A West Indian manatee and the American manatee are one and the same and are also known as a sea cow. It is the largest surviving member of the aquatic mammal order Sirenia. The Sirenia is an order of fully aquatic, herbivorous mammals inhabiting swamps, rivers, estuaries, marine wetlands, and coastal marine waters.
Florida Manatees are the largest of all living sirenians and are a subspecies of the West Indian manatee. They inhabit the more northern limit of sirenian habitats. Like other manatees, you will find them in freshwater rivers, estuaries and coastal waters off the Gulf of Mexico and the Atlantic Ocean. They will live to be more than 28 years old in the wild. “Snooty” a captive manatee lived to be 69 years old.
In the Crystal River and Blue Springs regions in central and north Florida is where you will find the largest concentrations of them.
Relations to humans and Manatee conservation
For hundreds of years, the West Indian manatee had been hunted for the meat and hide. Unfortunately, in Central and South America, they are still being hunted. Hunters aren’t their only problems, environmental stresses like red tide and cold waters cause several health problems like immunosuppression, disease and even death.
In 1893, the state of Florida passed legislation that prohibits the killing of manatees. With the passage of both the Federal Marine Mammal Protection Act and the Endangered Species Action in 1972 and 1973 respectively, the Florida manatee was further protected. Then in 1978, the Florida legislature passed the Florida Manatee Sanctuary Act.
Ship and boat strikes have led to many violent collisions with the propeller, maiming, disfiguring them and even death. It is not uncommon anymore to see a manatee with propeller scars on their backs. This is usually caused by larger vessels that do not have skegs (sternward extension of the keel of boats and ships which have a rudder mounted on the center line) in front of the propellers. In the highly populated St. Johns River with narrow channels, manatees have been cut in two by large vessels like ships and tug boats. More than 50 scars and disfigurements from vessel strikes have found on a single manatee. It is not uncommon for the lacerations to lead to infections, which can prove fatal. Likewise, internal injuries from being trapped between hulls and docks, have also been fatal.
Manatees may be able to hear speed boats and other watercraft approaching due to the frequency the boat makes. Unfortunately, it may not be able to hear an approaching boat while performing day-to-day activities or from distractions. The manatee has a tested frequency range of 8 kilohertz to 32 kilohertz. Many large boats emit very low frequencies. This confuses a manatee and explains a lack of awareness around boats. Research has indicated that if a boat has a higher frequency the manatees rapidly swim away from danger.
There are a number of manatee rehabilitation centers in the United States. In Florida, they include government-run and private critical care facilities and include Lowry Park Zoo, Miami Seaquarium, and SeaWorld Orlando. Before they are released back into the wild after their initial treatment, they are transferred to rehabilitation facilities. These include the Cincinnati Zoo and Botanical Garden, Columbus Zoo and Aquarium, Epcot’s the Seas, South Florida Museum and Homosassa Springs Wildlife State Park.
As of February 2016, 6,250 manatees were reported swimming in Florida’s springs.