Nutritional challenges of substituting farmed animals for wild fish in human diets

Abstract

Wild fisheries provide billions of people with a key source of multiple essential nutrients. As fisheries plateau or decline, nourishing more people will partially rely on shifting consumption to farmed animals. The environmental implications of transitions among animal-sourced foods have been scrutinized, but their nutritional substitutability remains unclear. We compared concentrations of six essential dietary nutrients across >5000 species of wild fishes, aquaculture, poultry and livestock species, representing >65% of animals consumed globally. Wild fishes are both more nutrient-dense and variable than farmed animals; achieving recommended intake of all nutrients with farmed species could require consuming almost four times more biomass than with wild fish. The challenge of substituting farmed animals for wild fishes are magnified in fishery-dependent nations with high biodiversity and prevalence of malnutrition. Ultimately, the better ability of wild fishes to meet multiple nutrients simultaneously underscores the importance of drawing upon a diverse portfolio of animal- and plant-based foods as societies seek to offset changes in fisheries while achieving healthy and sustainable diets.