Part of the attraction of livebait is its natural scent and flavor. Walleyes and other predators can detect extremely dilute concentrations of water-born chemicals that waft through the underwater world. Attractive scents often draw them toward prey.

And once a fish engulfs its prey, taste buds on the lips and tongue give it a final test to ensure its palatability. That's where some artificial baits fail. You have a bite and suddenly the fish is gone. Underwater films show the amazing speed at which a predator can spit out an objectionable item.

For this reason, crafters of soft plastic lures have, for nearly 20 years, been experimenting with impregnating natural scents and flavors into their baits. This task isn't easy, as plastisol, by its very nature does not release materials cooked into it. Materials that adhere to the surface of a worm or shad-style bait may dissolve into the water, providing an extremely dilute scent trail and a positive taste sensation.

Flavors used include natural extracts of baitfish and crayfish as well as artificial mixtures of amino acids found to be attractive to fish. Of course, experiments to test such flavors are time consuming and expensive. As a result, only a few manufacturers have undertaken such studies, most notably the scientific staff at Berkley.

Production of Berkley Power Bait launched a new generation of soft plastics, which has steadily worked itself into the mainstream of the walleye tackle industry. All the while, however, Berkley researchers knew there had to be a better way to infuse natural substances into artificial baits. For over a decade, Product Development Manager John Prochnow has been working on water soluble baits that readily release their ingredients and are biodegradable. Biodegradable, by the way, is defined as material that will degrade into carbon, oxygen, and diatomaceous earth within 12 months.

Gulp! is the culmination of these studies. Last year, production of three shapes of Power Naturals (corn kernel, maggot, and earthworm) opened the door to this new generation of impregnated baits. According to Prochnow, "This spring, the new Gulp! line expands deeply into the walleye and bass market. A 6-inch nightcrawler suitable for crawler harnesses will be available by May, along with three sizes (4-, 7-, and 10-inch) of swimming-tail worms; 2- and 3-inch grubs; and 4- and 7-inch "minnow-worms." Field tests at Lac Seul last summer found that the 6-inch Gulp! crawlers outfished live crawlers by 19 percent in trials during a walleye fishing expedition."

Prochnow says that the Gulp! line is made of water-based polymers instead of plastisol. "Water can permeate the entire bait, constantly releasing scents and flavors to attract fish. Tests show that active ingredients are released about 400 times faster than with standard flavored baits constructed of PVC plastic."

Being water-based, Gulp! baits must be kept in an air-tight container to keep them from shriveling in the sun like a real worm. They come packed in a jar, while engineers work on a resealable air-tight plastic bag.