Thanks to a team of researchers and Nature Conservancy staff, four female green sea turtles—named Savannah, Samantha, Dionne and Victoria—are now being tracked with satellite transmitters as they swim between foraging, mating and nesting areas.
The team hopes to gather valuable data that will help tell them where and how to better protect the turtles during the estimated 90% of their lives that they spend in the water.
How to Tag a Turtle
How do you attach a satellite tag to a 400-pound sea turtle that has come ashore to nest? Very carefully!
Emma Schultz, a Masters student in Marine Sciences at Savannah State University, led the team that set out to tag green sea turtles at the Conservancy’s Jack and Isaac Bay Preserve on St. Croix in the U.S. Virgin Islands. After they spotted a nesting turtle, often after hours of patrolling, they guided it into a wooden corral to keep the turtle from escaping, damaging the tag or injuring itself. About an hour of careful work was required to attach the tag to the shell, known as the carapace, of each turtle to allow the epoxy adhesive to dry. The turtles were then free to return to sea, where researchers can track their movements.
Green sea turtles can travel thousands of miles in their lifetimes, but it is largely unknown where they migrate to forage and how they spend their early years. This makes it difficult to keep track of a specific population, to study their behavior, or to know how best to protect them while they are in the water.
In 1994, when the Conservancy started monitoring nesting sea turtles at its Jack and Isaac Bay Preserve, there were only about eight green sea turtles nesting at the site. The Conservancy’s Sea Turtle Conservation Program at the preserve includes beach patrols to prevent poaching and to help rescue and release turtle hatchlings as well as data collection to monitor population growth. The green sea turtle population now numbers over 300 nesting individuals and scientists credit much of this recovery to the removal of threats like poaching and coastal development.
However, since sea turtles spend so much of their lives at sea, protecting them on land isn’t enough. That’s why Kemit-Amon Lewis, a Conservation Manager at the Conservancy, contacted his former graduate advisor, Dr. Dionne Hoskins of Savannah State University, to see if she was interested in using satellites to track the turtles that nest at the 300-acre Jack and Isaac Bay Preserve. Hoskins and Shultz launched the project with the support of the National Oceanic and Atmospheric Administration, the U.S. Virgin Islands Division of Fish and Wildlife and the Conservancy.
Endangered Green Sea Turtles
Green sea turtles are listed on the IUCN Red List and are federally and locally protected under the U.S. Endangered Species Act and the U.S. Virgin Islands Endangered and Indigenous Species Act, respectively. Green sea turtle populations have declined due to turtles becoming entangled in fishing gear, eating trash that they mistake for food, falling victim to poaching and hunting, and losing nesting habitat to coastal development. By tracking sea turtles and identifying where their populations come into contact with threats we can help protect them.
In addition to migratory data from satellite tagging, Schultz is studying the genetics of the Caribbean green sea turtle population at Jack and Isaac Bay Preserve. This will help reveal how closely related the population there is to other populations around the world. If the population at Jack and Isaac Bay Preserve is genetically unique, it will be especially important to conserve them in order to maintain genetic variability.
Genetic variability helps ensure the survival of the species, as it allows a species to continue to evolve in response to environmental pressures and changes. Protecting the nesting population of green sea turtles on this St. Croix preserve could help improve the chance of survival for the green sea turtle populations across the wider Caribbean.