Navigating a Sea of Sound

The ocean is an increasingly noisy place. Sounds from shipping, oil and gas exploration, and other human activities are making it more difficult for marine mammals to hear. “Hearing is the main way marine mammals find their way around the ocean,” notes WHOI biologist Aran Mooney (in foreground) who teamed up with colleagues in Alaska for the first hearing study on wild beluga whales in Bristol Bay. After guiding whales into shallow waters with the help of Alaskan natives, the research team gave the animals physical exams and hearing tests. The latter are performed using suction cups, which attach a small speaker to the whale’s jaw and sensors on the animal’s head and back. The brain’s response to sounds is then recorded on a computer.(Photo courtesy of Aran Mooney, Woods Hole Oceanographic Institution)