When endangered sea turtles lay and bury their eggs on a beach, the beach is usually closed to the public until those eggs hatch. To help predict when these beaches may reopen, a nest-monitoring sensor that looks like an egg has been created.
The device is part of the TurtleSense system, developed by a team led by Dr. Erin Clabough of the University of Virginia and Samuel Wantman of the open research group Nerds Without Borders. It was tested at 74 loggerhead turtle nests on the Cape Hatteras National Seashore in North Carolina during the 2013-2017 nesting season.
The sensor unit itself includes a motion-sensing accelerometer, a temperature sensor, and a microprocessor, all contained within a waterproof polyurethane sphere the same size, shape and color as a turtle egg. It is connected by a 6-meter wire to a communication unit - the latter in the form of a sealed PVC pipe tower containing a microprocessor, battery and a cell phone module.
When conservation workers first notice a sign of a new egg laying, they carefully dig up the top layer of eggs, gently remove them, leave the sensor in place, then replace the egg and put it back on. Fill in the eggs. A communication device, located on the top of the sand next to the nest, wirelessly relays data from buried sensors.
In field studies, sensor data suggest that there is typically a period of time when hatchlings move intensively in the nest, followed by a pause, before the hatchlings all dig out of the nest and head to the surface. This pattern suggests that hatchlings are able to sense each other's movements, allowing them to wait, then emerge as a group and reduce the chance of any one of them being killed by a predator.
"As each turtle emerges, it climbs up to the top of the egg with its siblings, creating a commotion among all the other baby turtles in the nest. When there is no more commotion, there will be A quiet period of time may be the motivation for all the hatchlings to boil out of the nest together," explains Wantman.
Importantly, once the initial wave of agitation is detected, it is possible to predict how long the quiet period will last and thus almost predict the exact date when the larvae will appear. TurtleSense has also been shown to accurately identify nonviable nests that no longer have to be monitored or waited for.
"It's absolutely magical to see baby turtles stick their heads out of the sand and sprint into the ocean, but it's an unpredictable event," Clabough said. "The TurtleSense system is a low-cost, innovative A solution that remotely allows us to detect in real time how baby turtles synchronize their developmental movements within the nest. We can use this system to detect hatching and better predict when hatchlings will appear on the beach.”
