Acoustics

Acoustics Research and Gallery

Dr. Aaron Thode leader of Acoustic investigations

Dr. Aaron Thode of Scripps Institution of Oceanography at the University of California in San Diego, California began investigations of the underwater sounds and noise in Laguna San Ignacio in 2005. Dr. Thode and his graduate researchers are continuing these on going investigations today.

The goal of the acoustics research program is to document the numerous sources of underwater sound in the lagoon, including gray whale sounds, and to monitor those sources of sound over time to identify trends and changes in physical, biological and man-made noise in the lagoon.

Recording Techniques & Methods:

Acoustic team in Laguna San Ignacio

The primary method for monitoring and recording underwater sounds in the lagoons is to place digital recording devices on the bottom of the lagoon in specific areas, and to record the underwater sounds for a month or more each winter. Another method is to use a “hydrophone” or underwater microphone to record sounds from a boat drifting in the lagoon or attached to a whale with suction-cups. Our acoustic researchers have documented the sounds of wind, rain, and the changing tides in the lagoon. Also the sounds of invertebrates like “snapping shrimp” fish, and of course the vocalizations of gray whales during the winter. Researchers have also recorded and monitored the presence and numbers of fishing and whale-watching boats that operate in the lagoon. All of these recordings have documented the diversity of sounds in the lagoon and their seasonal trends.

Acoustics researchers in Laguna San Ignacio

 

In this “Acoustic Gallery” you may select and listen to examples of the sounds recorded in the lagoon and learn about what the researchers have discovered about their frequency, intensity, and diversity within the lagoon during the winter months. There are examples of sounds from gray whales, fish, invertebrates, the wind, rain, and the tides. There are also examples of the sounds produced by whale-watching and fishing boats that operate in the lagoon. Each example includes a brief description of the recorded sound, a “spectrogram” or picture showing the frequency of the sounds over the time, and an audio recording in MP3 format that you can play to hear the sounds.

Many of these recording are of low frequency sounds, and they are best heard on a computer sound system that has a wide frequency response including the lower frequencies. You can also use a pair of good quality headphones to accurately hear these recordings on a computer.

 

ADD SOUND RECORDIINGS FROM VIEMO VIDEO FILES