Characterizing three shallow-water locations off Goa, India, using passive acoustic data

Area of Science:

• Marine acoustics
• Estuarine ecology
• Bioacoustics

Background:

• Shallow-water acoustic environments are complex, influenced by biological, geological, and anthropogenic sound sources.
• Understanding these soundscapes is crucial for marine ecosystem health assessment.

Purpose of the Study:

• To quantitatively characterize shallow-water acoustic environments in Goa's estuarine systems.
• To identify and analyze fish sounds and their spectral characteristics.
• To differentiate contributions of biophony, geophony, and anthrophony to the soundscape.

Main Methods:

• Passive acoustic monitoring using waveform and peak power spectral densities (PSDs).
• Identification of fish species (Colletteichthys dussumieri, Terapon threaps) and their vocalizations.
• Cluster analysis to differentiate sound sources (biophony, geophony, anthrophony).

Main Results:

• Specific spectral levels and frequencies were recorded for toadfish (Batrachoididae) in the Mandovi estuary and Tiger Perch (Terapontidae) in the Zuari and Sal estuaries.
• Root-mean-square sound pressure level (SPLrms) was found to be influenced by water flow, temperature, and wind, varying across estuaries.
• Cluster analysis successfully characterized the contributions of different soundscape components.

Conclusions:

• Passive acoustics provide valuable insights into estuarine soundscape composition and environmental influences.
• Fish vocalizations and environmental factors significantly shape shallow-water acoustic environments.
• This research contributes to baseline acoustic data for Goa's estuarine systems.