This policy brief critically analyses why current governance frameworks—particularly Regional Fisheries Management Organisations (RFMOs)—are failing to sustainably manage migratory and straddling marine species. It highlights key structural weaknesses, including fragmented mandates, inadequate monitoring of non-target species, and insufficient adaptation to climate-driven shifts in species distributions. The paper examines how bycatch, weak enforcement, and narrow taxonomic scopes contribute to ongoing biodiversity loss. It also explores the limitations of current quota allocation systems and governance fragmentation across jurisdictions.