Characterization of the marine soundscape at the core habitat of Indo-Pacific humpback dolphins
Tzu-Hao Lin, Lien-Siang Chou
Institute of Ecology and Evolutionary Biology, National Taiwan University
Office of Protected Resources, National Marine Fisheries Service, Silver Spring, MD, USA
The soundscape in shallow waters displays a high level of spatial variation due to the difference in ocean environments, biological communities, and human activities. Many marine animals rely on sound for orientation; therefore, the soundscape has been hypothesized as one of the environmental indicators for marine animals. The population of Indo-Pacific humpback dolphins in western Taiwan waters is critically endangered. The anthropogenic noise might alter the marine soundscape evidently. However, the importance of soundscape for the habitat selection of cetacean remains unclear until now. In this study, underwater recorders were deployed in inshore waters to compare the difference of soundscape between the core habitat and non-core habitat of humpback dolphins. The result indicates that the composition of soundscape scene is different among our recording stations. At the core habitat, soundscape was characterized by the nighttime chorus of croakers and the quiet ambient sound in the daytime. On the contrary, snapping shrimp sounds represent the most dominated sound at the non-core habitats. The current result indicates that humpback dolphins prefer soundscape dominated by the chorus of their prey resources. The potential impacts of human activities on marine soundscape should be carefully evaluated in the future.