Pollachius virens

Pollachius virensis aspeciesofmarine fishin the genusPollachius. Together withP. pollachius, it is generally referred to in theUnited Statesaspollock. It is commonly known in Britain as thecoalfish,coley, orsaithe(/seɪð/or/seɪθ/),and the young fish may also be calledpodleysin Scotland and northern England.
This species can be separated fromP. pollachiusby looking at the relative lengths of the upper and lower jaws.P. pollachiushas a longer underslung lower jaw whileP. virenshas approximately equal upper and lower jaw lengths. This gives a very different profile to the head. In general,P. pollachiusis a brown or golden colour with a dark back whileP. virensis bright silver with a very dark green back.P. virensgenerally appears to have relatively smaller eyes. Thelateral lineofP. pollachiushas a noticeable kink over the pectoral fins while that ofP. virensis straighter.
The flesh of coalfish (P. virens) is darkly coloured (hence the common name) while that ofP. pollachiusis similar to other members of the cod family. This dark colour in the fresh uncooked flesh may have led to the undeserved reputation of this fish as poor for eating.
It is common in the northern parts of theNorthern Atlantic, including theBay of Biscay. Adults can typically live up to 16–20 years and grow to 100–120 centimetres (39–47 in) but individuals up to 130 cm (51 in) and weight up to 32 kg (70 lb 9 oz) have been caught.Juveniles tend to be found close to shore, particularly in rocky areas, and tend to move out into deeper waters as they grow. The currentIGFAAll-Tackle World Record is 22.7 kilograms (50 lb 1 oz) which was caught atSaltstraumeninNorway.
Saithe reach sexual maturity at 4–9 years old and areiteroparous, batch spawners with determinate fecundity.Females produce, depending on their size, between 500 thousand and 9 million eggs which are1.0 to 1.3 millimetres (5⁄128to7⁄128in) in diameter.
Saithe is fished year-round using gear such as Danishseine nets,trawlers,long linesandgill netsand is often caught in mixed species fishery with othergroundfishspecies such ascodand whiting. The main fishing grounds in the eastern Atlantic are in theBarents Sea, aroundIceland, around theFaeroe Islandsand in theNorth SeaandCeltic Sea. Landings in the eastern Atlantic have fluctuated around 300–700 thousand metric tons (300,000–690,000 long tons; 330,000–770,000 short tons) in the period 1980–2017. All the stocks in eastern Atlantic are assessed byInternational Council for the Exploration of the Sea(ICES) which publish a recommendations on an annual basis for Total Allowable Catch.
The commercial catch of saithe in the western Atlantic is taken by USA andCanadaand has fluctuated around 5–45 thousand metric tons (4,900–44,300 long tons; 5,500–49,600 short tons) per year between 1980 and 2018. The population in the western Atlantic is assessed by USANational Oceanic and Atmospheric Administration(NOAA) andFisheries and Oceans Canada.
All four stocks assessed in the eastern Atlantic and the stock in the western Atlantic are harvested sustainably with many saithe fisheries having been certified as sustainable by theMarine Stewardship Council.
Coalfish is edible and has commercial value, although it is considerably less valuable than premiumwhitefishsuch ascodandhaddock.To achieve asalmon-like orange color, it can be salted and smoked. InGermany, the fish is commonly sold asSeelachs(literally 'sea salmon'), although it is notclosely related to any salmon.
While a great deal of saithe consumed in Europe are caught in British waters, it is not a popular fish with consumers there. Most of the British saithe catch is thus exported to France, where it is widely eaten.
Saithe often congregate around fish farms and feed on uneaten salmon feeds which have passed through the net walls of the cages. It is the opinion of fishermen that the fish caught close to fish farms is of poor quality. Quality testing shows that the there is relatively minor differences in fillet quality between fish which were caught close to fish farms and those that were not; however, catches taken close to fish farms have a higher proportion of fish of poor quality.There is a detectable difference in taste between saithe associated and not associated with fish farms, but there are conflicting results on which tastes better and is probably a matter of consumer preference.
Saithe is also used as food fordomestic cats.