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NOAA's Marine Mammal Acoustic Guidance

Status of NOAA's Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammals

The National Oceanic and Atmospheric Administration (NOAA) is developing acoustic guidance for assessing the effects of anthropogenic sound on marine mammal species [pdf] under our jurisdiction.

Specifically, the Guidance provides acoustic threshold levels for onset of permanent threshold shift (PTS) and temporary threshold shifts (TTS) for all sound sources. It is intended to be used by NOAA analysts/managers and other relevant user groups/stakeholders, including other federal agencies to better predict a marine mammal’s response to sound exposure in a manner that has the potential to trigger certain requirements under one or more of NOAA’s statutes (e.g., MMPA, ESA, and National Marine Sanctuaries Act). Due to the complexity and variability of marine mammal behavioral responses, NOAA will continue to work over the next year on developing guidance regarding the effects of anthropogenic sound on marine mammal behavior.

To develop these acoustic threshold levels, NOAA has compiled, interpreted, and synthesized best available information currently available on the effects of anthropogenic sound on marine mammals, as well as developed a method for updating these levels through a systematic, transparent process. The document outlines NOAA's updated acoustic threshold levels and describes in detail how the thresholds were developed and how they will be updated in the future.

Where are we in the Process?
We are in the public comment step of the process. The process to finalize the guidelines includes the following steps:

  1. NOAA internal review
  2. External peer review
    » Peer Review Report [pdf]
  3. Public comment
  4. Finalize and release guidance

NOAA's draft acoustic Guidance [pdf] has undergone an internal review, an external peer review, and received informal input from key federal partners. The external peer review, which was completed September 2013, focused on the scientific and technical studies used in the analysis for the development of proposed onset PTS and TTS acoustic threshold levels.

Comment on the Draft Guidance

The comment period on the draft guidance opened in December 2013 (78 FR 78822) and closed on March 13, 2014 (79 FR 4672). Comments received are available on

Public meeting/ webinar

NOAA Fisheries held a public meeting to inform interested parties and solicit comments on the proposed acoustic guidance. The meeting was held on January 14, 2014, in the NOAA Science Center in Silver Spring, MD. A transcript from the meeting is now available.

Meeting materials:

Once the peer review and public comments are addressed, NOAA will finalize and release the acoustic guidelines for onset PTS and TTS.

Frequently Asked Questions Regarding NOAA's Acoustic Guidance are also available (updated Nov 2014).

For more information, please contact:

Amy R. Scholik-Schlomer
NMFS Protected Resources Acoustic Coordinator
1315 East West Highway
Silver Spring, MD 20910

Updated: November 5, 2014