Adult leatherback turtle. Credit: NOAA.

Scientists have identified locations likely used by leatherback turtles for feeding during their migration between nesting beaches in the Caribbean and food-rich waters off New England and Nova Scotia. Establishing where the turtles feed will help improve conservation measures for this endangered species already contending with many threats from human activities in the region, including unintended capture in fishing gear, loss of nesting habitat, and vessel strikes.

The NOAA-funded researchers used satellite transmitter data from 52 leatherbacks tagged between 2017 and 2022 off the coasts of Massachusetts and North Carolina to track turtle movements. The team then used a statistical model to analyze these movements, which included turtle diving, to estimate where “area restricted searching” occurred, a behavior thought to be associated with foraging.

Study results suggest that leatherback turtles feed along Nantucket Shoals, as expected, during the late summer and early autumn, but also suggest that key foraging areas exist in the middle and south Atlantic coastal zones, as well. In the mid-Atlantic, foraging behavior was concentrated between Cape Hatteras, North Carolina, and the mouth of Delaware Bay during the summer. In the south Atlantic, foraging behavior took place over a large area along the coastline and the edge of the continental shelf during every season. The findings provide evidence that both the mid- and south Atlantic bights may be significant foraging grounds for leatherback turtles.

Data from the study can serve as a baseline for comparison with turtle behaviors in the future under different environmental conditions, such as climate change and the construction of offshore wind farms. Conservation managers can use the findings to inform their strategies to mitigate these and other potential threats to leatherbacks.

The project is part of a NOAA effort to evaluate how highly migratory and protected species are using a network of state and federal marine protected areas in the Gulf of Maine and off southern New England and how this overlaps with areas of human use. Understanding the benefits of existing protected areas to species at risk will inform recommendations for potential new or expanded protected areas and ensure their viability for future generations. The NCCOS Competitive Research Program partially funded the Massachusetts portion of the research.