The effects of noise on marine life is a huge area of study (it even has its own conference!) but I find I'm very overwhelmed when trying to explain to a non-biologist or non-acoustician what those effects are, why we should care, and what sound levels are harmful, etc. Besides very broad discussions of the various impacts of noise (dosits.org has a nice little write up), I would like to know what the "law" is on what sound levels are "too loud". Where can I find those numbers?


2 Answers 2


The most recent official document is the "2018 Revision to: Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0) put forth by the Office of Protected Resources division of NOAA (National Oceanic and Atmospheric Administration). The full document can be found here:


Suggested citation:

National Marine Fisheries Service. 2018. 2018 Revisions to: Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0): Underwater Thresholds for Onset of Permanent and Temporary Threshold Shifts. U.S. Dept. of Commer., NOAA. NOAA Technical Memorandum NMFS-OPR-59, 167 p.

The onset of a permanent threshold shift (PTS, indicating permanent change in hearing thresholds) is given for each of 5 marine mammal hearing groups and range from 155 dB to 232 dB, depending on the type of sound (impulsive vs non-impulsive) ;and the measurement type (peak sound pressure level vs weighted cumulative sound exposure level).

Table ES3 from National Marine Fisheries Service 2018


This NOAA website has some summaries of efforts within the United States, as well as helpful links and example data that may be accessible for non-experts.

For example: https://media.fisheries.noaa.gov/2022-05/MM%20Acoustic%20Thresholds%20%28508%29_secure%20%28May%202022%29.pdf


The main site is: https://oceannoise.noaa.gov


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