Dolphins have to 'shout' above noise of passing ships to
Acoustics - Dolphin Research Center
How Noise Pollution Is Silencing Whale Songs – and Why That's a
Dolphins Can Shout Underwater, but It's Never Loud Enough - The
Dolphins 'shout' to get heard over noise pollution - BBC News
Dolphins must shout over underwater noise to communicate •
Dolphins 'shout' over loud underwater noise - study
Sea Watch Foundation » Dolphins and whales are living in noisy waters
petition: Human Noise Pollution in Oceans is Forcing Dolphins to
The Underwater World — A Silent World No More
Dolphins 'shout' to compensate for human-made background noise
TailWinds - What's new in the news
Whales go quiet and dolphins shout in loud oceans, new studies
Dolphins 'shout' to compensate for human-made background noise