Passive acoustic metrics to understand shallow water biodiversity off Malvan area in the west coast of India

Abstract

Underwater soundscape monitoring is an effective method to understand the biodiversity of an ecosystem. In this context, quantitative characterization of shallow water soundscape of the Burnt Island located off Malvan area in the west coast of India (WCI) is carried out. The soundscape characterization involves analysis of the “waveform”, “spectrogram”, and the “power spectral density” (PSD) of the recorded passive acoustic data. Biophonies such as the fish chorus of <em>Terapon theraps</em>, sparse calls of Carangidae along with another unnamed fish species community is reported. Evaluation of the PSDs and corresponding peak frequencies to distinguish the wave-breaking sound and fish species are also covered. Three acoustic metrics namely acoustic entropy (H), acoustic richness (AR), and acoustic complexity index (ACI) of passive acoustic recordings are computed and analyzed to understand their role in relation to fish chorus, wave-breaking, and sparsely available fish sound.