Public acceptability of fisheries policy remains a key challenge for successful governance, constraining the set of feasible management options. To many, public opinion seems mysterious – rarely aligned with scientific evidence, yet not random, as it is shaped by frames, narratives, and social factors. Here, we examine public acceptance of governing a new fishery through a survey experiment conducted in ten countries. As a case, we consider the mesopelagic zone, a largely untapped resource with high biomass and economic potential. However, mesopelagic fishing also entails ecological and social risks, including impacts on food webs, carbon sequestration, and global equity. Acceptance varied substantially across countries. Support was lower in wealthier countries, such as Germany and the Netherlands, where respondents also favored stricter regulation, and higher in Indonesia, Nigeria, the Philippines, and, to a lesser extent, Spain, where support for regulation was weaker. Different frames have different effects across countries. For example, emphasizing risks to food webs reduced acceptance in Argentina and Nigeria, while highlighting disproportionate burdens on the Global South further lowered support only in Nigeria. At the individual level, confidence in government and large companies increased support for mesopelagic fishing, whereas other demographic factors played smaller roles. These findings emphasize the role of equity concerns and localized public opinion in shaping policy for fisheries and highlight the context-dependent power of narrative framing.