When the Hunter Became the Hunted

In waters off Mexico’s Guadalupe Island, Woods Hole Oceanographic Institution (WHOI) engineers deployed the REMUS SharkCam, a torpedo-shaped robotic vehicle with a special system to track and film great white sharks in the ocean.

“We wanted to test the technology to prove that it was a viable tool for observing marine animals and to collect substantial data about the animals’ behavior and habitat,” said WHOI engineer Amy Kukulya.

The team got the footage it was hoping for—and then some. A number of sharks attacked the SharkCam, leaving behind impressive teeth marks and providing the first close-up observations of predatory behavior below the surface.

SharkCam showed that sharks take advantage of the visibility in Guadalupe’s clear waters. The sharks hide in the darkness of deeper waters as they stalk their prey. Seals are silhouetted near the surface by sunlight from above, offering highly visible targets. The sharks attack from below with bites to the seals’ fins or midsections, then wait for the prey to bleed out. (REMUS, in this case, had no blood to shed!)

The team returned to Guadalupe in 2015 with two vehicles, including a deeper-diving REMUS equipped with lights, and recorded previously undocumented shark sleeping, territorial, gliding, and nighttime behaviors. The technology has now been adapted to study other marine animals, including endangered sea turtles.  

The research was published December 2015 in the Journal of Fish Biology, with lead author Greg Skomal (Massachusetts Division of Marine Fisheries) and co-authors Amy Kukulya, E.M. Hoyos-Padilla (Pelagios-Kakunjá) and WHOI engineer Roger Stokey. The Discovery Channel funded the research.