For scientists at Stanford's Hopkins Marine Station near Monterey, shadowing great white sharks typically involves both looking and listening. Real-time maps plot the predators' movements, tracked by high-tech eves dropping equipment tuned to the sound of their tags.
"The tags we use are acoustic," says spokesperson Randy Kochevar. "It's a little plastic encased tag that gives off a chirp or ping."
For years, the listening posts have been mainly on boats or buoys. But now, instead of waiting for the sharks to come to them, the team, led by renowned ocean researcher Barbara Block, is perfecting a system to more efficiently go to the sharks.
To do that, they're employing vessels called wave gliders. They are self-propelled drones, powered by the movement of ocean swells. On-board communication equipment allows them to be controlled from a laptop computer almost anywhere in the world.
The Wave Gliders are manufactured in Sunnyvale by a company called Liquid Robotics. Founder Roger Hine says solar panels built onto the deck can power an expanding array of scientific instruments. At the same time the propulsion system, which trails under the water line, made the wave-glider virtually unsinkable during a recent 9,000 mile test voyage to Australia.
"At one point it ran into the biggest storm a Wave Glider has ever been in," says Hine. "This is a category 4 tropical cyclone, so 10-meter wave height and astronomical winds."
Researchers now believe advanced monitoring equipment will allow the Wave Glider to explore the ocean in ways never before possible. From tracking hurricanes at wave-top level, to unlocking the secret world of ocean going creatures, like great whites.
"So when we detect an animal, we might get info about physical environment, water temperature," says Kochevar. "We've talked about putting DNA samplers on there. So we're trying to use these not only to better understand the big predators, but the environment that surrounds them."
Liquid robotics has also just received news about that voyage to Australia. The Wave Glider is being honored with a Guinness world record, for the longest journey of an unmanned autonomous surface vehicle.
Written and produced by Tim Didion