Defenders' Experts
Florida Manatee Background and Recovery
Defenders of Wildlife plays a key role in protecting the endangered Florida manatee. Our staff are members of the federal Florida Manatee Recovery Team and the state’s Manatee Conflict Resolution Forum.
Description
The Florida manatee, a subspecies of the West Indian manatee, is a large gray aquatic mammal that inhabits the coastal estuaries and rivers of the southeast United States. It is torpedo-shaped with two forelimbs and a broad paddle-shaped tail. Florida manatees average about 10 feet in length. Adults generally weigh between 1,500 and 1,800 pounds, but older individuals can grow to greater than 12 feet long and weigh over 2,000 pounds.
Range
The southeast United States is the northern extent of the West Indian manatee’s range. In the summer, Florida manatees can be found as far north as the Carolinas and Virginia and as far west as Louisiana. However, the majority of the population stays within Florida, Georgia, and Alabama in warmer months. In winter, manatees migrate to warm water sources found in Florida such as natural springs and man-made power plants.
Population Status
Although there is no precise census of Florida manatees, the highest number counted during an annual aerial survey was 3,300 in 2001. This is still considered the minimum number of Florida manatees in the wild today. No one knows how many there were historically but it is likely they were never found in very large numbers.
Threats
The largest known immediate threat to Florida manatees is collisions with watercraft. In 2006, 92 manatees were killed by watercraft, the second highest number on record. In 2007, there were 73 watercraft-related deaths. So far in 2008, through July 25, preliminary reports show there have been 58 manatees killed by boats. It is unknown how many manatees are seriously injured from boat collisions each year or how the injuries affect other life functions such as reproduction. Population scientists believe that unless this cause of death is curtailed, the manatee population will not recover.
The greatest long-term threat involves the loss of warm-water habitat that manatees need when temperatures dip in the low 70sF. Scientists predict that a large percentage of the manatee population will be lost in the next few decades when aging electric power plants will be shutting down. Many manatees aggregate in the warm-water outfalls at these plants on cold winter days.
Red tide also remains a threat to the manatee population, particularly in southwest Florida. In 1996, at least 149 manatees died from exposure to the toxic algal blooms. In 2005, 2006, and 2007, red tide killed 93, 62, and 52 manatees, respectively. Red tide occurs almost every year in the Gulf of Mexico. Although a natural occurrence, there is currently a debate among scientists as to whether blooms of the Florida red tide organism, Karenia brevis, are exacerbated by nutrients associated with run-off in developed coastal areas.
Protection Status
Manatees are currently listed as endangered under the federal Endangered Species Act and by the state of Florida. They are also protected under the Marine Mammal Protection.Defenders was a lead plaintiff in federal lawsuits against the U.S. Fish & Wildlife Service and the Florida Fish & Wildlife Conservation Commission claiming inadequate protections for Florida manatees. The outcome was a landmark settlement in 2000 that resulted in many additional protection measures for manatees.
As a result of the lawsuits, the U.S. Fish & Wildlife Service added 17 refuge and sanctuary areas. The Florida Fish & Wildlife Conservation Commission also added many other state speed zones and safe havens to their manatee protection regulations.
List of new federal protection areas
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