Sonar-free zones proposed for marine mammals' sake

By Jan TenBruggencate
Advertiser Science Writer

The Navy's new low-frequency sonar system booms through the ocean, detecting enemy submarines at distances much greater than with standard sonar.

The Navy's proposed tests would broadcast sounds into waters frequented by marine mammals, including the humpback whale. Environmentalists fear the noise generated by the sonar tests could harm the animals, which rely on sound to communicate. Advertiser library photo

The system's official name is Surveillance Towed Array Sensor System Low Frequency Active Sonar.

The National Marine Fisheries Service says the sonar "has the potential to harass marine mammals incidental to its operation."

The Navy denies that it is a serious threat to marine life, but is willing to limit the new sonar's use. The fisheries service is proposing to grant the Navy a five-year "incidental take" permit to operate the intrusive sonar system if it agrees to avoid "offshore biologically important areas" — where marine mammals are known to gather for breeding, feeding, migrating and calving. A public hearing is set for 1 to 5 p.m. Saturday at the Marriott Waikiki Hotel.

One area of concern is Penguin Banks, the shallow shelf that extends from the western end of Moloka'i into the Kaiwi Channel.

The banks would be off limits to the sonar system from Nov. 1 to May 1 each year when humpback whales are present. Penguin Banks is part of the Hawaiian Islands Humpback Whale National Marine Sanctuary. Other areas are off the U.S. East Coast, the Antarctic Convergence Zone, and an area called the Costa Rica Dome.

The Navy says the system meets its need "for improved capability to detect quieter and hard-to-find foreign submarines at long range."

The sonar was tested in Hawai'i in 1998. The Navy did not find that humpback whales were harmed, but noted changes in singing behavior in response to the sonar. Last year, several species of marine mammals beached themselves and several died in the Bahamas after Navy sonar testing in a shallow-water trench in the region.

Necropsies showed six whales died from hemorrhaging around the brain and ear bones. The mid-frequency sonar that was used has been around since World War II and it would be wrong, the Navy says, to assume a low-frequency sonar system could result in the same tragedy.

Environmentalists point to that case as proof that high-power sonar can disorient and kill whales and other sea mammals. "It is undeniable evidence of just how dangerous and unpredictable intense sound can be in the ocean," said attorney Joel Reynolds of the Natural Resources Defense Council.

Details of the sonar system are available on the Web. For more on the National Marine Fisheries Service undersea noise programs, see this Web site.

National Oceanic and Atmospheric Administration Fisheries will accept written comments on the proposal until May 18. Address comments to Donna Wieting, Chief, Marine Mammal Conservation Division, Office of Protected Resources, National Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910-3225.

Los Angeles Times contributed to this report.