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Study shows manatees try to stay away from boats

Scientists conclude the controversial method of slowing boats may be the best protection for them.

TALLAHASSEE - Scientists say they have documented for the first time that manatees react to approaching boats by swimming quickly toward deeper water, a finding that suggests slow-speed zones may be one of the keys to their survival.

The two-year project by researchers from Mote Marine Laboratory, Florida State University and the Florida Marine Research Institute found the endangered sea mammals tend to swim away and increase their speed when a boat passes within 80 feet of them.

The manatees' response was the same whether boats approached at slow or high speed, prompting the researchers to conclude that slowing down boats may be the best way to reduce collisions with manatees.

Environmentalists have long contended that slow-speed zones and better enforcement of boating rules is necessary. But boaters contend there are better ways to protect manatees, such as developing satellite tracking technology so boaters can avoid the animals.

Collisions with boats are the primary cause of documented unnatural manatee deaths. Many living manatees bear the scars of multiple boat collisions.

Manatees are often hit because they linger near the water's surface to eat and breathe. They also move into warmer shallow waters close to the coastline in winter, increasing their chances of being hit by boats.

"Unfortunately, the manatees' response of swimming toward the nearest deep water sometimes took them directly into the path of the approaching boat," said Randall Wells, director of Mote's Center for Marine Mammal and Sea Turtle Research.

The researchers used an 18-foot boat with a video camera suspended above it by a helium-filled balloon to observe the manatees' reactions when boats approached. The research took place in Sarasota Bay in areas of high boat traffic.

Florida is the only state with a permanent natural manatee population, so the annual numbers are closely watched. The lumbering mammals are on the state and federal endangered species list, with the Florida population estimated at about 3,000.