From todays Toronto Sun newspaper

BY ARIEL DAVID, AP

The songs that whales and dolphins use to communicate, orient themselves and find mates are being drowned out by human-made noises in the world's oceans, UN officials and environmental groups said yesterday.

That sound pollution -- everything from increasing commercial shipping and seismic surveys to a new generation of military sonar -- is not only confounding the mammals, it also is further threatening the survival of these endangered animals.

Studies show that these cetaceans, which once communicated over thousands of kilometers to forage and mate, are losing touch with each other, the experts said on the sidelines of a UN wildlife conference in Rome.

"Call it a cocktail-party effect," said Mark Simmonds, director of the Whale and Dolphin Conservation Society, a Britain-based NGO. "You have to speak louder and louder until no one can hear each other anymore."

An indirect source of noise pollution may also be coming from climate change. Research suggests rising levels of carbon dioxide are increasing the acidity of the Earth's oceans, making sound travel farther through sea water.

Some sound frequencies are travelling 10% further than a few centuries ago and that could increase to 70% by 2050 if greenhouse gases are not cut, the conference was told.

More than 100 governments are gathered in Rome for a meeting of the UN-backed Convention on the Conservation of Migratory Species of Wild Animals.

The agenda of the conference includes ways to increase protection for endangered species, including measures to mitigate underwater noise.

Environmental groups are increasingly finding cases of beached whales and dolphins that can be linked to sound pollution, Simmonds said.

Marine mammals are turning up on the world's beaches with tissue damage similar to that found in divers suffering from decompression sickness. The condition, known as the bends, causes gas bubbles to form in the bloodstream upon surfacing too quickly.

Scientists say the use of military sonar or seismic testing may have scared the animals into diving and surfacing beyond their limits.

The sound of a seismic test used to locate hydrocarbons beneath the seabed can spread 3,000 km under water, said Veronica Frank of the International Fund for Animal Welfare.