Understanding Everglades Invaders:
Ecophysiology of the African Jewelfish (Hemichromis letourneuxi)
Abstract
A dozen species of non-indigenous fishes have colonized the wetlands of south Florida. Although some of these species continue to spread geographically, others remain local. Information relating to their biology, ecology, and environmental tolerances has been accumulating, but data gaps remain for several common species. These data are needed to understand and model the ultimate range expansion, habitat occupation and dynamics of non-native fishes, and are particularly important for risk assessments. In this series of studies, we are experimentally determining the environmental tolerances of African jewelfish Hemichromis letourneuxi to salinity, low dissolved oxygen (hypoxia) and low temperatures. The species is presently expanding its range rapidly throughout the freshwater wetlands of south Florida, where it may compete with native fishes for food and nesting sites (Fuller and others 1999; W.F. Loftus, pers. comm., 2007). These data will be used to estimate the habitats that this species may ultimately colonize in the Florida ecosystem.
African jewelfish in South Florida
The African jewelfish Hemichromis letourneuxi is native to the north and northwestern regions of Africa. Although the species has been present in the canals of south Florida since the 1950s, its geographic range has expanded greatly in recent years and continues to spread throughout south Florida habitats, from Everglades National Park to Big Cypress National Park (Loftus and others 2006). The species competes with native fishes for food and nesting sites and preys directly on native fishes (Fuller and others, 1999; W.F. Loftus, pers. comm., 2007). It is unclear what the ultimate distribution of H. letourneuxi will be, but tolerance to environmental stress is a limiting factor.
African jewelfish (Hemichromis letourneuxi)
Photo by Howard Jelks, U.S.G.S.
Studies on African jewelfish:
Click above to go to the Individual Studies
References
Fuller, P. L., Nico, L.G. and J.D. Williams. 1999. Nonindigenous Fishes Introduced into Inland Waters of the United States. Special Publication 27. Bethesda, MD: American Fisheries Society.
Loftus, W. F., Trexler J. C., Dunker, K., Liston, S. E. and J. S. Rehage. 2006. Introduced Fishes in Short-Hydroperiod Wetlands: Evaluation of Sampling, Status, and Potential Effects. Final Report from USGS to Everglades NP for Agreement # CESI IA F5284-04-0039.
For more information, contact:
|
U.S. Department of the Interior |
U.S. Geological Survey
