Anthropogenic Noise Negatively Impacts Dolphin Communication

Abstract

Human impacts on wildlife have been persistent since the beginning of the Industrial Revolution. In addition to habitat destruction, pollution, and climate change, noise as a result of human activity, or anthropogenic noise, has had significant impacts on marine animals (Sørensen et al., 2023). In the ocean, sound transmits over 4.3 times faster than on land, so marine creatures often utilize auditory signals to communicate across vast distances. However, ambient noise in marine environments as a result of human activity has also been increasing since the 1900s, with commercial shipping, marine exploration, and tour boats all being primary contributors (Hildebrand, 2004). Anthropogenic noise has demonstrated to be disruptive to animal species that use acoustic signals in order to communicate, including dolphins (Sørensen et al., 2023). Bottlenose dolphins (Tursiops truncatus) in particular are known to use complex vocal signals to convey information about identity, location, and food sources. Recently, bottlenose dolphins have faced increased contact with humans in the temperate and tropical waters of the Atlantic and Pacific Oceans where they live. Anthropogenic noise in these habitats significantly alters vocal behavior by masking their auditory signals, hindering dolphin whistle recognition by conspecifics, and disrupting hunting activities (Nakahara, 1999). Dolphins may alter the frequency and complexity of their whistles in response to heightened noise pollution, but even the modulations themselves pose a risk to overall dolphin health (Fouda et al., 2018). To better understand dolphin behavior and the repercussions of human marine activity, we review how bottlenose dolphins communicate during hunts, how anthropogenic noise impedes on this communication, how the dolphins acclimate to such impacts, and how dolphins' responses to these impacts can negatively impact their wellbeing, survival, and reproductive success. Furthermore, we examine ways to mitigate these impacts by reducing sources of anthropogenic noise in high conflict areas.