Shrimp baiting uses a cast net, bait and long poles. The long poles are used to mark a specific location and then bait is thrown in the water near the pole. After several minutes the cast net is thrown as close to the bait as possible and the shrimp are caught in the net.
The bait balls can be made of just about anything a shrimp will eat. The most common bait is a mixture of powdered clay and fish meal (typically ground menhaden). Other popular baits are flour, corn meal, cat food, chicken feed. The bait typically includes a binding agent such as clay or Portland cement. The balls range in size from a tennis ball to a softball and are typically flattened out to a hamburger shape.
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http://en.wikipedia.org/wiki/Shrimp_baiting 
