Fishing plastic waste silently undermines coastal livelihoods, ecosystems and wellbeing — yet evidence remains fragmented. This paper sets out a rigorous protocol for systematically mapping what we know, and crucially, what we do not. By bringing together environmental, social, economic, political and technical impacts, it lays the groundwork for an open, interactive evidence base to guide policy, community action and global treaty discussions. It is a foundational step toward making the lived impacts of fishing plastics visible and actionable.