Disclaimer:

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.

---

Common name: Blue Tilapia

Synonyms and Other Names: Sarotherodon aurea, Tilapia aurea; Israeli tilapia

Taxonomy: available through www.itis.gov

Identification: In general, cichlids (Cichlidae) are superficially similar to sunfishes and black basses (Lepomis and Micropterus; family Centrarchidae). Cichlids can be distinguished from centrarchids by a single nostril opening on each side of the head (vs. two in centrarchids) and the presence of a discontinuous or two-part lateral line (vs. continuous in centrarchids).

Distinguishing characteristics, synonyms, photographs, keys, and discussion of hybrids were provided in Trewavas (1983); for identification also see Page and Burr (1991), and Skelton (1993). Illustrations and diagnoses of larval and small juveniles of introduced populations were given by McGowan (1988). Color photographs were presented in Axelrod et al. (1985) and Axelrod (1993). Many or most accounts of "Tilapia nilotica" in U.S. ponds probably refer to O. aureus, likely imported from Israel, before the two species were shown to be distinct (Trewavas 1983).

Blue Tilapia is closely related to, and often confused with, Nile Tilapia (O. niloticus). These two species can generally be distinguished by the following characteristics (Trewavas 1983):

	Blue Tilapia	Nile Tilapia
Number of dorsal spines	15-16 (mode 16)	16-18 (mode 17)
Total dorsal fin rays	27-30 (mode 28)	29-31 (mode 30)
Banding on caudal fin	No distinct bands/stripes	Distinct, regular dark stripes
Male breeding coloration	Metallic blue	Red
Dorsal fin margin	Vermillion	Dark grey or black

 

Size: 51 cm (Lee et al. 1980 et seq.

Native Range: Tropical and subtropical Africa, and Middle East. Native range includes Senegal, Niger, and many smaller drainages and lakes in Africa and Middle East (Trewavas 1983; Skelton 1993).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

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

Means of Introduction: This species has been introduced through a combination of means, including stocking and experimental work by states and private companies (e.g., the electric power industry), and release by individuals seeking to use the species as a sport fish, as forage for warmwater predatory fish, as a food source, and as a means of aquatic plant control. Introductions and spread have resulted by way of escapes or releases from aquaculture facilities and experimental control areas, and from various other holding sites (e.g., zoological parks); through aquarium and bait bucket releases; and by intentional transport by anglers and private individuals (Courtenay and Hensley 1979a; Lee et al. 1980 et seq.; Courtenay et al. 1984, 1986; Muoneke 1988; Courtenay and Williams 1992). The exact reasons for and sources of some introductions are uncertain (e.g., Texas) (Hubbs et al. 1978; Courtenay and Hensley 1979a). Apparently, power companies became interested in using so-called "tropical fishes" for food or sport in heated effluent ponds used to cool effluents from both fossil fuel fired and nuclear generating plants, where temperatures often became too high to support populations of native fishes (Courtenay and Hensley 1979a). Blue tilapia and redbelly tilapia were inadvertently introduced into Hyco Reservoir in North Carolina in 1984 after a small number of fish escaped from a holding cage located in the heated discharge area during an on-site agricultural study (Crutchfield 1995).

Status: Established or possibly established in ten states. Established in parts of Arizona, California, Florida, Nevada, North Carolina, and Texas. Possibly established in Colorado, Idaho, Oklahoma, and Pennsylvania. Reported from Alabama, Georgia, and Kansas. For more than a decade it has been considered the most widespread foreign fish in Florida (Hale et al. 1995).

Impact of Introduction:

Summary of species impacts derived from literature review. Click on an icon to find out more...

Ecological	Economic	Other

The blue tilapia is considered a competitor with native species for spawning areas, food, and space (Buntz and Manooch 1969; Noble and Germany 1986; Muoneke 1988; Zale and Gregory 1990). Courtenay and Robins (1973) reported that certain streams where this species is abundant have lost most vegetation and nearly all native fishes. It has invaded the Taylor Slough portion of Everglades National Park where it is considered a major management problem for the National Park Service (Courtenay 1989; Courtenay and Williams 1992). The blue tilapia's local abundance and high densities in certain areas have resulted in marked changes in fish community structure (Muoneke 1988, and citations therein). A dramatic reduction in native fishes in the Warm Springs area of Nevada coincided with invasion of this species (Scoppettone et al. 1998, 2005).

Blue tilapia have also been implicated as the cause for unionid mussel declines in two Texas water bodies, Tradinghouse Creek and Fairfield reservoirs (Howells 1995).

Remarks: Oreochromis aureus has been used widely in aquaculture and is able to live and reproduce in brackish waters. The origin of the U.S. stocks of O. aureus, imported as Tilapia nilotica, was Israel (Courtenay and Hensley 1979a). Voucher specimens taken from the lower Colorado river system, Arizona, in 1980 were initially reported as mango tilapia Tilapia (= Sarotherodon) galilaea; but these were later determined by D. Thys van den Audenaerde to be O. aureus. Some lower Colorado River populations in California and Arizona may be hybrids with O. niloticus (Courtenay et al. 1984, 1986). Although all species from the genus Oreochromis readily hybridize (D'Amato et al. 2007), electrophoretic studies on tilapia sampled from 12 Texas reservoirs indicated that most populations were O. aureus without indicating genetic introgression with other tilapia species (Howells 1991b). There is a 1971 record of Alabama fish overwintering in outdoor ponds at Auburn University (Courtenay and Hensley 1979a, Courtenay et al. 1986); however, tilapia introduced into that state typically begin to die each fall when water temperatures reach about 10°C (Smith-Vaniz 1968). This species was stocked in aquaculture ponds in Iowa to test growth potential; although it reproduced there, it did not overwinter (Pelgren and Carlander 1971; Courtenay and Hensley 1979a). In the southwestern United States, the Central Arizona Project canal system is proving to be a major dispersal route for blue tilapia (Courtenay, personal communication).

Collection and reported localities were mapped for all or part of the United States, mainly Florida, by Courtenay et al. (1974), Foote (1977), Courtenay and Hensley (1979a), Lee et al. (1980 et seq.), Loftus and Kushlan (1987), and Menhinick (1991). Hale et al. (1995) reviewed the history of blue tilapia in Florida.

Voucher specimens: Alabama (AUM 20907), Florida (UF 23163, 40306, many others), Kansas (KU 13026, 22917), North Carolina (UNCC uncatalogued), Pennsylvania (PSU 2031).

References: (click for full references)

Anonymous. 1992. Two new fish records set. Texas Parks and Wildlife News, January 17, 1992. 7 pp.

Axelrod, H. R. 1993. The most complete colored lexicon of cichlids. Tropical Fish Hobbyist Publications, Inc., Neptune City, NJ.

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.

Buchanan, T.- Department of Biology, Westark College, Fort Smith, AR.

Buntz, J., and C. S. Manooch. 1969. Tilapia aurea (Steindachner), a rapidly spreading exotic in south central Florida. Proceedings of the Southeastern Association of Game and Fish Commissioners 22:495-501.

Burgess, G. H., C. R. Gilbert, V. Guillory, and D. C. Taphorn. 1977. Distributional notes on some north Florida freshwater fishes. Florida Scientist 40(1):33-41.

Courtenay, W.R., Jr. 1989. Exotic fishes in the National Park system. Pages 237-252 in Thomas, L.K, ed. Proceedings, 1986 Conference on Science in the National Parks: Management of exotic species in natural communities. US National Park Service and George Wright Society. Washington, DC.

Courtenay, W. R., Jr., and D. A. Hensley. 1979a. 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.

Courtenay, W. R., Jr., and C. R. Robins. 1973. Exotic aquatic organisms in Florida with emphasis on fishes: a review and recommendations. Transactions of the American Fisheries Society 102:1-12.

Courtenay, W. R., Jr., and J. D. Williams. 1992. Dispersal of exotic species from aquaculture sources, with emphasis on freshwater fishes. Pages 49-81 in A. Rosenfield, and R. Mann, editors. Dispersal of living organisms into aquatic ecosystems. Maryland Sea Grant Publication, College Park, MD.

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. A. Hensley, J. N. Taylor, and J. A. McCann. 1986. Distribution of exotic fishes in North America. Pages 675-698 in C. H. Hocutt, and E. O. Wiley, editors. 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. 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.

Courtenay, W. R., Jr., H. F. Sahlman, W. W. Miley, II, and D. J. Herrema. 1974. Exotic fishes in fresh and brackish waters of Florida. Biological Conservation 6(4):292-302.

Crittenden, E. 1963. Status of Tilapia nilotica Linnaeus in Florida. Proceedings of the Southeastern Association of Game and Fish Commission 16:257-262.

D'Amato, M.E., M.M. Esterhuyse, B.C.W. van der Waal, D. Brink, and F.A.M. Volckaert. 2007. Hybridization and phylogeography of the Mozambique tilapia Oreochromis mossambicus in southern Africa evidenced by mitochondrial and microsatellite DNA genotyping. Conservation Genetics 8: 475-488.

Edwards, R. J., and S. Contreras-Balderas. 1991. Historical changes in the ichthyofauna of the lower Rio Grande (Rio Bravo del Norte), Texas and Mexico. Southwestern Naturalist 36(2):201-212.

Foote, K. J. 1977. Annual performance report: blue tilapia investigations. Study I: preliminary status investigations of blue tilapia. (Job I-1 through Job I-7; period July 6, 1976-June 30, 1977). Report to the Florida Game and Fresh Water Fish Commission. 71 pp.

Gennings, R.M. - Georgia Department of Natural Resources, Atlanta, GA. Response to NBS-G nonindigenous questionaire.

Grabowski, S. J., S. D. Hiebert, and D. M. Lieberman. 1984. Potential for introduction of three species of nonnative fishes into central Arizona via the Central Arizona Project ? A literature review and analysis. REC-ERC-84-7. U.S. Department of the Interior, Bureau of Reclamation, Denver, CO.

Habel, M. L. 1975. Overwintering of the cichlid, Tilapia aurea, produces fourteen tons of harvestable size fish in a south Alabama bass-bluegill public fishing lake. Progressive Fish-Culturist 37:31-32.

Hales, L. S., Jr. 1989. Occurrence of an introduced African cichlid, the blue tilapia, Tilapia aurea (Perciformes: Cichlidae), in a Skidaway River tidal creek. Department of Zoology and Institute of Ecology, University of Georgia, Athens, and Marine Extension Service Aquarium, Georgia Sea Grant College Program, Savanna, GA. Unpublished mimeograph. 12 pp.

Herlong, D. - Carolina Power and Light Company.

Howells, R. G. 1991b. Electrophoretic identification of feral and domestic tilapia in Texas. Texas Parks and Wildlife Department, Management Data Series 62, Austin, TX. 11 pp.

Howells, R. G. 1992a. Annotated list of introduced non-native fishes, mollusks, crustaceans and aquatic plants in Texas waters. Texas Parks and Wildlife Department, Management Data Series 78, Austin, TX. 19 pp.

Howells, R. G. 1992b. Guide to identification of harmful and potentially harmful fishes, shellfishes and aquatic plants prohibited in Texas. Texas Parks and Wildlife Department Special Publication, Austin, TX. 182 pp. (+ appendices).

Howells, R. G. 1995. Losing the old shell game: could mussel reproductive failure be linked to tilapia? Info-Mussel Newsletter 3(8):4.

Hubbs, C., R. J. Edwards, and G. P. Garrett. 1991. An annotated checklist of freshwater fishes of Texas, with key to identification of species. Texas Journal of Science, Supplement 43(4):1-56.

Hubbs, C., T. Lucier, G. P. Garrett, R. J. Edwards, S. M. Dean, E. Marsh, and D. Belk. 1978. Survival and abundance of introduced fishes near San Antonio, Texas. Texas Journal of Science 30(4):369-376.

Kushlan, J. A. 1986. Exotic fishes of the Everglades: a reconsideration of proven impact. Environmental Conservation 13:67-69.

Langford, F. H., F. J. Ware, and R. D. Gasaway. 1978. Status and harvest of introduced Tilapia aurea in Florida lakes. Pages 102-108 in R. O. Smitherman, W. L. Shelton, J. H. Grover, editors. Proceedings of the culture of exotic fishes symposium, fish culture section, American Fisheries Society, Auburn, AL.

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.

Loftus, W. F., and J. A. Kushlan. 1987. Freshwater fishes of southern Florida. Bulletin of the Florida State Museum of Biological Science 31(4):255.

McGowan, E. G. 1988. An illustrated guide to larval fishes from three North Carolina piedmont impoundments. Report by Carolina Power and Light Company, Shearon Harris Energy and Environmental Center, New Hill, NC. 113 pp.

Menhinick, E. F. 1991. The freshwater fishes of North Carolina. North Carolina Wildlife Resources Commission. 227 pp.

Moore, V. - Idaho Fish & Game, Boise, ID.

Muoneke, M. I. 1988. Tilapia in Texas waters. Texas Parks and Wildlife Department, Inland Fisheries Data Series 9, Austin, TX. 44 pp.

Noble, R. L., and R. D. Germany. 1986. Changes in fish populations of Trinidad Lake, Texas, in response to abundance of blue tilapia. Pages 455-461 in R. H. Stroud, editor. Fish culture in fisheries management. American Fisheries Society, Bethesda, MD.

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.

Pelgren, D. W., and K. D. Carlander. 1971. Growth and reproduction of yearling Tilapia aurea in Iowa ponds. Proceedings of the Iowa Academy of Science 78:27-29.

Pigg, J. 1978. The tilapia Sarotherodon aurea (Steindachner) in the North Canadian River in central Oklahoma. Proceedings of the Oklahoma Academy of Science 58:111-112.

Red River Authority of Texas. 2001. Red and Canadian Basins Fish Inventory: Red River County. Red River Authority of Texas.

Rogers, W. A. 1961. Second progress report on stocking and harvesting of tilapia and channel catfish in Alabama's state-owned and managed public fishing lakes. Federal Aid Project F-10. Alabama Department of Conservation. 10 pp.

Scoppettone, G.G., P.H. Rissler, M.B. Nielsen, and J.E. Harvey. 1998. The status of Moapa coriacea and Gila seminuda and status information on other fishes of the Muddy River, Clark County, Nevada. Southwestern Naturalist 43(2) :155-122

Scoppettone, G.G., J.A. Salgado, and M.B. Nielsen. 2005. Blue tilapia (Oreochromis aureus) predation on fishes in the Muddy River system, Clark County, Nevada. Western North American Naturalist 65(3) :410-414

Skelton, P. H. 1993. A complete guide to the freshwater fishes of southern Africa. Southern Book Publishers, Halfway House, South Africa.

Skinner, W. F. 1984. Oreochromis aureus (Steindachner; Cichlidae), an exotic fish species, accidentally introduced to the lower Susquehanna River, Pennsylvania. Proceedings of the Pennsylvania Academy of Science 58:99-100.

Skinner, W. F. 1986. Susquehanna River tilapia. Fisheries 11(4):56-57.

Skinner, W. F. 1987. Report on the eradication of tilapia from the vicinity of the Brunner Island Steam Electric Station. Pennsylvania Power and Light Company, Allentown, PA. Unpublished mimeograph. 18 pp.

Smith-Vaniz, W. - Ichthyologist, National Biological Service, Gainesville, FL.

Smith-Vaniz, W. F. 1968. Freshwater fishes of Alabama. Auburn University Agricultural Experiment Station, Auburn, AL. 211 pp.

Smith-Vaniz, W. F., J. D. Williams, L. G. Nico, and W. Loftus. Key to the cichlid fishes of Florida. Unpublished mimeograph (in prep).

Stauffer, J. R., Jr., S. E. Boltz, and J. M. Boltz. 1988. Cold shock susceptibility of blue tilapia from the Susquehanna River, Pennsylvania. North American Journal of Fisheries Management 8:329-332.

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.

Texas Parks and Wildlife Department. 2001. Fish Records: Water Body - All Tackle. Texas Parks and Wildlife Department. April 24, 2001.

Tilmant, J.T. 1999. Management of nonindigenous aquatic fish in the U.S. National Park System. National Park Service. 50 pp.

Trewavas, E. 1983. Tilapiine fishes of the genera Sarotherodon, Oreochromis, and Danakilia. Publication No. 898. British Museum of Natural History, London, UK

U.S. Fish and Wildlife Service (USFWS). 2002. USFWS memorandum on Tilapia Removal Program on the Virgin River, Clark County, Nevada and Mohave County, Arizona. http:// http://www.fws.gov/southwest/es/arizona/Documents/Biol_Opin/02299_Tilapia_Removal_Virgin_River.pdf. Accessed on 4 October 2007.

Zuckerman, L.D., and R.J. Behnke. 1986. Introduced fishes in the San Luis Valley, Colorado. 435-452 in R.H. Stroud, ed. Fish culture in fisheries management. Proceedings of a symposium on the role of fish culture in fisheries management at Lake Ozark, MO, March 31-April 3, 1985. American Fisheries Society, Bethesda, MD.

Zale, A.V. - Oklahoma State University (formerly); National Biological Service, Bozeman, MT (currently).

Zale, A. V. 1987. Periodicity of habitation of a stenothermal spring run in north-central Florida by blue tilapia. North American Journal of Fisheries Management 7:575-579.

Zale, A. V., and R. W. Gregory. 1990. Food selection by early life stages of blue tilapia, Oreochromis aureus, in Lake George, Florida: overlap with sympatric shad larvae. Florida Scientist 53:123-129.

Other Resources:

Global Invasive Species Database Factsheet

US Fish and Wildlife Service Ecological Risk Screening Summary for Oreochromis aureus

Author: Nico, L.G., Fuller, P., and Neilson, M.E.

Peer Review Date: 6/19/2013

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.