Anthropogenic Sound and Marine Mammals in the ArcticThe fifth in our series of science briefs and analyses, this report was prepared for The Pew Charitable Trusts' work in the U.S. Arctic by Kate Stafford, and released in July of 2013. Download the complete report »
Marine mammals, including those found in the Arctic, depend more on their hearing than other senses because sound travels well underwater. Bowhead whales; walrus; ringed, ribbon, and bearded seals; and other marine mammals rely on the sounds they make and hear to navigate, contact one another, court potential mates, find food, and avoid predators. The Arctic soundscape has long been shaped by their clicks and calls, as well as by wind, waves, and sea ice.
Today, the rapid loss of summer sea ice is opening this once largely inaccessible region to ship traffic, oil exploration, and other industrial activities. These changes mean the Arctic Ocean is becoming noisier—and that could have a profound impact on animals that rely on sound to survive.
This science brief looks at how anthropogenic, or man-made, sounds from ship engines, seismic surveys, and drilling machinery overlap with and may interfere with sounds produced and received by marine mammals. Studies show that whales, for example, respond to anthropogenic noise by leaving the area, reducing respiration or surface time, and decreasing calls to other whales. A study of northern right whales suggests they may be chronically stressed from high levels of sounds from ships. Additionally, collisions between animals and ships may result if the former are unable to locate and avoid the vessels because of masking, or interference, created by the sounds of the ships.
Commercial development is a relatively new phenomenon in the Arctic, so many questions about the impacts of noise, particularly anthropogenic, on its marine ecosystem are still unanswered. Future research should be conducted and monitoring should be designed to assess the sensitivity of marine mammals to noise and to determine what can be done to reduce or mitigate the potential impact of anthropogenic noise.
Many questions about Arctic marine mammals and the impacts of sound, particularly anthropogenic sound, in their ecosystem remain unanswered. Future research should be conducted and monitoring should be designed to better understand the sensitivity of marine mammals to noise. Future research might seek answers to the following questions:
- What is the best way to document the response of Arctic marine mammals to sound?
- In what areas and during what times of year are marine mammals most affected by anthropogenic increases in sound?
- What are the cumulative effects of increases in ambient sound levels for Arctic marine mammals?
- What effect does the decrease in seasonal ice cover have on ambient noise levels?
- Are there differences in responses to sound or its impacts on marine mammals specific to species, age, sex, or season?
- What are the most effective mitigation strategies for reducing potential impacts?
- What evidence is there of marine mammals being struck by vessels?
- What cumulative effect has noise in the marine ecosystem had on the ability of Alaska Natives to successfully pursue subsistence practices?