The US Navy has agreed to scale back the deployment of a new kind of high-intensity sonar system due to its unfortunate effects on marine life.
Last year, the National Marine Fisheries Service issued a permit to the US Navy to use its new Low Frequency Active (LFA) sonar in over 75% of the world’s oceans. But a group of environmentalists – including the NRDC (Natural Resources Defense Council) sued the US government over its original permit, which would have allowed world-wide testing and training of the system over a period of five years.
In August, a US Federal judge ruled that the system could endanger whales, porpoises and fish and ordered the parties concerned to reach a settlement.
Now, they have. Under the terms of the agreement, the US Navy will have to limit use of the new sonar system to specific areas along the eastern seaboard of Asia, the East and South China Seas, and the Philippine Sea. What’s more, the agreement does not allow LFA sonar in the waters off the Hawaiian Islands, where the US Navy had been permitted to use the system this year.
In addition to geographical limits, the Navy agreed to certain seasonal exclusions, which conservationists believe will protect critical whale migrations, and to coastal exclusions ranging from 30 to 60 nautical miles. None of the limits apply during war or heightened threat conditions.
The LFA sonar system is capable of generating sounds up to 140 decibels more than 300 miles away from the sonar source. Many scientists believe that blasting such intense sounds over large expanses of the ocean could harm entire populations of marine mammals and fish. During testing off the California coast, noise from a single LFA system was detected across the breadth of the North Pacific.
‘This agreement safeguards both marine life and national security,’ said Joel Reynolds, director of the Marine Mammal Protection Project at NRDC, the lead plaintiff and counsel in the case. ‘It will prevent the needless injury, harassment, and death of countless whales, porpoises and fish, and yet allow the Navy to do what is necessary to defend our country.’
The announcement comes just days after the scientific journal Nature reported that intense, active sonar may kill certain marine mammal species by giving them decompression sickness or ‘the bends’ – the same illness that can kill scuba divers who surface too quickly from deep water. The international team of scientists that authored the study said compressed nitrogen apparently formed large bubbles in the tissue of whales exposed to intense active sonar, damaging their vital organs and causing internal bleeding and possibly intense pain.