Low-Frequency Active sonar blows out the brains of whales
I was disappointed (though not surprised) by the email I just received from the Natural Resources Defense Council (“the Earth’s best defense” – give me a job?):
The American people have rejected it. The federal courts have ruled against it. But the U.S. Navy won’t take NO for an answer.
It’s bringing back a sonar system so powerful it can impact whales 300 miles away with its ear-splitting noise. Its effects are so far-reaching — and so unknown — it could threaten the survival of entire populations of marine mammals.
Now the Navy wants to deploy this Low- Frequency Active (LFA) sonar system across a staggering 70 percent of the world’s oceans. And the Bush Administration has given the public only 15 days to register our opposition.
I feel obliged to keep my words civil, given the proximity to semester – I don’t want to telegraph to my new students the fact that any sailors in our classroom will run out, holding their ears (I’m Australian; we swear a lot?). Actually, I should have spotted this story a week ago. Good thing I sign up to mailing-lists.
LFA sonar and the military
For those who came in late: Low-Frequency Active sonar was in the news rather a while ago. The US military is exempt from environmental ‘rules’ that would otherwise prevent this sort of thing, making for fractious debates between the save-the-world-invade-a-country and the save-the-world-plant-a-tree crowds.
Military active sonar works like a floodlight, emitting sound waves that sweep across tens or even hundreds of miles of ocean, revealing objects in their path. But that kind of power requires the use of extremely loud sound. Each loudspeaker in the LFA system’s wide array, for example, can generate 215 decibels’ worth – sound as intense as that produced by a twin-engine fighter jet at takeoff.
Some mid-frequency sonar systems can put out over 235 decibels, as loud as a Saturn V rocket at launch. Even 100 miles from the LFA system, sound levels can approach 160 decibels, well beyond the Navy’s own safety limits for humans.
LFA sonar and marine mammals
Pierce Brosnan has had a long involvement with environmental concerns. Dismiss this because he is voicing it over and I shall have a very low opinion of you, indeed.
From the Whale and Dolphin Conservation Society:
European veterinary pathologists have recently published an alarming article in the journal Nature that identifies unusual lesions and a possible mechanism for noise-related injury in some of the animals stranded around the UK and those from the Canary Islands, including deep diving beaked whales and Risso’s dolphins as well as common dolphin and a harbour porpoise.
Internal damage – holes in tissues – that can lead to death in cetaceans is reported and appears to be caused by a condition known in humans as decompression sickness or ‘the bends’. It is currently unclear whether this happens as a result of fright response as an individual attempts to swim away from the sound and exceeds its physiological tolerances as it comes to the surface, or as a direct result of the physical impact of the sound.
Whatever the mechanism of injury, the authors of the article show that the damage is caused to vital internal organs, in particular the liver of the animal, and this leads in some cases to death.
From the NRDC:
Evidence of the harm such a barrage of sound can do began to surface in March 2000, when whales of four different species stranded themselves on beaches in the Bahamas after a U.S. Navy battle group used active sonar in the area.
Investigators found that the whales were bleeding internally around their brains and ears. Although the Navy initially denied responsibility, the government’s investigation established with virtual certainty that the strandings were caused by its use of active sonar.
Since the incident, the area’s population of Cuvier’s beaked whales has all but disappeared, leading researchers to conclude that they either abandoned their habitat or died at sea.
A map of the mass stranding of Cuvier’s beaked whales in 1996. The red arrows are the tracklines of the NATO vessel – the orange arrows display areas of beaked whale strandings.
Numerous mass stranding events and whale deaths across the globe have been linked to military sonar use.
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.
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 1999: Four beaked whales strand in the U.S. Virgin Islands during Navy maneuvers offshore.
May 2000: A beaked whale strands in Vieques as naval exercises are about to begin offshore.
May 2000: Three beaked whales strand on the beaches of Madeira during NATO naval exercises near shore.
April 2002: A beaked whale and a humpback whale strand near Vieques during an offshore battle group training exercise.
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 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.
June 2004: As many as six beaked whales strand during a Navy sonar training exercise off Alaska.
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.
July 2004: Four beaked whales strand during naval exercises near the Canary Islands.
January 2005: At least 34 whales of three species strand along the Outer Banks of North Carolina as Navy sonar training goes on offshore.