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THE EFFECTS OF ANTHROPOGENIC NOISE ON ATTENTION, LEARNING, MEMORY, AND COMMUNICATION IN BOTTLENOSE DOLPHINS

LOCATION: HAWAII, UNITED STATES

Jason Bruck, PhD
Stephen F. Austin State University
Paige Stevens
Oklahoma State University
Laela Sayigh, PhD
Woods Hole Oceanographic Institution
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PROJECT SUMMARY

Paige Stevens

As human activities continue to expand across the globe, the level of consequential anthropogenic, human-made, noise continues to rapidly increase. Sources of oceanic anthropogenic noise include private and commercial boat traffic, personal watercrafts including Jet skis, cruise ships, oil extraction and exploration, and sonar. Despite the Marine Mammal Protection Act (MMPA), cetaceans continue to be negatively impacted by anthropogenic noise, partly due to our lack of knowledge on its long-term effects. Cetaceans live in an environment with pervasive sound where they rely on acoustics to navigate their surroundings, hunt, socialize, teach their young, recognize potential dangers, and identify individuals. Thus, they are at an increased risk of mortality and poor welfare under these conditions, with consequences as dire as destruction to hearing structures and death.

Paige Stevens

While many studies have examined the impact of anthropogenic noise by monitoring clinical signs in cetaceans’ biology, what remains unknown is how nuisance sounds affect cognition: attention, learning, and memory. These cognitive processes are necessary for survival in animals like bottlenose dolphins that use intelligence to feed, socialize, and reproduce. Anthropogenic noise effects on attention may manifest as sensitization or habituation. The sensitization effect is an observed increase in behavioral response to a repeated eliciting environmental stimulus while the habituation effect is an observed decrease in response to eliciting environmental stimuli. If dolphins sensitize to human-made oceanic noises, time spent with conspecifics, as well as the welfare of wild populations may decrease due to cognitive load and energy spent on behavioral responses in an environment where noises can travel long distances.

The effects of anthropogenic noise on attention from a dolphin.

Paige Stevens

Therefore, there is a critical need to discover the cognitive impacts of noise on cetaceans as marine mammals face increasing challenges due to pollution, overharvesting, hunting, and loud sounds. In the absence of such knowledge, the development of effective intervention strategies to help reduce the negative impacts of humans on critical marine life will likely remain difficult.

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