U.S. ordered to lower Navy sonar levels to protect whales

U.S. officials have wrongly allowed the Navy to use sonar at levels that could harm whales and other marine mammals in the world’s oceans, a federal appeals court in San Francisco has ruled.

The decision Friday by the Ninth U.S. Circuit Court of Appeals would scale back the Navy’s use of low-frequency sonar in the Atlantic, Pacific and Indian oceans and the Mediterranean Sea under authority that was granted in 2012.

Sonar, used to detect submarines, can injure whales, seals and walruses and disrupt their feeding and mating. Environmental groups led by the Natural Resources Defense Council filed suit in San Francisco in 2012, arguing that the Obama administration had approved emissions at sound levels that violated the Marine Mammal Protection Act.

A federal magistrate disagreed but was overruled Friday by the appeals court, which said government officials had disregarded their own experts’ warnings about sonar’s potential impacts.

Under the 2012 standard, which is scheduled to expire in 2017, the National Marine Fisheries Service required the Navy to reduce sonar levels in areas known to have high populations of marine mammals but failed to order similar protections in other areas where their presence was uncertain, the court said. Those included some offshore zones that had been protected in the past and others listed by scientists as likely habitats, the court said.

The protected zones showed a “bias toward U.S. waters,” the court said, with several zones on the Atlantic and Pacific coasts of the United States but none on the Pacific coast of South America and only a scattered few in other waters.

“The result is that a meaningful proportion of the world‘s marine mammal habitat is under-protected,” Judge Ronald Gould said in the 3-0 ruling, which would also set standards for future renewals of the program. He said the government had failed to comply with a law that requires it to make sure its peacetime oceanic programs have “the least practicable adverse impact on marine mammals.”

Bob Egelko is a San Francisco Chronicle staff writer. Email: begelko@sfchronicle.com Twitter: @egelko

Read the ruling: http://cdn.ca9.uscourts.gov/datastore/opinions/2016/07/15/14-16375.pdf.