In a new report, experts say sounds such as sonar used in drilling, fishing activity, and giant tankers moving through the water have made them seas louder than ever before.
And these noises are reportedly damaging marine mammals hearing, with animals having to resort to desperate measures to speak to each other.
For dolphins, this involves “shouting” at each other so they can be heard over the din.
Humpback whales, on the other hand, go quiet if they are competing against a nearby boat.
Biologist Helen Bailey, of the University of Maryland, published her findings in the journal Biology letters after using underwater microphones to listen to the animals.
She said: “A lot of people imagine that underwater is this really quiet place, but it isn’t.”
Bailey says this is a particular problem because of how important dolphin communication is.
The mammals speak to each other through “whistles”, alerting their pod to the presence of fish or relaying other important information.
But when competing with noises coming from fishing lanes, dolphins can only communicate very limited information.
She explained it is like a person trying to tell their friend they have lost a set of keys in a quiet home compared to a packed bar room.
She said: “Imagine your friend has lost her keys: At home, you might say, ‘Hey, your keys are between these couch pillows’.
“But in a noisy bar you’d simply shout, ‘Keys!’ A similar loss of information happens with these flatter whistles.”
Janet Mann, an expert in bottlenose dolphins at Georgetown University, warned the increasing loudness of the ocean could have an effect on the animals dating.
She said: ”The water is a perfect medium for conducting sound, which is great if you are a fin whale that needs to find a mate 100 miles away, but not so great if there are loud human-made sounds that interfere with your attempts to find a date.”