Herrings are forage fish, mostly belonging to the family Clupeidae. They often move in large schools around fishing banks and near the coast. The most abundant and commercially important species belong to the genus Clupea, found particularly in shallow, temperate waters of the North Pacific and the North Atlantic oceans, including the Baltic Sea, as well as off the west coast of South America. Three species of Clupea are recognized. The main taxa, the Atlantic herring, accounts for over half the world's commercial capture of herrings.
Herrings played a pivotal role in the history of marine fisheries in Europe, and early in the twentieth century their study was fundamental to evolution of fisheries science. These oily fish also have a long history as an important food fish, and are often salted, smoked, or pickled.
Herring are very high in the long-chain Omega-3 fatty acids EPA and DHA. They are a source of vitamin D.
Water pollution influences the amount of herring that may be safely consumed. For example, large Baltic herring slightly exceeds recommended limits with respect to PCB and dioxin, although some sources point out that cancer-reducing effect of omega-3 fatty acids is statistically stronger than the cancer-causing effect of PCBs and dioxins. The contaminant levels depend on the age of the fish which can be inferred from their size. Baltic herrings larger than 17 cm may be eaten twice a month, while herrings smaller than 17 cm can be eaten freely. Mercury in fish also influences the amount of fish that women who are pregnant or planning to be pregnant within the next one or two years may safely eat.
Herring has been a staple food source since at least 3000 B.C. There are numerous ways the fish is served and many regional recipes: eaten raw, fermented, pickled, or cured by other techniques.
A typical Dutch delicacy is Hollandse Nieuwe (Dutch New), which is raw herring from the catches around the end of spring and the beginning of summer. This is typically eaten with raw onion. Hollandse nieuwe is only available in spring when the first seasonal catch of herring is brought in. This is celebrated in festivals such as the Vlaardingen Herring Festival and Vlaggetjesdag in Scheveningen. The new herring are frozen and enzyme-preserved for the remainder of the year. The herring is said to be eaten "raw" because it has not been cooked, though it has been subjected to a degree of curing. The first barrel of Hollandse Nieuwe is traditionally sold at auction for charity. Very young herring are called whitebait and are eaten whole as a delicacy.
In Sweden, Baltic herring ("Strömming") is fermented to make surströmming.
Pickled herrings are part of Scandinavian, Nordic, Dutch, German (Bismarckhering), Polish, Baltic, Eastern Slavic and Jewish cuisine. Most cured herrings uses a two-step process. Initially, the herrings are cured with salt to extract water. The second stage involves removing the salt and adding flavorings, typically a vinegar, salt, sugar solution to which ingredients like peppercorn, bay leaves and raw onions are added. Other flavors can be added, such as sherry, mustard and dill. The tradition is strong in Scandinavia, The Netherlands, Iceland and Germany.
In the Philippines, dried herring is popularly eaten during breakfast, along with garlic rice and eggs.
A kipper is a split, gutted and cold smoked herring, a bloater is a whole gutted and cold smoked herring and a buckling is a whole herring, gutted apart from roe or milt and then hot smoked herring. All are staples of British cuisine. According to George Orwell in The Road to Wigan Pier, the Emperor Charles V erected a statue to the inventor of bloaters.
Smoked herring is a traditional meal on the Danish island in the Baltic Sea, Bornholm. This is also the case in Sweden where one can get hard fried/smoked "Strömming" named "Sotare" in places like Skansen, Stockholm.
In Scotland, herrings are traditionally filleted, coated in seasoned pin-head oatmeal, and fried in a pan with butter or oil. This dish is usually served with "crushed" buttered boiled potatoes.
In Sweden, herring soup is a traditional dish.
In Southeast Alaska, western hemlock boughs are cut and placed in the ocean before the herring arrive to spawn. The fertilized herring eggs stick to the boughs, and are easily collected. After being boiled briefly the eggs are removed from the bough. Herring eggs collected in this way are eaten plain or in herring egg salad. This method of collection is part of Tlingit tradition.