The latest numbers put the Florida population at roughly 6,000 manatees, up from a low of around 1,200 in 1991.
While boat collisions and drownings don't kill as many manatees as they once did, the mammals still face some daunting threats, says James Powell, a manatee specialist with the Sea to Shore Alliance in Sarasota, Florida.
Manatees are the doughboys of the ocean. Egg-shaped and docile, they spend their days eating plants and algae and basking in warm water. Knowing how these awkward-looking mammals react to hearing a boat or other threat is vital to saving them. (Learn how we're loving manatees to death.)
That's why researchers contacted National Geographic's Crittercam team in 2001. They needed help outfitting manatees with video cameras to see what the animals were doing with their day—a challenge that went to Kyler Abernathy, director of research for remote imaging, and his colleagues. Little did they know that they'd meet their match in the manatee.
Thwarted by an Egg-Shaped Animal
First the scientists tried attaching cameras to manatees using suction cups. That didn't work, says Abernathy, because the cups wouldn't seal on rough manatee skin. Next they tried gluing the cameras on. "Even biomedical glues that surgeons use to glue your skin and tissues together wouldn't stick to [manatees] well," he says.
The tubby animals wriggled out of harnesses that attached a camera to the manatees backpack-style. So the team devised a belt that wrapped around the animal's belly, which the mammals hated even more.
They would twist and turn and drag the camera along the mud on the bottom trying to get the belt off, says Abernathy. "Seven seconds after we had let [one manatee] go, the whole belt and everything was floating beside the boat," he says.
After three years of designing and testing, they finally hit on something that stayed put: a loose harness fastened around the top of a manatee's tail, with an attached camera floating above and behind the animal. Abernathy hopes a project comes along in the near future that utilizes the fruits of the team's labor.
Despite the recent rise in manatee numbers, in some years hundreds of manatees die in Florida. In 2013, 829 individuals died—the most deaths ever recorded since biologists started tracking manatee numbers. (Learn more about this mass die-off.)
Toxins from a huge bloom of microscopic ocean algae were partly responsible, says Powell. But a hundred manatees from Florida's Indian* River appear to have just died for no reason.
"If there were more of these events, it could knock back a lot of the progress that's been made over the years," Powell cautions.
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Correction, March 30, 2016: This article originally misnamed the Indian River as the India River.