Aquaculture has existed for millennia, reaching industrial scales in recent decades, and will play an increasingly important role in feeding the world (1–6). As this industry grows, we must ensure that it is ecologically and socially sustainable. However, the current production process for the food given to farmed fish still threatens coastal ecosystems and the livelihoods of local fishers, especially in the Global South (2–7). Before aquaculture is scaled up further, its global environmental and socioeconomic footprint should be carefully reimagined.

Because small fishes are at the bottom of the trophic pyramid, overharvesting can lead to the collapse of local ecosystems (8, 9). In many places, these small fish also serve as vital, local food sources. Small fish caught in the Global South are increasingly used for fish meal production for livestock and aquaculture rather than for direct human consumption. These practices have disrupted food security in places such as Bangladesh, Gambia, and Ghana (7, 10), as affordable protein has shifted from poorer coastal communities to richer markets. Widespread illegal, unreported, and unregulated fisheries support unsustainable, large-scale fish meal production for regional use or for growing global markets.

To achieve the goals of the United Nations Decade of Ocean Science for Sustainable Development, we must develop strategies to make aquaculture truly sustainable in the Global South and beyond. This will require concerted support for technological advances such as new water recirculation and offshore innovations to efficiently rear species ranging from algae to large predator fish. To meet UN goals within a decade, we also need faster development of environmentally and socially responsible ingredients for fish feed (2–6) and effective policies to support sustainable development production schemes and human nutrition initiatives in affected coastal communities. Fisheries and aquaculture policies should include environmental governance strategies focused on seawater quality and biodiversity protection (such as farm level sustainability certification), comprehensive sustainability assessments, socioeconomic dimensions, capture fisheries, and improved feed ingredient production (1–6, 11, 12).