Fish harvested by Indian-flagged vessels beyond territorial waters may be duty-free and treated as exports under prescribed rules. The provision establishes a special customs regime under which fish harvested by Indian-flagged vessels beyond territorial waters may be brought into India free of duty, and fish landed at foreign ports may be treated as export of goods, subject to rules. The Board is empowered to prescribe the form and manner of entry and to regulate declaration, custody, examination, assessment, clearance, transit and transhipment necessary to implement those measures.