University of Central Florida biologists and coastal Floridians have been nursing baby sea turtles into the Atlantic Ocean for a long time and wondering: Where do they go and what do they do in the deep blue?
Now a UCF biology professor has some answers, thanks to a tracking instrument about the size of a fig that cost $4,000 and was glued to the shells of 17 young sea turtles released in small groups from 2009 to 2011.
What Kate Mansfield and a team of other researchers have discovered is that little loggerheads may ease into a remote part of the ocean, the Sargasso Sea, where they can spend many years lounging, eating and growing up among floating piles of sargassum seaweed. Researchers had previously assumed the threatened species rode the whirlpool that circles clockwise around the Atlantic.
"It turns out the turtle tracks are a lot more variable than just following this big doughnut around the ocean," Mansfield said. "Sargassum provides them with refuge. The turtles are brown, and they blend really well with that habitat, and there are a number of little organisms (crabs and fish) that turtles might eat."
There's more than curiosity behind the effort to find out what loggerheads are doing early in a traveling life that can last more than a half-century and will include repeated visits to their birthplaces to lay their own eggs, but not until they have been away for more than 20 years.
Some of the most important beaches in the world for loggerhead nesting are along Florida, a state that has worked for decades to document and protect nests and to minimize perils for hatchlings such as bright lights that can disorient their march to the sea.
"So one of the questions is: 'Okay, if a hatchling sees a light and goes the wrong way for a little while, how does that affect their incredible journey offshore?'" said Robbin Trindell, sea-turtle-program leader at the Florida Fish and Wildlife Conservation Commission.
"The more we understand about what they do offshore, the more we can understand how important it is to limit impacts to them during that short time we have them under our care on the beach," Trindell said.
Mansfield's turtle-tracking research also has been a journey. She began in the mid 2000s to develop a method of attaching instruments to young sea turtles for the type of research already done for many years with adult turtles.
But though the devices will stick to grown-up turtles for years, the shells of juveniles grow so quickly that no standard technique would work for more than a few weeks.
In time, Mansfield and colleagues got help from a manicurist, who suggested starting with a nontoxic, acrylic coating because turtle shells are built with much the same stuff as fingernails.
With the acrylic coating as a foundation, the researchers glue down a small piece of old wetsuit as soft bedding for the tracking device, which is then attached with hair-extension glue because it is flexible and waterproof.
The trackers, despite their tiny size and weighing about as much as four pennies, send a signal to satellites that includes location, temperature and how much power is being produced by solar chargers.
The 17 turtles were followed for a few as 27 days to as many as 220 days before the devices fell off. That may not seem like much time, but researchers previously knew little about their whereabouts during that period. What happens afterward is up for further tracking, which is already being done.