Filling ecological and social data gaps for small-scale fisheries is crucial for global conservation of shark species. In 2016, international protection of vulnerable smooth hammerhead sharks (Sphyrna zygaena) resulted in a seasonal fishing ban to protect juvenile sharks in Peru's small-scale fisheries. Richer data on the fisheries' social-ecological dynamics are necessary to understand fishery impacts and the ban's efficacy. Semi-structured interviews with 88 Peruvian gillnetters revealed that fishers are cognizant of their impacts on the hammerhead population and further, that historical fishery impacts on the species are more severe than reflected in official records. On balance, respondents welcome conservation measures: 76% of respondents were in favor of the ban. However, most respondents also voiced objections to the ban, with unfairness emerging as a central theme including with regards to impracticality, economic severity, ecological necessity, and the burden of compliance. These objections may directly and indirectly stem from a lack of transparency and fisher participation in the ban development-and-implementation process. Fishers suggested alternative or additional options for hammerhead management, such as minimum sizes or dynamic “move-on” spatial closures. These results point to the benefits of a participatory process that engages fishers in practical and more equitable conservation solutions.