Directional orientation of pomacentrid larvae to ambient reef sound

Abstract

The mechanisms by which reef fish larvae locate settlement habitat at the end of their pelagic phase are unclear. We used an in situ binary choice chamber and an artificial source of reef sound to determine whether pomacentrid larvae can use ambient sound to locate reefs. Larvae were caught in light traps and then placed in a submerged binary choice chamber with an artificial source of reef sound ~80 m from one end of the chamber. At night, larvae moved towards the sound source; during the day, larvae showed no preference. These results suggest that pomacentrid larvae can detect reef sound and are capable of directional hearing. While other studies have shown that reef fish larvae respond to reef sound, and that the adults of some species can localize underwater sound sources, the localization of underwater sound by fish larvae has not been demonstrated previously.