Atlantic herring

Atlantic herring
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Clupeiformes
Family:	Clupeidae
Subfamily:	Clupeinae
Genus:	Clupea
Species:	C. harengus
Binomial name
Clupea harengus Linnaeus, 1758

Clupea harengus in a barrel

Atlantic herring (Clupea harengus) is a fish in the family Clupeidae. It is one of the most abundant fish species on earth. Herring can be found on both sides of the Atlantic Ocean, congregating in large schools. They can grow up to 45 centimetres (18 in) in length and weigh more than 0.5 kilograms (1.1 lb). They feed on copepods, krill and small fish, while their natural predators are seals, whales, cod and other larger fish.

The Atlantic herring fishery has long been an important part of the economy of New England and the Canadian Maritime provinces. This is because the fish congregate relatively near to the coast in massive schools, notably in the cold waters of the semi-enclosed Gulf of Maine and Gulf of St. Lawrence. North Atlantic herring schools have been measured up to 4 cubic kilometres (0.96 cu mi) in size, containing an estimated 4 billion fish.

Taxonomy

The small-sized herring in the inner parts of the Baltic Sea, which is also less fatty than the true Atlantic herring, is considered a distinct subspecies (Clupea harengus membras) ("Baltic herring"), despite the lack of a distinctive genome.

Description

Atlantic herring have a fusiform body. Gill rakers in their mouths filter incoming water, trapping any zooplankton and phytoplankton.

Atlantic herring are in general fragile. They have large and delicate gill surfaces, and contact with foreign matter can strip away their large scales.

They have retreated from many estuaries worldwide due to excess water pollution although in some estuaries that have been cleaned up, herring have returned. The presence of their larvae indicates cleaner and more–oxygenated waters.

Range and habitat

Clupea harengus distribution on a NASA SeaWIFS image - the main concentrations are in the North Atlantic and the North Sea

Atlantic herring can be found on both sides of the ocean. They range across North Atlantic waters such as the Gulf of Maine, the Gulf of St Lawrence, the Bay of Fundy, the Labrador Sea, the Davis Straits, the Beaufort Sea, the Denmark Straits, the Norwegian Sea, the North Sea, the English Channel, the Celtic Sea, the Irish Sea, the Bay of Biscay and Sea of the Hebrides.^[1] Although Atlantic herring are found in the northern waters surrounding the Arctic, they are not considered to be an Arctic species.

Ecology

Herring-like fish are the most important fish group on the planet. They are also the most populous fish.^[2] They are the dominant converter of zooplankton into fish, consuming copepods, arrow worms chaetognatha, pelagic amphipods hyperiidae, mysids and krill in the pelagic zone. Conversely, they are a central prey item or forage fish for higher trophic levels. The reasons for this success is still enigmatic; one speculation attributes their dominance to the huge, extremely fast cruising schools they inhabit.

Predators

Orca, cod, dolphins, porpoises, sharks, Rockfish^{[disambiguation needed ]}, seabird, Whale, squid, Sea Lion, Seal, tuna, Salmon, and fishermen.

Feeding

Slow motion macrophotography video (50% timelag, looping, each image shifted to compensate the rolling microturbulences from the waves) of feeding juvenile herring (38 mm) on copepods - the fish approach from below and catch each copepod individually. In the middle of the image a copepod escapes successfully to the left. Scanned with the ecoSCOPE

Herring are pelagic–prey includes copepods, amphipods, larvalsnails, diatoms by larvae below 20 millimetres (0.79 in), peridinians, molluscan larvae, fish eggs, euphausids, mysids, small fishes, menhadenlarvae, pteropods, annelids, tintinnids by larvae below 45 millimetres (1.8 in), Haplosphaera, Calanus, Pseudocalanus, Acartia, Hyperia, Centropagidae, Temora, Meganyctiphanes norvegica.

Young herring capture copepods predominantly individually ("particulate feeding" or "raptorial feeding"),^[3] a feeding method also used by adult herring on large prey items like euphausids.

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.

Herring ram feeding on a school of copepods. All fish in the school open the opercula and mouth at the same time (the red gills are visible) (click to enlarge). The fish swim in a grid with a distance of the jumplength of their prey, as indicated in the animation below.

Life history

Transparent eggs with the eyes visible, one larva hatched. Observe the yolk.

Reproduction

At least one herring stock 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 ft). North Sea (bank) herrings spawn at up to 200 metres (660 ft) in autumn. Eggs are laid on the sea bed, on rock, stones, gravel, sand or beds of algae. "...the fish were darting rapidly about, and those who have opportunity to see the fish spawning in more shallow water ... state that both males and females are in constant motion, rubbing against one another and upon the bottom, apparently by pressure aiding in the discharge of the eggs and milt" (Moore at Cross Island, Maine).

Freshly hatched larva in a drop of water besides a match to demonstrate how tiny it is. The black eyes and the yolk are visible.

Females may deposit from 20,000 up to 40,000 eggs, according to age and size, averaging about 30,000. In sexually mature herrings, 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, seaweeds or stones, by means of their coating mucus, or to any other objects on which they chance to settle.

Juvenile herring. Length ca. 38 mm, ca. 3 months old (still transparent). Visible are the otoliths, the gut, the silvery swimbladder and the heart.

If the egg layers are too thick they suffer from oxygen depletion and often die, entangled in a maze of fucus. 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 disposed eggs. The individual eggs are 1 to 1.4 millimetres (0.039 to 0.055 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), 11 days at 10 °C (50 °F). Eggs die at temperatures above 19 °C (66 °F).

Very young larvae imaged in situ in the typical oblique swimming position. The animal in the upper right is in the classical S-shape of the beginning phase of an attack of probably a copepod. The remains of the yolk and the long gut are very well visible in the transparent animal in the middle.

Development

The larvae are 5 to 6 millimetres (0.20 to 0.24 in) long at hatching, with a small yolk sac that is absorbed by the time the larva reaches 10 millimetres (0.39 in) is reached. Only the eyes are well pigmented (a camera works only with a black housing). The rest of the body nearly transparent, virtually invisible under water and natural luminance conditions.

The dorsal fin forms at 15 to 17 millimetres (0.59 to 0.67 in), the anal fin at about 30 millimetres (1.2 in)—the ventral fins are visible and the tail becomes well forked at 30 to 35 millimetres (1.4 in)—at about 40 millimetres (1.6 in) the larva begins to look like a herring.

The 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. But distinguishing clupeoids one from another in their early stages, requires critical examination, especially telling herring from sprats.

At one year they are about 10 centimetres (3.9 in) long, first spawning at 3 years.

Schooling

Atlantic herring can school in huge numbers. Radakov estimated herring schools in the North Atlantic can occupy up to 4.8 cubic kilometres with fish densities between 0.5 and 1.0 fish/cubic metre. That's several billion fish in one school.^[4]

school of juvenile herring close to the surface

Herring are amongst the most spectacular schoolers ("obligate schoolers" under older terminology). They aggregate in groups that consist of thousands to hundreds of thousands or even millions of individuals. The schools traverse the open oceans.

Schools have a very precise spatial arrangement that allows the school to maintain a relatively constant cruising speed. Schools from an individual stock generally travel in a triangular pattern between their spawning grounds, e.g. Southern Norway, their feeding grounds (Iceland) and their nursery grounds (Northern Norway). Such wide triangular journeys are probably important because herring cannibalize their own offspring. A herring school can react very quickly to evade predators; they have excellent hearing. Around SCUBA divers and remotely operated vehicles they can form a vacuole ("fountain effect"). The phenomenon of schooling is far from understood, especially the implications on swimming and feeding-energetics. Many hypotheses have been put forward to explain the function of schooling, such as predator confusion, reduced risk of being found, better orientation, and synchronized hunting. However, schooling has disadvantages such as: oxygen- and food-depletion and excretion buildup in the breathing media. The school-array probably gives advantages in energy saving although this is a highly controversial and much debated field.

Schools of herring can on calm days sometimes be detected at the surface from more than a mile away by the little waves they form, or from a few meters at night when they trigger bioluminescence in surrounding plankton ("firing"). All underwater recordings show herring constantly cruising reaching speeds up to 108 centimetres (43 in) per second, and much higher escape speeds.

Relation to humans

Fishery

The Atlantic herring fishery is managed by multiple organizations that work together on the rules and regulations applying to herring. As of 2010 the species was not threatened by overfishing.^[5]

Aquarium care

Because of their feeding habits, cruising desire, collective behavior and fragility they survive in very few aquaria worldwide despite their abundance in the ocean. Even the best facilities leave them slim and slow compared to healthy wild schools.

References

• "Clupea harengus". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=161722. Retrieved 11 March 2006. 
• Kils, U., The ecoSCOPE and dynIMAGE: Microscale Tools for in situ Studies of Predator Prey Interactions. Arch Hydrobiol Beih 36:83-96;1992

Further reading

• Bigelow, H.B., M.G. Bradbury, J.R. Dymond, J.R. Greeley, S.F. Hildebrand, G.W. Mead, R.R. Miller, L.R. Rivas, W.L. Schroeder, R.D. Suttkus and V.D. Vladykov (1963) Fishes of the western North Atlantic. Part three New Haven, Sears Found. Mar. Res., Yale Univ.
• Eschmeyer, William N., ed. 1998 Catalog of Fishes Special Publication of the Center for Biodiversity Research and Information, no. 1, vol 1-3. California Academy of Sciences. San Francisco, California, USA. 2905. ISBN 0-940228-47-5.
• Fish, M.P. and W.H. Mowbray (1970) Sounds of Western North Atlantic fishes. A reference file of biological underwater sounds The Johns Hopkins Press, Baltimore.
• Flower, S.S. (1935) Further notes on the duration of life in animals. I. Fishes: as determined by otolith and scale-readings and direct observations on living individuals Proc. Zool. Soc. London 2:265-304.
• Food and Agriculture Organization (1992). FAO yearbook 1990. Fishery statistics. Catches and landings FAO Fish. Ser. (38). FAO Stat. Ser. 70:(105):647 p.
• Joensen, J.S. and Å. Vedel Tåning (1970) Marine and freshwater fishes. Zoology of the Faroes LXII - LXIII, 241 p. Reprinted from,
• Jonsson, G. (1992). Islenskir fiskar. Fiolvi, Reykjavik, 568 pp.
• Kinzer, J. (1983) Aquarium Kiel: Beschreibungen zur Biologie der ausgestellten Tierarten. Institut für Meereskunde an der Universität Kiel. pag. var.
• Koli, L. (1990) Suomen kalat. [Fishes of Finland] Werner Söderström Osakeyhtiö. Helsinki. 357 p. (in Finnish).
• Laffaille, P., E. Feunteun and J.C. Lefeuvre (2000) Composition of fish communities in a European macrotidal salt marsh (the Mont Saint-Michel Bay, France) Estuar. Coast. Shelf Sci. 51(4):429-438.
• Landbrugs -og Fiskeriministeriet. (1995). Fiskeriårbogen 1996 Årbog for den danske fiskerflåde Fiskeriårbogens Forlag ved Iver C. Weilbach & Co A/S, Toldbodgade 35, Postbox 1560, DK-1253 København K, Denmark. p 333-338, 388, 389 (in Danish).
• Linnaeus, C. (1758) Systema Naturae per Regna Tria Naturae secundum Classes, Ordinus, Genera, Species cum Characteribus, Differentiis Synonymis, Locis 10th ed., Vol. 1. Holmiae Salvii. 824 p.
• Munroe, Thomas, A. / Collette, Bruce B., and Grace Klein-MacPhee, eds. 2002 Herrings: Family Clupeidae. Bigelow and Schroeder's Fishes of the Gulf of Maine, Third Edition. Smithsonian Institution Press. Washington, DC, USA. 111-160. ISBN 1-56098-951-3.
• Murdy, Edward O., Ray S. Birdsong, and John A. Musick 1997 Fishes of Chesapeake Bay Smithsonian Institution Press. Washington, DC, USA. xi + 324. ISBN 1-56098-638-7.
• Muus, B., F. Salomonsen and C. Vibe (1990) Grønlands fauna (Fisk, Fugle, Pattedyr) Gyldendalske Boghandel, Nordisk Forlag A/S København, 464 p. (in Danish).
• Muus, B.J. and J.G. Nielsen (1999) Sea fish. Scandinavian Fishing Year Book Hedehusene, Denmark. 340 p.
• Muus, B.J. and P. Dahlström (1974) Collins guide to the sea fishes of Britain and North-Western Europe Collins, London, UK. 244 p.
• Robins, Richard C., Reeve M. Bailey, Carl E. Bond, James R. Brooker, Ernest A. Lachner, et al. 1991 Common and Scientific Names of Fishes from the United States and Canada, Fifth Edition. American Fisheries Society Special Publication, no. 20. American Fisheries Society. Bethesda, Maryland, USA. 183. ISBN 0-913235-70-9.
• Robins, Richard C., Reeve M. Bailey, Carl E. Bond, James R. Brooker, Ernest A. Lachner, et al. 1991 Common and Scientific Names of Fishes from the United States and Canada, Fifth Edition. American Fisheries Society Special Publication, no. 20. American Fisheries Society. Bethesda, Maryland, USA. 183. ISBN 0-913235-70-9.
• Whitehead, P.J.P. (1985). FAO species catalogue. Vol. 7. Clupeoid fishes of the world (suborder Clupeioidei). An annotated and illustrated catalogue of the herrings, sardines, pilchards, sprats, shads, anchovies and wolf-herrings Part 1 - Chirocentridae
• Whitehead, P.J.P. (1985). FAO species catalogue. Vol. 7. Clupeoid fishes of the world (suborder Clupeioidei). An annotated and illustrated catalogue of the herrings, sardines, pilchards, sprats, shads, anchovies and wolf-herrings Part 1 - Chirocentridae, Clupeidae and Pristigaste FAO Fish. Synop. 125(7/1):1-303.
• Whitehead, Peter J. P. 1985. Clupeoid Fishes of the World (Suborder Clupeoidei): An Annotated and Illustrated Catalogue of the Herrings, Sardines, Pilchards, Sprats, Shads, Anchovies and Wolf-herrings: Part 1 - Chirocentridae, Clupeidae and Pristigasteridae FAO Fisheries Synopsis, no. 125, vol. 7, pt. 1. Food and Agriculture Organization of the United Nations. Rome, Italy. x + 303. ISBN 92-5-102340-9.

External links

1. ^ C.Michael Hogan, (2011) Sea of the Hebrides. Eds. P.Saundry & C.J.Cleveland. Encyclopedia of Earth. National Council for Science and the Environment. Washington DC.
2. ^ Guinness Book of Records
3. ^ Kils 1992
4. ^ Radakov DV (1973) Schooling in the ecology of fish. Israel Program for Scientific Translation, translated by Mill H. Halsted Press, New York. ISBN 9780706513516
5. ^ "Atlantic States Marine Fisheries Commission: Atlantic Herring". http://www.asmfc.org/atlanticHerring.htm. Retrieved 2009-07-02. 

• Information on Fishbase
• Information on clupea.de
• Atlantic herring (Clupea harengus) pages on Gulf of Maine Research Institute