This Regulation, based on the provisions of the Croatian Law on marine fisheries, prescribes the following bluefin tuna (Thunnus thynnus) related fishing provisions: generic conditions for fishing; conditions for the possibility of exercising the right to fishing quota allocation; transfer of the right to register the surrounding purse seiner net from one to another privilege for commercial fishing at sea; state quota for bluefin tuna fishing with a purse seiner and conditions and criteria for the allocation of an individual purse seine quota; compensation for the assigned catch quota; method and conditions for issuing and transferring the Permit for tuna fishing with purse seiner; term for which the Permit is issued and the form of such Permit; data delivery; sampling; unloading and transshipment; trade; joint fishing operations; register of vessels that participate in catching, transporting, growing and landing tuna; transfer at sea; observer programme on engaged fishing vessels; handling of accidental catches of sensitive species. This text ensures the implementation of the Regulation (EU) 2016/1627 of the European Parliament and of the Council on a multiannual recovery plan for bluefin tuna in the eastern Atlantic and the Mediterranean, and repealing Council Regulation (EC) No. 302/2009. This Ordinance is harmonized with Recommendation 21-08 of the International Commission for the Protection of Atlantic Tunas (ICCAT), which establishes a multi-year protection and management plan for bluefin tuna in the eastern Atlantic and the Mediterranean Sea.