Marine biologists have been studying the movement and habitats of loggerhead turtles using satellite tags for some time. But in the past, they were only able to follow the movements of adults, because the transmitting devices were too big to attach to younger, smaller turtles. So, the travels of younger turtles are not well understood.
But now, the technology has improved and the transmitters have gotten smaller. Last month, National Oceanic and Atmospheric Administration (NOAA) scientists outfitted an adolescent turtle named Coco with a satellite tag and released it back into the wild. Coco is the first adolescent loggerhead to be tracked on the West Coast.
Coco was originally picked up by the Coast Guard, because it (the turtle's sex is undetermined) appeared to need medical attention. When veterinarians deemed the turtle healthy enough to be returned to the sea, they decided to use the occasion to tag it with a tracker. Coco was released 50 miles off the coast of San Diego, by scientists Tomo Eguchi and Jeff Seminoff, on April 15. The turtle was about the size of a dinner plate, and as an adult may grow up to three feet in length.“We know that there are juvenile loggerheads in this part of the Pacific, but they’re small and very hard to spot,” said Eguchi in a statement. “So we don’t have good data on what types of habitat they’re using.”
Tracking the turtle will help protect this endangered species. Scientists know that the young turtles sometimes share territory with swordfish, because the turtles have gotten caught by the gillnets used by fishermen. NOAA has established a Pacific Loggerhead Conservation Area off the shores of Southern California. Turtles are thought to swim in these areas when the water temperature is higher. Last summer, conservation managers closed the area to fishing for the first time when water temperatures rose. Gathering more data on the young turtle’s movements will help better predict when fishing should be prohibited.
A number of young turtles have also been tracked in the Atlantic ocean. Another challenge to tracking the young turtles has been that their shells aren’t a reliable spot to stick sensors, because the fast growing shells slough them off. Last year, Dr. Kate Mansfield published some surprising findings after figuring out that using an acrylic base coat is the best way to attach something to the turtle’s keratin shell—much like attaching a fake nail. Mansfield learned that the young turtles spend time in the calm waters of the Sargasso Sea, when it was previously believed that they followed the currents of the North Atlantic Gyre all the way to the Canary Islands.
Hopefully Coco will help us better understand how turtles travel around the Pacific. We can all follow the turtle’s journey, which so far has covered over 435 miles, on this map.