Robots: The new whale sleuths
WOODS HOLE, Jan 10, 2013 (Cape Cod Times - McClatchy-Tribune Information Services via COMTEX) --
It would be a whole lot easier to study whales if they were like birds, says Woods Hole Oceanographic Institution researcher Mark Baumgartner.
A hawk glides silently overhead, and a sentinel crow high up in a treetop cries out. Other crows answer and gather to chase the intruder away.
It's pretty easy to understand the interaction and locate all the participants.
Whales, however, are more like phantoms, spending most of every day underwater. It's hard to know where they are or what they are doing, or in Baumgartner's case, what they are eating.
Until five years ago, Baumgartner, who studies predator and prey relationships, never dreamed that his research into whales and the food they eat would rely on 5-foot-long instrument-packed torpedoes known as electric robot gliders. Now it looks like a byproduct of his research, which uses these gliders to locate whales, could help prevent ships from colliding with the mammals, their biggest cause of death and injury.
Baumgartner used to travel to where whales congregate, take plankton samples, and note environmental conditions and behavior of the marine mammals. But he could see them only when they surfaced. Bad weather and darkness at night made it difficult to study the whales for anything more than a few hours at a time.
"I quickly realized that these gliders could give us access to places that are very difficult for us to access," Baumgartner said. "Nobody knows what whales are doing in the middle of the ocean."
The central Gulf of Maine, where North Atlantic right whales, the most endangered whale species on Earth, and other whale species are known to gather in the fall, is remote and the weather is usually horrible.
But in November, Baumgartner, his WHOI research partner, glider specialist Dave Fratantoni, and a team of researchers and crew from WHOI, the University of Rhode Island, the National Marine Fisheries Service, New England Aquarium and University of New Hampshire released two electric robot gliders in the area known as Outer Fall.
Ups and downs
A robot glider has a battery-powered electric buoyancy pump that fills a ballast tank, causing it to sink. Its stubby backswept wings provide lift in the water, much as they would in air, and it glides down while traveling forward until it approaches the bottom at 600 feet. Then, the pump discharges the ballast water and the glider rises to the surface.
During their recent trip to the gulf, researchers repeated this sawtooth pattern for weeks, the voyage guided by programmed GPS locations.
Baumgartner's robots carried a bottle-shaped instrument that uses hydrophones to listen for whale calls. When a call came in, the instrument, known as a DMON, scanned through a library of stored whale sounds and identified the species. Other instruments collected data on environmental conditions, such as water temperature, salinity and even the type and density of the plankton in the area.
Every few trips to the surface, the gliders paused to send information to a satellite that relayed the data back to WHOI. In heavy seas, a balloon inflates to hold up the tail so the antenna is clear of the water.
"It's a nice platform to put together stories about why whales are in particular areas," Baumgartner said.
A little over two weeks later, when he went out to retrieve the gliders and take oceanographic and zooplankton samples, Baumgartner already had enough environmental information to know that bottom temperatures were abnormally warm and that there wasn't enough food out there to support a major aggregation of whales this year.
"Before I left the dock, I knew it would be a strange year for whales," he said.
They also had no trouble finding whales as the gliders led them to their quarry like audio bloodhounds. They were so good at finding whales that Baumgartner realized the technology might have other applications. "Where whales are and why they are there, these vehicles are very good at figuring that out," he said.
The scientists' information on right whale locations in that area led the Fisheries Service to issue a warning to mariners to reduce their speeds and post lookouts for these highly endangered whales. Right whales, which often spend long periods on the surface, are especially vulnerable to ship strikes. The Fisheries Service uses aerial surveys to try to locate groups of right whales and warn mariners.
Representatives from the Fisheries Service and the Provincetown Center for Coastal Studies did not return phone calls Wednesday regarding possible applications for the research. However, a statement from WHOI quoted Sofie Van Parijs, leader of the Passive Acoustic Research Group at NOAA's Northeast Fisheries Science Center, saying that the gliders could complement whale programs that depend on human observation.
"The idea is that if you have a fleet of these, you could use them over a wide area. I know that this kind of listening technology can do a better job than airplanes and even ships," Baumgartner said.
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