Navy sonar testing has been up for debate for awhile because researchers believe the underwater noise could disturb whales and dolphins. This comes as the U.S. Navy announced plans to increase sonar testing over the next five years.
Reported mass strandings of certain whale species have increased worldwide since the military started using sonar half a century ago. Scientists think the sounds scare animals into shallow waters where they can become disoriented and wash ashore, but technology capable of close monitoring has emerged only in about the last decade.
Aside from strandings, biologists are concerned marine mammals could suffer prolonged stress from changes in diving, feeding and communication, which is disrupted from sonar testing.
Two recent studies off the Southern California coast found certain endangered blue whales and beaked whales stopped feeding and fled from recordings of sounds similar to Navy sonar.
Beaked whales are highly sensitive to sound and account for the majority of beachings near Navy sonar exercises. Scientists, however, were surprised by the reaction of blue whales — the world’s largest animal — long thought to be immune to the high-pitched sounds. It’s unclear how the change in behavior would affect the overall population, estimated at between 5,000 and 12,000 animals.
The studies involved only a small group of tagged whales and noise levels were less intense than what’s used by the Navy. Shy species, such as the Cuvier’s beaked whale that can dive 3,000 feet below the surface, have taken years to find and monitor.
“This is a warning flag and deserves more research,” said Stanford University biologist Jeremy Goldbogen, who led the blue whale study published this summer in the journal Proceedings of the Royal Society B.Both studies were done by a team of independent scientists as part of a Navy-funded, five-year project launched in 2010 to understand how sonar affects marine mammals.
Navy officials say it’s vital to national security that sailors receive sonar training in real-life conditions.
Environmentalists have long claimed that sonar harms marine mammals, which use acoustics to mate and forage. They want more protections and accuse the Navy of rushing to obtain five-year permits under the Marine Mammal Protection Act from the National Marine Fisheries Service to increase its sonar testing in U.S. waters without considering the latest science.
“If you deafen a marine mammal for even a short period time, you are affecting its ability to survive,” said Michael Jasny of the Natural Resources Defense Council, whose group has sued to force the Navy to add more protections.
A federal judge in September ruled marine fisheries officials did not consider the best available data when it approved permits last year for operations stretching from Northern California to the Canadian border.
The agency has until August to reassess how it will protect ocean life.