TurtleSense helps scientists predict hatching of sea turtles

The research was led by Erin Clabough of the University of Virginia and Samuel Wantman of Nerds Without Borders and their results have been published in PLOS ONE.

Sea turtle populations worldwide are in decline due to human activities, with Loggerhead, Green, Hawksbill, Kemp’s Ridley, Leatherback and Olive Ridley sea turtles listed as threatened species.

Conservation efforts largely focus on protecting hatchlings once they emerge, ensuring they head out to sea instead of toward the bright lights of towns.

Conservationists can count the days since eggs were laid to predict when they will hatch and then watch the nest, but these efforts are inaccurate and labour-intensive.

In the current study, researchers used the TurtleSense system to monitor loggerhead sea turtle nests on Cape Hatteras National Seashore, North Carolina, to see if they could predict more accurately when the turtles would emerge from the nest.

According to the team’s paper, TurtleSense’s main components are the sensor placed in the nest, and an external communication tower adjacent to it.

Sensor circuitry includes an accelerometer, temperature sensor, and microprocessor on a small circuit board. The accelerometer records any changes in motion detected within or around the nest, and the temperature sensor records the temperature fluctuations inside the nest.

The circuit board is sealed inside a polyurethane sphere designed to keep moisture out and resemble the size, shape, and coloration of a sea turtle egg. The sensor egg is attached to a 6m cable ending with a connector that plugs into a communication unit that remotely transmits data on the movement of hatchlings within the nest.

With the sensor egg in place, the researchers identified a pattern of intense hatchling movement within the nest, followed by a pause, which let them predict almost the exact day when the young turtles would dig out of the sand. Their results suggest that hatchlings can detect motion, which allows them to communicate and head out together as a group. The system also accurately identified non-viable nests where monitoring was no longer necessary.

According to the team, TurtleSense could reduce the cost and labour required to monitor endangered turtle nests and to help conservationists make better decisions about nest management. The system can also shorten beach closures and enable communities to engage in turtle-based ecotourism. While this study focused on Loggerhead turtles, the researchers also monitored Olive Ridley and Green Turtle nests and saw similar patterns, suggesting that the system will work for a range of sea turtle species.

"It’s absolutely magical to witness baby turtles poke their heads out of the sand and sprint towards the ocean, but it’s an event that can be very hard to predict,” Clabough said in a statement. “The TurtleSense system is a low-cost, creative solution that remotely allows us to detect how baby turtles synchronise developmental movement within the nest in real time. We can use the system to detect hatching and to better predict when the hatchlings will emerge onto the beach."