Quantifying changes in the Laccadive Sea soundscape: A comparison of the COVID-19 pandemic and post-pandemic periods

The impact of the COVID-19 pandemic on worldwide trade and human activities extended even to ocean depths, resulting in changes in underwater acoustic environments. This study emphasizes the deep water soundscape of the Laccadive Sea by performing passive acoustic measurements over two distinct periods-November 2020-May 2021 and March 2022-December 2022-to reveal temporal variations and underlying patterns during the COVID-19 pandemic and post-pandemic periods. This research focuses on a comprehensive analysis of ambient noise spanning a frequency range from 20 to 2000 Hz. Biophonic sources dominate within the 200-2000 Hz range during the pandemic period. This study emphasizes the increased shipping noise levels at 63 and 125 Hz frequencies during the post-pandemic period. The results indicate an increase in overall ambient noise post-pandemic periods, particularly within low-frequency bands associated with shipping. These findings suggest a temporary decrease in ambient noise in the acoustic environment of the Laccadive Sea during the pandemic, which was likely influenced by human activity restrictions.