Scientists track the world’s largest turtles to previously unknown feeding grounds

Leatherback turtles, the largest of all living turtles, undertake vast migrations that can span several years. They travel from subtropical and tropical nesting grounds to temperate feeding areas. Despite decade-long monitoring efforts, there are still areas, notably the northwest Atlantic Ocean, where little is known in terms of turtle migration routes and feeding grounds.

Using new and more sophisticated tracking technology, a team of US researchers set out to identify migratory corridors and potential foraging areas used by leatherback turtles along the US east coast . The results were published in Frontiers of marine science.

“Using models of movement behavior, we show that leatherback turtles migrating along the eastern seaboard of the United States exhibit inferred foraging behavior in specific areas of the South Atlantic Bight (SAB) , which is the coastal area extending from North Carolina to the upper Florida Keys; the Mid-Atlantic Bight (MAB), which is the coastal region extending from Massachusetts to North Carolina, and southern New England (SNE),” said Dr. Mitchell Rider, a postdoctoral researcher at the University of Miami. “It appears that MAB could be an important feeding area for leatherback turtles.”

New feeding grounds discovered

To track the turtles, researchers attached satellite transmitters to two groups of leatherback turtles. The first group was identified off the coast of Massachusetts over the summer, the second off the coast of North Carolina in the spring.

Off the coast of Massachusetts is a known feeding area from which leatherback turtles migrate north after feeding. Tracking them from there allowed researchers to identify secondary feeding and wintering areas along the continental shelf. Tracking turtles captured off North Carolina allowed them to assess their diving and movement behavior along migratory routes and identify subsequent feeding areas. Between 2017 and 2022, 52 leatherback turtles were successfully tracked for between 15 and 302 days.

The researchers’ results suggest that in addition to known foraging areas in the SNE and Nova Scotia, leatherback turtles use the SNE, MAB and SAB regions both as migratory corridors and for foraging. “The high use of MAB by both groups of leatherback turtles is the most important finding of our study. High use was primarily characterized by inferred foraging behavior,” Rider said. “To date, several studies have tracked leatherback turtles in this region, but we are the first to go further and characterize the behaviors associated with their movement patterns.”

Knowledge for conservation

New insights into the foraging areas and movement ecology of leatherback turtles along the northwest Atlantic shelf will likely open new doors for future work on leatherback turtles in the MAB and SAB, he said. indicated the researchers. “Now that we understand the major hotspots where foraging occurs, we need to focus our attention on these specific areas by implementing methods that allow for direct observations,” Rider explained. “For this, we need to implement more styles of in situ research, such as animal video surveillance.”

Despite their now deeper understanding of leatherback turtle movements and diets, more work remains to be done, the researchers said. This includes studying leatherback turtles in the SAB, as this area appears to be used by turtles for wintering, nesting in the spring, and foraging during the summer.

Their findings are also important for the conservation of endangered species, the researchers said. Leatherback turtles are prone to accidental capture and collisions with fishing boats. The new findings could be used to highlight key areas for conservation and help prevent these accidents. Additionally, MAB and southern New England are expected to see a large number of offshore wind farms developed, and conservationists could use this knowledge to help mitigate impacts on endangered turtles.