Twenty-two miles south of New York’s Fire Island, in an ocean region jam-packed with shipping traffic, there’s a bobbing yellow-and-blue buoy that’s actually a robot spy. It’s using advanced acoustic equipment to eavesdrop on whales gliding below the waves. By conducting reconnaissance on the cetaceans, it will help keep them alive.
People onboard a ship that hits a whale may never realize what happened—but the animal can’t ignore the incident so easily.
“If a whale is struck by a large ship going over 10 knots, it’s likely going to be a lethal encounter,” says Mark Baumgartner, a marine ecologist at the Woods Hole Oceanographic Institute.
Up to a third of whales found dead in certain areas show evidence of a boat or ship strike, according to the group Whale and Dolphin Conservation. For an endangered species, those losses can be especially hard to take. But if people know which whale species are swimming in which areas, and when, they can slow down their boats or pause their machines until the animals are out of danger.
The robotic buoy in New York, a joint project between WHOI and the Wildlife Conservation Society’s New York Aquarium, sits in a body of water called the New York Bight. Whales here are at especially high risk of being hit; a recent paper found the Delaware Bay and ports of New York and New Jersey are the deadliest areas for whales along the entire East Coast.
The device is 4 feet wide, dangling long cables called stretch-hoses that attach it to a weighted platform on the seafloor, 125 feet below. The platform is the actual spy: Its equipment picks up whale calls and attempts to identify the different species that make them.
It does this by recording audio and processing it into visualizations called pitch tracks—sets of wiggly, multicolored lines Baumgartner compares to sheet music. By comparing these tracks to a library of known whale calls, the platform can guess what whales passed by. It’s listening for four animals: humpbacks, right whales, fin whales and sei whales.
After this analysis, the platform sends its intel back up the stretch hoses to the buoy. Every two hours, the buoy makes a call via satellite to a computer in Baumgartner’s lab and dumps all the data it has collected. The raw data are posted online as they arrive.
Then, an analyst (human, not robotic) goes over the pitch tracks and makes a final determination about what whales passed through, using the buoy’s guesses as a guide. Since being deployed June 23, the buoy already has picked up fin whale calls on several days.
This particular buoy is only one of Baumgartner’s marine eavesdropping projects. Off the coast of Maine, he has another listening buoy, as well as a robotic, surfboard-shaped boat called a wave glider towing the same listening equipment about 20 feet below the ocean’s surface.
Next month, his team will deploy a buoy off the coast of Martha’s Vineyard. In the Chukchi Sea, off northwest Alaska, his technology is on another kind of robotic boat called a Slocum glider that’s collecting data, too.
The Slocum glider looks like a little airplane, and dives continuously between the surface and seafloor. Baumgartner has other Slocum gliders deployed off of Nova Scotia and Quebec, both operated by Nova Scotia’s Dalhousie University. He’ll drop another wave glider into the New York Bight in the fall.
While the New York buoy is only listening for four whale species, the system can be tuned to monitor different frequencies and find other animals. The Alaska glider, for example, listens for bowhead whales and certain seals. Once researchers retrieve a device and bring it back to the lab—the buoys stay at sea for about a year, the gliders for a few months—they comb through the actual audio recordings to find out how accurate the pitch track results were. They can also listen to the audio for calls from additional species.
So far, results from the WHOI system have shown that a human analyst, using the pitch tracks and the automated guesses to identify whales, is about 95 percent accurate. Baumgartner hopes to eventually create a system that works in real time. It could alert ships to slow down and give whales time to swim away, or tell developers who are installing wind turbines to pause their pile drivers. The Martha’s Vineyard buoy will replace an earlier buoy in the same location, a Coast Guard training range with live gunfire.
“We thought this would be a way to help them schedule their training exercises in a responsible way to try to avoid interactions with large whales,” Baumgartner says.
Baumgartner says the research took inspiration from the Right Whale Listening Network, an older, ongoing project led by Christopher Clark at Cornell University. That system uses buoys that listen for just one species—the North Atlantic right whale—and send back 2-second audio snippets.
“That system has worked really well,” Baumgartner says. But, he adds, it’s limited by its focus on one species and its brief recordings. Without listening to the context around each whale call, it can be easy to mistake a humpback for a right whale.
Tracking the movements of right whales is important because the species is critically endangered. There are fewer than 500 alive—and between 1970 and 2007, at least 24 died after collisions with vessels. Even whale species doing a little better, though, have lives largely invisible to humans.
Baumgartner says many basic science questions have yet to be answered about where different whale species spend their time, especially near New York. Aside from influencing shipping routes and naval exercises, his project has a simpler goal: to gather some of this missing information about the ocean’s biggest residents.
Baumgartner also hopes the project will inspire the public to care more about the ocean, and make people more aware of the wildlife living just offshore.
“If there were 80-ton, 80-foot-long endangered species in Central Park,” he says, “people would know all about them.”