ICCAT Contracting parties agreed to establish a positive or "white list" of vessels authorised to fish tuna and swordfish in the Atlantic. Those on the list will be the only legitimate vessels which may land these species. This innovative system aims to ensure that ICCAT members exercise the necessary control over their fleet and prevent their vessels from engaging in illegal operations. At the same time, a "black list" of vessels from non-Contracting parties which have engaged in IUU activities, has been established. Although the effectiveness of this system has been weakened in the past by constant changing of flag and registration by vessels included on the list, it nonetheless constitutes a basis allowing ICCAT to invoke trade sanctions against flag states whose vessels have been involved in illegal fishing. ICCAT was the first Regional Fisheries Organisation to encourage the application of trade sanctions to non-contracting flag States involved in IUU fishing.