All I have to is look out the front windows of my house in Titusville and I can see the Delaware River through the trees. It may be only 1,000 feet from my house but I'd have cross River Road and then swim across the Delaware and Raritan Canal to get there. There are access points a mile each way and the Trenton Makes Bridge is 7 miles downriver from the house.
The bulk of my Delaware River fishing has been way, way up river at the start where the West Branch empties from the Cannosville Reservior and the East Branch from the Pepacton. Over the years I have smallmouth and shad fished far more south between PA and NJ.
The Delaware River is one of the highest producing spawning ground for striped bass, behind the Chesapeake and Hudson Rivers. There are several factors that affect the spawn such as water temperature, salinity, and quality. They say, kind of like in others rivers and bays, and the ocean too, that 50 degrees is the switch....well looking at the below USGS chart we are at that point.
I remember in 2012 I was on assignment for The New York Times about striped bass fishing in the Delaware at Trenton. I made the below images of a sure fire way to catch them, saki rigs catching river herring and then live-lining them. You knew the fish were there when the boats would formulate a line below the piers for The Trenton Makes Bridge. The river herring are now protected so you don't see as many anglers out there or at least using a snag and drop technique.
The Delaware River is tidal up to Trenton so, like the ocean and bays, tides can affect the fishery. Now this little intro comes with zero, none, zilch, actual striped bass fly fishing on my part. I know guys from here that grew up fishing here and I see them down on the beaches and jetties, they, of course know far more than I do. But, exploring and learning something new is exciting to me and I look forward to wetting a line, maybe as early as tomorrow.
First I have to remember to get a NJ Freshwater fishing license though......