herring, common name for members of the large, widely distributed family Clupeidae, comprising many species of marine and fresh-water food fishes, including the sardine ( Sardinia ), the menhaden ( Brevoortia ), and the shad ( Alosa ). Herrings are relatively small but very abundant; they swim in huge schools, feeding on plankton and small animals and plants.
The adult common herring, Clupea harengus, found in temperate and cold waters of the North Atlantic, is about 1 ft (30 cm) long with silvery sides and blue back. It lays up to 30,000 eggs, which sink to the sea bottom and develop there; the young mature in three years. Other species lay their eggs in seaweed in shallow waters, and still others, the anadromous types, spawn in large rivers. Best known of these is the American shad, Alosa sapidissima. Another common anadromous herring is the alewife, A. pseudoharengus (15 in./37.5 cm), found along the Atlantic coast from Nova Scotia to South Carolina and landlocked in Lake Ontario and the Finger Lakes of New York.
The menhaden, also called bunker or pogy, is a species of the Atlantic coast of North America. It was used by Native Americans to fertilize their cornfields (its name is the Narraganset word for "fertilizing"). The vast majority of the menhaden caught, some 500 million pounds or more a year since the 1970s (until catch limits were imposed in 2012), is converted into oil and fish meal for dietary supplements, fertilizer, and fish and animal feed. Menhaden are also important as food for other wild fishes.
The skipjack, a streamlined, steel-blue herring 15 in. long, is found in the Mississippi River and the Gulf of Mexico. Its name, which is also applied to the much smaller and unrelated silversides and to a much larger and unrelated bonito (see tuna), describes any fish with a habit of leaping clear of the water.
Of the smaller food herrings and related species, the anchovies and sardines are the most important. The American anchovies, Engraulis encrasicholus, belong to the closely related family Engraulidae, are about 4 in. (10 cm) long, inhabit warm seas, and are chiefly valuable as food for other fishes. Spanish and Italian anchovies, found in the Mediterranean and nearby Atlantic, are cured by a process involving fermentation; the small European herrings (called sprats, or brislings) are cured without fermentation and are sold as Norwegian, or Swedish, anchovies and sardines. The name sardine is also applied to various small fish packed with oil or sauce in flat cans; the name sprat is sometimes applied to certain American species of commercial herring. The true sardine from France, Spain, and Portugal is usually the young pilchard ( Sardinia pilchardus ) of Mediterranean and Atlantic coastal waters.
Sardine fishing and canning are an important industry in Maine, where small herrings are used, and in California, where the sardine is a species closely related to the European pilchard. The larger herrings are dried, smoked, salted, or pickled and sold in nearly all parts of the world under such names as bloaters, kippers, and red herrings. Many herring species have been overfished, and catch limits have been placed on some species. Herring species also fluctuate in response to natural conditions, e.g., the anchovies off Peru are adversely affected by El Niño.
Herrings are classified in the phylum Chordata, subphylum Vertebrata, class Osteichthyes, order Clupeiformes, family Clupeidae.