Sound exposure level as a metric for analyzing and managing underwater soundscapes

• Published in: The Journal of the Acoustical Society of America
• Main Authors: Martin, S. Bruce, Morris, Corey, Broker, Koen, O'Neill, Caitlin
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: PORPOISE PHOCOENA-PHOCOENA; TEMPORARY THRESHOLD SHIFTS; INDUCED HEARING-LOSS; MARINE MAMMALS; IMPULSE NOISE; AMBIENT NOISE; OCEAN; RESPONSES; RECOVERY; HUMANS; Phocoena phocoena
• Online Access: https://hdl.handle.net/11370/f6fda836-5df4-4876-876f-b605c5e5ae8f; https://research.rug.nl/en/publications/f6fda836-5df4-4876-876f-b605c5e5ae8f; https://doi.org/10.1121/1.5113578; https://pure.rug.nl/ws/files/118493853/1.5113578.pdf

The auditory frequency weighted daily sound exposure level (SEL) is used in many jurisdictions to assess possible injury to the hearing of marine life. Therefore, using daily SEL to describe soundscapes would provide baseline information about the environment using the same tools used to measure injury. Here, the daily SEL from 12 recordings with durations of 18-97days are analyzed to: (1) identify natural soundscapes versus environments affected by human activity, (2) demonstrate how SEL accumulates from different types of sources, (3) show the effects of recorder duty cycling on daily SEL, (4) make recommendations on collecting data for daily SEL analysis, and (5) discuss the use of the daily SEL as an indicator of cumulative effects. The autocorrelation of the one-minute sound exposure is used to help identify soundscapes not affected by human activity. Human sound sources reduce the autocorrelation and add low-frequency energy to the soundscapes. To measure the daily SEL for all marine mammal auditory frequency weighting groups, data should be sampled at 64kHz or higher, for at least 1min out of every 30min. The daily autocorrelation of the one-minute SEL provides a confidence interval for the daily SEL computed with duty-cycled data. (C) 2019 Acoustical Society of America.