Sound detection of reef sounds by larvae of coral-reef fishes

Abstract

Nearly all teleost reef fishes are pelagic during the larval stage, returning at the end of this stage to settle in a reefal habitat. Little is known about their sensory capabilities or how larvae detect and locate a reef. Sound is the most likely cue, particularly since reef shrimp and fish choruses are audible at considerable distances. Playback experiments off Lizard Island, Great Barrier Reef, broadcast nocturnal reef sounds and artificial sounds (pure tones) in the presence of settlement stage larvae of the coral-reef damselfish Chromis atripectoralis, released during the day within 100 m of the underwater speaker 500–1000 m from the nearest reef. Larvae consistently swam to the south in the absence of playback and during playback of artificial sounds. During playback of reef sounds, they showed no overall swimming direction, indicating that they can hear and can distinguish between a sound with potential biological significance and one without. Light traps with and without playback of reef sounds on 33 paired (playback: nonplayback) trap nights resulted in higher catches for 14 of 17 families for which >10 individuals were trapped. This suggests that not only can larvae hear, but they also have some aural localization capability.