WOODS HOLE, Mass. — August 20, 2012 — When the whale known as Touché is hungry for a school of fatty fish, he circles below them, fashioning a net of air by streaming bubbles from his blowhole. Then he corkscrews toward the surface of the Gulf of Maine, herding the fish into an ever tighter packet with the bubbles and his 30-ton body. Finally he opens his jaw wide, takes a monstrous gulp and relaxes, breathing deeply at the water’s surface.
Then he dives again. Over and over.
Touché’s feeding strategy, captured in June by an electronic tag attached to his back, is of keen interest to scientists tracking North Atlantic humpback whales off Cape Cod.
“Every time we go out and put another tag on, we learn something else,” said Dave Wiley, research director of the Stellwagen Bank National Marine Sanctuary in Massachusetts, who returned to shore recently after plying its waters for two weeks with researchers from several institutions.
For Dr. Wiley, the most striking insight is that each humpback has its own set of behaviors, often confounding efforts to generalize about the species.
“We’ve got examples sometimes of hundreds of feeding events that are almost all identical for that particular whale but are different than the hundred feeding events that we have for a different whale,” he said. As a result, Dr. Wiley’s papers about the humpback are full of caveats.
“It’s frustrating and complicated and fascinating all at the same time,” he said.
More broadly, he and his colleagues hope to use their findings to push for changes in fishing and shipping rules to protect the humpbacks.
The Stellwagen sanctuary is prime habitat for a pencil-size schooling fish called the sandlance that draws a host of predators, from the humpbacks to fin whales, minke whales, dolphins, striped bass and bluefin tuna.
Yet the sanctuary’s proximity to land — 25 miles from Boston and three miles from the tip of Cape Cod — also means it is heavily used by humans.
On a bright summer day, its waters may be packed with half a dozen whale-watching boats and thousands of recreational and commercial fishing vessels, sailboats and yachts — and that’s just at the surface. The depths abound with ropes connecting strings of lobster pots and webs of fixed fishing gear that stretch across like tennis nets.
Most human-caused deaths of humpbacks occur when whales are struck by passing ships or become entangled in fishing gear, Dr. Wiley said. But policy makers could not reduce the risks because they did not know enough about how the whales move underwater.
“Our whole goal is to collect data to influence policy,” Dr. Wiley said.
For decades, humpback behavior was poorly understood because of the difficulty of shadowing the whales as they roamed the North Atlantic. The breakthrough was the DTAG, engineered in 1999 at the Woods Hole Oceanographic Institution in Massachusetts.
Unlike satellite tags, which transmit location, typically over a long period of time, DTAGs stay attached for 36 hours at most and record information like speed, depth and audio. They also carry a three-axis accelerometer that measures the front-to-back, side-to-side orientation of the whale.
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