Herring are various species of forage fish, belonging to the order Clupeiformes. Herring often move in large schools around fishing banks and near the coast, found particularly in shallow, temperate waters of the North Pacific and North Atlantic Oceans, including the Baltic Sea, as well as off the west coast of South America. Three species of Clupea (the type genus of the herring family Clupeidae) are recognised, and comprise about 90% of all herrings captured in fisheries. The most abundant of these species is the Atlantic herring, which comprises over half of all herring capture. Fish called herring are also found in the Arabian Sea, Indian Ocean, and Bay of Bengal. Herring played an important role in the history of marine fisheries in Europe, and early in the 20th century, their study was fundamental to the development of fisheries science. These oily fish also have a long history as an important food fish, and are often salted, smoked, or pickled. Herring were also known as "silver darlings" in the United Kingdom.
Species
A number of different species, most belonging to the family Clupeidae, are commonly referred to as herrings. The origins of the term "herring" is somewhat unclear, though it may derive from the same source as the Old High German heri meaning a "host, multitude", in reference to the large schools they form. The type genus of the herring family Clupeidae is Clupea. Clupea contains only two species: the Atlantic herring (the type species) found in the North Atlantic, and the Pacific herring mainly found in the North Pacific. Subspecific divisions have been suggested for both the Atlantic and Pacific herrings, but their biological basis remains unclear.
In addition, a number of related species, all in the Clupeidae, are commonly referred to as herrings. The table immediately below includes those members of the family Clupeidae referred to by FishBase as herrings which have been assessed by the International Union for Conservation of Nature.
Also, a number of other species are called herrings, which may be related to clupeids or just share some characteristics of herrings (such as the lake herring, which is a salmonid). Just which of these species are called herrings can vary with locality, so what might be called a herring in one locality might be called something else in another locality. Some examples:
Characteristics The species of Clupea belong to the larger family Clupeidae (herrings, shads, sardines, menhadens), which comprises some 200 species that share similar features. These silvery-coloured fish have a single dorsal fin, which is soft, without spines. They have no lateral line and have a protruding lower jaw. Their size varies between subspecies: the Baltic herring (Clupea harengus membras) is small, 14 to 18 cm (about 5.5 to 7 inches); the proper Atlantic herring (Clupea harengus harengus) can grow to about 46 cm (18 in) and weigh up 700 g (1.5 lb); and Pacific herring grow to about 38 cm (15 in).
Life cycle
At least one stock of Atlantic herring spawns in every month of the year. Each spawns at a different time and place (spring, summer, autumn, and winter herrings). Greenland populations spawn in 0–5 metres (0–16 feet) of water, while North Sea (bank) herrings spawn at down to 200 m (660 ft) in autumn. Eggs are laid on the sea bed, on rock, stones, gravel, sand or beds of algae. Females may deposit from 20,000 to 40,000 eggs, according to age and size, averaging about 30,000. In sexually mature herring, the genital organs grow before spawning, reaching about one-fifth of its total weight. The eggs sink to the bottom, where they stick in layers or clumps to gravel, seaweed, or stones, by means of their mucous coating, or to any other objects on which they chance to settle. If the egg layers are too thick they suffer from oxygen depletion and often die, entangled in a maze of mucus. They need substantial water microturbulence, generally provided by wave action or coastal currents. Survival is highest in crevices and behind solid structures, because predators feast on openly exposed eggs. The individual eggs are 1 to 1.4 mm (3⁄64 to 1⁄16 in) in diameter, depending on the size of the parent fish and also on the local race. Incubation time is about 40 days at 3 °C (37 °F), 15 days at 7 °C (45 °F), or 11 days at 10 °C (50 °F). Eggs die at temperatures above 19 °C (66 °F). The larvae are 5 to 6 mm (3⁄16 to 1⁄4 in) long at hatching, with a small yolk sac that is absorbed by the time the larvae reach 10 mm (13⁄32 in). Only the eyes are well pigmented. The rest of the body is nearly transparent, virtually invisible under water and in natural lighting conditions. The dorsal fin forms at 15 to 17 mm (19⁄32 to 21⁄32 in), the anal fin at about 30 mm (1+3⁄16 in)—the ventral fins are visible and the tail becomes well forked at 30 to 35 mm (1+3⁄8 in)— at about 40 mm (1+9⁄16 in), the larva begins to look like a herring. Herring larvae are very slender and can easily be distinguished from all other young fish of their range by the location of the vent, which lies close to the base of the tail; however, distinguishing clupeoids one from another in their early stages requires critical examination, especially telling herring from sprats. At one year, they are about 10 cm (4 in) long, and they first spawn at three years.
Ecology
Prey
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