Acoustic sensors developed at Woods Hole Oceanographic Institution (WHOI) and Clark's group at Cornell University can pick up these sounds. Researchers helped place buoys in shipping channels off the coast of New England last year to do just that. The connected underwater acoustic system is designed to detect a common call of the right whale, which is known to traffic these waters.
"There's a brain on the buoy," says Cornell's Clark, who helped conceive the project. He explains how the buoy system automatically sends each suspected whale call to his lab, where it can be scrutinized by human brains. If they decide it's a right whale, a phone call is then made to any approaching ships instructing them to take the proper measures—which almost always means to slow down. (Clark's team is currently working with the U.S. Coast Guard and the National Oceanic & Atmospheric Administration to make this process more sophisticated—alerting mariners on their computerized navigational maps with a blinking buoy.)
More recently, researchers from Analysis, Design & Diagnostics, Inc., of Jacksonville, Fla., joined the mission. Their aim is to expand the range of whale call frequencies that can be identified, allowing them to locate, and potentially save, more species of marine mammals. Two ships currently cruise Florida's Gulf Coast with processing systems that are linked to a hydrophone lying on the ocean floor. More sensors could be deployed from small boats, even dropped out of airplanes.
Last week, company president Gary Donoher submitted a proposal to the U.S. Navy, which is seeking help from an organization to do marine mammal monitoring at ranges throughout the world. In two or three years, he hopes his sensors will be working in real-time, 24/7.
"We are using the sound they make to help protect them," Donoher says, noting the difficulty of sorting out whale calls from the ocean's "cacophony of noise" as well as the problem of detecting whales when they aren't vocalizing. He points out a similar problem for heat sensing, because many species of whales can stay submerged for long periods of time.
Most experts agree that no single approach can do the entire job of keeping a lookout for whales. Donoher advocates combining "complementary technologies" to look, listen and feel for them. "Whether navy or commercial, if you are trying to protect marine mammals, you need multisensor capability," he says. "That is the ideal."