AUTEC, Sonar and Whales

by Larry Smith

In the minds of some people, the American naval facility on the Bahamian island of Andros is another mysterious Area 51 – the top-secret military base in Nevada that has been imaginatively linked to UFOs and inter-dimensional vortexes.

And believe it or not - AUTEC’s deepwater sensors in the Tongue of the Ocean were recently used by scientists from the University of California in an effort to detect cosmic neutrinos emitted by intergalactic black holes.

But environmentalists regard the hundreds of square miles of deep ocean off the Atlantic Underwater Testing and Evaluation Centre near Fresh Creek as a killing field for whales and dolphins.

AUTEC was set up in 1965 to research anti-submarine warfare for the Western Alliance using live targets and synthetic torpedoes in a realistic environment. Those activities rely on a detection system called tactical active sonar that was first deployed on warships about 40 years ago.

As one British submariner who took part in these exercises explained: “We would travel up and down the range, whilst other NATO submarines, warships and helicopters would fire torpedoes at us. “

In fact, this writer was one of several Bahamian journalists aboard a Royal Navy helicopter carrier in 1976 that took part in a four-day exercise off Andros involving US, British, Dutch and Bahamian forces.

Codenamed Operation Clay, the exercise featured mock commando landings. And the carrier, HMS Bulwark, conducted manoeuvres with a nuclear-powered British attack submarine undergoing trials at AUTEC.

Today, AUTEC employs over 400 Americans and 170 Bahamians. The 1983 lease agreement provides for the use of land sites, airspace and seabed for a payment of $10.8 million a year. Andros was selected because of its deep water close to shore, but there are increasing concerns among environmentalists that ear-splitting military sonar threatens whales and other marine mammals throughout the world’s oceans.

That’s because whales and dolphins navigate, hunt and communicate using sound waves. Hearing is their primary sense, and because sound travels so well in water, the noise can be miles away and still seem like it is just around the corner.

"Whales exposed to high-intensity sonar have been found bleeding from the eyes and ears, with lesions the size of golf balls in their organ tissue," said Michael Jasny of the New York-based Natural Resources Defence Council. "Biologists are concerned that the whales we see dying on the beaches are only the tip of an iceberg and that many more are dying at sea,"

And according to the US National Oceanographic and Atmospheric Administration, “The effect of man-made sounds on marine mammals has become a clear conservation issue. Strong evidence exists that military sonar has caused the strandings of beaked whales in several locations.”

Experts say high-intensity sonar disorients whales and can damage their ears, causing them to surface too quickly and strand on shorelines where they often die. Although whale strandings have been reported around the world for hundreds of years, environmentalists say the numbers are increasing.

Modern sonar sends out loud pings that appear to frighten and disorient whales, especially deep-diving species such as the beaked whales, about which we know little. And in fact, the US Navy is spending $50 million on research to understand how marine mammals are affected by sound.

This research includes investigating marine mammal locations, abundance, and movement at sea; studying the effects of sound on their physiology and behaviour; and finding ways to mitigate those effects.

For the past 15 years, the Bahamas Marine Mammal Survey - based at Sandy Point, Abaco - has been carrying out field studies of whales and dolphins, with funding from Earthwatch Institute, and has documented 24 species in Bahamian waters. They have also been involved in a monitoring programme at AUTEC that detects whales using the base’s underwater microphones.

The BMMS has collated reports of marine mammal strandings in the Bahamas dating back to the 1940s: “The data show a relatively consistent number of strandings from the 1960s to the 1980s, that begins to increase in the 1990s,” Diane Claridge said recently. “Then there is a sharp rise, with peaks in 2000 and 2002 from two mass stranding events. We've recorded 78 strandings in the past six years, which is unusually high compared to previous years.”

In 2002 some 40 oceanic dolphins stranded on Long Island where about half died of exposure and starvation. Researchers have not determined exactly why these deepwater animals entered the shallows at Deadman's Cay Sound in the first place. There were rumours of naval activity in the area at the time, but that was never confirmed.

In the more famous 2000 event, 17 whales and dolphins came ashore on Abaco and Grand Bahama during a confirmed US naval exercise in the Providence Channel. Seven of the animals died and the BMMS was able to conduct post-mortems on all of them.

Claridge and former BMMS scientist Ken Balcomb reported their findings in the May 2001 issue of the Bahamas Journal of Science*: “We concluded that there must have been an enormous acoustic event...that triggered a behavioural flight response by several species, but predominantly Cuvier’s beaked whales.”

Both the US National Marine Fisheries Service and the US Navy came to similar conclusions based on the post-mortems, “which indicated that the injuries were all consistent with an intense acoustic or pressure event.”

Beaked whales are more sensitive to the 180 decibel sonar levels used by the US Navy than other species. For comparison, experts say that typical ocean noise levels in the Bahamas range from 40 decibels with no shipping to 68 decibels with heavy shipping. For humans, a sound level of 85 decibels causes permanent hearing damage, and a sound level of 125 decibels causes ear pain.

“As far as I am aware, current mitigation practices at AUTEC consist of observers on ships before and during exercises, slowly ramping up sonar as an exercise begins, and ensuring that no one ship outputs more than 180 decibels,” Claridge said. “I believe they also consider the cumulative effect if multiple ships are using sonars simultaneously.”

But apparently this isn't enough to prevent harm to beaked whales from active sonar. To find out what type of mitigation would be effective, the US Office of Naval Research has been funding a monitoring programme at AUTEC, which listens for whales in the Tongue of the Ocean.

According to the BMMS, this system can be used to look at changes in the density of beaked whales (and other species) before, during and after naval exercises. And it can also determine whether whales are moving in and out of the area as a result of naval activity. Claridge has been to AUTEC several times to work on the programme.

“What is really interesting to me is that beaked whales are detected pretty much all the time. I didn't expect them to be found so frequently in an area where military exercises have taken place regularly for the past 40 years. Additionally, sperm whales, several dolphin species and short-finned pilot whales are commonly seen and heard, and appear to be in the Tongue of the Ocean year round.”

However, there has reportedly been more naval activity in the Tongue of the Ocean lately as other test sites have closed. US Embassy officials say about a dozen exercises take place at AUTEC every year – each lasting several days.

“If the number of exercises using active sonar has increased, and we know that the number of strandings has increased, then there is definitely reason for concern considering the correlation between sonar exercises and strandings that have been reported in scientific publications,” Claridge said.

Beaked whales are the most mysterious of the 80 cetacean species because they favour the deep ocean. In fact, what little we do know of them has largely come from stranded animals. Sightings of them at sea are rare due to their long dive times and unobtrusive surfacing behaviour, but a preference for deep-water habitats makes them relatively common in the deep basins and channels of the Bahamas.

Claridge says AUTEC could usefully implement follow-up surveys for distressed animals after each exercise and conduct environmental impact assessments prior to any exercises conducted in the Bahamas.

She also called for a stranding response workshop to train people on various islands in how to collect data from dead whales as well as how to help live ones: “We need the data because with every whale that strands and no data/specimens are collected, we really can't say why they died.”

Environmentalists want navies to take common-sense precautions during peacetime sonar training. Such measures include avoiding migration routes and feeding or breeding areas; and listening with passive sonar to ensure that whales are not in the area before switching on active sonar.

According to the American Cetacean Society, “The controversy between the military and environmental groups arises out of the need to maintain a certain level of national security and not injure or kill every living thing in the ocean by doing so.”

But the military says worldwide naval use of active sonar has been correlated with the stranding of only 50 whales during the 10-year period from 1996-2006: “To help put this number in perspective, this equates to less than a quarter of one per cent of the 3500-plus strandings that occur each year on US shores,” according to a US Navy fact sheet.

A recent report by the United Nations Environment Programme rated sonar last among current threats to dolphins, porpoises and related species. Sonar was reported to threaten only about 4 per cent of these species, compared with 70 per cent endangered by fishing and 56 per cent by pollution.

And it wasn’t too long ago that many whale species were being hunted to the point of extinction. In fact, commercial whaling has been around since at least the 11th century; and at its peak, during the mid-20th century, the global whaling industry was killing more than 50,000 whales a year.

*The Bahamas Journal of Science was published by Media Enterprises (www.bahamasmedia.com) from 1993 to 2006 when it became the Bahamas Naturalist and Journal of Science, co-published with the Bahamas National Trust.