Coral Reefs DOI 10.1007/s00338-007-0294-y 123 REPORT Nocturnal relocation of adult and juvenile coral reef Wshes in response to reef noise S. D. Simpson · A. JeVs · J. C. Montgomery · R. D. McCauley · M. G. Meekan Received: 2 February 2007 / Accepted: 8 August 2007  Springer-Verlag 2007 Abstract Juvenile and adult reef Wshes often undergo migration, ontogenic habitat shifts, and nocturnal foraging movements. The orientation cues used for these behaviours are largely unknown. In this study, the use of sound as an orientation cue guiding the nocturnal movements of adult and juvenile reef Wshes at Lizard Island, Great Barrier Reef was examined. The Wrst experiment compared the move- ments of Wshes to small patch reefs where reef noise was broadcast, with those to silent reefs. No signiWcant responses were found in the 79 adults that were collected, but the 166 juveniles collected showed an increased diversity each morning on the reefs with broadcast noise, and signiWcantly greater numbers of juveniles from three taxa (Apogonidae, Gobiidae and Pinguipedidae) were collected from reefs with broadcast noise. The second experiment compared the movement of adult and juvenile Wshes to reefs broadcasting high (>570 Hz), or low (<570 Hz) frequency reef noise, or to silent reefs. Of the 122 adults collected, the highest diversity was seen at the low frequency reefs; and adults from two families (Gobiidae and Blenniidae) preferred these reefs. A similar trend was observed in the 372 juve- niles collected, with higher diversity at the reefs with low frequency noises. This preference was seen in the juvenile apogonids; however, juvenile gobiids were attracted to both high and low sound treatments equally, and juvenile stage Acanthuridae preferred the high frequency noises. This evi- dence that juvenile and adult reef Wshes orientate with respect to the soundscape raises important issues for man- agement, conservation and the protection of sound cues used in natural behaviour. Keywords Post-settlement migration · Coral reef Wshes · Reef noise · Nocturnal movement · Orientation · Patch reefs Introduction Juvenile and adult reef Wshes often undergo nocturnal foraging movements, ontogenetic habitat shifts, and migrations. At small scales (m–100 m), site-attached adult cardinalWshes (family Apogonidae) can navigate success- fully across reef habitat to feed at night, returning to shelter sites before sunrise (Marnane 2000; Kolm et al. 2005). Ontogenetic migrations can take place at slightly larger scales (m–km), where reef Wshes settle into nursery areas, rather than directly into adult habitats. For example, sea- grass beds are known to be important nursery grounds (Pollard 1984; Beck et al. 2001) from which Wshes later undergo ontogenic migrations to adjacent coral reef habitat (Shulman and Ogden 1987; Nagelkerken et al. 2000). At larger spatial scales, adult reef Wshes (e.g., Acanthuridae, Serranidae, Lethrinidae and Lutjanidae) may migrate tens Communicated by Biology Editor M. P. Lesser. S. D. Simpson (&) Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Kings Buildings, Edinburgh EH9 3JT, UK e-mail: s.simpson@ed.ac.uk; simpsonstephen@hotmail.com A. JeVs · J. C. Montgomery Leigh Marine Laboratory and School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand R. D. McCauley Centre for Marine Science and Technology, Curtin University, GPO Box U 1987, Perth 6845, Australia M. G. Meekan Australian Institute of Marine Science, PO Box 40197, Casuarina, Darwin, NT 8010, Australia