In the video, the large sea turtle looks like Pac-Man swallowing little white ghosts as it swims through the murky green waters and devours the unfortunate jellyfish in its path.
Chomp. Chomp. Chomp.
One by one, the gelatinous blobs disappear, as viewers get a turtle’s-eye view of a leatherback turtle’s dinner.
The feeding is one of Amy Kukulya’s favorite parts of the extensive footage of the turtles that she and a team of researchers from the Woods Hole Oceanographic Institution captured recently while studying the endangered animals off Cape Cod.
“It’s really cool,” Kukulya, an engineer with the institution, said of the video. “In one sequence it’s like bam, bam, bam, bam.”
She thinks the turtle may have eaten 10 jellyfish in about a minute.
From September through October, Kukulya and Kara Dodge, a postdoctoral research scientist, led a group that used special equipment to track and follow the turtles. Researchers want to better understand their movements, feeding habits, and how often they come up to breathe as the animal’s traverse highly trafficked fishing areas.
Kukulya said the crew tagged the turtles with a transponder that contains two cameras — one in front, and one in back. Then, using the “REMUS TurtleCam,” a torpedo-shaped autonomous underwater vehicle that swims nearby, they followed the turtles as they searched for food.
The system works like a game of “Marco Polo,” according to Kukulya. The underwater robot sends out a ping, and the transponder on the turtle replies. Then the robot goes chasing after the animal.
The “TurtleCam” has seven cameras onboard, giving researchers three-dimensional views of the turtles. The cameras inside the transponder, which is attached with a suction cup to a turtle’s shell, provide the turtle’s-eye-view.
The project was paid for through funds from donors, and a sizeable grant to WHOI and the Massachusetts Division of Marine Fisheries from the National Oceanic and Atmospheric Administration.
The “TurtleCam” is the same autonomous underwater vehicle that was used to document never-before-seen activity of great white sharks in Cape Cod and Mexico. The so-called “SharkCam” was made famous during “Shark Week,” which airs on the Discovery Channel, in 2014.
Kukulya said to turn the “SharkCam” into the “TurtleCam,” and get it to work efficiently, the device required some tweaks. Because leatherbacks have a swimming trajectory that’s different from a great white’s — the turtles tend to zig and zag, and come up for air — it required an entirely new algorithm so it could keep up with the docile creatures.
Researchers also had to modify the tag that’s attached to a turtle’s shell. On sharks, experts use an intramuscular dart to affix a tracking device to the predators. For turtles, the suction cup method is used instead.
Kukulya said WHOI has a “clever release device” that floods the suction cup with water when they’re finished recording. The release causes the transponder to detach. It then floats to the surface, and experts can recover it, along with the video footage.
“We had no idea how well it would work — whether the tag would stay on, or whether the turtle would be spooked, or if they didn’t like having a vehicle nearby,” she said. “Fortunately, the vehicle is smart and nimble enough to stand off far enough not to interfere” with the turtles’ natural instincts.
The “TurtleCam” still needs some adjustments. But after the team’s first successful mission in September, and the taggings that followed, Kukulya and researchers plan to conduct five similar trips next summer.
“It’s amazing to see the blood, sweat, and tears of this effort come together,” she said. “We can definitely make positive changes with this information.”