Distinct voices fill the fish soundscape at night

To map a fish soundscape, researchers put a recording device in an underwater cave 120 meters down in one of the canyons that line Sodwana Bay (shown) in South Africa. That local aquatic community includes coelacanths, ray-finned fish, sharks and other species.

Ros in Wonderland/Flickr (CC BY-NC-ND 2.0)

By Helen Thompson

April 6, 2015 at 5:54 pm

With the hum of ships on the surface and a cacophony of undersea creatures, the ocean can be a noisy place. Fish fill the underwater soundscape differently at night versus during the day, researchers report April 6 in the Proceedings of the National Academy of Sciences.

A team of researchers from France and Belgium bugged an underwater cave off the coast of South Africa to listen in on the local fish community. Compared with fish calling during the day, nocturnal fish send out more distinct sounds that don’t overlap as much in frequency. In the dark, ensuring that sound signals are heard becomes vital.

While the soundscape underwater still remains somewhat enigmatic, researchers know a good deal about the soundscape above ground (especially in the U.S.) and how human noise pollution interferes with animal chatter.