Herring are small, oily fish of the genus Clupea found in the shallow, temperate waters of the North Pacific and the North Atlantic, including the Baltic Sea. Two species of Clupea are currently recognized, the Atlantic herring (Clupea harengus) and the Pacific herring (Clupea pallasii), each of which may be divided into subspecies. Herrings move in vast schools, coming in spring to the shores of Europe and America, where they are caught, salted and smoked in great quantities. Canned "sardines" (or pilchards) seen in supermarkets may actually be sprats or round herrings. In The Netherlands, herring have played a major role in historical and economic development dating back to the 14th century. All of the 200 species in the family Clupeidae share similar distinguishing features. They are silvery colored fish that have a single dorsal fin. Unlike most other fish, they have soft dorsal fins that lack spines, though some species have pointed scales that form a serrated keel. They have no lateral line and have a protruding lower jaw. Their overall size varies from species to species: the Baltic herring is small, usually about 14 to 18 centimeters in length, the Atlantic herring can grow to about 46 cm (18 inches) in length and weigh up to 1.5 pounds (680 g), and Pacific herring grow to about 38 cm (15 inches). Predators of adult herring include seabirds, dolphins, porpoises, striped bass, seals, sea lions, whales, and humans. Sharks, dog fish, tuna, cod, salmon, halibut and other large fish also feed on adult herring. Many of these animals also prey on juvenile herring.