Skomal spends most of his time studying great white sharks off the coast of Cape Cod, Massachusetts, U.S., where he is based. For all their infamy, not much is known about the movement ecology of this type of shark. Due to the resurgence of pinniped (or seal, sea lion and walrus) populations on the East Coast of the U.S., white sharks are often clustered around swimming areas, which Skomal refers to as "little green dots" from the way he marks sharks on his distribution charts.

"The more we know about the daily behavioral patterns of sharks around the area, the better equipped we will be to advise beach managers on how to keep people safe," he explained.

Most of what researchers do know about sharks comes from predation events when the fish breaches in pursuit of food or a shark is fished or beaches itself on land. This is a narrow window into the daily life of sharks, as they spend up to 60 percent of their time deep below the surface.

To learn more about shark behavior when the organisms are out of sight, Skomal and his team use acoustic tags and—more recently—autonomous underwater vehicles (AUVs) to get a peek at where the mysterious fish travel.

Dr. Greg Skomal, a shark biologist and recreational fisheries program manager, talked about how little is known about sharks during his recent 2018 Enrichment in the Fall keynote lecture. Image courtesy of Shutterstock.

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Skomal is somewhat of an expert at tagging sharks, working with a spotter pilot in the sky to identify sharks in the water. He prefers to tag them in the water in order to keep the sharks and beachgoers safe. Acoustic tags, which are placed just below the dorsal fin of the shark, give researchers insight into local movement patterns, but AUVs are able to track the three-dimensional movements of sharks and environmental parameters and capture video footage.

Skomal and his team partnered with the Woods Hole Oceanographic Institution and the Discovery Channel to adapt AUVs to shark research, producing the REMUS SharkCam. The operation was deployed in the waters around Guadalupe Island off the coast of Mexico. Skomal's local research partner Mauricio Hoyos had a hypothesis about why sharks rarely breach the water around Guadalupe Island—the shark was staying deep and striking prey from below.

Shark biologist Dr. Greg Skomal noted that 49 percent of shark species are 'data deficient' during his 2018 Enrichment in the Fall keynote lecture on campus. File photo.

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When the team retrieved the AUV, they found scratches and markings on the vehicle as well as video footage to confirm how the damage was sustained.

"This was a classic predatory strike and something we usually see at the surface. Based on the movements we plotted, we were able to establish a predatory strike zone," Skomal explained. "We got some great information, including the first shots of white sharks sub-surface. We're definitely moving in the right direction."

Next, Skomal and his team are deploying an even bigger AUV with more depth capacity.

"I think it's time to go back to whale sharks. Whale sharks are a well-studied population with a great foundation of research, so it is the perfect species to take to the next level in terms of technology," Skomal concluded.