Groups fight Navy's low-frequency sonar
April 16, 1998
The Navy finished controversial low-frequency sound tests on humpback whales in March
Web posted at: 6:46 p.m. EDT (2246 GMT)
By Environmental News Network staff
(ENN) -- Environmentalists around the world are alarmed at the possibility that low-frequency sound tests, similar to those just concluded by the Navy off the coast of Hawaii, may have been responsible for a mass stranding of Cuvier's beaked whales in the Ionian Sea in 1996.
Environmental groups and a number of cetacean scientists are campaigning against the U.S. Navy's Low-Frequency Active Sonar (LFAS) because they fear it will harm all marine mammals. The system has been under development for the past decade in response to a new generation of "quiet" nuclear and diesel electric submarines.
According to the National Oceanic and Atmospheric Administration (NOAA), hearing is a marine mammal's most important sense. LFAS consists of very loud, very
low-frequency sounds designed to carry long distances underwater. It was developed by the Navy to detect submarines across large distances.
To test the system, the Navy targeted a series of sonic "pulses" of increasingly higher decibel levels at whales from progressively closer distances until and unless the whales showed any signs of distress or noticeable changes in behavior.
The tests began off California in 1997 and concluded off Hawaii in March. A coalition of environmental groups sued to stop the tests, but the suit was dismissed by the courts, and the tests continued.
Although no one can say for sure what the long-term impacts of low-frequency sound will be, environmentalists are concerned that noise being broadcast at 195 decibels could disrupt whale migrations, breeding, mating and feeding, and potentially damage countless other forms of aquatic life. According to the U.S. Marine Mammal Commission, "If the LFA sonar system is made available for worldwide employment as proposed, all species and populations of marine mammals could possibly be affected."
The tests in Hawaii took place during the peak of the humpback whale birthing and breeding season in an area designated as a whale sanctuary.
Meanwhile, in the March 5 edition of Nature, A. Frantzis of the Department of Biology at the University of Athens, Greece, suggests LFAS may have been to blame for the strandings of 12 Cuvier's beaked whales in Kyparissiakos Gulf in the Ionian Sea, May 12-13, 1996. The species is
deep-diving and very rarely mass strands.
After looking for possible causes of the stranding, Frantzis and colleagues discovered that the NATO Research Vessel Alliance had been conducting LFAS tests the day prior to the strandings.
Noting that LFAS tests had previously been tentatively linked with Cuvier's strandings elsewhere, Frantzis concluded in the Nature article, "We know that LFAS was used in Kyparissiakos Gulf. We also know that no other LFAS tests or mass strandings have occurred in the Greek Ionian Sea since 1981. Taking the past 16.5-year period into account, the probability of a mass stranding occurring for other reasons, during the period of the LFAS tests is less than 0.07 percent. Although pure coincidence cannot be excluded, it seems improbable that the two events were independent."
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