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Highlights
Why the United States Needs SURTASS LFA
SURTASS LFA Systems Description
Key Facts
Enviromental Impact Analysis
Scientific Research
Preventative Measures
Frequently Asked Questions
Frequently Asked Questions
Diver Studies
Terminology
Glossary
Files To Download
Contact Us
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SURTASS LFA
SURTASS LFA

Why Active Sonar?

Passive Sonar

Active Sonar

Passive Sonar    Active Sonar

Relative Loss of Sonar Capability

For more details click here

Continue with introduction


Environmental Concerns

The environmental concern is that LF sound will disturb and/or injure marine life.

What is disturbance?
  • Technically, disturbance ranges from any noticeable behavioral change to severe avoidance.

What is injury?

  • Injury includes tissue damage, permanent threshold shift in hearing, and in some cases, resonance on internal organs. Note: Resonance does not necessarily equal damage and damage is not always linked to resonance.

The SURTASS LFA Environmental Impact Statement (EIS) effort started in 1996:

  • Misunderstandings and difficulties of communication between scientists and the public led to opposition by environmental organizations and concerned individuals.
  • For example, the Navy has applied for a permit for the incidental taking of marine mammals associated with the use of SURTASS LFA.
  • Many concerned citizens believe “take” means to "kill” and that the Navy is requesting authorization to harm thousands of marine mammals. This is wrong.
  • “Take" means only that the animal will be in a region where it may hear the sound and may possibly respond in some way.
What did the Navy do to analyze disturbance? Click HERE to see.

What did the Navy do to prevent injury? Click HERE to see.

For more details on the potential for resonance to cause damage in marine mammals, click HERE.

Click HERE for NRDC's Report Sounding the Depths: Supertankers, Sonar, and the Rise of Undersea Noise

For more details on the Navy's application for a permit for the incidental taking of marine mammals associated with the use of SURTASS LFA, click HERE.

Continue with introduction


What did the Navy do to analyze disturbances?

Assembled a team of independent marine biologists: 
Dr. Chris Clark
Dr. Chris Clark
(Click here for resume)
Dr. Kurt Fristrup
Dr. Kurt Fristrup
(Click here for resume)
Dr. Peter Tyack
Dr. Peter Tyack
(Click here for resume)
Marine mammals rely on sound for a wide variety of critical functions (much as terrestrial animals use light).  Because baleen whales use low frequency (LF) sound, they were selected as indicator species for a 3-phase Scientific Research Program (SRP).
4 species of baleen whales were studied in the SRP:

Blue Whale Fin Whale Gray Whale Humpback Whale 
Blue Whale           Fin Whale          Gray Whale       Humpback Whale

   
An independent scientific team, under controlled experimental conditions, played SURTASS LFA signals and observed whale behavior.
 
Phase I Map Phase II Map Phase III Map
Click Here for
more details about
Phase I
Click Here for
more details about
Phase II
Click Here for
more details about
Phase III

Continue with introduction


Scientific Research Program

Phase I - blue and fin whales feeding

            Research Approach                                  Results

Research Approach
(Click on the picture to see a larger version)

  • 19 animal observations

  • No overt behavioral responses

  • No changes in whale
    distribution could be related to LFA operations

Phase II - gray whales migrating

Shore Observers

                  Results 

Shore Observers

Source in migration corridor - whales changed course to avoid it.

Source in
migration corridor
- whales changed course to avoid it
Source moved farther offshore with higher noise level to achieve same received level in migration corridor - whales did not change course. Source moved farther offshore with higher noise level to achieve same received level in migration corridor
-whales did not change course
Phase III - humpback whales breeding

Scientists on Cory

Results

Scientists on Cory

Risk function against all measured ping received levels

Based on the findings from the Scientific Research Program, SURTASS LFA can be operated safely and effectively, under the proposed geographic and monitoring mitigation measures.

Continue with introduction


Based on the best available scientific information, the risk of injury (including that from resonance effects) from SURTASS LFA is confined to a relatively small area very close to the vessel.

In order to mitigate the possibility of injury, the Navy designed, developed, tested, and validated a High Frequency Marine Mammal Monitoring (HF/M3) sonar.
HF/M3 Tow Surtass Receive Array Mitigation Zones
(Click on the picture to see a larger version) (Click on the picture to see a larger version) (Click on the picture to see a larger version)
The HF/M3 sonar will provide very high probability that no marine mammal will be exposed to high sound levels in the LFA mitigation zone (at or above 180 dB.)

The HF/M3 sonar has been tested and its performance validated with controlled bottlenose dolphins in August 2000 off the southern California coast. Click HERE for more details. 

The Navy continues to pursue marine mammal research: $7M in 2001 and approximately $12M in 2002. Click HERE for more details.  


           

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| Highlights | Why the United States Needs SURTASS LFA |
| SURTASS LFA Systems Description | Key Facts | Environmental Impact Analysis |
| Scientific Research | Preventive Measures | Public Involvement |
| Frequently Asked Questions | Diver Studies | Terminology |
|
Glossary | Files to Download | Contact Us |
| Home |

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