Deepwater jigging can be one of the most successful methods when sand eels are in 30 to 70 feet of water. Jig the bottom five feet of the column, where the biggest striped bass hang out. When the drift is fast, it's important to use a jig that is heavy enough to stay on the bottom, in the strike zone.
I like to work the jig sharply in the vertical plane and keep a taut line on the drop. Striped bass have a tendency to hit the jig just as it starts to fall after being lifted. If there is too much slack in your line, you will not be able to feel the bump, and you'll miss the strike.
Also effective is the Shimano butterfly-jigging technique. This is much different than the traditional high-sticking snap-jigging method. When you're butterfly jigging, the jig comes off the bottom in a zigzag pattern.
When sea herring are the primary bait in an area, it is time to break out the large swimming plugs and surface poppers. In my area, we have a number of plug-makers that spin custom wood swimmers that are absolutely deadly: Lefties, Wades, Greg Cuozzo's Pajama Plugs, Cyclones, Big Dons, McFaddens, Bottomlys and Gary 2s are some of the favorites, but they aren't widely available. These plugs track on the surface or just below. If you can't get these custom swimmers, the traditional 6- to 10-inch plugs will work, as will large surface poppers or shad bodies fished on jig heads. I like a green, blue, gold or pearl back fading to a white underbelly.
If you've ever wanted to catch a striped bass on fly, then December is the time to do it. This time of year, striped bass will strike indiscriminately at your fly as they gorge themselves on the bait. When sand eels dominate, long, slender, slim-profile flies work best. Weighted heads on all patterns help to put them deeper in the water column. From the boat, fish these flies on fast-sinking lines or heads. The Rio Outbound series Type 8 sinking line or 30 feet of a Rio T-14 head attached to an intermediate running line will sink fast, with minimal drag. From the surf or jetty, you can also fish these flies using a 200- to 350-grain sinking line or a clear intermediate striped bass line. Time your cast so it falls on the backside of a wave rather than the face, which will only push your line into the beach.
When herring are the main baits, you will want to fish large Deceiver-type streamers, Popovics's Bucktail Deceivers and Hollow Fleyes. Any of these patterns, or similar ones of the same configuration, are easy to cast and present a wide and long profile in the water. Big synthetic bunker flies or other herring patterns will also work. From the boat or surf, fish these flies on an intermediate line or floating line. When fly-fishing, be ready to set the hook hard with a strip strike when you feel a bump.
If trolling is your game, umbrella rigs with colored tube tails fished on wire line or heavy mono with drails right near the bottom work well when sand eels are present. This usually results in constant hookups, particularly when your rig is dragged over a lump or high spot. Trolling shad rigs and plugs works best when sea herring are present. Most boaters opt not to troll, as the heavy gear and tackle require much more work and effort than is necessary to hook fish.
When you hit it right, the final run of the year puts you into big bass, and lots of them. All you have to do is pay attention to where they are, gear up and show up.