Part 2: Naval Sonar Is Harming Thousands of Marine Mammals

Written By Susan Kahoud –  When several kinds of whales and dolphins began beaching themselves after the U.S. Navy held practice submarine warfare exercises using very loud sonar and occasional live bombs, scientists and conservationists realized that those two things are connected.

At issue now is that the Navy insists on continuing these exercises, even though they acknowledge that it will disturb thousands of marine mammals and kill some of them.

Naval sonar used during “war games” of searches for hidden submarines is not just disturbing the peace of marine life. It is so loud that it is hurting, and in some cases killing, whales. And as part of the Navy’s sonar games, live bombs are occasionally used. The noise sometimes blows out the ears of whales, resulting in death.

Some scientists are uncertain about whether all whales that drive themselves up on beaches after such Navy games are injured directly by the sound or suffer from rapid decompression as a result of ascending too rapidly. Almost certainly, both things happen.

Dr. Peter Tyack, professor of Marine Mammal Biology at the University of St. Andrews in Scotland, says that Navy sonar may pose risks of hearing loss, stress, disorientation and disruption of feeding (1). Linda S. Weilgart of Dalhousie University reports, “Whales have been found to die within hours, by stranding or deaths at sea, from even a transient and relatively brief exposure to moderate levels of mid-frequency military sonar.”

Toothed whales such as sperm, killer, and beaked whales, and dolphins, use their own sonar capabilities to navigate along coastlines, identify underwater objects, and migrate to feeding and breeding grounds.  However, if their natural sonar is overlapped by frequencies from naval sonar, disruption of communication and disorientation may occur.

A rarely seen Cuvier’s beaked whale breaches off the island of El Hierro in the Canary Islands. Here, scientists and engineers from WHOI, University of La Laguna (Canary Islands) and University of Aarhus (Denmark) have been studying the natural behavior of these whales to help interpret their reactions to sonar testing elsewhere, which may make them vulnerable to stranding. Photo by Natacha Aguilar, University of La Laguna, taken under permit from the Canary Islands Government.

Tyack states, “Whales that have most often beached and died are beaked whales…the odds of seeing a beaked whale at the surface are close to zero so visible monitoring [before the games start] is ineffective…”

In 2012 the National Marine Fisheries Service received an application from the Navy requesting permission to conduct increased sonar training and exercises from 2014 to 2019, in the Atlantic and Pacific oceans and the Gulf of Mexico.

The Natural Resources Defense Council reported on September 23, 2013 in an action alert titled, “Navy Refuses to Protect Marine Mammals from Deadly Sonar,”: The U.S. Navy says it will ignore a unanimous recommendation by the California Coastal Commission to reduce the harmful effects of naval sonar on the state’s marine mammals, which would violate California law. The Navy is planning to dramatically increase its use of dangerous sonar and high-powered explosives off the coast of Southern California during training and testing. It predicts that such operations will kill hundreds of marine mammals — and injure thousands of others — over the next five years. New research shows that the Navy’s California training is already putting entire whale populations at risk, including endangered blue whales, the largest animal on Earth.

tagged whale

A beaked whale being tagged. The research was conducted under a permit issued by the Bahamas Department of Resources and under permit # 981-1707 issued by the National Marine Fisheries Service under the authority of the Marine Mammal Protection Act and the U.S. Environmental Protection Agency. Photo by Ari Friedlaender, Duke University.

This issue needs advocates who are concerned enough to let the Navy know of their feelings. The Natural Resources Defense Council ( can keep you up to date, if you get on their mailing list for this issue. Go to:

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Susan Kahoud is a longtime environmentalist with special interest in protecting endangered wildlife and habitat.

One Comment on “Part 2: Naval Sonar Is Harming Thousands of Marine Mammals

  1. A great article about the ways in which environmental noise impacts whales and other ocean mammals. I really appreciated the clarity that the author provides for those of us who are non-scientists. This was a wake-up call for me to do some deeper thinking about the impact of human activity on all of earth’s creatures. I sincerely hope that those involved can join together to come up with creative solutions for protecting whales and other sea mammals. Thanks for the informative article! I would like to see more on this in the future.

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