With practice you can pick out whether a boat uses a diesel or petrol power engine, hear pumps, and bubbles from outboard exhausts. Some boats are very quiet and you can only hear them at a range of 30-50 metres. Both make underwater sounds but not much has been recorded or described in scientific literature. A Dugong nursing pups will call them over distances of a few hundred metres. There is much work to be done recording and cataloging these 'vocalizations'.
Many fish can make sounds.
There are 'Croaker Fish' which as the name implies make 'croaking' sounds. There are species of coral dwelling fish that make sounds by gnawing on coral - perhaps to scare preditors or attract mates. Large Groupers make 'grunts' to signal theiir displeasure at your presence. There may be many more if we start looking for them. Again, this is an excellent place for the amateur scientist to make meaningful contributions to marine science.