Aquaculture plays a pivotal role in addressing global food security, particularly as wild-capture fisheries approach ecological saturation and can no longer meet rising nutritional demands. Fishmeal—valued for its high-quality protein profile—has emerged as a critical feed component, yet its continued use raises pressing concerns linked to ecological degradation and growing geopolitical uncertainty. This paper explores the structural vulnerabilities of the global fishmeal supply chain, drawing attention to the overharvesting of forage fish, climate-induced stock instability—reflected in a roughly 40% decline in production between 2013 and 2023—and the compounding effects of trade restrictions, including U.S.–China tariff escalations (2023–2025) and regional import bans. Unsustainable exploitation of pelagic species threatens marine biodiversity and disrupts ecological trophic networks, while global crises such as pandemics and maritime transport bottlenecks further expose fragilities in the system. In synthesizing these dynamics, the review calls for a transition toward ecosystem-based fisheries governance, geographically decentralized feed production, and strategically resilient supply chains. The analysis concludes with policy imperatives that prioritize international cooperation, anticipatory regulatory mechanisms, and adaptive management strategies to mitigate converging risks to aquaculture’s long-term sustainability.