From the list that fineshot1 provided, monitor the following channels:
9, 16, 17, 21A, 22A, 23A, 81A, 82A, 83A. 81A, 82A, & 83A are listed as U.S. Government, but they are used by the Coast Guard. 17 is the Marine Police VHF channel. Although they operate on the state trunk system, they have capabilities on that channel also. It is also used by the tow boats. The 300MHz frequencies that FLRAILMAN posted are also used by the Coast Guard.