Herring, common name for fish of the widely distributed family Clupeidae. The true herring (Clupea harengus), a relatively small, bony, soft-rayed fish with an elongate, laterally compressed body, is silvery in colour, shading to bluish or bluish green on the back. One of the most abundant of fishes, it is widely distributed throughout temperate and subarctic waters of the Northern Hemisphere, and is the only member of the genus found in Canadian waters. Adults move in vast schools, often many kilometres long, and migrate annually to spawning grounds in shallower waters. Herring feed on larger ZOOPLANKTON, abundant on or at the edge of the Continental Shelf. They are a major food of larger fishes (eg, COD, SALMON, TUNA, FLATFISHES) and birds.
Herring, abundant on Pacific and Atlantic coasts, also occur occasionally in Arctic waters. The Pacific subspecies (C. h. pallasi) differs from the Atlantic form (C. h. harengus) in several respects. Pacific herring spawn in spring, directly onto vegetation in intertidal and subtidal waters. They usually mature in their third year and seldom live more than 8 years. Their maximum standard length is about 26 cm. Atlantic herring spawn either in spring or autumn, usually over a gravel bottom. They mature in their fourth or fifth year, live 18 years or more and attain lengths of 35 cm or over.