Examples of synthetic baits: Berkley Gulp and Fishbites. These come in many versions. They leave a scent in the water that attracts fish. Many fishermen have had good luck with them fishing for stripers.
Berkley Gulp and Fishbites have turned the fishing bait industry on its head.

Real Bloodworms

Berkley Gulp "Bloody Sandworms"
In the spring, bloodworms are the bait of choice to catch the first striped bass of the season. But bloodworms are sometimes hard to find. Bait and tackle shops don't always have them; and when they do they are very expensive. Berkley Gulp and Fishbites have provided us with an alternative: synthetic baits. These synthetic baits slowly decompose in water, releasing a scent that is claimed to be stronger than the real thing. Synthetic Gulp "Bloody" Sandworms are shown on the right.
The consensus among fishermen is that these do work as-good-as, or better than, real bait.
Berkley Gulp now comes in many other versions besides bloodworms. They have clams, various baitfish, and sand eels.
The sand eels and swimming mullet are both very good for striped bass. Slip them on a lead jighead, or add them as a trailer on your bucktail.
The swimming mullet are also an outstanding bait for catching fluke.
The bait shops are now stocking a wide range of Berkley Gulp and Fishbites synthetic bait choices. Give them a try.