Whales and dolphins depend on sound to stay together in their family groups and whales used to be able to go on large hunting expedition to find their food, calling each other when they found it.
However, according to a new study underwater noise pollution means they can only hear each other for around 10 miles.
UK marine biologist Dr. Steve Simpson says that shipping noise causes stress in whales and, by looking at the hormones of the whales we can see that they are chronically stressed by noise. When they encounter very loud noises it can even cause damage in their ears and lungs.
He is now working with shipping companies to design boat engines that make less noise. However, noise pollution is just one among many threats for whales and dolphins. Oil and chemical spills, plastic pollution and rising sea temperatures are also big concerns.
There is still a lot of work to be done such as creating quiet sanctuaries around whale migration routes and the places they like to feed or reproduce.