The sound of silence may soon fill our oceans, once the home of millions of rare and beautiful fish, coral, marine mammals and other life.
The silence may, ironically, be caused by the sounds of naval sonar, which is now known to cause the beachings that kill off whales, dolphins and other cetaceans.
Can anything be done to prevent whale beachings brought on by sonar?
Sonar and the Seas
Sonar is, in simplest terms, an echo. When something makes a sound, it produces sound waves that move through a medium (usually water or air). When those sound waves hit a solid object, they are reflected back toward their source.
That's why you hear an echo when you clap at a distance from a solid wall; in a split-second, your clap is echoed back to you. Bats, whales, dolphins and other animals use echolocation to find objects, like food or solid obstacles, in poor light or total darkness.
Over centuries of evolution, cetaceans have developed astoundingly precise echolocation, and can tell the difference between objects as small as a BB pellet from 50 feet away, according to Science Wire. These intelligent animals have learned to use low-frequency sounds to find food, family members, mates and to migrate across vast ocean distances.
How Humans Use Sonar
Technology has taught humans to use sonar, too. Airguns used in oil exploration, and military sonar used by ships and submarines, employ the same physical properties of sonar that bats and whales use.
But there's a dark side to the powerful sonar used by ocean-going vessels: They use sonar at frequencies between 100 hertz and 500 hertz, exactly the same frequencies used by whales and dolphins.
And while whales send out signals at volumes between 160 and 190 decibels, the sonar used by the U.S. Navy is much more powerful: Some systems operate at more than 235 decibels -- comparable to a Saturn V rocket at blastoff, and producing sound waves that can travel across hundreds of miles of ocean, according to the Natural Resources Defense Council (NRDC).
By the U.S. Navy's own estimates, their sonar can have a volume of 140 decibels, even 300 miles from the source -- that's 100 times more powerful than the level known to change the behavior of whales.
Proof that Sonar Kills
The evidence that sonar is killing whales is as damning as it is grim: In 2000, four different species of whales beached themselves in the Bahamas. The Navy initially denied responsibility, until the government's investigation confirmed that sonar caused the mass whale beachings. After the incident, the Bahama's population of beaked whales almost disappeared.
In 2002, At least 18 whales from three different species beached themselves in the Canary Islands during submarine exercises in the area. The following year, 11 harbor porpoises beached themselves in Washington State as the USS Shoup tested its sonar system. In 2004, 200 whales crowded into the waters of Hanalei Bay in Hawaii as a large Navy sonar exercise took place nearby.
There are dozens of similar examples, but in many cases the injuries and death counts are similar. Disturbingly, many of these animals were bleeding from the eyes and ears and suffered from bleeding around their brains; some also had severe lesions in their organ tissue.
Research from July 2013 found that, as expected, beaked whales were particularly sensitive to sonar. But the study also revealed that blue whales -- the largest animals ever to have lived -- also stopped feeding and rapidly fled from areas where sonar was being used.
Sonar and Whale Beachings: Will it Ever Stop?
It's worth mentioning that populations of blue whales have plunged about 95 percent over the last 100 years, largely due to whaling, but possibly due to other causes -- like sonar activity.
"For whales and dolphins, listening is as important as seeing is for humans -– they communicate, locate food and navigate using sound," Sarah Dolman of the group Whale and Dolphin Conservation told the Guardian.
"Noise pollution threatens vulnerable populations, driving them away from areas important to their survival, and at worst injuring or even causing the deaths of some whales and dolphins," Dolman added. Still, there are no accepted international standards regarding noise pollution; Dolman and others are calling for an urgent re-evaluation of the environmental impacts of military sonar activities.
Will the use of sonar change in time to save the whales and dolphins? Kenneth Hess, a U.S. Navy spokesman, told the Guardian that permit conditions for naval exercises were reviewed annually, adding (in a less-than-reassuring statement): "We will evaluate the effectiveness of our marine mammal protective measures in light of new research findings."
A spokesman for Britain's Royal Navy told the Guardian, "The Royal Navy already limits its use of sonar around whales. We are committed to taking all reasonable and practical measures to protect the environment and mitigate effects on marine mammals. This new research will be taken into account in the regular review of ... active sonar mitigation procedures."
In other words, the injury and death of whales, dolphins and other marine life will continue, at least until intense political pressure -- greater than the power of a Saturn V rocket at blastoff -- makes it stop.