Home Subscribe Print Edition Advertise National Editions Other Languages


Printer version | E-Mail article | Give feedback

Does Sonar Harm Whales?

By Robyn Grace
Oct 28, 2005

Why whales strand themselves on beaches remains a mystery. (Vanderlei Almeida/AFP/Getty Images)
High-resolution image (1566 x 2100 px, 300 dpi)

MARION BAY, Tasmania - Why whales strand themselves on beaches remains a mystery.

Disease, the drive to stay with a sick pod member, and confusing underwater topography are all theories regularly put forward to explain the heartbreaking sight of beached whales dying lingering deaths on Australia's beaches.

Another intriguing theory re-emerged this week when more than 100 long-finned pilot whales beached and died at Marion Bay, east of Hobart.

It was one of the biggest mass strandings in Tasmania, already renowned for such tragic events.

But the presence nearby of two Royal Australian Navy ships may revive the debate in Australia on the possible effects of sonar on whales - a debate that has gained much more attention elsewhere in the world.

HMAS Diamantina and HMAS Huon were using short-range, high-frequency sonar to search for an anchor from a sunken wreck.

The use of sonar has long been speculated to have an adverse impact on the ability of whales and dolphins to navigate.

Just last week, a coalition of environmental groups sued the US Navy over its use of sonar, saying that the ear-splitting sounds can cause mass whale and dolphin strandings and internal bleeding.

Environmental campaigners cite a case in 2000, when four different species of whales stranded on beaches in the Bahamas after a US Navy battle group used active sonar in the area.

Investigators found that the whales were bleeding internally around their brains and ears.

Less than two years ago, the US Navy was stopped from testing a powerful sonar system in most of the world's oceans after a federal judge ruled that it could "irreparably harm" whales, dolphins and fish.

Campaigners say military active sonar works like a floodlight, emitting soundwaves that sweep across the ocean, revealing objects in their path, but requiring the use of extremely loud sound.

" ... we know that high-intensity sonar, which some military vessels use, can disrupt the navigation system of whales and dolphins," Greens Senator Christine Milne said this week.

Following this week's stranding, scientists took samples from about 110 carcasses that littered the normally picturesque Marion Bay coast in an attempt to explain the pilot whales' deaths.

"Some of the data that we gather could add an important piece to the puzzle of understanding why whales strand," marine biologist Rosemary Gales said.

The navy has been quick to distance itself from the strandings, saying the ships arrived at Marion Bay around 4pm (AEDT) Tuesday - at least five hours after the first whales stranded.

A defence spokesman said the later presence of the two ships was "purely coincidental".

"Whale strandings occur frequently around the Australian coastline and may be potentially attributed to a range of causes including environmental conditions, disease, natural pod behaviour and ageing," he said.

"Theories linking a range of causes including strandings to sonar use lack scientific credibility."

Marion Bay is a notorious spot for whales strandings, so much so that surfers have dubbed the beach the whale boneyard.

But Senator Milne demanded her federal counterparts "come clean" on naval activity and on seismic testing in the area, which has also been blamed for harming whales.

Federal Environment Minister Ian Campbell confirmed seismic testing had been carried out 440 km from the site of the latest Tasmanian stranding, but said Senator Milne was too quick to lay blame.

"Even Aristotle, in his writing thousands of years ago, acknowledged the frequent, unexplained strandings, noting 'It is not known why they sometimes run aground on the seashore; for it is asserted that this happens rather frequently when the fancy takes them and without any apparent reason'," he said.

About 80 per cent of Australia's whale strandings occur in Tasmania.

The state's Department of Primary Industries, Water and Environment (DPIWE) said why whales strand is not fully understood, but causes could include inner ear infections, heavy seas and topographical features.

Pilot whales are one of the most commonly stranded species in Tasmanian waters, and were involved in 68 recorded strandings involving 2,768 whales up to October 2003.

Two of these strandings occurred at Marion Bay, with 150 whales beaching themselves in 1998 and 100 in 1990.

Tasmanian Greens environment spokesman Nick McKim this week called for a national summit to discuss issues surrounding whale strandings.

"This would not be about playing the blame game, it would be about attempting to solve this issue. We need to proactively address the situation," he said.

State Environment Minister Judy Jackson would not comment on the proposal but told parliament strandings occurred "many years before there were any naval ships in the world".

Given Tasmania's history, it seems likely there will be many more such whale deaths, despite the attempts of volunteers who try to save the mammals.

"I always feel like crying when I go and look at them ... I wished I could have saved them all," said rescuer Ingrid Albion.