Herring are forage fish, mostly belonging to the family of Clupeidae. Herring often move in large schools around

fishing bank An ocean bank, sometimes referred to as a fishing bank or simply bank, is a part of the seabed that is shallow compared to its surrounding area, such as a shoal or the top of an underwater hill. Somewhat like continental slopes, ocean bank sl ...

s 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 Atlantic herring (''Clupea harengus'') is a herring in the family (biology), family Clupeidae. It is one of the most abundant fish species in the world. Atlantic herrings can be found on both sides of the Atlantic Ocean, congregating in large ...

, 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 Smoking is the process of flavoring, browning, cooking, or preserving food by exposing it to smoke from burning or smoldering material, most often wood. Meat, fish, and ''lapsang souchong'' tea are often smoked. In Europe, alder is the tradi ...

, or pickled. Herring are also known as "silver darlings".

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 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''.Pauly, Daniel (2004
''Darwin's Fishes: An Encyclopedia of Ichthyology, Ecology, and Evolution''
Page 109, Cambridge University Press. . ''Clupea'' contains only two species: the

(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 FishBase is a global species database of fish species (specifically finfish). It is the largest and most extensively accessed online database on adult finfish on the web.

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 ''Coregonus artedi'', commonly known as the cisco, is a North American species of freshwater whitefish in the family Salmonidae. The number of species and definition of species limits in North American ciscoes is a matter of debate. Accordingly ...

, which is a

salmonid Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes . It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whitefis ...

). 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,

shad The Alosinae, or the shads,Alosinae

s, 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 The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelial ...

and have a protruding lower jaw. Their size varies between subspecies: the

Baltic herring Atlantic herring (''Clupea harengus'') is a herring in the family Clupeidae. It is one of the most abundant fish species in the world. Atlantic herrings can be found on both sides of the Atlantic Ocean, congregating in large schools. They can ...

(''Clupea harengus membras'') is small, 14 to 18 cm; 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).

Lifecycle

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 of water, while North Sea (bank) herrings spawn at down to in autumn. Eggs are laid on the sea bed, on rock, stones, gravel, sand or beds of

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

. 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 in diameter, depending on the size of the parent fish and also on the local race. Incubation time is about 40 days at , 15 days at , or 11 days at . Eggs die at temperatures above . The larvae are long at hatching, with a small yolk sac that is absorbed by the time the larvae reach . 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 , the anal fin at about —the ventral fins are visible and the tail becomes well forked at 30 to — at about , 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 long, and they first spawn at three years.

Ecology

Prey

Herrings consume

copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...

arrow worm The Chaetognatha or chaetognaths (meaning ''bristle-jaws'') are a phylum of predatory marine worms that are a major component of plankton worldwide. Commonly known as arrow worms, about 20% of the known Chaetognatha species are benthic zone, be ...

s, pelagic amphipods, mysids, and krill in the

pelagic zone The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...

. Conversely, they are a central prey item or forage fish for higher trophic levels. The reasons for this success are still enigmatic; one speculation attributes their dominance to the huge, extremely fast cruising schools they inhabit. Herring feed on

phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'. Ph ...

, and as they mature, they start to consume larger organisms. They also feed on zooplankton, tiny animals found in oceanic surface waters, and small fish and fish larvae. Copepods and other tiny crustaceans are the most common zooplankton eaten by herring. During daylight, herring stay in the safety of deep water, feeding at the surface only at night when the chance of being seen by predators is less. They swim along with their mouths open, filtering the plankton from the water as it passes through their gills. Young herring mostly hunt copepods individually, by means of "particulate feeding" or "raptorial feeding",Kils U (1992)
The ATOLL Laboratory and other Instruments Developed at Kiel
' U.S. GLOBEC News, Technology Forum Number 8: 6–9. a feeding method also used by adult herring on larger prey items like krill. If prey concentrations reach very high levels, as in microlayers, at fronts, or directly below the surface, herring become

filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

s, driving several meters forward with wide open mouth and far expanded opercula, then closing and cleaning the gill rakers for a few milliseconds. Copepods, the primary zooplankton, are a major item on the forage fish menu. Copepods are typically long, with a teardrop-shaped body. Some scientists say they form the largest animal

biomass Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bi ...

on the planet. Copepods are very alert and evasive. They have large antennae (see photo below left). When they spread their antennae, they can sense the pressure wave from an approaching fish and jump with great speed over a few centimetres. If copepod concentrations reach high levels, schooling herrings adopt a method called

ram feeding Aquatic feeding mechanisms face a special difficulty as compared to feeding on land, because the density of water is about the same as that of the prey, so the prey tends to be pushed away when the mouth is closed. This problem was first identifi ...

. In the photo below, herring ram feed on a school of copepods. They swim with their mouths wide open and their operculae fully expanded. The fish swim in a grid where the distance between them is the same as the jump length of their prey, as indicated in the animation above right. In the animation, juvenile herring hunt the copepods in this synchronised way. The copepods sense with their antennae the pressure wave of an approaching herring and react with a fast escape jump. The length of the jump is fairly constant. The fish align themselves in a grid with this characteristic jump length. A copepod can dart about 80 times before it tires. After a jump, it takes it 60 milliseconds to spread its antennae again, and this time delay becomes its undoing, as the almost endless stream of herring allows a herring to eventually snap up the copepod. A single juvenile herring could never catch a large copepod. Other pelagic prey eaten by herring includes fish eggs, larval snails,

diatom A diatom (Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising sev ...

s by herring larvae below ,

tintinnid Tintinnids are ciliates of the choreotrich order Tintinnida, distinguished by vase-shaped shells, the name deriving from a Latin source meaning a small tinkling bell, that are called'' loricae'', which are mostly protein but may incorporate min ...

s by larvae below ,

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

an larvae, menhaden larvae, krill, mysids, smaller fishes, pteropods,

annelid The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecol ...

s, '' Calanus'' spp.,

Centropagidae Centropagidae is a family of copepods in the order Calanoida. Its members are particularly known as plankton in coastal waters and in fresh water in Australia and southern South America. They are also found on subantarctic islands and in lakes i ...

, and '' Meganyctiphanes norvegica''. Herrings, along with Atlantic cod and sprat, are the most important commercial species to humans in the Baltic Sea.Friedrich W. Köster, et al. "Developing Baltic Cod Recruitment Models. I. Resolving Spatial And Temporal Dynamics Of Spawning Stock And Recruitment For Cod, Herring, And Sprat." ''Canadian Journal of Fisheries & Aquatic Sciences'' 58.8 (2001): 1516. Academic Search Premier. Web. 21 Nov. 2011. p. 1516

/ref> The analysis of the stomach contents of these fish indicate Atlantic cod is the top predator, preying on the herring and sprat. Sprat are competitive with herring for the same food resources. This is evident in the two species'

vertical migration Diel vertical migration (DVM), also known as diurnal vertical migration, is a pattern of movement used by some organisms, such as copepods, living in the ocean and in lakes. The word ''diel'' comes from the Latin ''dies'' day, and means a 24- ...

in the Baltic Sea, where they compete for the limited zooplankton available and necessary for their survival.Casini, Michele, Cardinale, Massimiliano, and Arrheni, Fredrik. "Feeding preferences of herring (Clupea harengus) and sprat (Sprattus sprattus) in the southern Baltic Sea." ''ICES Journal of Marine Science'', 61 (2004): 1267–1277. Science Direct. Web. 22 November 2011. p. 1268

/ref> Sprat are highly selective in their diet and eat only zooplankton, while herring are more eclectic, adjusting their diet as they grow in size. In the Baltic, copepods of the genus ''

Acartia ''Acartia'' is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions. Classification This genus contains the majority of species in the fam ...

'' can be present in large numbers. However, they are small in size with a high escape response, so herring and sprat avoid trying to catch them. These copepods also tend to dwell more in surface waters, whereas herring and sprat, especially during the day, tend to dwell in deeper waters.

Predators

Humpback whale lunging through a herring school

Predators of herring include seabirds, marine mammals such as dolphins,

porpoises Porpoises are a group of fully aquatic marine mammals, all of which are classified under the family Phocoenidae, parvorder Odontoceti (toothed whales). Although similar in appearance to dolphins, they are more closely related to narwhals an ...

, whales, seals, and sea lions, predatory fish such as sharks, billfish, tuna, salmon,

striped bass The striped bass (''Morone saxatilis''), also called the Atlantic striped bass, striper, linesider, rock, or rockfish, is an anadromous perciform fish of the family Moronidae found primarily along the Atlantic coast of North America. It has al ...

cod Cod is the common name for the demersal fish genus '' Gadus'', belonging to the family Gadidae. Cod is also used as part of the common name for a number of other fish species, and one species that belongs to genus ''Gadus'' is commonly not call ...

, and halibut. Fishermen also catch and eat herring. The predators often cooperate in groups, using different techniques to panic or herd a school of herring into a tight bait ball. Different predatory species then use different techniques to pick the fish off in the bait ball. The sailfish raises its sail to make it appear much larger.

Swordfish Swordfish (''Xiphias gladius''), also known as broadbills in some countries, are large, highly migratory predatory fish characterized by a long, flat, pointed bill. They are a popular sport fish of the billfish category, though elusive. Swordfis ...

charge at high speed through the bait balls, slashing with their swords to kill or stun prey. They then turn and return to consume their "catch". Thresher sharks use their long tails to stun the shoaling fish. These sharks compact their prey school by swimming around them and splashing the water with their tails, often in pairs or small groups. They then strike them sharply with the upper lobe of their tails to stun them.Seitz, J.C
Pelagic Thresher
. ''Florida Museum of Natural History.'' Retrieved on December 22, 2008.

Spinner shark The spinner shark (''Carcharhinus brevipinna'') is a species of requiem shark, in the family Carcharhinidae, named for the spinning leaps it makes as a part of its feeding strategy. This species occurs in tropical and warm temperate waters worldw ...

s charge vertically through the school, spinning on their axes with their mouths open and snapping all around. The sharks' momentum at the end of these spiraling runs often carries them into the air. Some whales

lunge feed A bait ball, or baitball, occurs when small fish swarm in a tightly packed spherical formation about a common centre. It is a last-ditch defensive measure adopted by small schooling fish when they are threatened by predators. Small schooling f ...

on bait balls. Lunge feeding is an extreme feeding method, where the whale accelerates from below the bait ball to a high velocity and then opens its mouth to a large gape angle. This generates the water pressure required to expand its mouth and engulf and filter a huge amount of water and fish. Lunge feeding by

rorqual Rorquals () are the largest group of baleen whales, which comprise the family Balaenopteridae, containing ten extant species in three genera. They include the largest animal that has ever lived, the blue whale, which can reach , and the fin wha ...

s, a family of huge baleen whales that includes the blue whale, is said to be the largest biomechanical event on Earth.

Fisheries

Adult herring are harvested for their flesh and eggs, and they are often used as baitfish. The trade in herring is an important sector of many national economies. In Europe, the fish has been called the "silver of the sea", and its trade has been so significant to many countries that it has been regarded as the most commercially important fishery in history. Purse seining for herring, southeast Alaska, nd (COBB 212)

Purse seining for herring, southeast Alaska, nd (COBB 212)

Environmental Defense have suggested that the

(''Clupea harengus'') fishery is an environmentally responsible fishery.

As food

Herring has been a

staple food A staple food, food staple, or simply a staple, is a food that is eaten often and in such quantities that it constitutes a dominant portion of a standard diet for a given person or group of people, supplying a large fraction of energy needs and ...

source since at least 3000 BC. The fish is served numerous ways, and many regional recipes are used: eaten raw, fermented, pickled, or cured by other techniques, such as being smoked as kippers. Herring are very high in the long-chain omega-3 fatty acids

EPA The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it be ...

and

DHA DHA, Dha and dha may refer to: Chemicals * Docosahexaenoic acid, a 22:6 omega-3 fatty acid * Dehydroandrosterone, an endogenous androgenic steroid * Dehydroascorbic acid, an oxidized form of ascorbic acid * Dehydroacetic acid, a pyrone derivati ...

. 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 PCB may refer to: Science and technology * Polychlorinated biphenyl, an organic chlorine compound, now recognized as an environmental toxin and classified as a persistent organic pollutant * Printed circuit board, a board used in electronics * ...

and

dioxin Dioxin may refer to: * 1,2-Dioxin or 1,4-Dioxin, two unsaturated heterocyclic 6-membered rings where two carbon atoms have been replaced by oxygen atoms, giving the molecular formula C4H4O2 *Dibenzo-1,4-dioxin, the parent compound also known as ...

, although some sources point out that the cancer-reducing effect of omega-3 fatty acids is statistically stronger than the carcinogenic 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 may be eaten twice a month, while herrings smaller than 17 cm can be eaten freely.

Mercury in fish The presence of mercury in fish is a health concern for people who eat them, especially for women who are or may become pregnant, nursing mothers, and young children. Fish and shellfish concentrate mercury in their bodies, often in the form of m ...

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.

History

The herring has played a highly significant role in history both socially and economically. During the Middle Ages, herring prompted the founding of

Great Yarmouth Great Yarmouth (), often called Yarmouth, is a seaside town and unparished area in, and the main administrative centre of, the Borough of Great Yarmouth in Norfolk, England; it straddles the River Yare and is located east of Norwich. A pop ...

, Amsterdam, and Copenhagen. In 1274, while on his deathbed at the monastery of Fossanova (south of Rome, Italy), when encouraged to eat something to regain his strength, Thomas Aquinas asked for fresh herring.Process of Canonization of St. Thomas Aquinas, Testimony of Br. Peter of Montesangiovanni
/ref>

References

Citations

Sources

* * Dewhurst HW (1834
''Clupea harengis'' or the common herring
In: ''The Natural History of the Order Cetacea'', Oxford University. Pages 232–246. * Geffen, Audrey J (2009
Advances in herring biology: from simple to complex, coping with plasticity and adaptability:
''ICES Journal of Marine Science'', 66 (8): 1688–1695. * Gilpen JB (1867
"On the common herring (''Clupea elongata'')"
''Proceedings and Transactions of the Nova-Scotian Institute of Natural Science'', 1 (1): 4–11. * O'Clair, Rita M. and O'Clair, Charles E., "Pacific herring," ''Southeast Alaska's Rocky Shores: Animals''. pg. 343–346. Plant Press: Auke Bay, Alaska (1998). * Stephenson RL (2001
The role of herring investigations in shaping fisheries science
In F. Funk, J. Blackburn, D. Hay, A.J. Paul, R. Stephen- son, R. Toresen, and D. Witherell (eds.) ''Herrings: Expectations for a New Millennium'', Alaska Sea Grant College Program. AK-SG-01-04. pp. 1–20. . * Stephenson, R. L., Melvin, G. D., and Power, M. J. (2009
"Population integrity and connectivity in Northwest Atlantic herring: a review of assumptions and evidence"
''ICES Journal of Marine Science'', 66: 1733–1739. * Whitehead PJP, Nelson GJ and Wongratana T (1988) FAO species catalogue, volume 2: ''Clupeoid Fishes of the World''

FAO Fisheries Synopsis 125, Rome. . tp://ftp.fao.org/docrep/fao/009/t0835e/t0835e.zip Download ZIP (16 MB)

External links

from National Geographic (2003)
Atlantic Herring
from the Gulf of Maine Research Institute
Nutrition Facts for Herring

Prospecting herring waste – from ScienceNordic

PNAS Population-scale sequencing reveals genetic differentiation due to local adaptation in Atlantic herring.
{{Authority control Clupeidae Seafood Commercial fish Oily fish Fish common names