Habitat Acoustics and the Low-Frequency Communication of Shallow Water Fishes

Many teleosts known to produce sounds during territorial and breeding activities live in coastal, transitional or freshwater habitats characterized by shallow, or very shallow, water. The variability of ambient noise levels and the complexity of sound propagation conditions make acoustic communication in such environments problematic, especially at lower frequencies. Yet, use of low frequencies for communication (sound signals and hearing) is common among these species (e.g. toadfishes, gobies, blennies, darters, sculpins). This chapter examines the relationships between environmental factors and the sound emitted by shallow water teleosts, focusing in particular on the role of the calling site and ambient noise for the sound frequencies employed for communication. Two ecological factors, nest site acoustics and noise windows, appear to favor the use of low-frequency sounds by teleosts living in shallow noisy habitats by providing higher S/N ratios for communication. The final part of the chapter examines the variety of fish audiograms and emphasize the importance of ambient noise as possible main environmental factor shaping the auditory sensitivity, especially among shallow water fishes. A theoretical argumentation is provided to explain how this would be accomplished.