Researchers report acoustic links between coral reef degradation and reef fish recruitment. Widespread damage to coral reefs is exacerbated by the absence of fish communities that could potentially promote reef recovery. Reef fish populations rely on acoustic cues to guide habitat selection and settlement, but degraded reefs have altered acoustic characteristics. Timothy A. C. Gordon and colleagues compared nocturnal soundscapes from 10 lagoonal reefs surrounding Lizard Island in Australia's northern Great Barrier Reef that were recorded in the same location, at the same time points, and under similar conditions in November 2012 and November 2016. During the intervening period, three major events severely degraded the reef: Cyclone Ita, Cyclone Nathan, and a global mass bleaching event in 2016. In field experiments at Lizard Island, the authors used light trap chambers and artificial patch reefs, coupled with loudspeakers broadcasting recordings of predegradation reef sound, postdegradation reef sound, and open ocean sound, to examine habitat selection and settlement in wild fishes. Postdegradation soundscapes had significantly reduced acoustic complexity, richness, and sound-pressure levels, compared with predegradation recordings. In addition, soundscapes from damaged reefs were 8% less attractive to fish larvae, and resulted in 40% reduced settlement of juvenile fish, compared with predegradation equivalents. Further, postdegradation soundscapes were no more attractive to the fish than open ocean sounds. Degradation of global reef soundscapes may reduce future fish settlement and limit reef resilience, according to the authors.
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Article #17-19291: "Habitat degradation negatively affects auditory settlement behavior of coral reef fishes," by Timothy A. C. Gordon et al.
MEDIA CONTACT: Timothy A. C. Gordon, University of Exeter, UNITED KINGDOM; tel: +447707659528; e-mail: < tg333@exeter.ac.uk >
Proceedings of the National Academy of Sciences