Author
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Mitchell, Andrew |
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Submitted to: American Fishery Society (Fish Health Section) Proceedings
Publication Type: Abstract Only Publication Acceptance Date: 4/5/2005 Publication Date: 7/27/2005 Citation: Mitchell, A.J. 2005. Centrocestus formosanus in cultured and wild fishes: Impact on fish, distribution in the United States, and host information [abstract]. American Fishery Society (Fish Health Section) Proceedings. p. 23. Interpretive Summary: Technical Abstract: Centrocestus formosanus is a trematode that produces severe alterations in the gills of many freshwater fishes, most notably cartilage proliferation around the encysted trematode in the branchial tissues. It has caused significant losses among cichlids, characids, and cyprinids raised by tropical fish producers since the early 1980s. In 1997, these losses were estimated at $3.5 million annually. The trematode was found in wild fish from a lake in Pasco County, Florida in December 1985 and, in 1990, it was observed in wild fish in the San Antonio River near the San Antonio Zoo. In October of 1996, the trematode was observed in a federally listed endangered species, the fountain darter Etheostoma fonticola, collected from the Comal River, Comal County, Texas. Additional collections from this river during the following two years revealed that about 15 fish species were infected and several, including the fountain darter, were found with massive infections that were obviously affecting the health of the fish. Light infections of the gill trematode were also found in the fountain darter in the nearby San Marcos River. Investigation of several west Texas springs revealed the trematode infecting five state or federally listed fishes (endangered) at San Felipe Creek, Val Verde County; San Solomon Springs, Reeves County; and Phantom Lake Springs, Jeff Davis County. In the spring of 2003, the parasite was observed in western Utah in fish at Gandy Warm Springs, Millard County, and Goshen Warm Springs, Utah County. The gill trematode has a complex life cycle involving definitive hosts (birds and possibly some mammals) and intermediate hosts (an aquatic snail and several fish species). In the USA, the green heron Butorides virescens has been shown to serve as a definitive host but other aquatic birds are thought to serve as hosts. The first intermediate host, the red-rim melania Melanoides tuberculatus, an exotic snail, has been found in 16 southern or western states. This snail exhibits resistance to desiccation, molluscicides, and disinfectants and it out-competes some established mollusks, partly because of its ability to reproduce parthenogenically and to brood young internally. The red-rim melania also can carry other trematodes including two human pathogens. |
