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.
Many fishermen claim that these synthetic baits 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. To see some Berkley Gulp baitfish imitations, follow this link:
Berkley Gulp Baitfish Imitations