TECH: Sonar Risk to Whales May Increase


This week, the White House challenged a court order that restricted the U.S. Navy’s use of sonar, the undersea technology that is believed to greatly endanger the lives of whales.


The crux of the issue is a set of military exercises under way off the coast of Southern California. The ongoing battle between the Navy and groups such as the California Coastal Commission and the National Resources Defense Council had escalated this month: on January 3, a California judge ruled that sonar could not be used within 12 nautical miles of the coast and included several stipulations for monitoring and avoiding marine mammals when they are spotted. But government lawyers said in a court filing Tuesday that the use of mid-frequency sonar in those exercises was “essential to national security.” The filing, which will be contested by environmental groups and likely lead to a protracted court battle, claims that the Navy is exempt from the Coastal Zone Management Act and the National Environmental Policy Act.

So, is sonar key to national security? The Navy claims that sonar is the only effective way to detect other, potentially hostile, submarines. The active sonar that the Navy uses for detecting and locating vehicles under water emits sound waves that sweep across up to a few hundred miles of ocean. The sound levels from some mid-frequency sonar systems—which operate at frequencies between 2 and 8 kilohertz—can be more than 200 decibels at their source. The technology has been around since the 1960s and is used by more than a dozen countries, on hundreds of naval ships. A new generation of ultraquiet, diesel-electric submarines are tougher to detect and can fire missiles inland from off the coast, compelling the navy to step up its military drills closer to shore.

But what happens to the whales? They have been found beached on numerous occasions in the aftermath of sonar exercises, with bleeding around their heads and ears. A study in the journal Nature in 2003 suggested that the stranded animals suffered from a condition similar to a severe case of “the bends,” the decompression sickness known to sometimes kill scuba divers who surface too quickly. But even those that are not dying are affected by the din in their ocean homes: sonar and other sources of noise pollution—from supertankers, seismic activity from oil drillers and some 50,000 cargo vessels—throw off the whales’ ability to find each other, and sources of food, over long distances. According to some reports, ocean noise has been doubling every ten years.

It’s hard to prove, once and for all, that sonar is indeed the sound that kills whales: with so many sources of noise, the ocean has become a bombastic environment for marine mammals. But does that mean that the Navy should have free reign? After all, the issue is just about exercises. How hard can it be to operate sonar in a way that attempts to limit the harm to these endangered animals?

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