Stay here, but keep quiet: the effects of anthropogenic noise on Guiana dolphins (Sotalia guianensis) in Southeastern Brazil.

Abstract

AbstractShipping is the principal source of anthropogenic noise in the aquatic soundscape of coastal areas. Noise can have temporary or permanent effects on the physiology, behavior, and ecology of the marine mammals and, as noise pollution is considered to be an important threat to Guiana dolphins (Sotalia guianensis), we focused on this question in the present study. We modeled the impacts of anthropogenic noise on the acoustic behavior and distribution of these dolphins. We considered the acoustic parameters and occurrence of Guiana dolphins as the response variables and Sound Exposure Levels (SEL) and environmental factors as the explanatory variables. The dolphins used noisier areas but communicated mainly in less noisy areas, given that anthropogenic noise levels induced a reduction in whistle rates. Although the dolphins did not appear to avoid the noisiest areas, their communication was impaired, and there may be areas in which communication is impracticable in this species.