Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing

The Technical Guidance 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.