Dolphin changes in whistle structure with watercraft activity depends on their behavioral state

Area of Science:

• Marine biology
• Bioacoustics
• Animal communication

Background:

• Dolphins use whistles for social identification and environmental information exchange.
• Dolphin whistle characteristics can adapt to changing environments.
• Limited data exists on dolphin acoustic responses to watercraft and behavioral states.

Purpose of the Study:

• To investigate how bottlenose dolphins acoustically respond to different watercraft activities.
• To determine if dolphin acoustic responses vary with behavioral state.
• To assess the impact of dolphin-watching boats on dolphin communication.

Main Methods:

• Recorded bottlenose dolphin whistles in the presence of research and dolphin-watching boats.
• Analyzed whistle characteristics, including frequency and duration.
• Correlated acoustic changes with specific behavioral states, such as foraging.

Main Results:

• Dolphins emitted lower frequency and longer whistles when interacting with dolphin-watching boats.
• These acoustic modifications were particularly pronounced during foraging activities.
• Dolphin whistle characteristics were significantly altered by the presence of dolphin-watching boats.

Conclusions:

• Dolphin-watching boat traffic significantly impacts dolphin acoustic communication.
• Changes in whistle characteristics suggest a response to anthropogenic noise and activity.
• Disruption of communication may hinder essential behavioral states like foraging.