Underwater sound pressure levels in the Port of Santos: Representative sample of forty-five days

Abstract

Among the several ways that human activities interfere in oceanic environment, acoustic noise is recognized as one of the most pervasive. Man-produced noise can have important consequences in marine fauna, since it impacts animal hearing as well as physiological and behavioral responses of oceanic organisms, inducing temporary or permanent injuries. Particularly, it can affect marine mammal communication, aquaculture and even fish industry productivity. Hazardous effects of anthropogenic noise on marine life have been intensively investigated over the last decades. Nevertheless, it was just recently that measurement of underwater anthropic noise close to harbors and industrial areas has become a true concern of environmental agencies in Brazil. On this subject, one case of great interest is the Port of Santos, the busiest container port in Latin America. This harbor is located on the Brazilian southeast coast, close to conservation areas with rich marine biodiversity, including marine mammals. For that reason, monitoring of underwater noise in the harbor area is especially important. In response to this need, an underwater noise monitoring program is established, providing quantitative information regarding harbor activities and marine traffic noise. Database presented in this work is characterized by calculation of the Power Spectral Density (PSD), Probability Distribution of 1/3 octave band levels, percentiles and Sound Pressure Levels (SPL) calculations. This work aims at complementing the nowadays limited information and can be regarded as a reference for future studies on underwater noise for Brazilian coastal areas.