Trophic levels are an organism's position in the food web. Think of a hierarchical pyramid with apex predators (like sharks and tuna) at the top and primary producers (like plants and algae) at the bottom. The ground floor of this pyramid lays the foundation for the entire food web - providing the first sources of energy (or food) for all other organisms. But despite their modest position relative to the rest of the food chain, low trophic species might just hold the key to sustainable seafood farming.