UN to Investigate Undersea Noise Impact on Marine Mammals

PARIS, France, August 21, 2011 (ENS) – With noisy human activity on the world’s oceans disrupting the well-being of marine creatures, the United Nations is hosting a meeting to launch a decade-long investigation into the problem.

“Many marine species rely mainly on sound as a source of environmental information, in much the same way as human beings rely on their eyesight,” the UN Educational, Scientific and Cultural Organization, UNESCO, said of the study. The launch meeting will be held at the agency’s Paris headquarters from August 30 to September 1.

Marine scientists and representatives from the private sector and military establishments will use the meeting to plan the decade-long International Quiet Ocean Experiment aimed at filling the knowledge gaps so that management of ocean noise can be “more informed and effective,” UNESCO said.

Stranded humpback whale died on Big Gibber Beach, Myall Lakes National Park, New South Wales, Australia, cause of death unknown. August 19, 2011. (Photo courtesy NSW National Parks and Wildlife Service)

“Although very little research exists to prove any links, there is a growing suspicion that increasing noise levels, and some sounds in particular, are altering the behavior of marine animals and perhaps even reducing their capacity to perform normal life functions such as finding food, seeking out mates or avoiding predators,” UNESCO said in a statement announcing the new research project.

“Evidence suggests, for example, that several whale species have raised the volume of the squeaks, clicks and moans by which they communicate with each other,” said UNESCO.

Ocean noise cannot be contained within localized areas, so its impacts affect many aspects of marine life over vast areas of ocean.

In December 2008, the International Fund for Animal Welfare issued a report, “Ocean Noise: Turn It Down,” showing that the distance over which blue whales can communicate is down by 90 percent as a result of intensified noise levels.

Ship noise in the Pacific Ocean has doubled every decade over the past 40 years and the global shipping fleet is expected to double in size by 2025, after doubling between 1965 and 2003, the report calculates.

Airguns used in seismic surveys to identify undersea locations likely to bear oil or gas generate sounds that peak at up to 259 decibels.

These long submersible cannons are towed behind boats in complex arrays, firing shots of compressed air into the water about every 10 seconds for months. These sounds can travel more than 3,000 kilometers from the source.

The seismic survey vessel Orient Explorer approaches Greenpeace New Zealand inflatibles during a protest action against deep sea oil drilling off East Cape, New Zealand, April 10, 2011. (Photo by Malcolm Pullman courtesy Greenpeace New Zealand)

There are 90 seismic survey ships in the world, the IFAW report states, and a quarter of them are in use on any given day.

The airgun, which replaced dynamite as the oil and gas industry’s primary method of exploration, is not the only technology used today. Other methods, which also produce impulsive noise above 200 decibels, include sleeve exploders, gas guns, sparkers, and boomers. In addition seismic survey vessels typically employ multi-beam and sub-bottom profiling sonars whose source levels run as high as 237 dB.

In addition, there are an estimated 300 naval sonar systems worldwide able to generate pressure sound waves of more than 235 decibels. Pings this loud are over one billion times more intense than the 145 decibel upper limit deemed safe for humans.

Scientists have linked high intensity sonar with fatal strandings of whales and dolphins. In the mid to late 1980s, several mass strandings were thought to be associated with naval activities around the Canary Islands. Later, between 1992 and 1998, 28 Gervais’ beaked whales were stranded along the U.S. East Coast between Florida and Massachusetts, followed by more mass strandings in September 2002 after NATO tested low frequency sonar.

The Whale and Dolphin Conservation Society published a report in 2003, “Oceans of Noise,” which links the lethal nature of noise for marine mammals with strandings associated with the use of military sonar, such as the mass stranding of beaked whales in the Bahamas in March 2000.

“Despite the many unknowns that remain, it is apparent that noise pollution in the seas should be regarded as a fundamental threat to marine wildlife in general and whales and dolphins in particular,” said Mark Simmonds, WDCS director of science and a member of the Scientific Committee of the International Whaling Commission since 1994. “It is important that this is recognised at both national and international levels and that every effort be made to address it.”

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