Three-dimensional localization of sperm whales using a single hydrophone

Area of Science:

• Marine acoustics
• Bioacoustics
• Animal tracking

Background:

• Sperm whale localization is crucial for understanding their behavior and mitigating human impacts.
• Existing methods often require multiple sensors or complex data processing.
• Acoustic propagation in the ocean waveguide presents challenges for accurate localization.

Purpose of the Study:

• To demonstrate a novel three-dimensional localization method for sperm whales using a single acoustic sensor.
• To develop an automated technique that leverages multipath arrival information from sperm whale clicks.
• To investigate sperm whale foraging behavior in relation to fishing activities.

Main Methods:

• Acoustic localization based on ray-trace propagation modeling.
• Exploitation of multipath arrival information from sperm whale clicks.
• Comparison of recorded click patterns with modeled range-, depth-, and azimuth-dependent patterns.

Main Results:

• Successful three-dimensional tracking of sperm whales using data from a single hydrophone.
• Demonstration of the method with real-world data from acoustic recorders off southeast Alaska.
• Tracks suggest shallower foraging depths for sperm whales during longline hauls.

Conclusions:

• The developed method enables accurate sperm whale localization with minimal acoustic hardware.
• The technique simplifies automation by not requiring individual ray identification.
• Acoustic tracking data provides insights into sperm whale behavioral responses to anthropogenic activities.