Shad, bunker, shiner, pogey, and no telling how many other names, are all describing the menhaden (Brevoortia patronus). There are two in the gulf in my area: the gulf menhaden, with one large spot behind the gill cover with several smaller spots behind it, and the finescale menhaden with only one spot behind the gill cover. They grow to approximately one foot and are very similar in appearance to the freshwater shad, but are not the same fish. Menhaden are extremely oily, which is why they have been commercially netted for so many years for the oil and meal that can be produced from them. They are many people's "secret" bait for almost all species, using them alive, dead, or cut. They should be hooked just like all the other baits that I have written about so far -- For trolling, hook them through the nose; for bottom fishing, through the nose or over the anal fin; and as cut bait, they should be cut diagonally and hooked over the top of the cut surface.
Menhaden are plankton filter feeders and can only be caught with a cast net since they won't bite a hook. Sometimes when you see bait "striking" or rolling on the surface, it is a school of menhaden making surface slurps of minute surface food items. We used to be able to spot menhaden inside Tampa Bay in the summer time by the oil slick that will form over a large school. They also have a very distinctive smell if you are downwind of them. They are a very fast moving fish, and usually by the time you see them on your fish finder, they have moved far enough away from the boat so that you cannot net them. We try blind throws of the cast net in the area where we can see them flipping on the surface; this usually will produce bait. Menhaden are also very intolerant of low dissolved oxygen and will die quickly in a poorly aerated live well. Still, they are five star on my list of baits.
Just as a note, if you have never seen live menhaden, many of them have a small critter that comes crawling out of their mouths when they die. This is quite a surprise the first time you see it. It appears to be some sort of shrimp or crab that looks like a mantis shrimp and must live inside the mouth or gill area without hurting the menhaden. I don't remember seeing this written about in any of the fish books, but surely some biologist somewhere has seen this.