Marine Mammal Protection Act Public Comment Period

NOAA Fisheries is requesting information, suggestions, and comments concerning the Navy’s request for rulemaking and subsequent Letter of Authorization under the Marine Mammal Protection Act to govern the incidental take of marine mammals by the U.S. Navy’s Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) SONAR training and testing activities conducted under the authority of the Secretary of the Navy in the western and central North Pacific and eastern Indian Oceans beginning in August 2019.


The public is invited to comment on the proposed regulations here-

This will be NOAA Fisheries’ fourth rule for SURTASS LFA sonar operations under the Marine Mammal Protection Act. NOAA Fisheries’ proposed regulations and the subsequent Letter of Authorization will include required mitigation, monitoring, and reporting measures. For training and testing activities of the proposed action, these measures include:

  • Restricting the use of SURTASS LFA sonar such that it will not operate in Arctic and Antarctic waters;

  • Restricting the use of SURTASS LFA sonar from within the foreign territorial seas of other nations;

  • Restricting the use of SURTASS LFA sonar from within Hawaiian state waters (out to three miles) and over Penguin Bank, and ensuring that sound pressure levels (SPL) will not exceed 145 decibels (dB) within Hawaiian state waters;

  • Ensuring SPLs will not exceed 180 dB re 1 micro pascals (µPa) root mean square (rms) within 12 nautical miles of any emerged features of any coastline, or within designated offshore biologically important areas (OBIAs) for marine mammals; and

  • Minimizing exposure of marine mammals to SURTASS LFA sonar signal received levels of 180 dB re 1 µPa (rms) or more by suspending sonar transmission when animals enter the mitigation zone and using a highly effective monitoring program to detect their presence.


The Navy’s activities are likely to result in the incidental take of marine mammals by exposing them to low frequency sonar signals. The potential takes expected for this action are Level B harassment. No level A harassment takes (potential injury) are expected based on results from the past 16 years of operations and computer modeling of potential takes. No lethal takes are requested or expected for this action.

Please visit for more information on NOAA?s incidental take program under the MMPA.

More information on the SURTASS LFA action is available here -