A small, silvery, oily fish belonging to one of several species related to herring (family Clupeidae) and found in all oceans. The genus Sardinops includes the South American (S. sagax), Southern African (S. ocellatus), Californian (S. caeruleus), and Japanese (S. melanostictus) pilchards. The European pilchard, also known as the Cornish sardine and the sardine (Sardina pilchardus), is 15–20 cm long, swims in shoals feeding on plankton, and is found in the eastern North Atlantic, Mediterranean, and Black Sea. It is of great commercial importance. Smaller individuals are known as sardines, larger ones as pilchards.