Effects of Human-made Sound on the Behavior of WhalesLFA Research Program, Phase III

The illustrations below are sound spectrograms of a 7-minute recording of a singing humpback whale off of Hawaii recorded on 27 March 1998 during Phase III of the Low-Frequency Sound Scientific Research Program. During this recording, there were two experimental transmissions of the SURTASS LFA test signal from the research vessel (red boxes). The vessel was 3.5 km from the whale at the time of the first transmission (10:38), and 2.7 km for the second transmission (at 10:44). These recordings were made from a small observation vessel about 250 meters from the whale. The received levels for the LFA signals were 132 and 134 dB. The received level of the whale song at the observation vessel was 135 dB. To learn more about measurements of underwater sound, click here.

The colored backgrounds in the spectrogram indicate the different themes in the humpback's song. Theme changes are a normal part of humpback singing behavior.

To hear the sound shown in any of the four panels, click on the illustration.

The sound you will hear is speeded up five times faster than normal speed, which also raises the pitch of the whale song and the LFA signal by a factor of five (slightly more than two octaves). When playing the segments that contain the LFA signal, you can hear the signal start about eight seconds into the recording.
The spectrogram shows no obvious change in the singing behavior of this whale in response to the LFA signal.