National Oceanic and Atmospheric Administration Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing: Acoustic Threshold Levels for Onset of Permanent and Temporary Threshold Shifts (ID43)

NOAA has developed draft guidance for assessing the effects of anthropogenic sound on marine mammal species under NOAA's jurisdiction. The guidance provides updated received levels, or acoustic threshold levels, based on the best available science, above which individual marine mammals are predicted to experience changes in their hearing sensitivity (either temporary or permanent) for all underwater anthropogenic sound sources. This guidance is intended to be used by NOAA analysts and managers and other relevant user groups and stakeholders, including other federal agencies, when seeking to determine whether and how their activities are expected to result in particular types of impacts to marine mammals via acoustic exposure. Although NOAA has updated the acoustic threshold levels from those previously used, and these changes may necessitate new methodologies for calculating impacts, the application of the thresholds in the regulatory context under applicable statutes (Marine Mammal Protection Act, Endangered Species Act, and National Marine Sanctuaries Act) remains consistent with past NOAA practice.

Behavioral threshold levels were originally included in the draft guidance and reviewed by the peer reviewers. NOAA is continuing our examination of the effects of noise on marine mammal behavior and will focus our work over the next year on developing guidance regarding the effects of anthropogenic sound on marine mammal behavior. Behavioral response is a complex question and we determined we still need time to research and address it appropriately. Behavioral guidance will have a separate peer review plan (see ID 274). 

For their Phase 3 Acoustic Effects Analysis, the U.S. Navy recently (January 2015) provided NOAA with a technical paper describing their 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.

Upon evaluation, NOAA preliminarily determined that the Navy's proposed methodology reflects the best available science and are working to incorporate it into our Acoustic Guidance before it becomes final. Before doing so, we commissioned an independent peer review of the Navy's technical paper (i.e., second peer review). 

Additionally, NOAA has re-evaluated its methods for defining threshold usage for sources characterized as impulsive or non-impulsive using comments from the initial public comment period. This proposed methodology also underwent a separate independent peer review (i.e. third peer review).Following these peer reviews, we held a second public comment period (July-September 2015). 

After the second public comment period, while NOAA was working to address additional public comments and finalize the Technical Guidance, NOAA and the Navy further evaluated certain aspects of the U.S. Navy's methodology.  As a result, several recommendations/modifications were suggested. 

After consideration of these recommendations, NOAA has revised the Draft Technical Guidance to reflect these suggested changes and is proposing to solicit public comment on the revised sections of the document (i.e., not the entire document) via a focused 14-day public comment period (March 2016). Concurrent with this third public comment period, NOAA requested that the peer reviewers of the Navy's methodology review the updated sections of the Draft Technical Guidance and indicate whether the revisions would significantly alter any of the comments made during their original review.

Consistent with our Draft Guidance’s finalization procedure, once the follow-up peer review and public comment period processes are complete, NOAA will evaluate how to best incorporate the proposed methodologies into our Final Guidance.

ID: 43 Info. Type: HISA
Estimated Initial Dissemination Date: 12/31/2014
Actual Initial Dissemination Date (because behavioral portion separated out): 2/4/2014 
Estimated and Actual Second Dissemination Date: 6/1/2015 
Estimated and Actual Third Dissemination Date: 7/31/2015 
Estimated and Actual Disseminiation of Peer Review Report as follow-up to second review: 5/20/2016 
Estimated Dissemination Date of Final Work Product: 531/2016
Actual Dissemination Date of Final Work Product: 8/3/2016 

2018 Revised Technical Guidance:

Contact Person: Michael Liddel NOAA Locator 

Date First Posted in Peer Review Agenda: 12/16/2005

Estimated Peer Review Start Date: 7/5/2013 (first), 3/16/15 (second), 4/14/15 (third) 3/16/16 (fourth) 
Review type: individual letters
Expected number of peer reviewers: 4-10
Peer reviewers will be selected by: a designated outside agency. The Marine Mammal Commission nominated peer reviewers for the initial and second peer review. The Acoustical Society of America's Underwater Acoustics Technical Council nominated peer reviewers for the third peer review.

Will the public, including scientific or professional societies, be asked to nominate potential peer reviewers? 
The Marine Mammal Commission nominated peer reviewers. 

Will there be opportunities for the public to comment on the work product to be peer reviewed? yes

How and when? Initial peer review: There was a 45 day public comment period that opened December 27,
2013 and closed March 13, 2014. Additionally, there was a public meeting/webinar held in
Silver Spring, Maryland on January 14, 2014. Second and third peer review: There was a
second 30-day public comment period held subsequent to both peer reviews (July
2015-September 2015). Follow-up to second peer review: Follow-up will occur concurrently
to third 14-day public comment period (March 2016).

Will the agency provide significant and relevant public comments to the peer reviewers before they conduct their review? no

Primary disciplines or expertise needed in the review:Initial peer review: Reviewers had expertise in acoustics, acoustics in the marine environment, acoustic ecology, behavior, and marine mammal hearing. Second peer review: marine mammal hearing and/or noise-induced hearing loss. Third peer review: Sound propagation and physical and operational source characteristics for impulsive sound sources (i.e., high explosives, seismic airguns, and impact pile drivers).

Comments on Peer Review:

The charge statement, peer review nominations and reviewer credentials for the initial peer review 

Initial Peer review report

Letter to second set of peer reviewers 

Second peer review CVs, charge statements and peer review report:

Au: CV, charge statement 

LePrell: CV, charge statement 

Lucke: CV, charge statement 

Terhune: CV, charge statement 

Second peer review report 

Third peer review CVs, charge statements and peer review report:

Burkard: CV, charge statement

Dahl: CV, charge statement

Reichmuth: CV, charge statement

Williams: CV, charge statement 

Third peer review report 

Follow-up to second review: charge statements

Au charge

LePrell charge

Lucke charge 

Terhune charge 

Follow-up to second review - Peer Review Report 

Final work product