OMG - Call the Dock permitting section of the DEP - it is listed on the first page of DEP web site. There will be one or more permtting officers responsible for that district who will be very interested in this . Get the officers name plus email address, email your pictures, property address, GPS location if you can.
If the guy does not have a permit he could get a massive fine and have to pay for remidiation.

The DEP dock permitting dept will act on this right away.