San Diego: The Navy plans to increase sonar testing in US waters over the next five years even as studies it funded reveal worrying signs that the loud underwater noise could disturb whales and dolphins.
Reported mass strandings of certain whale species have risen worldwide since the military started using sonar half a century ago. Biologists also are concerned that marine mammals may suffer stress from changes in diving, feeding and communication.
Studies so far have involved a small group of tagged animals, and it`s unclear how changes in behaviour would affect populations.
For the first time, researchers coordinating with the Navy are conducting experiments using mid-frequency active sonar transmissions from ships.
Last summer, the team tagged six whales and dolphins off the Southern California coast. Results are still being analysed.