The Surveillance Towed Array Sensor System (SURTASS) Low Frequency Active (LFA) Sonar is a long range surveillance sonar the U.S. Navy requires for national security.
   

On August 10th, 2017, the Deputy Secretary of Defense invoked a National Defense Exemption (NDE), as he is authorized to do under the Marine Mammal Protection Act (MMPA), for continued SURTASS LFA sonar testing, training and operations. The Navy developed and employs SURTASS LFA sonar to meet the need for detecting quiet submarines at long range, and the system is critical to the national defense. The current MMPA "Final Rule" for SURTASS LFA sonar activities expires on August 14, 2017. The NDE will run for two years, or until a new Final Rule is issued, whichever comes first. The NDE will provide additional time for the National Marine Fisheries Service (NMFS) and Navy to consider and address issues raised in the rulemaking process. During the exemption period, the Navy will continue to comply with all mitigation and monitoring measures that were included in the proposed MMPA rule plus additional mitigation measures the Navy agreed to after its publication. NMFS issued a biological opinion for the SURTASS LFA sonar activities on August 11, 2017. Download NDE here.

Please see the Frequently Asked Questions page where answers to some commonly asked questions on the NDE are addressed. Additional questions should be directed to the Navy News Desk, (703) 697-5342.

The 2017 to 2022 Biological Opinion-Incidental Take Statement for SURTASS LFA sonar was signed and authorized 11 August 2017. Download here.

The Navy's 2017 Final Supplemental Environmental Impact Statement/Supplemental Environmental Impact Statement (SEIS/SOESI) for Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) Sonar is now available for download
The U.S. Environmental Protection Agency (USEPA) published the notice of availability of the SURTASS LFA Final SEIS/SOEIS on July 7, 2017 (82 FR 129: 31597) (EIS No. 20170121). Download here.

The Navy's August 2016 Draft Supplemental Environmental Impact Statement/Supplemental Overseas Environmental Impact Statement (SEIS/SOEIS) for Employment of Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) Sonar is now available for download.
The U.S. Environmental Protection Agency (USEPA) published the notice of availability of the SURTASS LFA Draft SEIS/SOEIS on August 26, 2016 (81 FR 166). Download here.

The NMFS's April 2017 Proposed Rule is now available for download.

2016 to 2017 ESA and MMPA Incidental Take Permits for SURTASS LFA Sonar.

2015 to 2016 ESA and MMPA Incidental Take Permits for SURTASS LFA Sonar.

The Navy's Notice of Intent (NOI) to prepare a Supplemental Environmental Impact Statement/Supplemental Overseas Environmental Impact Statement (SEIS/SOEIS) for Employment of Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) Sonar was published in the Federal Register (79 FR 37295) on June 5, 2015.

The Navy's March 2015 Supplemental Record of Decision (ROD) for the Final Supplemental Environmental Impact Statement/Supplemental Overseas Environmental Impact Statement (FSEIS/SOEIS) for Employment of Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) Sonar is now available for download.
The Navy published the Notice of Supplemental Decision and Availability in the Federal Register on April 2, 2015 (80 FR 17732); Download here.

The Navy's January 2015 Final Supplemental Environmental Impact Statement/Supplemental Overseas Environmental Impact Statement (SEIS/SOEIS) for Employment of Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) Sonar is now available for download.
The U.S. Environmental Protection Agency (USEPA) published the notice of availability of the SURTASS LFA Final SEIS/SOEIS on January 30, 2015 (80 FR 5109).

The Navy's August 2012 Record of Decision for the Final Supplemental Environmental Impact Statement / Supplemental Overseas Environmental Impact Statement (FSEIS/SOEIS) for Employment of SURTASS LFA SEIS is now available for download.

The Navy's June 2012 Final Supplemental Environmental Impact Statement / Supplemental Overseas Environmental Impact Statement (FSEIS/SOEIS) for Employment of SURTASS LFA SEIS is now available for download.

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