And in the waters of Hawaii, we thrill to the complex songs of humpback whales. Sound waves travel up to five times faster through water than through air. Whether serenading a prospective mate, navigating or hunting by sonar, avoiding predators or keeping their young close on a long migration, marine mammals depend on the acoustical qualities of water for their survival. They inhabit a universe of sound, not sight. Commercial shipping, oil drilling, fishing and military activities are the major players in this sorry symphony.
Ships are bigger, more numerous and louder than ever before.
To a whale, a supertanker is an overwhelming sheet of white noise, caused by cavitation, the bursting of water bubbles around the propellers. For their part, fishermen now use a variety of pinging devices to scare off dolphins. The devices work, saving the dolphins from incidental capture, but also excluding them from feeding grounds. Oil explorers use air guns to send jolts through the ocean floor. Scientists have joined the chorus.