Ambient noise levels of a protected marine community in Costa Rica before and during Covid-19.

Due to the Covid-19 pandemic lockdowns, anthropogenic noise levels over industrialized areas are at some of their lowest levels in decades. Similar patterns have been described in the ocean. Sound propagates faster and farther in water than in air, making it the primary way many marine animals communicate and orient themselves over long distances. In this study, we use acoustic data from autonomous underwater recorders deployed in September 2019 and 2020 at Caño Biological Reserve in Costa Rica to study the contribution of boat and humpback whales sound levels to the overall soundscape. The program dBWav was used to estimate overall RMS noise and in the presence and absence of boats and humpback whales. We predict a decrease in average noise levels and an increase in the contribution of humpback whales noise levels during 2020. This study provides insight into the impact of human activities on the soundscape of marine habitats