unreported and unregulated (IUU) fishing." In December 2022, the United States Secretary of the Treasury issued sanctions on Pingtan Marine Enterprise and related individuals over human rights abuses tied to China-based illegal fishing. Flag state liability Under the United Nations Convention on the Law of the Sea, states bear responsibility for the vessels (including fishing vessels) that fly their flag. While it is uncontroversial that individuals engaged in IUU fishing may be subject to legal sanctions, the extent to which flag states may be held liable under international law for the IUU fishing activities of their vessels is less clearly defined. In March 2013 the issue of flag state liability for IUU fishing was brought before the International Tribunal for the Law of the Sea in a request for an advisory opinion submitted by the Sub-Regional Fisheries Commission (SRFC) of West Africa. The SRFC asked the Tribunal to advise on the following four questions: What are the obligations of the flag State in cases where illegal, unreported and unregulated (IUU) fishing activities are conducted within the Exclusive Economic Zone of third party States? To what extent shall the flag State be held liable for IUU fishing activities conducted by vessels sailing under its flag? Where a fishing license is issued to a vessel within the framework of an international agreement with the flag State or with an international agency, shall the State or international agency be held liable for the violation of the fisheries legislation of the coastal State by the vessel in question? What are the rights and obligations of the coastal State in ensuring the sustainable management of shared stocks and stocks of common interest, especially the small pelagic species and tuna? In its submissions to the Tribunal, the SRFC emphasized the severity of the IUU fishing problem in West Africa and the need for a clear regime of flag state responsibilities with respect to vessels engaged in this trade. The SRFC argued that its member states had been unable to mount successful prosecutions against IUU fishers following boardings due to a lack of support and cooperation from flag states. A number of states and international organizations also made submissions adopting a range positions with respect to the four questions above. It was held by some states that the Tribunal lacked the advisory jurisdiction to respond to these questions. Both the government of Spain, a major contributor to