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Marine Mammals Sounding Off

Douglas NowacekThree weeks spent traveling the crystal clear waters of the Caribbean may sound like a vacation, but for Douglas Nowacek, it's part of the job. Nowacek, a new marine biologist at Duke, spends about two months out of the year on such research cruises. Still, he claims that his work isn’t necessarily as romantic as it seems.

“The rest of my time is spent staring at a computer screen just like everybody else,” he said. Nowacek, who has appointments both in the Nicholas School and the Pratt School of Engineering, travels the seas to study how marine mammals use sound to communicate and explore their environment.

His fascination with the acoustical abilities of dolphins and whales began in an undergraduate biology class at Ohio Wesleyan University, but it wasn’t until he immersed himself in the culture of marine science as part of a summer program at Duke that he decided to make a career of research.

“It was clear to me pretty quickly that people loved what they did,” Nowacek said.

After that experience, Nowacek wrote a grant to come back the next summer to conduct an independent study project on the vocalizations of bottlenose dolphins. He went on to earn his doctorate through the joint program of the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution. He was an assistant professor at Florida State University for five years.

Now his career has come full circle as Nowacek returns to Duke, this time as an associate professor of marine science and conservation and electrical and computer engineering. One of Nowacek’s interests is the effect of noise pollution on marine mammals.

In his postdoc and early faculty work, Nowacek studied the behavior of North Atlantic right whales, which are not only affected by noise but also by interactions with ships. Conservationists have suggested that ships sound an alarm to warn the endangered whales to move out of harm’s way. When Nowacek tested this idea, he found that whales responded to an alarm sound by coming to the surface to breathe but then submerging down to just a few meters below the surface while continuing to swim, where they were not visible but still vulnerable to ship strikes.

“The result was disappointing in terms of conservation, but it was interesting from an acoustic standpoint because it begs the question of why the whales responded that way,” Nowacek said. “In fact, their behavior is exactly what you would expect if they thought the sound had come from a predator – they came close to the surface to get air but then hid just below detection range.”

Tracking the behavior of right whales, or any wild animals, is a difficult task. The tags Nowacek uses in his research record acoustics, movement patterns, direction, water pressure, temperature, and – coming soon – GPS location. Part of his Pratt research is developing new technology for marine applications. He is also teaching a course in Acoustics and Hearing with Leslie Collins, chair of electrical engineering.

Through his teaching, Nowacek hopes to encourage students to think of animals differently than they have in the past – not just as complex organisms but also as acoustic signal processors. Currently, Nowacek is starting two major projects. The first takes him to the depths of the ocean, to develop a map of the prey that exist 600 to 1500 meters below the surface. The second takes him to the Antarctic to more accurately determine the amount of krill consumed by humpback whales. Both of these projects, and the rest of Nowacek’s research, have not strayed from the subject of marine mammals, but that does not mean that there are bounds to his curiosity.

“If I had a chance to do it all again, I would probably study bats or sharks,” Nowacek said. “But that is only because it would give me the opportunity to learn something completely new.”