FY21 LIVING MARINE RESOURCES (LMR) PROGRAM ENVIRONMENTAL NEED TOPICS

The purpose of this requirement is for a research project to investigate the potential relationship between perceived loudness and signal length in marine mammals in support of Naval Facilities Engineering Systems Command (NAVFAC) Engineering and Expeditionary Warfare Center (EXWC), Environmental, Living Marine Resources (LMR) Program. To remain in compliance, the U.S. Navy is required to assess the potential impacts to marine species from training and testing activities. There is a research need to understand at what duration of noise signal length marine mammals no longer perceive a signal, i.e. during such training and testing. Unlike physiological impacts (i.e., Temporary Threshold Shift, Permanent Threshold Shift), marine mammal behavioral response to noise is likely mediated by both context and perceived components of the signal rather than physical characteristics alone. One of the perceptual components of sound is the perceived loudness. Loudness is a psychoacoustic measure which does not track linearly with increase in signal amplitude. One factor that may lower perceived loudness and therefore reduce the potential for a behavioral response is the length of the signal. This project will further investigate the potential relationship between perceived loudness and signal length in marine mammals in order to understand the duration of which the signal is no longer perceived. The Period od Performance is from 3 November 2021 to 31 December 2023.