Navy Sonar vs. Marine Life

By Charles Kohlhase
February 2009

The Author is a Scientist and former Naval Officer based in Pasadena, California, USA

The U.S. Navy continues its sonar training exercises for detecting quiet diesel-electric submarines, with the damaging effects these far-traveling sound waves have on whales, dolphins, and many other forms of marine life. By using the power of science-based computer simulations, however, it is possible to achieve a solution which benefits the Navy, spares the marine life, and to a lesser extent helps with the economy, the shrinking energy reserves, and even the goal of reduced carbon emissions. In the long run, the Navy must find alternatives to sonar that can still meet submarine detection goals or which can protect the fleet if aggressive actions are taken by hostile submarines.

The Navy admits that detection of quiet submarines running on battery power is difficult, given the plethora of ocean sounds from natural and commercial sources, yet is unwilling to constrain their active sonar tests to protect marine life. The Navy stated in October 2008 (during the Winter vs NRDC case heard by the U.S. Supreme Court) that there were no recorded sonar-related marine mammal deaths off the California coast during the previous 40 years of sonar operations and that any such deaths were caused by non-sonar sources. Yet only three months later, the Navy admitted that nearly two million marine mammals each year may suffer “biologically significant impacts” from planned sonar operations off the eastern coast of the United States and in the Gulf of Mexico.

The Supreme Court reached a 5-to-4 decision in favor of the Navy, with Chief Justice Roberts writing, in effect, “We do not discount the importance of plaintiffs’ ecological, scientific, and recreational interests in marine mammals, however national security takes priority over whales and dolphins.” With the state of the world’s oceans and sharply declining marine populations at great risk, our value system must change under the Obama administration. We need Earth stewardship – not the military industrial complex conducting business as usual. This could be achieved by enforcing the Marine Mammal Protection Act of 1972 without granting 5-year exemptions to the Navy for “incidental take.”

Marine biologists point to numerous cases of stranded whales which have suffered physical trauma, including bleeding around the brain, ears, and other tissues. In the ocean darkness, many marine creatures use sound to navigate, find food, locate each other over great distances, breed, and care for their young. Naval sonar can disrupt feeding and even cause species to panic. Scientists are concerned about the cumulative effect of these impacts on marine populations. The International Whaling Commission, comprised of expert whale biologists, has reported that the effect of sonar on whale mortalities is both convincing and overwhelming. In late 2004, the European Parliament even voted 441 to 15 to cease the use of active sonar in European waters.

The Department of Energy stopped testing nuclear weapons fifteen years ago, changing to simulations run on super-computers to obtain information on bomb blast effects. The Navy should follow this precedent. Sonar was developed in 1916, thirty years before the atomic bomb, and we understand the physics of sonar transmission through water of varying density, depth, and to targets of different properties over varying types of undersea topography. In fact, computer programs can simulate a vastly greater spectrum of target conditions and noise sources than can ever be carried out in ship-based exercises. The Navy acknowledges the value of simulations, but argues that their personnel must “train as they fight.”

The U.S. defense budget is presently $623B per year, larger than the combined defense budgets of all other countries in the world. In today’s beleaguered economy, we need to start cutting back where we can. The U.S. Navy could reduce its operational costs by using simulations instead of fleet sonar exercises. Each destroyer-class ship uses daily an amount of diesel fuel equivalent to that of about 6,000 cars, so energy savings would be dramatic as well. It is also easier to develop countermeasures to hostile submarine strategies through quickly modified and accurate computer simulations than through an endless and incomplete variety of training exercises.

It is also imperative that the U. S. Navy seeks to develop detection schemes that do not harm marine life. Examples include magnetic anomaly detection, synthetic aperture radar to measure ocean height disturbance, highly sensitive gravimeter techniques, a network of nanotechnology-based detection bots, and other sensing techniques identified from brainstorming sessions with top scientists. It is time to be inventive and not trapped in ways of the past. The Navy currently spends less than 0.01% of their $150B annual budget on “marine mammal mitigation” research. This tragic shortfall must be remedied quickly.

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Copyright © 2009, C. Kohlhase