In 2012, we posted about how U.S Navy low frequency sonar training and testing could kill or deafen thousands of whales and dolphins.  Environmental groups, led by the Natural Resources Defense Council, filed a lawsuit in San Francisco arguing that actions violated the Marine Mammal Protection Act. Last Friday, the Ninth U.S. Circuit Court of Appeals agreed with the environmentalists, reversing a lower court decision upholding approval granted in 2012 for the Navy to use low-frequency sonar for training, testing and routine operations. The five-year approval covered peacetime operations in the Pacific, Atlantic, and Indian Oceans and the Mediterranean Sea. The appellate panel sent the matter back to the lower court for further proceedings.

As we posted in 2012, in an Environmental Impact Statement for 2014-2018, the Navy estimated that sonar training and testing might unintentionally harm marine mammals 2.8 million times a year over five years, including deafening 15,900 whales and dolphins and killing 1,800 more over the next five years, in testing in Hawaii, off the California and Atlantic Coasts, and in the Gulf of Mexico.