After nearly a century of people building dams on most of the world’s major rivers, artificial reservoirs now represent an immense freshwater footprint across the landscape. Yet, these reservoirs are understudied and overlooked for their fisheries production and management potential, indicates a study from the University of California, Davis. The study, published in the journal Scientific Reports, estimates that U.S. reservoirs hold 3.5 billion kilograms (7.7 billion pounds) of fish. Properly managed, these existing reservoir ecosystems could play major roles in food security and fisheries conservation.