The US Navy is proposing the use of active sonar in training and testing exercises off Hawaii and southern California and off the Atlantic coast and the Gulf of Mexico.
Sonar associated with trauma
Active sonar is used primarily to hunt for submarines. However, the possible impact on marine mammals, and particularly toothed whales, has been a subject of controversy for several years.
Exercises like the ones being planned could potentially cause trauma to cetacean's brain and ears and cause hearing loss thereby leading to mass strandings, activists claim.
Worst case estimates
According to the Navy's own figures, the exercises could potentially harm marine mammals a total of 33 million times over five years.
In an email to Discovery News, Zak Smith of the Natural Resources Defense Council said that this includes “nearly 2.000 deaths, nearly 16.000 instances of permanent hearing loss, and over 5 million instances of temporary hearing loss.”
The Navy stresses, that these are worst-case estimates.