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Passive acoustic evaluation and monitoring of coral reefs can offer fast, quantitative and non-invasive sensing that reveals aspects of ecological function important for resource management. Here we report associations between visually observed reef ecological metrics and biological aspects of reef soundscapes from 23 sites throughout Hawaii. Sites grouped along a principal component defined by an acoustic sliding scale: from protected or more remote sites at which lower frequencies were more dominant, to degraded sites which produced soundscapes dominated by higher frequency sound. Positive correlations between ambient biological sounds below 2 kHz and the density of benthic invertebrates (Pearson’s ρ = 0.61-0.76), their predators (ρ = 0.65-0.8), organism-scale bathymetric complexity (ρ = 0.6-0.62) and the quantity of crustose coralline algae (ρ = 0.6-0.62) suggest a connection between this part of the soundscape spectrum, habitat complexity and the density of benthic fauna. A positive correlation was also observed between the daytime soundscape in the 2 to 20 kHz band and the proportion of benthic macroalgal cover (ρ = 0.63-0.7), a key indicator of reef degradation. This study shows the possibility of soundscape-based sensing for rapid, inexpensive, and spatially integrative remote sensing of coral reef ecological state. Such quantitative methods could be used to ecologically assess vast areas of reef habitat autonomously in near real-time. They may be important for remote in-situ detection and characterization of subtle but significant ecological changes brought about by climate change and other more localized anthropogenic impacts.


Freeman, S. E., US Naval Research Laboratory, USA,

Freeman, L. A., National Research Council, USA,


Poster presentation

Session #:054
Date: 03/02/2017
Time: 15:30 - 16:30
Location: Poster/Exhibit Hall

Presentation is given by student: No

PosterID: 442