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NAS - Nonindigenous Aquatic Species |
Common Name: Japanese medaka
Identification: Distinguishing characteristics are provided by Masuda et al. (1984). Photographs or illustrations appear in Lee et al. (1980 et seq.), Masuda et al. (1984), and Axelrod et al. (1985:600).
Size: 4 cm.
Native Range: Eastern Asia. Japan, Korea, Taiwan, middle and eastern China as far south as Hainan (Lee et al. 1980 et seq.; Mauda et al. 1984).
Nonindigenous Occurrences: Medaka were introduced and possibly established in San Francisquito Creek, Santa Clara County, California, prior to about 1935 (Shapavalov et al. 1959, 1981; Lee et al. 1980 et seq.). Introduced to Oahu, Hawaii, in 1922 (Maciolek 1984), and to ponds in Long Island, Suffolk County, New York, where they were temporarily established during the 1970s and possibly before (Courtenay and Hensley 1979; Courtenay et al. 1984).
Means of Introduction: The California introduction reportedly resulted from an aquarium release (Snyder 1935). It was intentionally stocked in unknown numbers in Hawaii (Brock 1960; Maciolek 1984), possibly as a potential biological control for mosquitoes. Sources of and reasons for introductions in New York are not known, but may be associated with research or aquarium releases (Lee et al. 1980 et seq.).
Status: The New York population was extirpated as a result of the cold winter of 1978; the California population disappeared for reasons unknown (Courtenay et al. 1984). Contrary to information provided by some authors, the species was reported but apparently never established in California (Dill and Cordone 1997). In Hawaii, the species never became established (Brock 1960; Maciolek 1984).
Impact of Introduction: Unknown.
Remarks: According to Coates (1950), the California populations were thriving. Shapovalov et al. (1959, 1981) stated that there have been no records of Oryzias being taken from open waters of that state since about 1935. It was not mentioned by Moyle (1976a) or Swift et al. (1993) in their reports on freshwater fishes of California. Dill and Cordone (1997) referenced an early letter by Snyder and indicated that the first (and possibly only) record of this fish in California is based on a single specimen taken from San Francisquito Creek by Stanford University students. According to these authors, that single fish may be the only basis for Snyder (1935) and all subsequent mentions of this fish recorded for that state. This freshwater species shows broad temperature and salinity tolerances. Various color varieties or mutants are known and some of these are in the aquarium trade (Sakaizumi et al. 1983).
There are no known voucher specimens.
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.
Courtenay, W. R., Jr., and J. R. Stauffer, Jr., editors. 1984. Distribution, biology and management of exotic fishes. Johns Hopkins University Press, Baltimore, MD.
Courtenay, W. R., Jr., and D. A. Hensley. 1979. Survey of introduced non-native fishes. Phase I Report. Introduced exotic fishes in North America: status 1979. Report Submitted to National Fishery Research Laboratory, U.S. Fish and Wildlife Service, Gainesville, FL.
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.
Maciolek, J. A. 1984. Exotic fishes in Hawaii and other islands of Oceania. Pages 131-161 in W. R. Courtenay, Jr., and J. R. Stauffer, Jr., editors. Distribution, biology, and management of exotic fishes. The Johns Hopkins University Press, Baltimore, MD.
Masuda, H., K. Amaoka, C. Araga, T. Uyeno, and T. Yoshino, editors. 1984. The fishes of the Japanese Archipelago. Tokai University Press. Text: i-xxii + 437 pp.; atlas: pls. 1-370.
Moyle, P. B. 1976. Inland fishes of California. University of California Press, Berkeley, CA.
Shapovalov, L., W. A. Dill, and A. J. Cordone. 1959. A revised check list of the freshwater and anadromous fishes of California. California Fish and Game 45:159-180.
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.
Other Resources:
FishBase Fact Sheet
Author: Pam Fuller and Leo Nico
Revision Date: 11/18/1999 Citation for this information:
Pam Fuller and Leo Nico. 2009. Oryzias latipes. USGS Nonindigenous Aquatic Species Database, Gainesville, FL.
<http://nas.er.usgs.gov/queries/FactSheet.asp?speciesID=302> Revision Date: 11/18/1999
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