Underwater robot tracks sharks on the more
RESEARCH | Scientists at the University are using an underwater robot to find and follow sand tiger sharks and better understand their behavior and migration patterns in real time.
The innovative project, part of a multi-year partnership with Delaware State University, uses the robot to track sharks that the researchers previously tagged with transmitters.
Early in the project, “Our new, specially equipped glider OTIS—which stands for Oceanographic Telemetry Identification Sensor—detected multiple sand tiger sharks off the coast of Maryland that were tagged over the past several years,” says Matthew Oliver, assistant professor of oceanography. “This is the first time that a glider has found tagged sharks and reported their location in real time.”
OTIS is a remote-controlled device that looks like a yellow torpedo and normally darts through the ocean to sample water conditions. Oliver outfitted the apparatus with acoustic receivers that can recognize signals given off by the sharks’ transmitters as they travel through coastal waters, rapidly reporting the encounters.
The technology allows the course of OTIS to be changed to follow the sharks and test the water surrounding them. The approach will help scientists follow where the sharks are going more quickly than conventional tracking techniques.
Sand tigers are the largest commonly occurring shark in Delaware’s bay and coastal waters, serving as Delaware Bay’s apex predator and playing a key role in the ecological balance of the region.
“Sand tigers have suffered from a number of threats that ultimately led to population declines,” Delaware State’s Dewayne Fox says. “In 1997 sand tigers were listed as a ‘species of concern’ by the National Marine Fisheries Service, although very little is known of their migrations and habitat requirements.”
Together with their students, Oliver and Fox spent last summer inserting the transmitters into sand tiger sharks in Delaware Bay. Using bait, hooks and a little patience, they caught the sharks—up to 9 feet long—and carefully pulled them into a stretcher alongside their boat. Veterinarians from the Georgia Aquarium trained Oliver’s doctoral student, Danielle Haulsee, to insert the small transmitters in a quick surgery.
Scientists suspect that the sharks migrate widely along the Eastern Seaboard, and the Delaware research team plans to use newly collected information to map sand tiger shark habitats. They will cross-reference the sharks’ data with satellite and remotely sensed environmental conditions to create a comprehensive picture of the animals’ habitats.
In January, the ABC series Ocean Mysteries with Jeff Corwin aired an episode about the Delaware research, “Eye of the Sand Tiger.” The episode, which was filmed on location on Delaware Bay as Haulsee and her colleagues caught sand tigers and tracked their migrations, was shown on network affiliates nationwide.
“It was really cool to be working with Jeff because he was someone I grew up watching on TV,” Haulsee says. “He could even have been one of the reasons why I fell in love with the environment.”
Article by Teresa Messmore