Paul Shafland, director of the Non-Native Research Lab for the Florida Fresh Water Fish Commission, thinks the eels have been in Florida for about 10 years. Asian eels are survivors, however. They can breathe air, so they can foil a rotenone attack. Having no air bladder, they aren't easily killed by a dynamite concussion. They breed year-round and can change their sex from female to male as they age to balance the breeding population.
Some researchers declare that the eels gobble masses of small fish, including baby largemouth bass.
Shafland downplays the eel's impact on fisheries, though he thinks they could hurt crayfish populations if they get into the Everglades. But he's not as alarmist as other biologists on the case. Look at lampreys. No one knows how the eels arrived in Florida or Georgia. Shafland speculates that a commercial aquatic fish operation had a spill, or someone simply introduced the eel illegally.