In two reports published Aug. 30, the U.S. Navy acknowledges that bomb testing and sonar use over the next five years will likely kill hundreds of marine mammals and seriously injure thousands more.
To get permits for these training exercises, the military is required to report on the environmental impact of its proposed operations. By the Navy's own count, training procedures from 2014 through 2019 could result in the deaths of over 340 dolphins and whales.
Most of those deaths would be caused by bombs the Navy plans to detonate off the East Coast, in the Gulf of Mexico, and between Southern California and Hawaii. But some deaths—as well as "behavioral changes" for millions more susceptible marine mammals—could stem from the Navy's active sonar use, which environmentalists have been criticizing for years.
"Mid-frequency sonar is an intense noise source that propagates through the ocean at the frequency that certain whales and dolphins are most sensitive to," says Giulia Good Stefani, an attorney with the Southern California office of the Natural Resources Defense Council.
Researchers are still trying to fully understand the effects of sonar on marine mammals, but they've found connections between sonar and recent mass whale strandings. Sonar has been known to damage hearing in marine mammals, which can prove fatal for creatures that rely on echolocation to move through the ocean and find food.
But the Navy contends that bomb training and sonar operation are crucial to national security and cannot be simulated. In a video statement, Rear Admiral Kevin Slates describes these as "perishable skills that require training at sea under realistic conditions."
"We don't argue that the Navy doesn't need to train," counters Stefani. "We simply have asked the Navy to try to reduce the impact it's having on marine mammal populations."