The herring is a small, silver, oily schooling fish of the cold North Atlantic and Baltic (Clupea harengus and its Pacific cousin) — for a thousand years one of the most important food fishes on Earth and a pillar of northern European life. The flesh is soft, rich and strongly flavoured, eaten fresh but above all cured: salted in barrels, pickled into rollmops, soused and matjes, and cold- or hot-smoked into the kipper, bloater and buckling. Exceptionally rich in omega-3 oils and vitamin D, so abundant it once underpinned whole economies, the herring is the humble silver fish that fed the Hanseatic League and built the great Dutch fishery.