The instant invention describes an anti-biofouling structure for placement onto structures or surfaces that are exposed to aquatic environments. Embedded within the anti-biofouling structure are agents that can diffuse out of the structure and prevent the formation and/or accumulation of plant and animal species build-up that creates biofouling. The instant invention also describes system for preventing biofouling of an object stored in an aquatic environment which includes the anti-biofouling structure and a protective cover element constructed and arranged to fit various structures, such as boat propellers.