The Mote Marine Laboratory, in Sarasota, has just completed a two-year study that seems to indicate that manatees understand the connection between speedboat engines and injury, and sometimes make an effort to move out of the way or dive when a boat approaches them.
The study is far from conclusive, and the authors recognize that more research is needed. However, it is an important first step in understanding the interactions between manatees and the increasing number of boats in Florida. Manatees are good for the environment; they eat large amounts of nuisance weeds that would otherwise clog the waterways, and they are totally harmless to people or other sea animals.
Read this article from the Fort Myers News-Press for more on the study and its somewhat controversial results.