Sprat is the common name applied to a group of

forage fish Forage fish, also called prey fish or bait fish, are small pelagic fish that feed on planktons (i.e. planktivores) and other small aquatic organisms (e.g. krill). They are in turn preyed upon by various predators including larger fish, seabirds ...

belonging to the genus ''

Sprattus ''Sprattus'' is a genus of small oily fish of the family Clupeidae. They are more usually known by their common name, sprats. There are five species in the genus. Species * '' Sprattus antipodum'' (Hector, 1872) (New Zealand blueback sprat ...

'' in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Clupeidae. The term also is applied to a number of other small sprat-like forage fish ('' Clupeoides'', '' Clupeonella'', '' Corica'', '' Ehirava'', '' Hyperlophus'', '' Microthrissa'', '' Nannothrissa'', '' Platanichthys'', '' Ramnogaster'', '' Rhinosardinia'', and '' Stolothrissa''). Like most forage fishes, sprats are highly active, small,

oily fish Oily fish are fish species with fish oil, oil (fats) in soft tissues and in the coelomic cavity around the Gut (zoology), gut. Their fillet (cut), fillets may contain up to 30% oil, although this figure varies both within and between species. ...

. They travel in large

schools A school is the educational institution (and, in the case of in-person learning, the building) designed to provide learning environments for the teaching of students, usually under the direction of teachers. Most countries have systems of ...

with other fish and swim continuously throughout the day.Meskendahl, L., J.-P. Herrmann, and A. Temming. "Effects of Temperature and Body Mass on Metabolic Rates of Sprat, Sprattus Sprattus L." ''Marine Biology'' 157.9 (2010): 1917–1927. Academic Search Premier. Web. 26 November 2011. p. 192

/ref> They are recognized for their nutritional value, as they contain high levels of polyunsaturated fats, considered beneficial to the human diet. They are eaten in many places around the world. Sprats are sometimes passed off as other fish; products sold as having been prepared from

anchovies An anchovy is a small, common forage fish of the family Engraulidae. Most species are found in marine waters, but several will enter brackish water, and some in South America are restricted to fresh water. More than 140 species are placed in 1 ...

(since the 19th century) and others sold as

sardine Sardine and pilchard are common names for various species of small, oily forage fish in the herring suborder Clupeoidei. The term "sardine" was first used in English during the early 15th century; a somewhat dubious etymology says it com ...

s sometimes are prepared from sprats, as the authentic ones once were less accessible. They are known for their smooth flavour and are easy to mistake for baby sardines.

Species

True sprats

True sprats belong to the genus ''

'' in the family Clupeidae. The five species are: * Type species

Other sprats

The term also is commonly applied to a number of other small sprat-like forage fish that share characteristics of the true sprat. Apart from the true sprats,

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.

lists another 48 species whose common names ends with "sprat". Some examples are:

Characteristics

The average length of time from fertilization to hatching is about 15 days, with environmental factors playing a major role in the size and overall success of the sprat.Nissling, Anders. "Effects of Temperature on Egg And Larval Survival of Cod (Gadus Morhua) And Sprat (Sprattus Sprattus) In The Baltic Sea – Implications For Stock Development." ''Hydrobiologia'' 514.1-3 (2004): 115–123. Academic Search Premier. Web. 24 November 2011. p. 12

/ref> The development of young larval sprat and reproductive success of the sprat have been largely influenced by environmental factors. Some of these factors affecting the sprat can be seen in the Baltic Sea, where

specific gravity Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...

, water temperature, depth, and other such factors play a role in their success. In recent decades the number of sprat has fluctuated, due primarily to availability of

zooplankton Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...

, a common food source, and also from overall changes in Clupeidae total abundance. Although the overall survival rates of the sprat decreased in the late 1980s and early 1990s, there has been a subsequent increase. Recent studies suggesting a progression in the reproductive success of the sprat acknowledge that a significant increase in spawning stock biomass occurred. One of the main concerns for reproductive success for the sprat include exceedingly cold winters, as cold temperatures, especially in the Baltic Sea, have been known to affect the development of sprat eggs and larvae. The metabolic rate of the sprat is highly influenced by environmental factors such as water temperature. Several related fish, such as the

Atlantic 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 northern Atlantic Ocean, congregating in large schools. ...

(''C. harengus''), have much lower metabolic rates than that of the sprat. Some of the difference may be due to size differences among the related species, but the most important reason for high levels of metabolism for the sprat is their exceedingly high level of activity throughout the day.

Distribution

Fish of the different species of sprat are found in various parts of the world including New Zealand, Australia, and parts of Europe. By far, the most highly studied location where sprat, most commonly ''Sprattus sprattus'', reside is the

Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North European Plain, North and Central European Plain regions. It is the ...

in Northern Europe. The Baltic Sea provides the sprat with a highly diverse environment, with spatial and temporal potential allowing for successful reproduction.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 November 2011. p. 1516

/ref> One of the most well-known locations in the Baltic Sea where they forage for their food is the

Bornholm Bornholm () is a List of islands of Denmark, Danish island in the Baltic Sea, to the east of the rest of Denmark, south of Sweden, northeast of Germany and north of Poland. Strategically located, Bornholm has been fought over for centuries. I ...

Basin, in the southern portion of the Baltic Sea.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> Although the Baltic Sea has undergone several ecological changes during the last two decades, the sprat has dramatically increased in population.Casini, Michele, Massimiliano Cardinale, and Joakim Hjelm. "Inter-Annual Variation in Herring, Clupea Harengus, And Sprat, Sprattus Sprattus, Condition in the Central Baltic Sea: What Gives The Tune?." ''Oikos'' 112.3 (2006): 638–650. Academic Search Premier. Web. 22 November 2011. p. 638

/ref> One of the environmental changes that has occurred in the Baltic Sea since the 1980s includes a decrease in water salinity, due to a lack of inflow from the North Sea that contains high saline and oxygen content.

Ecology

In the Baltic Sea,

cod Cod (: cod) is the common name for the demersal fish genus ''Gadus'', belonging to the family (biology), 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 ''Gad ...

herring Herring are various species of forage fish, belonging to the Order (biology), order Clupeiformes. Herring often move in large Shoaling and schooling, schools around fishing banks and near the coast, found particularly in shallow, temperate wate ...

, and sprat are considered the most important species. Cod is the top predator, while the herring and sprat primarily are recognized as prey. This has been proven by many studies that analyze the stomach contents of such fish, often finding contents that immediately signify predation among the species. Although cod primarily feed on adult sprat, sprat tend to feed on cod before the cod have been fully developed. The sprat tends to prey on the cod eggs and larvae. Furthermore, sprat and herring are considered highly competitive for the same resources that are available to them. This is most present in the vertical migration of the two species in the Baltic Sea, where they compete for the limited zooplankton that is available and necessary for their survival. Sprats are highly selective in their diet and are strict zooplanktivores that do not change their diet as their size increases, like some herring, but include only zooplankton in their diet. They eat various species of zooplankton in accordance to changes in the environment, as temperature and other such factors affect the availability of their food. During autumn, sprats tend to have a diet high in '' Temora longicornis'' and '' Bosmina maritime''. During the winter, their diet includes ''Pesudocalanus elongates''. ''Pseudocalanus'' is genus of the order

Calanoida Calanoida is an order of copepods, a group of arthropods commonly found as zooplankton. The order includes around 46 families with about 1800 species of both marine and freshwater copepods between them. Description Calanoids can be distinguish ...

and subclass

Copepoda Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic (living in the water column), some are benthic (living on the sediments), several species have ...

that is important to the predation and diet of fish in the Baltic Sea. In both autumn and winter, a tendency exists for sprats to avoid eating '' Acartia'' spp., because they tend to be very small in size and have a high escape response to predators such as the herring and sprat. Although ''Acartia'' spp. may be present in large numbers, they also tend to dwell more toward the surface of the water, whereas the sprats, especially during the day, tend to dwell in deeper waters.

Fisheries

File:Time series for global capture of all sprats 2.png, Global commercial capture of sprats in million tonnes 1950–2010Based on data sourced from the relevan
FAO Species Fact Sheets
/ref> File:Global total production sprats.png, The total capture of sprats in 2010 reported by the FAO was 667,000 tonnes.

As food

In Northern Europe, European sprats are commonly smoked and preserved in oil, which retains a strong, smoky flavor. Sprat, if smoked, is considered to be one of the foods highest in

purine Purine is a heterocyclic aromatic organic compound that consists of two rings (pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted puri ...

content.Various food types and their purine content http://www.acumedico.com/purine.htm Sprats contain long-chain

polyunsaturated fatty acids In biochemistry and nutrition, a polyunsaturated fat is a fat that contains a polyunsaturated fatty acid (abbreviated PUFA), which is a subclass of fatty acid characterized by a backbone with two or more carbon–carbon double bonds. Some polyunsa ...

, including

eicosapentaenoic acid Eicosapentaenoic acid (EPA; also icosapentaenoic acid) is an omega−3 fatty acid. In physiological literature, it is given the name 20:5(''n''−3). It also has the trivial name timnodonic acid. In chemical structure, EPA is a carboxylic acid wi ...

(EPA) and

docosahexaenoic acid Docosahexaenoic acid (DHA) is an omega−3 fatty acid that is an important component of the human brain, cerebral cortex, skin, and retina. It is given the fatty acid notation 22:6(''n''−3). It can be synthesized from alpha-linolenic acid or ...

(DHA). They are present in amounts comparable to Atlantic salmon, and up to seven times higher in EPA and DHA than common fresh fillets of

gilt-head bream The gilt-head bream (''Sparus aurata''), also known as the gilthead, dourade, gilt-head seabream or silver seabream, is a species of marine Actinopterygii, ray-finned fish belonging to the Family (biology), family Sparidae, the seabreams or porg ...

. The sprats contain about 1.43 g/100 g of these polyunsaturated fatty acids that have been found to help prevent mental, neural, and cardiovascular diseases.Galina S. Kalachova, et al. "Content of essential polyunsaturated fatty acids in three canned fish species." ''International Journal of Food Sciences & Nutrition'' 60.3 (2009): 224–230. Academic Search Premier. EBSCO. Web. 26 October 2011. p.224

/ref> File:Sprattus sprattus.jpg, ''Sprattus sprattus'', the European sprat File:Visserijmuseum048.jpg, Creel (basket), Creel with sprat, National Fishery Museum, Belgium File:Visserijmuseum047.jpg, Oven for smoking sprat, National Fishery Museum, Belgium