COS 147-5 - CANCELLED - Harnessing biodiversity-based solutions for sustainable and nutritious aquatic food systems

Abstract: Biodiversity sustains multiple ecosystem functions and services, such as the production of essential dietary nutrients provided by fisheries to billions worldwide. At the same time, fisheries are transforming Earth’s rivers, lakes and oceans and are a lead cause of global declines in aquatic biodiversity. Here we ask how insights from the relationship between biodiversity and ecosystem function can be applied to decouple the ecological impacts of fisheries from their role in nourishing humanity, among the greatest sustainability challenges humanity faces in the 21^st century. Specifically, we integrate fish species biogeographic information together with trait and nutrient content data into an optimization framework to address how biodiversity can maximize nutrition while reducing exploitation across the globe.

We find that countries endowed with higher fish biodiversity can sustain nutritionally complete diets with less food. This beneficial effect emerges through complementarity, which is strongest in more speciose countries. Indeed, fishing for complementary fish portfolios can reduce the harvests needed to meet nutritional outcomes by >60% in comparison to fishing for the most nutritious species, and >90% when fishing for random portfolios. These differences between complementarity and selection also increase exponentially with additional consideration of more nutrient axes. Beyond leading to a reduction in harvests, complementary portfolios rarely include vulnerable species. These results suggest that biodiversity-based solutions to food systems can unlock a triple win for diets, sustainable fisheries, and conservation of biodiversity at a global scale.