Go to this link for a list of all marine channels/ frequencies:
http://www.marinewaypoints.com/learn/vhf.shtml
The following channels on the list are used by the Coast Guard:
9, 16, 21A, 22A, 23A, 81A, 82A, 83A.
Channel 17 is the State Police Marine Division VHF channel. Most of their transmissions are on the State Trunk System but they use the VHF channel occasionally. The tow boats also use it.
Private/recreational boaters and party boats use 68, 69, 71, & 72. I was told the party boats also use 63 and 65, not sure though.
Channel 13 is used to request a bridge opening.
If you live near the area of Sandy Hook Bay/New York Harbor the boats and tug boats use
12, 28, & 88. I've only verified the tugs on Channel 12.