Just like humans, marine animals use sound as a way to communicate with one another. They generate sounds to attract mates, defend territories, maintain coordination in groups, and generally pass on information. Whales and dolphins are celebrated for their sounds, but many species of fish and marine invertebrates also use sound. Animals change the rate of sound production and the structure of the sounds to send different messages. Some sounds may be used to startle or scare off predators, including the loud sounds produced by invertebrates such as spiny lobsters.

Fish, such as this bar jack, communicate using sounds for protection and mating. Photo courtesy of Robert A. Patzner, University of Salzburg, Austria, http://www.zoologie.sbg.ac.at/people/patzner_home.htm

The majority of studies focusing on animal sound used in underwater communication have been done with marine mammals. Marine mammals use sound to communicate over long and short distances. Communication over long distances is usually associated with reproduction, territoriality, and maintenance of group structure. Some whales and dolphins travel in large groups and over great distances, so it is important for them to use sound to communicate with one another to maintain the group. Communication over short distances among marine mammals is used in social interactions involving aggression, individual identification, and to maintain mother-offspring contact. Most marine mammals use sound to regain contact when members of a group are separated. Research on how animals use sound in the sea continues to reveal new sounds and their use in communication.

Dolphins travel in large groups, therefore sound is important to communicate with one another to maintain the group. Photo courtesy of NOAA.

For more information on how specific marine animals communicate using sound, use the following links:
Marine Mammals	Fish	Invertebrates