WOODS HOLE -- At a dissection table, a marine biologist is taking the first steps toward building a remote-control shark.
Funded by the US Department of Defense, Jelle Atema wants to understand a shark's brain well enough to take it over -- to get it to obey commands to smell and sense what's going on in the water around it.
''I want to sit here in my office, call up Charlie Shark out in Hawaii, and say, 'Go follow that wake,' " said Atema, who splits his time between Boston University and the Marine Biological Laboratory in Woods Hole. Ultimately, he said, a shark could help the military by surveying hard-to-reach areas for dangerous chemicals or other hazards.
The shark is ideally suited for this research, he said, in part because it has a strikingly large nose.
''I'm totally in awe," said Atema, walking away from the dissection bench. ''I can't believe how big it is. It's five times bigger than an eel's nose."
Sharks can detect extremely subtle odor cues, weak magnetic fields, and probably minuscule fluctuations in water pressure, such as the turbulence left in a fish's wake, said Atema, who has spent his career studying how lobsters smell.
Now he just has to figure out how to harness those skills -- an idea that is not as far-fetched as it may seem.
Neuroscientists have already succeeded in gaining radio-control over a rat. Two years ago, at the State University of New York Downstate Medical Center in Brooklyn, a researcher with a laptop was able to direct a rat that normally liked to hide in a corner through a three-dimensional maze. The ''ratbot," also partially funded by the US military, could eventually be used to find victims in a collapsed building and smell out explosives, according to John K. Chapin, who published that finding and still heads up the rat research.
The rat is ''steered" with electrodes in its brain, which tickle whiskers on each side to get it to turn where the scientist wants it to go. When the rat goes in the desired direction, it is rewarded by an electrical stimulation in a part of the brain that produces a feeling of euphoria.
Atema's approach is different. He is trying to direct the shark by directly controlling its senses, rather than offering it a reward for doing the ''right" thing. The Defense Department's Advanced Research Projects Agency, known as DARPA, recently awarded Atema $600,000 for the first year of a four-year research grant to pursue the project.
The shark research is a natural sequel to both the rat study and work Atema and his team did to create a mechanical lobster and make it follow an odor. In the shark project, he said via e-mail, the ''real problem has been shifted from building the robot which is difficult but more easily controlled, to using a [live] shark which does not need to be built, but has to be controlled. The latter requires fundamental understanding of the way brains work."
Not much is known about how sharks are so sensitive to smells and turbulence, so Atema is starting slowly, first dissecting the brains of blue sharks to get a better sense of how they are wired to smell and ''feel" the water around them.
Once he understands the nerve paths that transmit sensory signals to the brain, Atema said he will try to direct a live shark by spraying an appealing smell, and mapping its brain as it senses the odor and turns toward it.
Step three will be to use that map to steer the shark from within its own brain -- without the need for an external smell, or a reward.
Because he can't possibly mimic all the electrical signals in a shark's brain, Atema said the trick will be to find the simplest possible pattern of electrical signals to catch the shark's attention and redirect it. An engineer is working with the marine biologists to figure out how to transmit those commands, possibly via a backpack strapped on to the shark as it swims ceaselessly through the open ocean. (A shark's ability to swim nonstop is also an asset to the project, because its handlers won't have to give it time to take naps.)
Atema said he and his colleagues expect their research will be controversial.
''The first thing we did was discuss the ethics of this approach, and we agreed that what we want to do is probably OK," he said in an interview.
There are some who will worry that, once researchers gain control over sharks, they will move on to humans. But Atema said he doesn't believe ''anyone is even remotely thinking that way. That's what we have a society for, to prevent these excesses."
He prefers another comparison.
''We have used dogs for thousands of years around the world to help us smell, pigeons to carry messages, etc.," he said.
''To me, it's not that different" to direct a shark by remote control.