Omega-3 EPA and DHA fatty acids are vital for human health, but current human nutritional requirements are greater than supply. This nutrient gap is poised to increase as demand increases and the abundance of aquatic foods and the amount of omega-3 they contain may dwindle due to climate change and overfishing. Identifying and mitigating loss and inefficiencies across the global aquatic supply chain has great potential for narrowing this nutrient gap. Here, using an optimization model, we show that omega-3 supply to humans could potentially increase by as much as 50% (reaching 630 kt y−1) compared to present baseline by shifting feed inputs to produce species that have the highest omega-3 content per feed input (i.e. carp and crustaceans), diverting other production flows towards direct wild fish consumption, improving byproduct utilization, and reducing waste at the retail and consumer level. We then discuss the implications of our findings by prioritizing policies and identifying demand- and supply-side interventions to realize these ambitious changes. This work emphasizes the urgency needed in managing aquatic resources towards greater utilization of resources and highlights the extent to which even partial adaptation of the measures we propose can have on narrowing the present and future nutrient gap as novel alternative sources of omega-3 become available on a larger scale.
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Fig. 1. Global aquatic omega-3 supply chain. Edges and nodes of the model, their names and acronyms are taken from Hamilton et al. (2020). ZP stands for zooplankton, NPP for net primary production, DOM for dissolved organic matter, FM&O for fishmeal and oil, FO for fish oil, and PP for phytoplankton. All Flows are enumerated from r1 till r41. Major flows include direct consumption of wild fish (r18), omega-3 fed for aquaculture (r26−r32), aquaculture supply (r25,r33−r39), losses (r17,r22,r23,r24), recycling (r19,r40) and final supply (r41). System boundaries of our model are indicated in a gray dashed line. Flows outside our model boundaries (r1−r10) are constant. In aquaculture, ’others’ refers to milkfish, perch, and other freshwater species. ‘Carp/cat/cyp’ stands for carps, catfish and cyprinids nei. Unfed aquaculture encompasses mollusks, algae and carps that require no inputs of omega-3 and are net producers of omega-3.