NOAA's Marine Mammal Acoustic Technical Guidance
NOAA Technical Memorandum: Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing
Purpose of the Acoustic Guidance
The Technical Guidance provides acoustic thresholds for onset of permanent threshold shift (PTS) and temporary threshold shifts (TTS) in marine mammal hearing for all sound sources. It is intended to be used by NOAA analysts and managers, other federal agencies, and other relevant user groups/stakeholders to better predict how a marine mammal’s hearing will respond to sound exposure. The manner of response has the potential to trigger certain requirements under one or more of NOAA’s statutes (MMPA, ESA, and National Marine Sanctuaries Act).
To develop these acoustic thresholds, NOAA Fisheries compiled, interpreted, and synthesized best available information on the effects of anthropogenic sound on marine mammals' hearing, as well as developed a method for updating these levels through a systematic, transparent process. The document outlines NOAA Fisheries' updated acoustic thresholds and describes in detail how the thresholds were developed and how they will be updated in the future.
Due to the complexity and variability of marine mammal behavioral responses, NOAA will continue to work over the next years on developing additional guidance regarding the effects of anthropogenic sound on marine mammal behavior.
Process to Develop Acoustic Technical Guidance
The Technical Guidance has undergone an internal review, three external peer reviews, three public comment periods, and received informal input from key federal partners
External Peer Reviews
The first 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 thresholds. (Report link)
The second external peer review evaluated a U.S. Navy Technical paper provided to NOAA in January 2015 as part of the Navy's Phase 3 Acoustic Effects Analysis. The paper describes the Navy's proposed methodology for updating auditory weighting functions and subsequent numeric thresholds for predicting auditory effects (TTS/PTS thresholds) on marine animals exposed to active sonars and other active acoustic sources utilized during Navy training and testing activities. (Report link)
Follow-up to second external review: Concurrent with the third public comment period, NOAA requested that peer reviewers of the Navy's methodology review the updated sections of the Draft Guidance and indicate whether the revisions would significantly alter any of the comments made during their original review. (Follow-up peer review charge link)
The third external peer review evaluated proposed methodology for defining threshold usage for sources characterized as impulsive or non-impulsive. This methodology was modified using comments from the initial public comment period. (Report link)
First Public Comment Period
During this time 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 available as well as the Public Meeting One-Pager [pdf] and Presentation [pdf].
Second Public Comment Period
The second public comment period opened on July 31, 2015 and closed September 14, 2015 (80 FR 45642). Comments received are available on regulations.gov.
Third Public Comment Period
The third public comment period opened on March 16, 2016 and closed March 30, 2016 (81 FR 14095). Comments received are available on regulations.gov.
The following additional information and resources are provided as part of the Technical Guidance's finalization:
- Federal Register Notice, including:
- Responses to relevant and substantive comments made during all three public comment periods
- Explanation on how NOAA and applicants should transition to use of this Technical Guidance
- Optional User Spreadsheet: a companion spreadsheet associated with alternative methodology provided in Appendix D of the Technical Guidance
- Informational Presentations: providing additional information on various aspects of the Technical Guidance
Frequently Asked Questions Regarding NOAA Fisheries' Technical Acoustic Guidance are also available (updated August 2016).
For more information, please contact:
Amy R. Scholik-Schlomer
NMFS Protected Resources Acoustic Coordinator
1315 East West Highway
Silver Spring, MD 20910
Updated: March 23, 2017