515 ILCS 5/15-10

A "commercial musselor" is defined as any individual who takes mussels by hand, except as provided by administrative rule, or who uses any of the mussel devices defined by this Code for the taking of mussels protected by the terms of this Code. All commercial musselors shall have a commercial mussel license. All individuals assisting a licensed commercial musselor in taking mussels from any waters of this State must have a commercial mussel license.