Variation in foraging activity influences area-restricted search behaviour by bottlenose dolphins

Area of Science:

• Marine biology
• Bioacoustics
• Animal behavior

Background:

• Area-restricted search (ARS) behavior is key to understanding predator foraging patterns.
• Drivers of ARS in marine environments are not well understood.
• Passive acoustics and automated data processing offer new research avenues.

Purpose of the Study:

• Investigate drivers of ARS behavior in dolphins using passive acoustics.
• Determine if dolphins increase residency in foraging areas after prey encounters.
• Link vocalizations to foraging success.

Main Methods:

• Used passive acoustic monitoring to study dolphin foraging.
• Analyzed echolocation buzzes and bray calls as foraging proxies.
• Employed a convolutional neural network for bray call identification.

Main Results:

• Found a positive correlation between encounter duration and foraging proxies (echolocation buzzes, bray calls).
• Demonstrated that dolphins engage in ARS behavior in response to increased prey availability.
• Confirmed bray calls as a reliable indicator of salmon predation attempts.

Conclusions:

• Prey encounter rates are a significant driver of ARS behavior in bottlenose dolphins.
• Passive acoustic monitoring combined with deep learning is effective for studying vocal marine animals.
• This research provides empirical evidence for ARS behavior drivers in marine predators.