Florida is second only to Hawaii in total number of exotic plants and animals, with more than 2,000 known exotics - most notably plants and insects.
Florida officials expect to spend $100 million over the next decade just to remove two invasive plants, water hyacinth and hydrilla, from state waterways.
Ballast water taken on by ships in one port and discharged in another is a prime conduit for the transport of invasive species. The international nature of modern-day shipping greatly increases the opportunity for marine organisms to "hitchhike" from one part of the globe to another. Scientists estimate that an average of 40,000 gallons of ballast water is released in U.S. coastal waters every minute.
An extreme example of an ecosystem invasion is the San Francisco Bay-Delta , dubbed "the nation's most invaded estuary." So many exotic plants and animals have been introduced to this system, and so successfully, that scientists estimate that 80 percent of the living bio-mass in the Bay-Delta is now non-native. The San Francisco Bay system currently harbors 212 exotic species, with a new one appearing at the rate of one every 14 weeks since 1962.
Coyotes, steadily migrating eastward from Texas and other states, are now found in every county in Florida - although their impact on wildlife populations and the environment is not thought to be significant.
The Australian spotted jellyfish, a giant among its kind at up to 25 pounds, first appeared in the Gulf of Mexico in the year 2000. A probable hitchhiker to the Caribbean in ballast water from a ship, from there it may have drifted with the currents into the Gulf. The jumbo jelly can devour huge numbers of fish eggs and larvae, and severely clog shrimp nets, thus taking both an environmental and economic toll.
About 22 percent of all the non-native aquatic species found in the United States come from South America, followed by Asia (20 percent), Eurasia (16 percent), Europe (13 percent), Africa (12 percent), Central America (6 percent) and Australia (2 percent).
Fishes constitute the largest group of non-native introductions of aquatic species in the United States, followed by plants, reptiles, amphibians, and mollusks.