Ambient sound as a cue for navigation by the pelagic larvae of reef fishes

Sound is a potentially important navigational cue for organisms in aquatic environments. Most reef fishes produce pelagic larvae that must locate suitable settlement habitat for the completion of their life-cycle. We used light traps and underwater loudspeakers to determine whether reef fish larvae are attracted to sounds produced on a reef. 'Sound traps' caught more triplefin (a benthic reef fish) larvae than did 'silent traps', demonstrating that the larvae of some reef fishes may use sound as a navigational cue in the field. Catches of pilchard larvae, a pelagic fish, did not vary between treatments. These results are the first demonstration, of which we are aware, of sound as a potential navigational cue in the aquatic environment.