Tracking leatherback sea turtle migration along the U.S. coast

Leatherback sea turtle behaviors in the Northwest Atlantic shelf have been illuminated through a pivotal study conducted by marine scientists at the University of Miami Rosenstiel School of Marine, Atmospheric and Earth Science and the National Oceanic and Atmospheric Administration Southeast Fisheries Science Center.

The research provides a detailed map of the migration and foraging habits of these majestic creatures along the U.S. coastline. The findings introduce new insights that challenge previous understandings and emphasize the urgent need for targeted conservation efforts.

A new understanding of leatherback movements

Historically, researchers recognized that leatherback turtles migrate from the warmer South and Mid-Atlantic Bights to the food-rich waters near New England and Nova Scotia during the summer. They return south as winter approaches. However, the specifics of their journey and activities remained largely unknown.

Mitchell Rider is a research scientist at Rosenstiel School’s NOAA Cooperative Institute for Marine and Atmospheric Studies and lead author of the study.

“Our findings signify a paradigm shift in understanding leatherback turtle behavior along the U.S. coastline,” said Rider. “By highlighting key foraging grounds and migration patterns, we aim to inform targeted conservation strategies to safeguard the future of these magnificent creatures.”

The journey of the leatherback turtle revealed

Using advanced satellite tags, the researchers tracked the movements of 52 leatherback sea turtles from 2017 to 2022. These tags, attached to turtles off the coasts of Cape Cod, Massachusetts, and Beaufort, North Carolina, provided valuable data on location, depth, and water temperature.

The tagging and monitoring effort unveiled significant activity off Cape Cod and Nantucket. Here, leatherbacks feast on the abundant jellyfish present in late summer and early fall. Similarly, signs of feeding behavior in the Mid-Atlantic Bight mark it as a crucial foraging area. However, further research is needed to pinpoint the turtles’ exact diet.

Researchers have identified the South Atlantic Bight as a versatile habitat. It supports various stages of the leatherback’s migration cycle, including nesting and overwintering. Observations of feeding behavior along the continental shelf ridge further highlight this area’s significance.

Consequently, this research reveals an extensive utilization of the U.S. coastline by leatherbacks. This is particularly true within the Mid-Atlantic Bight, South Atlantic Bight, and Southern New England regions.

Implications for leatherback turtle conservation

“A key finding was further defining the Mid-Atlantic Bight as a critical foraging ground for leatherbacks from past studies, identified through sophisticated behavioral analysis,” said Rider.

“This study provides a comprehensive understanding of leatherback behaviors that distinguishes between their migration and foraging activities.”

Moreover, the research underlines the leatherbacks’ vulnerability to threats such as incidental capture by fisheries and vessel strikes. With offshore wind farms developing in critical regions, these findings provide invaluable guidance.

The groundbreaking study advances our knowledge of leatherback sea turtles’ migration and foraging patterns, shaping future conservation strategies. Furthermore, the study paves the way for more effective protection of critical habitats such as nesting beaches.

Conservation efforts are underway globally to protect these ancient mariners, including the implementation of fishing gear modifications to reduce bycatch.

More about leatherback sea turtles

Leatherback sea turtles are remarkable creatures, distinguished from other sea turtles by their lack of a bony shell. Instead, they possess a unique, leathery skin overlaying bony plates, which gives them their name. They are the largest of all living turtles and can grow up to two meters in length and weigh as much as 900 kilograms. 

Migration 

These turtles are highly migratory, undertaking vast journeys across oceans to feed on their preferred prey, jellyfish. Their ability to regulate their body temperature allows them to thrive in colder waters, a rarity among reptiles. 

Special adaptation 

Leatherbacks have a special adaptation in their throat, a series of backward-pointing spines, to help them swallow slippery jellyfish and prevent their prey from escaping once caught.

Reproduction 

Reproduction is a fascinating aspect of their life cycle. Females return to the beaches where they were born, every two to three years, to lay their eggs in the sand. 

They dig nests with their flippers, deposit their eggs, and then cover them before returning to the sea. The hatchlings emerge after about two months and make their perilous journey to the ocean, facing numerous predators along the way.

Significant threats 

Despite their awe-inspiring nature, leatherback sea turtles face significant threats from human activities. They are vulnerable to bycatch in fishing gear, plastic pollution, and the harvesting of their eggs from nesting beaches. Climate change also poses a threat, as it affects their nesting sites and the availability of their jellyfish prey. 

The study is published in the journal Frontiers in Marine Science.

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