Summary adapted from social media post by Anna Testorf:
One of our recent studies illustrates how noise from large ships and other vessels decreases overall foraging success of fish-eating killer whales through a process known as auditory masking. Knowing how vessel noise affects killer whales can inform actions to mitigate noise and promote health and survival of these vulnerable populations
Auditory masking is when the noise from ships and vessels overshadows the returning echoes produced by killer whales.
Why is this a problem? Killer whales have difficulty receiving information about where food is, and miss foraging opportunities. They then spend more time and energy searching for fish during noise, and finding fewer. The resulting energetic cost of foraging with auditory masking from vessel noise may not be sustainable.
For every increase in noise level by 1 decibel:
- 4% increase in odds of searching for prey
- 58% decrease in odds of females chasing food
- 12.5% decrease in odds of catching prey
What does this mean? As ambient noise increases, killer whale foraging habitat decreases. Less habitat means fewer opportunities to take in enough calories to sustain the population’s needs.
Authors: Jennifer B. Tennessen, Marla M. Holt, Brianna M. Wright, M. Bradley Hanson, Candice K. Emmons, Deborah A. Giles, Jeffrey T. Hogan, Sheila J. Thornton, Volker B. Deecke
Journal: Global Change Biology
DOI: https://doi.org/10.1111/gcb.17490
Media coverage: National Geographic, KUOW, KIRO 7, Capital Daily, Vancouver Sun, UW News, MSN, and E&E NEWS
Photo credit: A male orca travels quickly near a large cargo ship transiting through the Salish Sea. Photo by Candice Emmons, NOAA Fisheries.
