Where Are the Sea Turtles?
Image by Michal B.
If you spend any time on Sanibel or Captiva’s beaches during May-October, you’ll likely never question where the sea turtles are. Wooden stakes and yellow flagging tape mark off hundreds of sea turtle nests, and there’s usually sets of tracks still visible in the sand from a turtle’s appearance on a previous night.
Florida’s sea turtle nesting season spans May through October. Yet, spend any amount of time on our beaches outside those months, say from November-March, and you’d be forgiven in not knowing that sea turtles frequent these islands at all.
So where are the turtles during winter and early spring? When they’re not nesting, where do they go?
“The short answer is at their foraging grounds,” said SCCF Sea Turtle Biologist Jack Brzoza. “After a long, resource-demanding nesting season, turtles need to spend time feeding and building back up their energy stores to complete the whole process again in another 1-3 years typically.”
Sea turtles are capital breeders, meaning the energy they need for reproduction is acquired in advance and stored in reserve to fuel this process, Brzoza explained. During the months a sea turtle spends nesting, it’s believed they do not allocate time to forage for food, but may instead only forage opportunistically.
“The nesting process is extremely energetically demanding and costly,” Brzoza said. “Energy is needed to fuel sea turtles’ migration from foraging grounds to nesting grounds, as well as mating, egg formation, and about 4-6 iterations of nesting activity — crawling on the beach, digging an egg chamber, laying eggs, covering the nest, and crawling back along the beach.”
Sea turtles may also make extremely long migrations from nesting grounds to foraging grounds and back again.
“Not every turtle uses the same foraging area, and tracking turtles with satellite telemetry has allowed scientists to learn where some turtles go,” Brzoza said. “From transmitters placed on loggerheads, SCCF and our regional partners like Mote Marine Lab and the Conservancy of Southwest Florida have been able to learn the foraging areas for multiple turtles that nest on our islands. They forage along the Florida Shelf in the Gulf of Mexico, along the Yucatan Peninsula, in the Florida Keys, and in the Caribbean in the Bahamas and off the Cuban coast.”
Right now, many sea turtles who nest on Sanibel and Captiva may still be in these areas or elsewhere amassing resources to nest again. But in just a couple months, some of those turtles will begin making their way to our local waters.
“A short while after that, as they begin expending energy during the nesting process, we’ll be encountering them, or the signs they leave behind, on our beaches,” Brzoza said.
*Note: Satellite telemetry data is obtained from communication between the transmitter and orbiting satellites which gives a positional fix, or the location of the animal being tracked. However, the signals being received that provide the location data have varying levels of accuracy. Not every point represents the exact location of the turtle, but rather conveys the turtle’s relative position with accuracy ranging from about 150 to over 1000 meters. Pepper did not venture on land during her migration. Although several data points show her track on land, these points were most likely generated during poor signal and have a greater location inaccuracy. Pepper never left the water during her migration. For the points that show up on land, she was more likely just relatively close to shore in that general region.