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September 25, 2009

Sonar: Acoustic Harassment

U.S. Navy poses risk to endangered and threatened species when using low frequency sonar

The Humane Society of the United States

Surveillance Towed Array Sensor System Low Frequency Active sonar is the U.S. Navy's newest must-have defense technology. The Navy claims that LFA sonar will be able to detect today's "quieter" submarines so reliably that it plans to deploy LFA routinely throughout most of the world's oceans. The only problem is that LFA sonar may harm whales and other marine mammals. This sonar will generate one of the loudest sounds that human beings can make in the ocean. Worse, because they are low-frequency in nature, these sounds can travel for hundreds of miles, effectively ensonifying thousands of cubic miles of ocean.

The Humane Society of the United States fears that LFA sonar may pose too great a risk of causing severe adverse effects to marine animal populations. LFA may damage or destroy marine mammal hearing, as well as disrupt calving, breeding, feeding, and communication. There may be other impacts, too, like those seen when a glass shatters as an opera singer hits a high note. A sound wave can cause material that resonates in its frequency to vibrate, shatter, shear, or tear. Some air spaces in mammals (and fish) may react to LFA sonar in this manner. All of this is too high a price to pay for questionable security against the latest breed of submarines.

The Navy has produced an Environmental Impact Statement, as required by law, to assess the effects of LFA sonar technology on the marine environment. Based on the EIS, the National Marine Fisheries Service is producing regulations that would govern how LFA sonar could be used in the world's oceans. The HSUS (along with several other organizations) believes the Navy and NMFS are proceeding without giving adequate consideration to the potential harm LFA sonar could inflict on the marine environment. We have produced comments at every step of the regulatory process, and we have communicated via various channels with the Navy, NMFS, and Congressional officials expressing our concerns about LFA sonar. Our principal concern is that the environmental analyses upon which the Navy and NMFS are relying have several shortcomings:

 

  • Their assessments are based on insufficient data about how sound affects marine mammals, sea turtles, and other marine animals.

  • They overinterpret the small amount of data available on sound and marine mammals, and reach non-precautionary (and poorly supported) conclusions that LFA sonar will not harm marine mammals in any significant way.

  • They fail to adequately consider the possibility that LFA sonar could seriously injure and even kill marine mammals, sea turtles, and other marine animals. At the same time, they place unjustified confidence in the Navy's ability to prevent such injuries and deaths through detection of marine animals within a "zone of exclusion" around the sound source.

  • They do not discuss alternate hypotheses for observed marine mammal reactions to loud, low-frequency sound.

  • They set an arbitrary standard for the level of sound that will harass or injure marine mammals and sea turtles. This standard has no empirical basis and is vastly less precautionary than standards being established by other countries.

  • They neglect to adequately discuss the shortcomings of LFA sonar in accomplishing the Navy's goal of detecting "quiet" enemy submarines while remaining undetected itself.

In March 2000, a mass stranding of beaked whales, minke whales, and one dolphin occurred off the Bahamas after a Navy exercise in which mid-frequency active sonars were used. While beaked whale mass strandings have occurred in the past (many coincident with nearby naval maneuvers), this was the first time that a qualified scientist was on hand to collect the appropriate samples from fresh carcasses to determine cause of death. The most recent results of the on-going investigation into this incident indicate that these whales died from the impacts of a loud sound acting on their air spaces—that is, from resonance effects. The Navy has had to admit that mid-frequency sonars may pose a serious risk to certain marine mammal species; even so, it continues to maintain that LFA sonar, which operates at a lower frequency than the Bahamas sonars, will be safe for all marine mammals. The HSUS strongly objects to this cavalier interpretation.

While The HSUS recognizes the need to develop a system capable of protecting our servicemen and women against a new generation of submarines, LFA and other active sonars pose a terrible risk to endangered and threatened marine species. The Navy should abandon plans to deploy LFA sonar worldwide and focus instead on other promising technologies that do not pose such a risk. It must also reevaluate its use of all active sonars and consider mitigation measures that will protect marine mammals from the negative impacts witnessed in the Bahamas.

more information in PDF format

Testimony on LFA Sonar

Commentary on Draft Environmental Impact Statement on SURTASS LFA Sonar

Commentary on the Proposed Rule Regarding Taking of Marine Mammals During SURTASS LFA Sonar Operations

Presentation at Acoustical Society of America Conference

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