Global Short Term Trend: Increase of 10-25% to decline of 30%
Comments: Current information suggests that the Florida manatee population (subspecies latirostris) is growing (USFWS 2007), but the latest good population estimate is from 2001. The Antillean manatee population (subspecies manatus) in Puerto Rico, while not as well studied as the Florida manatee, is also thought to have increased over the past 40 years and is now stable or slowly increasing (USFWS 2007). Little is known about trends in areas outside U.S. jurisdiction (USFWS 2007).
Based on status and trend information primarily from Florida and secondarily from Puerto Rico, USFWS (2007) concluded that the West Indian manatee no longer meets the definition of an endangered species. However, because of the threats of potential habitat loss and watercraft collisions and the concerns regarding the adequacy of regulatory mechanisms associated with those threats, USFWS (2007) stated that the West Indian manatee should be classified as threatened.
Global Long Term Trend: Decline of 30-50%
Comments: Over the long term, extent of occurrence has not changed much, but population size and habitat quality presumably have declined to a large but undetermined degree.
In Florida, the overall range has not changed over the long term, but the winter range has shifted from one based solely on natural warm waters to one based primarily on warm-water outlets of power plants (almost two-thirds of population) (USFWS 2007).