"We’ve got to get over this idea that wildlife from the ocean is essential for our food security. What we now are beginning to understand is the high cost of eating fish. What does it take to make a pound of tuna? A lot of halibut or cod. What makes the halibut? Smaller fish. What do they eat? Krill. Krill eat phytoplankton, zooplankton. Over the years thousands of pounds of phytoplankton make a single pound of tuna. So that tuna is expensive in terms of the carbon that it has captured. The more fish we take out of the sea, the more carbon dioxide gets released into the atmosphere."