For purposes of this chapter— (1) The term “ artificial reef ” means a structure which is constructed or placed in waters covered under this chapter for the purpose of enhancing fishery resources and commercial and recreational fishing opportunities. (2) The term “ State ” means a State of the United States , the District of Columbia, Puerto Rico , the United States Virgin Islands, American Samoa, Guam, Johnston Island, Midway Island, and Wake Island. (3) The term “ waters covered under this chapter ” means the navigable waters of the United States and the waters superjacent to the Outer Continental Shelf as defined in section 1331 of title 43 , to the extent such waters exist in or are adjacent to any State. ( Pub. L. 98–623, title II, § 206 , Nov. 8, 1984 , 98 Stat. 3397 .)