Fish meal fed salmon require more energy inputs than soy fed salmon. Feeding salmon with fish meal leads to a pyramid of energy use of 80,000 kJm-2yr-1 for plankton, 2,500 kJm-2yr-1 for small fish, and 200 kJm-2yr-1 for salmon. In contrast, feeding salmon with soy results in lower energy requirements of 50,000 kJm-2yr-1 for soy and 7,000 kJm-2yr-1 for salmon.