Marine Mammal Acoustic Technical Guidance
2018 Revision to: Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing
Purpose of the Technical Guidance
The Technical Guidance (PDF,178 pages) provides thresholds for onset of permanent threshold shift (PTS) and temporary threshold shifts (TTS) in marine mammal hearing for all underwater 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.
To develop these 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 Guidance outlines NOAA Fisheries' 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.
2017 Presidential Executive Order 13795
Section 10 of the Presidential Executive Order 13795, Implementing an America-First Offshore Energy Strategy (April 28, 2017) called for a review of the 2016 Technical Guidance. To assist the Secretary of Commerce in his review under EO 13795, NOAA Fisheries conducted a 45-day public comment period that opened on May 31, 2017 and closed July 17, 2017 (82 FR 24950) and held a meeting with federal agencies (September 25, 2017). Comments received are available on regulations.gov. Additional information on the review process under Executive Order 13795 can be found in Appendix C of the 2018 Revised Technical Guidance.
Revised Technical Guidance (2018)
NOAA Fisheries’ evaluation of comments received during this review affirms that the Technical Guidance is based upon the best available science. The threshold levels established in the 2016 Guidance will remain the same. Applicants when referring to Technical Guidance or its associated optional user tools should refer to the 2018 revised version of this document, not the 2016 version of the Technical Guidance.
NOAA Fisheries has revised the Technical Guidance to address implementation concerns and facilitate its use by applicants, thereby further advancing the intent of E.O. 13795. Specifically, we updated the optional User Spreadsheet tool to provide more capabilities for applicants and developed a new instructional manual for this optional tool. We also plan on convening two working groups in 2018, one to explore impacts of noise on low-frequency cetacean (baleen whale) hearing and the second to explore exposure duration for all marine mammal species. We will continue to coordinate with Federal Agencies to advance our understanding of the impacts of sound on marine mammals.
In 2018, NOAA Fisheries held a 45-day public comment period (83 FR 48291) for user feedback to help improve the usability of our optional User Spreadsheet Tool and Instruction Manual for User Spreadsheet Tool. Comments received are available on regulations.gov. In July 2020, NOAA Fisheries made some technical updates to the optional User Spreadsheet tool, as well as developed a web version of the tool (Web Calculator Tool) and corresponding instruction manuals.
In association with this 2018 public comment period, the International Association for Geophysical Contractors (IAGC) submitted their final comments to NOAA Fisheries in late 2020 (IAGC Supplemental User Guide and IAGC Alternative Calculator). Based on recommendations where NOAA Fisheries concurs with IAGC, NOAA Fisheries made additional modifications to our optional User Spreadsheet tool and associated User Manual (December 2020).
Both tools will be updated as new science or information becomes available. NOAA Fisheries plans to evaluate these tools on a regular basis (before the end of each calendar year) to incorporate any necessary updates.
- 2018 Revision to Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (PDF,178 pages)
- User Spreadsheet Tool (optional) (MS Excel) (Updated December 2020)
- Instruction Manual for User Spreadsheet Tool (optional) (PDF, 103 pages) (Updated December 2020)
- Web Calculator Tool (optional) (R-Shiny) (July 2020)
- Instruction Manual for Web Calculator Tool (PDF, 62 pages) (July 2020)
Development of 2016 Technical Guidance
The 2016 Technical Guidance underwent an internal review, three external peer reviews, a follow-up peer review, 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)
More information about these additional peer reviews
First Public Comment Period
The comment period on the initial draft guidance opened in December 2013 (78 FR 78822) and closed on March 13, 2014 (79 FR 4672). Comments received are available on regulations.gov.
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 (Download File PDF, 10 pages) from the meeting is available as well as the Public Meeting One-Pager (Download File PDF, 2 pages) and Presentation (Download File PDF, 17 pages).
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.
Finalization of 2016 Technical Guidance
The 2016 Technical Guidance was finalized on August 4th, 2016 with publication of a Federal Register Notice (81 FR 51693), which included:
- 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
Other NMFS Acoustic Thresholds and Tools
- Summary of Marine Mammal Protection Act Acoustic Thresholds
- Summary of Endangered Species Act Acoustic Thresholds (Fishes and Sea Turtles)
- Introduction to NMFS’s Multi-Species Pile Driving Calculator and Associated Multi-Species Pile Driving Calculator
Recommendation for High-resolution Geophysical Source & Transmission Loss Analysis and Associated Level B Harassment Isopleth Calculator
Acoustic Guidance for Assessment of Down-the-Hole (DTH) Systems
For more information, please contact:
Amy R. Scholik-Schlomer
NMFS Protected Resources Acoustic Coordinator
1315 East West Highway
Silver Spring, MD 20910