Sound pollution is just one of many problems affecting the world's oceans.
Plastic and chemical pollution, acidification and rising sea temperatures are also causing big concerns.
But unlike other pollutions, sound is easy to tackle because once we stop making the noise, the pollution is gone.
Experts like Dr. Steve Simpson are now working with shipping companies to design boat engines that make less noise.
Quiet sanctuaries are also being created for areas around whale migration routes or the places mammals like to feed or reproduce.
But there's still a lot of work to be done, and finding out more about how to protect marine life from man-made sound is a huge task.
To help them with their work, scientists are now asking for help from volunteers who live on the ocean.