National Resources Defense Council – 2014-03-09 01:36:28
http://www.nrdc.org/wildlife/marine/sonar.asp
Lethal Sounds
The use of military sonar poses a deadly threat to whales and other marine mammals
Numerous mass strandings and whale deaths across the globe have been linked to military sonar use.
Whales and other marine mammals rely on their hearing for life’s most basic functions, such as orientation and communication. Sound is how they find food, find friends, find a mate, and find their way through the world every day.
So when a sound thousands of times more powerful than a jet engine fills their ears, the results can be devastating — and even deadly.
This is the reality that whales and other marine mammals face because of human-caused noise in the ocean, whether it’s the sound of airguns used in oil exploration or subs and ships emitting sonar. Manmade sound waves can drown out the noises that marine mammals rely on for their very survival, causing serious injury and even death.
How Sonar Harms Whales
If you’ve ever seen a submarine movie, you probably came away with a basic understanding of how sonar works. Active sonar systems produce intense sound waves that sweep the ocean like a floodlight, revealing objects in their path.
Some systems operate at more than 235 decibels, producing sound waves that can travel across tens or even hundreds of miles of ocean. During testing off the California coast, noise from the Navy’s main low-frequency sonar system was detected across the breadth of the northern Pacific Ocean.
By the Navy’s own estimates, even 300 miles from the source, these sonic waves can retain an intensity of 140 decibels — a hundred times more intense than the level known to alter the behavior of large whales.
The Navy’s most widely used sonar systems operate in the mid-frequency range. Evidence of the danger caused by these systems surfaced dramatically in 2000, when whales of four different species stranded themselves on beaches in the Bahamas. Although the Navy initially denied responsibility, the government’s investigation established that mid-frequency sonar caused the strandings.
After the incident, the area’s population of Cuvier’s beaked whales nearly disappeared, leading researchers to conclude that they either abandoned their habitat or died at sea. Similar mass strandings have occurred in the Canary Islands, Greece, Madeira, the US Virgin Islands, Hawaii and other sites around the globe.
Deadly Impacts of Sonar
Many of these beached whales have suffered physical trauma, including bleeding around the brain, ears and other tissues and large bubbles in their organs.
These symptoms are akin to a severe case of “the bends” — the illness that can kill scuba divers who surface quickly from deep water. Scientists believe that the mid-frequency sonar blasts may drive certain whales to change their dive patterns in ways their bodies cannot handle, causing debilitating and even fatal injuries.
Stranded whales are only the most visible symptom of a problem affecting much larger numbers of marine life. Naval sonar has been shown to disrupt feeding and other vital behavior and to cause a wide range of species to panic and flee. Scientists are concerned about the cumulative effect of all of these impacts on marine animals.
Even the Navy estimates that increased sonar training will significantly harm marine mammals more than 10 million times during the next five years off the US coast alone.
NRDC has been a leader in the battle to regulate sonar use and protect whales and other species from its harmful effects. In 2008, a case filed by NRDC against the US Navy was heard by the US Supreme Court.
Whale Strandings
There is no question that sonar injures and kills whales and dolphins.
– Joel Reynolds, NRDC senior attorney
January 2006 — At least four beaked whales strand in the Gulf of Almeria, Spain, while sonar exercises take place offshore.
January 2005 — At least 34 whales of three species strand along the Outer Banks of North Carolina as Navy sonar training goes on offshore.
July 2004 — Four beaked whales strand during naval exercises near the Canary Islands.
July 2004 — Approximately 200 melon-headed whales crowd into the shallow waters of Hanalei Bay in Hawaii as a large Navy sonar exercise takes place nearby. Rescuers succeed in directing all but one of the whales back out to sea.
June 2004 — As many as six beaked whales strand during a Navy sonar training exercise off Alaska.
May 2003 — As many as 11 harbor porpoises beach along the shores of the Haro Strait, Washington State, as the USS Shoup tests its mid-frequency sonar system.
September 2002 — At least 14 beaked whales from three different species strand in the Canary Islands during an anti-submarine warfare exercise in the area. Four additional beaked whales strand over the next several days.
May 2000 — Three beaked whales strand on the beaches of Madeira during NATO naval exercises near shore.
October 1999 — Four beaked whales strand in the US Virgin Islands during Navy maneuvers offshore.
October 1997 — At least nine Cuvier’s beaked whales strand in the Ionian Sea, with military activity reported in the area.
May 1996 — Twelve Cuvier’s beaked whales strand on the west coast of Greece as NATO ships sweep the area with low- and mid-frequency active sonar.
October 1989 — At least 20 whales of three species strand during naval exercises near the Canary Islands.
December 1991 — Two Cuvier’s beaked whales strand during naval exercises near the Canary Islands.
