Assessing the Impact of Underwater Noise on Endangered Dolphins

Dolphins rely on sound to navigate, communicate, forage and go about daily living. Impacts on dolphins of human activities that increase underwater noise (recreation, fishing and boating traffic) is difficult to detect solely through visual observations of dolphin behavior. Researchers will evaluate the acoustic response of both Indo-Pacific humpback dolphins and Irrawaddy dolphins to underwater noise levels in two sites in Northwest Peninsular Malaysia. Dolphin acoustic (sound) data will be collected via onboard boat-based surveys using underwater recorders. The data will be analyzed to compare dolphin sounds under different environmental variables and types of human activities. This information will be used to assess metabolic costs (stress levels) to the animals and help inform conservation strategies to protect two locally endangered dolphin species as well as other regional marine mammal species.