E. Burgess, N. Pronek, and J.G. Walls. 1985. Dr. Axelrod's atlas of freshwater aquarium fishes. Tropical Fish Hobbyist Publications, Inc., Neptune City, NJ.

Costa, W.J.E.M. 1990. Classificação e distribuição da família Rivulidae (Cyprinodontiformes, Aplocheiloidei). Revista Brasileira de Biologia 50(1):83-89.

Courtenay, W.R., Jr., D.A. Hensley, J.N. Taylor, and J.A. McCann. 1986. Distribution of exotici fishes in North America. 675-698 in Hocutt, C.H., and E.O. Wiley, eds. The zoogeography of North American freshwater fishes. John Wiley and Sons. New York, NY.

Courtenay, W.R., Jr., D.P. Jennings, and J.D. Williams. 1991. Appendix 2: exotic fishes. 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.

Dill, W.A., and A.J. Cordone. 1997. History and status of introduced fishes in California, 1871-1996. California Department of Fish and Game Fish Bulletin, volume 178.

Mills, D., and G. Vevers. 1989. The Tetra encyclopedia of freshwater tropical aquarium fishes. Tetra Press, Morris Plains, NJ.

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

Sterba, G. 1973. Freshwater fishes of the world. English translation and revision from German. Two volumes. Tropical Fish Hobbyist Publications, Inc., Neptune City, NJ.

Williams, J.D. and D.P. Jennings. 1991. Computerized data base for exotic fishes: the western United States. California Fish and Game 77(2):86-93.

Other Resources:
US Fish and Wildlife Service Ecological Risk Screening Summary for Austrolebias nigripinnis

Author: Nico, L.

Peer Review Date: 6/28/2011

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.