Small-Scale Variation in the Soundscapes of Coral Reefs

Coral reefs are complex habitats that emanate an array of sounds. These acoustic cues are integral to animal behaviors and are increasingly leveraged to discern ecological information. Reef soundscapes are often measured with an overarching view to characterize broad differences between reef sites. Further, there is a limited understanding of soundscape variation within particular reefs. Here, three acoustic recording methods (benthic recorders, vertical arrays, drifters) were used to address if and how soundscapes vary across coral reefs. Research took place at eight sites in the highly protected region of Jardines de la Reina, Cuba. Sound levels and frequency composition varied across small horizontal and vertical spatial scales. Horizontal differences were notable within reefs over meters, particularly when comparing recordings from adjacent dead and live massive coral. Vertically, sound levels and variation changed with distance from the benthos, with greater variation at lower frequencies. The drifter revealed sound levels that varied substantially relative to bottom type and nearby biota. Overall, the coral reef soundscape, like its biodiversity, was not uniform in distribution. Acoustic patterns varied substantially in ways that likely offer fine-scale acoustic cues to fishes and invertebrates. Moreover, this chapter highlights that small-scale spatial variation must be considered when implementing broad scale eco-acoustic monitoring of coral reef habitats.