Ecological Acoustic Recorder

A Powerful Tool for Monitoring Coral Reef Ecosystems

Reefs in remote locations are difficult to monitor. The Coral Reef Ecosystem Division (CRED) and the Hawaiʻi Institute of Marine Biology, University of Hawaiʻi at Mānoa, use ambient marine sound to characterize the activities of marine organisms in coral reefs and their surrounding waters. By deploying an Ecological Acoustic Recorder (EAR), scientists can learn about the presence and activities of marine mammals, fishes, crustaceans, and other sound-producing marine life. For more information on the method of EAR, click here.

Long-term observations provide an understanding of interactions within coral reef communities. However, most monitoring instruments lack the ability to observe biological processes. An EAR provides a cost-effective tool for monitoring biological processes and human activities in marine environments. It can be left in place unattended for months at a time.

An EAR deployed on a rock floor of a coral reef in American Samoa. NOAA photo.
An EAR deployed on a rock floor of a coral reef in American Samoa. NOAA photo.

Using EARs to Monitor Coral Reef Ecosystems

Noise from vessel traffic can trigger the EAR's event detection hardware, providing a record of noise from human activities.
Noise from vessel traffic can trigger the EAR's event detection hardware, providing a record of noise from human activities.

The Pacific Islands Fisheries Science Center and the Hawaiʻi Institute of Marine Biology (HIMB), University of Hawaiʻi at Mānoa, developed the EAR program for these purposes:

  • Establish patterns of sound-producing organisms in nearshore waters
  • Monitor sound-producing marine species and their patterns and activity levels.
  • Establish long-term trends in acoustic activity of reef organisms (e.g., fishes and shrimps) and observe changes within seasons, temperature, currents, and tidal cycles, among other environmental influences
  • Determine levels of human activity, like blast fishing and vessels, in remote locations and marine protected areas
  • Develop ways to relate ambient sound to events like coral bleaching, storm damage, or disease outbreaks

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