Dolphins Use More Energy in Noisy Oceans

Written by on May 13, 2015 in Marine Life, Whales & Dolphins

A study published last month revealed that it takes more energy for dolphins to communicate with each other in louder waters. This is an important finding as our oceans are becoming increasingly noisy, primarily as a result of human activities like shipping and oil exploration.

Bottlenose dolphin mother and calf.

Bottlenose dolphin mother and calf. Photo credit: NOAA.

Scientists at NOAA Fisheries’ Northwest Fisheries Science Center (NWFSC ) and the University of California Santa Cruz discovered that dolphins need to raise their voices to be heard in noisy environments, requiring them to expend more energy. While the energy difference is slight, it has the potential to add up over time, particularly with young animals and nursing females that already expend more energy than most.

“If they’re repeatedly exposed to a lot of noise, the repeated effort to call louder or longer or more often — that’s where the impacts could become more significant,” Marla Holt, a research biologist at the Northwest Fisheries Science Center and lead author of the paper explained in a news release.

Previous research has found that some animals react to noise from nearby vessels by slapping their tails or jumping out of the water. When combined with raising their voices, the energy costs start to add up.

“You have to try to piece all these energetic costs together to analyze the increased metabolic expense that they incur when they’re around different sources of disturbance,” said coauthor Dawn Noren, a NWFSC research biologist.

To compensate for the increased energy expenditure the animals will likely have to consume more fish, which could be a problem for species like southern resident killer whales – a species that already has a limited food source – which produce sound similarly to the way dolphins do.

Southern Resident killer whales near the San Juan Islands.

Southern Resident killer whales near the San Juan Islands. Photo credit: NOAA.

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Copyright © 2015 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .


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