Since the U.S. Navy and the National Marine Fisheries Service (NMFS) continue to ignore the scientific warnings about powerful active sonars, animal and environmental advocates have turned to the federal courts to stop the use of these potentially lethal devices.

The HSUS is a co-plaintiff—along with the League for Coastal Protection, Cetacean Society International, Ocean Futures Society, and Jean-Michel Cousteau—in a suit filed August 7 by the Natural Resources Defense Council (NRDC) against the Navy and NMFS. The suit seeks to enjoin the Navy from deploying Surveillance Towed Array Sensor System (SURTASS) Low Frequency Active (LFA) sonar in the world's oceans.

The NRDC, The HSUS, and the others charge that the defendants are in violation of the Marine Mammal Protection Act (MMPA), the Endangered Species Act, and the National Environmental Policy Act.

In July, after years of controversy and debate, NMFS gave the U.S. Navy the go-ahead to use SURTASS LFA sonar despite a growing body of evidence that indicates human-generated noise—including active sonars—has a negative effect on marine mammals.

The NMFS officially exempted the Navy from a rule under the Marine Mammal Protection Act (MMPA), which prohibits incidental "take," defined as "to harass, hunt, capture, or kill, or attempt to harass, hunt, capture or kill" marine mammals with active sonars or other means. The Navy had applied for a "small take exemption" under the MMPA in 1999. The exemption will allow the Navy to use SURTASS LFA sonar for five years on two ships in oceans worldwide.

The sonar technology is the latest method for detecting increasingly quiet submarines. Unlike passive sonars, which merely listen, LFA and other active sonars transmit a loud sound, and then record the sound's echoes as it bounces off objects in its path.

In an environmental impact statement based on incomplete data, interpreted to support its aims, the Navy claimed that LFA sonar would not significantly harm marine life. A mass stranding of minke and beaked whales (and a dolphin) in the Bahamas in March 2000, caused by mid-frequency sonar, forced the Navy to acknowledge that some sonar could be deadly to marine mammals. But the Navy claims LFA sonar is safe.

The naval ships will take to the Atlantic and Pacific oceans, manned with 18 loudspeakers, each producing approximately 215 decibels of sound. (Which is the equivalent to about 150 decibels in the air, since the measurement scales are different for sounds in air and water.)

As part of the exemption, the NMFS has established a 180-decibel safety range based on the "best available science to date." If a ship locates a marine animal close enough to detect sounds at 180 decibels, the ship must cease operation of the LFA sonar. In setting the safety standard, however, the NMFS ignored a vast number of comments submitted by scientists who disputed that conclusion. These scientists believe that 180 decibels is a recklessly non-precautionary standard, given that the Navy's "best available science" only tested animal reactions up to an exposure level of 155 decibels—almost 1,000 times less powerful (the decibel scale is a logarithmic scale).

The NMFS estimates that marine animals within a kilometer of the sonar will be within the 180-decibel range. It relies on the ships to detect any animal within that range and to immediately shut off the LFA sonar until that mammal has left the area.

The Navy has proposed three methods of detection: 1. visual, using crew members specifically trained to locate marine mammals at sea during daylight hours; 2. passive, using the SURTASS sonar's hydrophones to detect vocalizing marine mammals; and 3. active, using (fish finding) sonar methods. Unfortunately, none of these methods is 100% reliable, and deep-diving animals, such as beaked whales who spend little time at the surface and have already shown a vulnerability to active sonars, are not likely to be detected.

"The 180-decibel safety zone is an arbitrary one," says Dr. Naomi Rose, HSUS marine mammal scientist. "There is no scientific basis for the assertion that marine mammals will not be harmed by this level of sound, nor that their calving, breeding, feeding, and communication behavior will not be disrupted, at times with fatal consequences."

In exempting the Navy from the MMPA prohibition on incidental take, the NMFS is admitting that LFA sonar harms marine mammals. However, it has determined that the number harassed will be "negligible"—that is, will not jeopardize the survival or population of any species. The permit requires that the Navy take various mitigation measures, which may or may not be adequate to protect marine life, and that it monitor and report the effects on marine mammals. The NMFS will review the exemption annually, relying on the reports of Navy personnel, to asses the effect of LFA sonar use on marine life.

"Given the Navy's investment in the use of LFA," observes Rose, "It is not unreasonable to doubt its ability to present unbiased reports on LFA's effects not only on marine mammals, but also fish and other marine life about which we know very little."

What You Can Do

Contact your legislators in Congress. Tell them that LFA poses a serious threat to marine life. Ask them not to allow a weakening of the MMPA that would make it easier for the Navy to use this kind of noise-producing technology.