Giant salvinia (Salvinia molesta) has been found growing in the Carolinas, the Gulf Coast states, the Colorado River, and California. The plant, which is native to South America, clogs channels, and causes fish kills by reducing the amount of oxygen in the water. A type of Australian weevil that feeds only on salvinia has been introduced to control the plant.
Photograph courtesy of USGS
Caption information from the Florida Department of Environmental Protection and the U.S. Geological Survey.