For purposes of carrying out export promotion and other fishery development responsibilities, the Secretary of Commerce (hereinafter in this section referred to as the “Secretary”) shall appoint not fewer than six officers who shall serve abroad to promote United States fishing interests. These officers shall be knowledgeable about the United States fishing industry, preferably with experience derived from the harvesting, processing, or marketing sectors of the industry or from the administration of fisheries programs. Such officers, who shall be employees of the Department of Commerce, shall have the designation of fishery trade officers.