A Victory for Marine Mammals: Court Rules to Restrict U.S. Navy Sonar Use

August, 2016


In 1972, the Marine Mammal Protection Act (MMPA) was enacted, among other reasons, to prohibit the take of marine mammals in U.S. waters. This month, it worked again in defense of our ocean’s whales, seals, dolphins and walruses by strongly restricting the use of sonar by the US Navy; a win for both environmentalists and marine life. 

Since 2012, the Navy has been permitted by the courts to use explosives and low-frequency sonar in peacetime training exercises throughout the Mediterranean Sea and the Pacific, Atlantic, and Indian Oceans. It was considered acceptable to affect around 30 whales and 24 pinnipeds each year, as long as the Navy delayed the use of sonar if marine mammals were known to be nearby. This was ruled to be a safe option for marine life.

But on July 15, the Ninth U.S. Circuit Court of Appeals came to the conclusion that it wasn’t. After a lawsuit filed by several environmental groups led by the Natural Resources Defense Council, the appellate court ruled 3-0 that the previous ruling failed to adequately protect marine mammals. According to the MMPA, peacetime operations must have the “least practicable adverse impact on marine mammals”, which had not been the case for the use of sonar in the past. 

Sonar, which uses sound propagation to navigate and detect objects, is known to create a sound disturbance to mammals capable of hearing it, causing them to react as if a threat is present. Impacts include beaching en masse, deafness, or animals returning from the deep too quickly out of fear, making the use of sonar fatal. It is so detrimental to marine mammals because of their ability to use sound for many aspects of life—including finding food, mating, escaping predators, social interaction, and navigation. 

The appellate court ruling requires the U.S. Navy to limit or eliminate the  use of sonar in certain regions. Signed in Honolulu, the deal restricts sonar from biologically important areas, such as well-known habitats or feeding zones, and requires that the National Marine Fisheries Service investigate all sonar-related animal injury or death.

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