In the 2000s, the Dutch beam trawl fleet was in chronic deficit and under pressure to reduce its environmental impact. Instead of converting to selective fishing gears, it successfully lobbied the European Commission with the support of public authorities and scientists to obtain derogations against formal scientific advice to practice a prohibited technique: electric trawling. Since then, electric trawling has expanded beyond regulatory threshold: 84 large trawlers now catch the vast majority of the Dutch flatfish quota, causing detrimental socio-environmental impacts. To assess whether the European Union's fisheries policies fulfilled legal objectives and implemented the 2030 Agenda, it appeared crucial to quantify how much public financial aid had been provided to the Dutch fishing sector for its conversion to electric trawling. The financial information enabling this evaluation was first concealed but was eventually obtained. We show that the institutional opacity surrounding electric trawling was not serendipitous and has served to dissimulate allocations of public monies to a prohibited fishing method (otter trawl), illegal licenses, and falsely 'scientific' fishing. In breach of EU laws, 20.8 million EUR of structural funds have so far been granted to this sector in the form of direct subsidies, i.e. over 30 times the amount acknowledged by the fishing industry. The findings presented here lift part of the veil surrounding electric trawling, but the complete reconstruction of the impacts of this fishing method can only be done when decision-makers and scientists disclose all data in full transparency and become the warrants of the public interest.