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48-467: Kivik is known for its annual market, usually taking place on the third Monday through Wednesday of July each year. It's also known for its abundant production of herring , apples and apple cider , usually sold in large quantities at the market. Kivik is the site of The King's Grave , a Bronze Age circular burial site, at 75 metres in diameter the largest in Sweden. The national park of Stenshuvud

96-556: A staple food 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 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

144-407: 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 feeders , 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

192-405: A few centimetres. If copepod concentrations reach high levels, schooling herrings adopt a method called ram feeding . 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

240-433: A fish's body. The functional units of the lateral line are the neuromasts, discrete mechanoreceptive organs that sense movement in water. There are two main varieties: canal neuromasts and superficial neuromasts. Superficial neuromasts are on the surface of the body, while canal neuromasts are along the lateral lines in subdermal, fluid-filled canals. Each neuromast consists of receptive hair cells whose tips are covered by

288-433: A flexible jellylike cupula. Hair cells typically possess both glutamatergic afferent connections and cholinergic efferent connections . The receptive hair cells are modified epithelial cells ; they typically possess bundles of 40–50 microvilli "hairs" which function as the mechanoreceptors. Within each bundle, the hairs are organized in a rough "staircase" from shortest to longest. The hair cells are stimulated by

336-450: A herring in one locality might be called something else in another locality. Some examples: 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:

384-437: A major item on the forage fish menu. Copepods are typically 1–2 mm ( 1 ⁄ 32 – 3 ⁄ 32  in) long, with a teardrop-shaped body. Some scientists say they form the largest animal biomass 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

432-409: 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 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

480-437: A transmitter. They are crucial participants in a corollary discharge system designed to limit self-generated interference. When a fish moves, it creates disturbances in the water that could be detected by the lateral line system, potentially interfering with the detection of other biologically relevant signals. To prevent this, an efferent signal is sent to the hair cell upon motor action, resulting in inhibition which counteracts

528-596: Is created, inducing a flow in the canal fluid. This moves the cupulae of the neuromasts in the canal, resulting in a deflection of the hairs in the direction of the flow. The mechanoreceptive hair cells of the lateral line structure are integrated into more complex circuits through their afferent and efferent connections. The synapses that directly participate in the transduction of mechanical information are excitatory afferent connections that utilize glutamate . Species vary in their neuromast and afferent connections, providing differing mechanoreceptive properties. For instance,

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576-465: Is to the south of the village. This article about a location in Skåne County , Sweden is a stub . You can help Misplaced Pages by expanding it . Herring Herring are various species of forage fish , mostly belonging to the family of Clupeidae . Herring often move in large schools around fishing banks and near the coast, found particularly in shallow, temperate waters of

624-524: 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

672-770: 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

720-686: 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). 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

768-549: 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

816-469: The blue whale , is said to be the largest biomechanical event on Earth. 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 economies around the world. 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. Herring has been

864-532: The evolution of fish , some of the sensory organs of the lateral line were modified to function as the electroreceptors called ampullae of Lorenzini . The lateral line system is ancient and basal to the vertebrate clade, as it is found in fishes that diverged over 400 million years ago. The lateral line system allows the detection of movement, vibration, and pressure gradients in the water surrounding an animal. It plays an essential role in orientation, predation, and fish schooling by providing spatial awareness and

912-486: 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 cells , known as hair cells , which respond to displacement caused by motion and transduce these signals into electrical impulses via excitatory synapses . Lateral lines play an important role in schooling behavior, predation, and orientation. Early in

960-558: The orbit of the eye are bigger and around twice as sensitive as those of surface-living fish. One function of schooling may be to confuse the lateral line of predatory fishes. A single prey fish creates a simple particle velocity pattern, whereas the pressure gradients of many closely swimming (schooling) prey fish overlap, creating a complex pattern. This makes it difficult for predatory fishes to identify individual prey through lateral line perception. Lateral lines are usually visible as faint lines of pores running along each side of

1008-508: The pelagic zone . 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 , 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

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1056-743: The Baltic, copepods of the genus Acartia 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 of herring include seabirds , marine mammals such as dolphins , porpoises , whales , seals , and sea lions , predatory fish such as sharks , billfish , tuna , salmon , striped bass , cod , and halibut . Fishermen also catch and eat herring. The predators often cooperate in groups, using different techniques to panic or herd

1104-568: The United Kingdom. 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:

1152-401: The ability to navigate in the environment. Analysis has shown that the lateral line system should be an effective passive sensing system able to discriminate between submerged obstacles by their shape. The lateral line allows fish to navigate and hunt in water with poor visibility. The lateral line system enables predatory fishes to detect vibrations made by their prey, and to orient towards

1200-409: The air. Some whales lunge feed 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 rorquals , a family of huge baleen whales that includes

1248-599: 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 , diatoms by herring larvae below 20 mm ( 13 ⁄ 16  in), tintinnids by larvae below 45 mm ( 1 + 3 ⁄ 4  in), molluscan larvae, menhaden larvae, krill , mysids , smaller fishes, pteropods , annelids , Calanus spp., Centropagidae , and Meganyctiphanes norvegica . Herrings, along with Atlantic cod and sprat , are

1296-477: 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

1344-477: 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 17 cm (6.7 in) 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

1392-401: The deflection of their hair bundles in the direction of the tallest "hairs" or stereocilia . The deflection allows cations to enter through a mechanically gated channel , causing depolarization or hyperpolarization of the hair cell. Depolarization opens Ca v 1.3 calcium channels in the basolateral membrane . Hair cells use a system of transduction with rate coding to transmit

1440-413: The directionality of a stimulus. The hair cells produce a constant, tonic rate of firing. As mechanical motion is transmitted through water to the neuromast, the cupula bends and is displaced according to the strength of the stimulus. This results in a shift in the cell's ionic permeability. Deflection towards the longest hair results in depolarization of the hair cell, increased neurotransmitter release at

1488-435: 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

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1536-466: The electrosensory lateral line lobe of electric fish . The MON is likely involved in the integration of excitatory and inhibitory parallel circuits to interpret mechanoreceptive information. The use of mechanosensitive hairs is homologous to the functioning of hair cells in the auditory and vestibular systems , indicating a close link between these systems. Due to many overlapping functions and their great similarity in ultrastructure and development,

1584-541: The excitation resulting from reception of the self-generated stimulation. This allows the fish to detect external stimuli without interference from its own movements. Signals from the hair cells are transmitted along lateral neurons to the brain. The area where these signals most often terminate is the medial octavolateralis nucleus (MON), which probably processes and integrates mechanoreceptive information. The deep MON contains distinct layers of basilar and non-basilar crest cells, suggesting computational pathways analogous to

1632-526: The excitatory afferent synapse, and a higher rate of signal transduction . Deflection towards the shorter hair has the opposite effect, hyperpolarizing the hair cell and producing a decreased rate of neurotransmitter release. These electrical impulses are then transmitted along afferent lateral neurons to the brain. While both varieties of neuromasts utilize this method of transduction, their specialized organization gives them different mechanoreceptive capacities. Superficial organs are exposed more directly to

1680-419: The external environment. The organization of the bundles within their organs is seemingly haphazard, incorporating various shapes and sizes of microvilli within bundles. This suggests coarse but wide-ranging detection. In contrast, the structure of canal organs allow canal neuromasts more sophisticated mechanoreception, such as of pressure differentials. As current moves across the pores, a pressure differential

1728-474: 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),

1776-494: 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

1824-581: The far field as waves. The lateral line system is ancient and basal to the vertebrate clade; it is found in groups of fishes that diverged over 400 million years ago, including the lampreys , cartilaginous fishes , and bony fishes . Most amphibian larvae and some fully aquatic adult amphibians possess mechanosensitive systems comparable to the lateral line. The terrestrial tetrapods have secondarily lost their lateral line organs, which are ineffective when not submerged. The electroreceptive organs, called ampullae of Lorenzini , appearing as pits in

1872-554: 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. Herrings consume copepods , arrow worms , pelagic amphipods , mysids , and krill in

1920-552: The lateral line system and the inner ear of fish are often grouped together as the octavolateralis system (OLS). Here, the lateral line system detects particle velocities and accelerations with frequencies below 100 Hz. These low frequencies create large wavelengths, which induce strong particle accelerations in the near field of swimming fish that do not radiate into the far field as acoustic waves due to an acoustic short circuit . The auditory system detects pressure fluctuations with frequencies above 100 Hz that propagate to

1968-412: 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",

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2016-635: The most important commercial species to humans in the Baltic Sea. 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 in the Baltic Sea, where they compete for the limited zooplankton available and necessary for their survival. 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

2064-604: The next one or two years may safely eat. 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 and Copenhagen and played a critical role in the medieval development of Amsterdam . 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. Lateral line The lateral line , also called

2112-471: 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

2160-441: 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. Spinner sharks 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

2208-457: 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

2256-466: The source to begin predatory action. Blinded predatory fishes remain able to hunt, but not when lateral line function is inhibited by cobalt ions . The lateral line plays a role in fish schooling. Blinded Pollachius virens were able to integrate into a school, whereas fish with severed lateral lines could not. It may have evolved further to allow fish to forage in dark caves. In Mexican blind cave fish, Astyanax mexicanus , neuromasts in and around

2304-424: The superficial neuromasts of the midshipman fish , Porichthys notatus , are sensitive to specific stimulation frequencies. One variety is attuned to collect information about acceleration, at stimulation frequencies between 30 and 200 Hz. The other type obtains information about velocity, and is most receptive to stimulation below 30 Hz. The efferent synapses to hair cells are inhibitory and use acetylcholine as

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