There are three species of manatees, including the West Indian manatee. The Florida manatee, which can eat up to 100 pounds (45 kilograms) of vegetation a day and weigh a half-ton on average, is a subspecies of the West Indian manatee.
"The gentleness and trusting nature of these animals is undeniable," said Pat Rose, who heads the Save the Manatee Club in Maitland, Florida.
There may have been tens of thousands of manatees in Florida's waters before human hunting and development drastically cut their numbers. In the early 1980s the manatee population may have stood at less than 2,000.
Thanks in part to strong protection efforts, Florida's manatee numbers today have been boosted to about 3,500 animals. The manatee is still listed federally as an endangered species, but its state designation was downgraded this year from "endangered" to "threatened."
Their recovery, however, is far from complete.
Manatees are under constant threat from the more than one million registered boats that ply Florida's waters. Boat strikes have killed some 1,400 animals over the past 30 years. Last year was the second deadliest year on record, with 79 manatees killed by boats.
(Related news: "Manatee Protections in Belize Should Be World Model, Expert Says" [September 27, 2006].)
"There's not a manatee born [in Florida] that will not have a propeller scar within two to three months," Meeks said.
Manatees can move readily between salt water and fresh water, but they can't survive in cold water for long periods. Each year, as temperatures drop, some manatees travel hundreds of miles in search of warm water.
"In Florida there are a host of problems related to manatees having to juggle their thermodynamic capabilities with their nutritional needsfeeding, habitat, and those kinds of things," Bonde said.
"We get fluxes of manatees moving in and out of different areas."
Explosive development in Florida, particularly in the southern part of the state, has steadily encroached on manatee habitat.
Much of the Everglades area, historically a favorite manatee dwelling spot, has been transformed by the dredging of canals and housing developments. (See Florida map.)
"We're now seeing unprecedented growth in Florida, and it's beginning to rival the terrible days when developers were making wholesale changesbulldozing and dredging," said Save the Manatees' Rose, who used to head Florida's Office of Protected Species.
While manatee populations are growing at healthy rates in northwest Florida and the upper St. John's River region, they are stalling or declining in eastern and particularly southwestern Florida.
Curiously, manatees have also become dependent on human industry.
In search of warm water, manatees have learned to winter in the warm water discharges of power plants along the Florida coast.
Unable to reclaim lost habitat in south Florida, manatees could be literally left out in the cold if these plants were to shut down.
"We know economically that these plants aren't going to run forever," said USGS's Bonde.
"I'm pretty optimistic about the future of the manatees, except when I think about this monster we've created with their dependence on artificial warm water."
This is why the relatively warm, spring-fed waters of the Suwannee River may become more important to manatees.
"If you compare the Suwannee River to other rivers in Florida, what's going on there in terms of stress and risks to manatees is pretty light," Rose said.
"It's anchored by such a big spring system that allows these animals to establish a good winter refuge."
Scientists would like to see places like Manatee Springs and Fanning Springs, which surface along the Suwannee River, made more accessible to manatees and turned into sanctuaries for the animals.
"Today there may be 20-plus manatees at Manatee Springs," Bonde said. "In the next ten years we hope that those 20 turn into 200."
"If manatees are going to make it, they have to rely on us to make concessions," he added.
"We end up taking so much of this planet that it's probably good practice for our wildlife [for us] to set aside buffers in areas where manatees can go and not be threatened, maybe something as simple as slowing boats down."
To Meeks, the "manatee warrior," manatees are an indicator of how well the river is doing.
"I'd love to live around manatees," he said. "I know the environment will be clean and healthy and that there will be fresh fish there."
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