C4ADS has published this report which says that behind the 4 million commercial fishing vessels in the global fleet lies a complex onshore network of shell companies, frequently concealing the true beneficiaries of this industry. It says that recent policy actions have shifted toward holding accountable ultimate beneficial owners (UBO), instead of, or in addition to, individual vessels for IUU fishing: the individuals who are responsible for and receive the greatest financial benefit from fishing operations. The report explores how ultimate beneficial ownership information in the fishing industry is an important tool to address IUU fishing, improve transparency, and build accountability. It conducted the first full mapping of UBO for vessels flagged to Spain and Ecuador and map the trawler and purse seine fleets of the UK and Indonesia, respectively. This analysis reveals barriers to investigating UBO and identifies opportunities to standardise and improve reporting requirements. As an example, it provides snapshots, including one for the UK.