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

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.

Automated summary

Wild fisheries provide billions of people with essential nutrients, and as fisheries decline, shifting consumption to farmed animals becomes necessary. However, the nutritional substitutability between wild and farmed animals remains unclear. This study compares nutrient concentrations across various animal sources and finds that wild fish are more nutrient-dense and variable than farmed animals. The challenge of substituting farmed animals for wild fish is particularly difficult in fishery-dependent nations with high biodiversity and malnutrition prevalence. The findings emphasize the importance of incorporating diverse animal- and plant-based foods in order to achieve healthy and sustainable diets while offsetting changes in fisheries.