Gray's Reef

photo of scientist with a fish
Brian Degan of the NCCOS Beaufort NC Lab deploys a SoundTrap in Gray’s Reef National Marine Sanctuary. Photo: NOAA

Why is it a concern?

Gray’s Reef National Marine Sanctuary (GRNMS) provides habitat for many acoustically active and sound-sensitive organisms. Gray’s Reef is one of four national marine sanctuaries currently involved in the Underwater Sound Monitoring Program, which aims to better understand the soundscape of the sanctuary. Hydrophone recordings have shown that GRNMS has a more natural soundscape than the other national marine sanctuaries involved in the program, due to the fact that it is not near noise sources such as shipping lanes and oil and gas development. However, increased human activity in the sanctuary, such as diving and fishing, are resulting in higher levels of anthropogenic noise.

The sanctuary’s soundscape consists of some identifiable sounds, like those produced by snapping shrimp, oyster toadfish, and dolphins, however other sounds are still yet to be associated with their origin. Changes in the soundscape caused by anthropogenic noise can act as stressors on marine organisms, and can result in masking signals (such as mating calls, social communication, and echolocation), annoyance (which can lead to physiological stress responses), and behavioral changes (such as noise avoidance) that are often overlooked. The effects of noise on marine organisms remains poorly understood, and further research is necessary to determine how anthropogenic sound influences the living resources in GRNMS.

Overview of Research

Project Name PI and contacts Links

NOAA Ocean Noise Reference Station, University of Georgia


Soundscape Monitoring Program, NOAA

This soundscape monitoring program takes place at Stellwagen Bank, Gray’s Reef, Florida Keys, and Flower Garden Banks national marine sanctuaries. Hydrophones are deployed and the data collected from them will ultimately be used to classify the acoustic signatures of the sites, including relative contributions of human-produced noise, as well as marine wildlife (invertebrates, fish and mammals) and geophysical sources (wind, waves).

Underwater Sound Monitoring Program

Science Needs and Questions

  • Continuously monitor the sanctuary’s acoustic environment, particularly within low frequency bandwidths
  • Monitor long-term variance and trends in underwater ambient noise arising from anthropogenic and natural sources
  • Integrate acoustic and vessel tracking data with other data regarding distribution of sound-producing activities
  • Analyze acoustic data for presence/absence and/or localization of sounds from the marine community
  • Use and develop analytic techniques to combine temporally specific geospatial data sets (e.g., animal behavior, bottom topography, prey fields and received levels of sound)
  • Provide data on spatial and temporal overlap between anthropogenic sound and marine organisms identified as sensitive to soundscape disruption

Education and Outreach Material

Podcast on Noise and Soundscapes in Gray’s Reef National Marine Sanctuary with Dr. Leila Hatch.

NPR All Things Considered Feature Story: There’s a Reef off Georgia’s Coast, And The Animals There Make a Racket with GRNMS Research Coordinator, Kimberly Roberson.

Video, How Hydrophones Record the Ocean Soundscapes with Dr. Jenni Stanley.

Discovery of Sound in the Sea offers many resources related to the issue of noise in the ocean.


Gray’s Reef National Marine Sanctuary Acoustic Impacts to Resources. 11 Dec. 2014.

Samuel, Molly. "There's A Reef Off Georgia's Coast, And The Animals There Make A Racket." WABE, 28 Mar. 2018,

Wright, Andrew J., et al. "Anthropogenic noise as a stressor in animals: a multidisciplinary perspective." International Journal of Comparative Psychology 20.2 (2007)