Leatherback sea turtles: Where the world's largest turtles go to eat

Leatherback sea turtles, renowned for their vast migrations from subtropical and tropical nesting sites to temperate foraging zones, have been the focus of decades of tracking efforts. Despite this, the northwest Atlantic Ocean remains a largely uncharted area in terms of their migratory paths and foraging grounds. 

Tracking leatherback foraging behavior 

A team of researchers led by the University of Miami, employing advanced tracking technology, embarked on a mission to delineate these routes along the US east coast.

Lead author Mitchell Rider, a postdoctoral researcher at the University of Miami, explained the use of movement behavior models to discern leatherbacks’ foraging behaviors. 

“Using movement behavior models, we show that leatherbacks migrating along the east coast of the US display inferred foraging behavior in specific areas in the South Atlantic Bight (SAB), which is the coastal area stretching from North Carolina to the upper Florida Keys; the Mid-Atlantic Bight (MAB), which is the coastal region running from Massachusetts to North Carolina; and southern New England (SNE).” 

According to the experts, the finding that the MAB might serve as a critical foraging ground is particularly noteworthy.

How the research was conducted

To track these majestic creatures, satellite transmitters were affixed to leatherback sea turtles in two locales: off Massachusetts during summer and off North Carolina in spring. This strategy allowed the researchers to trace secondary foraging and over-wintering areas and to assess the turtles’ diving and movement behavior along their migratory routes. 

From 2017 to 2022, 52 leatherbacks were meticulously tracked, uncovering their usage of the MAB, SAB, and SNE not only as migratory corridors but also as foraging grounds. 

Critical new insights 

“The high use of the MAB by both groups of leatherbacks is the most important finding of our study. High use was mostly characterized by inferred foraging behavior,” said Rider. “To date, several studies have tracked leatherbacks into this region, but we are the first to take that a step further and characterize the behaviors associated with their movement patterns.”

This knowledge has profound implications for both future research and the conservation of these endangered turtles, particularly as they face threats from incidental capture and vessel strikes. 

Broader implications 

The identification of foraging hotspots in the MAB and SAB could guide targeted conservation efforts and inform mitigation strategies for upcoming offshore wind farm developments. 

Rider’s call for more direct observation methods, such as animal-borne video surveillance, underscores the need for innovative research approaches to further unravel the mysteries of leatherback sea turtle migration and foraging behavior.

Leatherback sea turtles 

Leatherback sea turtles, known scientifically as Dermochelys coriacea, are the largest of all living turtles. Unlike other sea turtles, leatherbacks possess a unique, leathery shell instead of a hard, bony one. This distinctive shell is composed of skin and oily flesh. 

Leatherbacks are true giants of the ocean, with some individuals reaching lengths of up to 2 meters (about 6.5 feet) and weights exceeding 900 kilograms (nearly 2000 pounds).

Lifestyle

These turtles are highly migratory, traversing vast distances across the world’s oceans. They are found in the Atlantic, Pacific, and Indian Oceans, demonstrating a wide thermal tolerance that allows them to thrive in waters ranging from cold temperate to tropical. 

Diet

Their diet primarily consists of jellyfish, which they consume in large quantities, helping to control jellyfish populations.

Leatherback turtles play a crucial role in marine ecosystems. Their feeding habits influence the distribution and lifecycle of jellyfish and other marine creatures, and their nesting activities contribute to the health of beach ecosystems.

Threats

Despite their significance, leatherback sea turtles face numerous threats. These include habitat loss due to coastal development, accidental capture in fishing gear, pollution, and climate change. Their nesting sites are particularly vulnerable to human activities and natural predators, which can significantly impact hatchling survival rates.

Conservation 

Conservation efforts are underway globally to protect these ancient mariners. Measures include protecting nesting beaches, regulating fisheries to reduce bycatch, and conducting research to better understand their behavior and migration patterns. 

The survival of leatherback sea turtles is crucial for maintaining the balance of marine ecosystems, and concerted global conservation efforts are essential to ensure their future.

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

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