Pelagic describes fish that live in the open water column of seas and oceans rather than near the bottom or shore, from the Greek pelagos, sea. The group includes hugely important food species: herring, mackerel, sardines, anchovies, sprats, and tunas, the small oily species forming the base of marine food webs and the foundation of global fishmeal and canning industries. Pelagic fish typically school in vast numbers, migrate long distances, and feed on plankton or smaller fish. Their management is challenging because stocks straddle national boundaries and fluctuate with ocean conditions; collapses of Peruvian anchoveta and North Sea herring show the stakes. Nutritionally, small pelagics are among the most valuable foods on earth: rich in omega-3s, vitamin D, calcium when canned with bones, cheap, and with a low environmental footprint.