Deep Blue Dissonance

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Male blue whales in the Pacific Ocean, for instance, send out a specific call to find a mate. That call falls roughly in the same frequency as the hum a ship’s propeller makes as it pulls through the water. Underwater, hums carry: “You can hear container ships in the Pacific up by Alaska all the way down in Southern California,” Hildebrand says. As ever-faster vessels loaded with exports crisscross the globe in greater numbers, the ambient drone in the oceans threatens to drown out whales’ voices.

For a male blue whale on the make, “that’s a big problem,” Hildebrand says. “If the girl of your dreams is never going to hear you, you’re never going to breed.”

In 2003 and 2004, Hildebrand, along with Mark McDonald of WhaleAcoustics in Bellvue, Colorado, and Sean Wiggins of Scripps, measured noise levels south of the Santa Barbara Channel, an unusually diverse marine habitat off the Southern California coast. They then compared their data with recently declassified sound records from the same area made by the U.S. military from 1964 to 1966. What they found was an area of the ocean 10 times noisier than it was 40 years ago, rattling with engines, explosions, sonar, and ships.

Throughout the ocean, petroleum outfits use seismic air guns to sound the depths for oil-rich pockets, and fishing operations use acoustic deterrent devices to warn marine mammals away from their nets. But in Southern California’s coastal waters, which flow into two of the nation’s busiest ports, Hildebrand blames ship traffic for most of the noise. “It’s as if I put a freeway next to your house,” he says. “You wouldn’t be happy about it.”

Nature, of course, makes its own racket. Before humans harvested most of the ocean’s inhabitants, whistling dolphins, snapping shrimp, and clicking sperm whales filled the water with sound that, combined with the calving of glaciers and the rushing of tides, produced a ruckus to rival modern industry. Michael Stocker, director of the Lagunitas, California–based advocacy group Ocean Conservation Research, acknowledges that several centuries back, the ocean was even noisier than it is now. “But it was a different kind of noise,” Stocker says. To a whale, the sounds of technology may be like “somebody following you around all day running their fingernails down a blackboard.”

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