From the rules:

"7. TACKLE AND EQUIPMENT: All fish must be caught in a legal sporting manner. Trolling with combustion engine as a method of fishing is prohibited. ONLY RODS AND REELS, LINE AND FLIES DESIGNED EXCLUSIVELY FOR FLY FISHING MAY BE USED. No soft plastic baits, or any other type of bait, customarily used for fishing with other types of rod and reels may be used. No live or prepared bait is permitted. Liquid fish attractants are allowed. Only one (1) rod may be used at any one time. No other types of rod and reels (spinning, bait casting, spin-cast) are permitted in the boat during this tournament."

So, you can't use bait or plastics, but scents are allowed. I guess that means you can soak a fly in crawfish scent.