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Pollachius virens
Pollachius virens
from Wikipedia

Saithe
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Gadiformes
Family: Gadidae
Genus: Pollachius
Species:
P. virens
Binomial name
Pollachius virens
(Linnaeus, 1758)
Synonyms
  • Gadus virens Linnaeus, 1758
  • Merlangus virens (Linnaeus, 1758)
  • Gadus carbonarius Linnaeus, 1758
  • Merlangus carbonarius (Linnaeus, 1758)
  • Pollachius carbonarius (Linnaeus, 1758)
  • Gadus colinus Lacepède, 1800
  • Gadus sey Lacepède, 1800
  • Gadus purpureus Mitchill, 1814
  • Merlangus purpureus (Mitchill, 1814)

Pollachius virens is a species of marine fish in the genus Pollachius. Together with P. pollachius, it is generally referred to in the United States as pollock. It is commonly known in Britain as the coalfish, coley, or saithe (/sð/ or /sθ/),[1][2] and the young fish may also be called podleys or cuddies[3] in Scotland and northern England.[4]

Description

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This species can be separated from P. pollachius by looking at the relative lengths of the upper and lower jaws. P. pollachius has a longer underslung lower jaw while P. virens has approximately equal upper and lower jaw lengths. This gives a very different profile to the head. In general, P. pollachius is a brown or golden colour with a dark back while P. virens is bright silver with a very dark green back. P. virens generally appears to have relatively smaller eyes. The lateral line of P. pollachius has a noticeable kink over the pectoral fins while that of P. virens is straighter.

The flesh of coalfish (P. virens) is darkly coloured (hence the common name) while that of P. pollachius is 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 the Northern Atlantic, including the Bay of Biscay. Adults can typically live up to 16–20 years and grow to 100–120 centimetres (40–45 in) but individuals up to 130 cm (50 in) and weight up to 32 kg (71 lb) have been caught.[5] Juveniles tend to be found close to shore, particularly in rocky areas, and tend to move out into deeper waters as they grow. The current IGFA All-Tackle World Record is 22.7 kilograms (50 lb 1 oz) which was caught at Saltstraumen in Norway.[6]

Reproduction

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Saithe reach sexual maturity at 4–9 years old and are iteroparous, batch spawners with determinate fecundity.[7] Females produce, depending on their size, between 500 thousand and 9 million eggs which are 1.0 to 1.3 millimetres (5128 to 7128 in) in diameter.[8][9]

Fisheries

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Commercial landings in the eastern (top) and western Atlantic (bottom). Data from International Council for the Exploration of the Sea, NOAA and Fisheries and Oceans Canada[citation needed]

Saithe is fished year-round using gear such as Danish seine nets, trawlers, long lines and gill nets and is often caught in mixed species fishery with other groundfish species such as cod and whiting. The main fishing grounds in the eastern Atlantic are in the Barents Sea, around Iceland, around the Faeroe Islands and in the North Sea and Celtic Sea. Landings in the eastern Atlantic have fluctuated around 300,000–700,000 tonnes (330,000–770,000 short tons) in the period 1980–2017. All the stocks in eastern Atlantic are assessed by International 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 and Canada and has fluctuated around 5,000–45,000 tonnes (5,500–49,600 short tons) per year between 1980 and 2018. The population in the western Atlantic is assessed by USA National Oceanic and Atmospheric Administration (NOAA) and Fisheries 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 the Marine Stewardship Council.

As food

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Coalfish is edible and has commercial value, although it is considerably less valuable than premium whitefish such as cod and haddock.[10] To achieve a salmon-like orange color, it can be salted and smoked. In Germany, the fish is commonly sold as Seelachs[11] (literally 'sea salmon'), although it is not closely 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.[12]

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.[13] 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.[14][15]

Usually, Fish fingers are mostly made of saithe. Saithe is also used as food for domestic cats.

References

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Further reading

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Revisions and contributorsEdit on WikipediaRead on Wikipedia
from Grokipedia
Pollachius virens, commonly known as saithe or , is a of marine in the family , distinguished by its elongate, body, brownish-green dorsum, silvery-white ventrum, three dorsal fins, two anal fins, a small chin barbel, and a straight . It typically reaches a maximum length of 130 cm and weight of 32 kg, though commonly measures around 60 cm, with a lifespan up to 25 years. This boreal species inhabits temperate waters of the North Atlantic Ocean, distributed from the Barents Sea and Iceland to the Bay of Biscay in the eastern Atlantic, and from southwest Greenland to North Carolina in the western Atlantic, where it is most abundant on the Scotian Shelf, , and in the . It occupies benthopelagic habitats from shallow coastal areas to offshore depths of 37–364 m, preferring temperatures between 0.5–10.2°C, and migrates seasonally, moving inshore in spring and to deeper waters in winter. Ecologically, P. virens is an active, gregarious predator that feeds primarily on crustaceans and smaller fish, maturing between ages 3–6 years and spawning in winter batches from November to February over rocky bottoms at temperatures of 4.5–6°C, with pelagic eggs and larvae that disperse widely. Juveniles remain inshore for 1–2 years before joining adult schools. Commercially significant, it supports major fisheries in Europe and North America, harvested for fresh, smoked, canned, and frozen products, with global capture production fluctuating between 0 and 600,000 tonnes annually from 1980–2023, managed through total allowable catches and minimum mesh sizes to ensure sustainability.

Taxonomy

Classification

Pollachius virens is classified within the domain Eukarya, kingdom Animalia, phylum Chordata, subphylum Vertebrata, class , order , family , genus Pollachius, and species P. virens. This placement reflects its status as a ray-finned fish belonging to the cod family, characterized by elongate bodies and multiple dorsal fins typical of gadiforms. The species was originally described by in 1758 under the binomial Gadus virens in his , later reclassified into the genus Pollachius established by Nilsson in 1832 to distinguish it from other gadids based on morphological traits. This taxonomic revision highlights the historical grouping of pollock-like fishes within the broader genus before refined distinctions emerged. Pollachius virens is distinguished from its sister species Pollachius pollachius (pollack) primarily through the structure of the , which is straight and pale in P. virens but distinctly arched or kinked over the pectoral in P. pollachius. Fin ray counts also aid in identification, with P. virens typically exhibiting 29–33 dorsal soft rays and 27–30 anal soft rays, values that overlap but are used alongside lateral line morphology in taxonomic keys. Known commonly as saithe or , it shares the with P. pollachius but occupies distinct ecological niches.

Etymology and common names

The genus name Pollachius derives from the Irish Gaelic term pollag (or pullóg in Irish), which refers to the pollock fish and may stem from poll, meaning "head" or "top," possibly alluding to the species' protruding lower jaw or overall body profile. The specific epithet virens is the present participle of the Latin verb vireo, meaning "green" or "verdant," in reference to the greenish dorsal coloration of the fish. Common names for Pollachius virens vary regionally, reflecting linguistic and cultural differences. In the and , it is primarily known as saithe; in the and , as pollock; and more broadly as coalfish, due to the dark, coal-like appearance of its back. Other names include coley (in the UK) and goberge (in French-speaking regions). Historically, the name "pollock" has sometimes been applied interchangeably to P. virens and the unrelated Alaskan pollock (Gadus chalcogrammus), causing confusion in commercial and trade contexts, though the two species are distinct and occur in different oceans.

Description

Morphology

Pollachius virens possesses an elongated, body with a nearly circular cross-section, facilitating efficient in open water. The head features a terminal with the lower slightly protruding beyond the upper , and a small, inconspicuous chin barbel is present. Coloration varies but typically includes a dark green to brownish-green dorsum that transitions gradually to silvery sides and a white ventral surface, with the appearing pale. The species is characterized by three separate dorsal fins, two anal fins, and a forked caudal fin, with pectoral and pelvic fins in a thoracic position. The lateral line runs smoothly and straight along the entire length of the body to the tail, aiding in the detection of water vibrations and movements. Unlike the closely related Pollachius pollachius, which lacks a chin barbel, has a prominently protruding lower jaw, and features a dark, arched lateral line over the pectoral fin, P. virens can be distinguished by its shorter chin barbel, protruding lower jaw, and straight lateral line extending uninterrupted to the tail. Internally, P. virens is equipped with a that provides buoyancy control, typical of gadiform fishes, and supports hydrostatic regulation in varying depths. The system consists of neuromasts along the smooth canal, enabling sensitivity to hydrodynamic stimuli such as prey movements or currents.

Size and growth

Pollachius virens can grow to 100–120 cm, with a maximum recorded of 130 cm total length. The species can reach a maximum weight of 32 kg, though the International Game Fish Association (IGFA) all-tackle world record stands at 22.7 kg, caught in , . Growth in P. virens is rapid during juvenile stages, with individuals growing 10–15 cm per year in the first two years, reaching approximately 27–30 cm by the end of the second year. Growth slows in adults to 5–10 cm per year, allowing fish to attain about 50 cm by age 3. In the wild, P. virens has a typical lifespan of 16–20 years, though maximum ages up to 25 years have been reported. Sexual dimorphism in size is evident at maturity, with females growing slightly larger than males of the same age, as observed in mean lengths at age 7 across multiple regions. Growth rates between males and females do not differ significantly overall.

Distribution and habitat

Geographic distribution

Pollachius virens, commonly known as saithe or , has a primary distribution across the . In the eastern Atlantic, its range extends from the northward to the and , including waters around . In the western Atlantic, it occurs from southwest and the coast southward to the and occasionally to , though it is rare at the southern limits of this range. The species is particularly abundant in several key areas within its range. In the western Atlantic, high concentrations are found on the Scotian Shelf, , and in the . In the eastern Atlantic, notable abundances occur along the Norwegian coasts, in the , and around the southeast to west coasts of . Population structure analyses reveal distinct stocks of P. virens in the Northeast and Northwest Atlantic, with genetic evidence indicating limited transatlantic migration and restricted between these regions. Tagging studies support this, showing minimal cross-Atlantic recaptures. Recent warming in North Atlantic waters has been associated with northward distributional shifts for P. virens, including increased presence and abundance in Icelandic waters since the early 2000s, coinciding with a prolonged warm anomaly from the mid-1990s onward. As of 2023, over 20% of North Atlantic marine fishes, including P. virens, exhibit poleward shifts in the North and Barents Seas.

Habitat requirements

Pollachius virens occupies temperate to marine environments in the North , where it thrives preferring temperatures between 0.5–10.2 °C and salinities of 30 to 35 ppt. These conditions support its distribution across coastal and offshore areas, with preferences for rocky or sandy bottoms that provide suitable substrates for and . The species demonstrates tolerance for a broad depth range of 35 to 365 m, though specific preferences vary by life stage. Juveniles primarily inhabit nearshore waters at depths of 0 to 50 m, utilizing shallow littoral and intertidal zones as nursery areas. These young fish seek out structured environments such as , , rock, and submerged aquatic for from predators. In contrast, adults favor deeper offshore habitats at 100 to 300 m, where they aggregate over hard bottoms including rocky substrates and artificial reefs. Seasonal habitat shifts occur as P. virens migrates inshore during spring and summer, often to shallower coastal areas, before moving to deeper offshore waters in winter. These movements align with reproductive cycles. The species is frequently associated with beds and reefs, which offer complex structures for refuge and habitat complexity, particularly benefiting juveniles in nearshore intertidal zones. These areas are vulnerable to degradation, posing risks to juvenile and .

Biology and ecology

Reproduction

Pollachius virens attains between 3 and 6 years of age, typically at lengths of 40–70 cm, with females reaching maturity at slightly larger sizes than males. The is gonochoric, lacking hermaphroditism, and exhibits a close to 1:1 across populations. Spawning occurs as batch spawning over rocky or hard bottoms in offshore waters along the continental shelf at depths of 100–200 m, primarily from November to February, peaking in winter at temperatures of 4.5–6°C, with timing varying latitudinally—earlier in southern areas and later northward. Females produce 500,000 to 9 million eggs per spawning season, with strongly influenced by age and body size; hydrated eggs measure 1.0–1.3 mm in diameter and are pelagic. Eggs hatch after an of 10–15 days under optimal temperatures around 8–9°C, releasing pelagic larvae that initially rely on reserves. Larval development lasts 2–3 months in the before juveniles settle to benthic habitats, marking the transition to a demersal .

Diet and feeding

Juveniles of Pollachius virens primarily feed on small crustaceans, including copepods, amphipods, and euphausiids, supplemented by planktonic such as larvae and yearlings of other . constitute 69–80% of their diet by weight, with crustaceans dominating at around 69%, while make up only about 12%. This diet supports rapid early growth in coastal and inshore nursery areas, where prey availability influences feeding success. Adults exhibit a more piscivorous diet, preying predominantly on schooling fish such as (Clupea harengus), (Mallotus villosus), sand eels (Ammodytes spp.), Norway pout (Trisopterus esmarkii), and (Micromesistius poutassou), reflecting opportunistic feeding strategies. In the , crustaceans account for 30–40% of the diet by weight, with the remainder largely fish, though proportions vary by region and prey abundance. Smaller adults (41–65 cm) rely more heavily on crustaceans, shifting to fish-dominated diets as they grow larger (66–95 cm). Feeding occurs primarily during daylight hours as visual predators hunting in schools, targeting prey in the . Daily rations are estimated at 2–5% of body weight, enabling high consumption rates to meet energetic demands. Seasonal shifts favor increased intake in summer, when pelagic prey schools are more accessible, compared to higher proportions in other periods. These habits underscore P. virens as an opportunistic feeder responsive to environmental prey dynamics. As mid-level predators with a of 4.3 ± 0.4, P. virens plays a key role in pelagic food webs by transferring energy from and small to larger piscivores and humans through fisheries. This position highlights their importance in maintaining ecosystem balance across the North Atlantic.

Behavior and migration

Pollachius virens exhibits gregarious , forming large schools that enhance efficiency and provide protection from predators. These schools are commonly observed throughout the in both inshore and offshore environments, with individuals maintaining coordinated positions during movement. As active swimmers, P. virens can achieve burst speeds of up to 9.57 m/s (approximately 34 km/h) during evasion or pursuit, supporting their pelagic lifestyle. Migration patterns in P. virens are influenced by seasonal changes and reproductive needs, with adults moving to coastal waters in spring for feeding and spawning before shifting offshore in winter to deeper, warmer areas. Mark-recapture studies around reveal high site fidelity, as over 50% of tagged individuals are recaptured near release sites, though local movements of up to 500 km occur along migratory routes with variability by tagging area. Juveniles show similar inshore-offshore shifts, remaining more abundant in coastal zones during warmer months. In altered environments, P. virens congregates around open-cage farms, attracted to uneaten feed pellets and occasionally preying on escaped , which alters their local distribution and feeding opportunities. Diurnal activity in schools peaks during crepuscular periods and , when individuals are more dispersed compared to clustering, potentially optimizing predator avoidance and . Predation avoidance relies on schooling to create a confusion effect for predators and rapid burst swimming for escape, as demonstrated in juvenile aggregations. Common parasites include nematodes such as Anisakis simplex, Contracaecum sp., and Hysterothylacium aduncum, which are transmitted via prey but generally exert low impact on wild populations due to moderate intensities.

Fisheries and conservation

Commercial fisheries

Pollachius virens is targeted using a range of methods, primarily pelagic and demersal trawls, longlines, gillnets, and automated machines. Purse seines are also employed in some regions to capture schools of this pelagic gadoid. operations occur year-round across its range, though effort intensifies in summer when aggregate near coastal areas during migrations. Historical catches of P. virens in the eastern Atlantic have varied significantly across stocks, with the Northeast Arctic stock averaging over 100,000 tonnes annually from the 1980s through 2017, peaking at levels supporting TACs up to 164,000 tonnes in recent assessments. In the Faroes grounds division, annual landings ranged from 20,000 to 68,000 tonnes between 1980 and 2018, contributing to broader regional totals. Western Atlantic catches, primarily by and the , have been substantially lower, fluctuating between 5,000 and 45,000 tonnes per year from 1980 to 2018, often as part of multispecies fisheries. Economically, P. virens ranks as the second most harvested species in the Gadidae family after cod, supporting substantial export industries in Norway and Iceland. Norway exported 47,780 tonnes of saithe clipfish in 2024, valued at NOK 2.1 billion, while Iceland's fisheries contribute around one-third of national export revenue through marine products. The species is frequently taken as bycatch in mixed demersal trawls targeting other gadoids, adding to its overall commercial significance. Efforts to improve gear selectivity focus on codend mesh sizes of 110–135 mm in trawls, which allow smaller juveniles to escape and reduce of immature fish. Management includes seasonal quotas under regulations for eastern stocks and through the Northwest Atlantic Fisheries Organization (NAFO) for western areas, aiming to align harvests with sustainable levels.

Stock assessment and management

Stock assessments for Pollachius virens are primarily conducted by the International Council for the Exploration of the Sea (ICES) and the Northwest Atlantic Fisheries Organization (NAFO), employing age-based analytical models such as virtual population analysis (VPA) to estimate spawning stock biomass (SSB), recruitment, and fishing mortality. These models integrate commercial catch-at-age data, survey indices, and maturity ogives to reconstruct historical trends and project future stock dynamics. In the Northeast Arctic stock, the largest population, SSB was estimated at 728,000 tonnes in the 2024 assessment, above reference points (Bpa = 220,000 tonnes) but projected to decline to around 331,000 tonnes by 2026, with fishing mortality below maximum sustainable yield (MSY) levels. The 2024 benchmark assessment revised key parameters, resulting in lower SSB estimates but confirming stocks remain above MSY reference points as of 2025 advice. Similarly, North Sea and Icelandic stocks remain above reference points as per 2024–2025 ICES assessments, indicating healthy population levels across major areas. The global conservation status of P. virens is by the , though it is classified as Least Concern in European waters; NatureServe assigns it a G5 ranking, denoting global security. All major stocks are considered sustainably harvested under current practices, with no overfished designations in recent evaluations. Historical in the and 1990s caused sharp declines in SSB across the Northeast Atlantic and , reducing populations by up to 80% in some regions before management interventions stabilized them. Ongoing threats include in mixed demersal fisheries, climate-driven range shifts that may alter migration patterns and success, and degradation of juvenile nursery habitats from and warming waters. Management strategies emphasize precautionary approaches through harvest control rules and quotas set by regional bodies. Total allowable catches (TACs) are advised annually by ICES; for instance, the 2025 TAC for the Northeast Arctic stock is 193,117 tonnes, and for the stock is 79,071 tonnes (as of 2024 ICES advice implemented in 2025). Marine protected areas off Iceland's northern and eastern coasts restrict to safeguard demersal communities, including saithe juveniles. Rebuilding protocols activate if SSB drops below critical thresholds like Blim (e.g., 120,000 tonnes in the Northeast Arctic), mandating reduced fishing mortality to restore biomass toward MSY targets.

Uses

As food

Pollachius virens, commonly known as saithe or Atlantic pollock, is valued in culinary applications for its firm, flaky white flesh and mild to slightly fishy flavor, making it a versatile whitefish suitable for various preparation methods. Fresh fillets are commonly grilled, pan-fried, baked, or poached to highlight their delicate taste and low oil content, which prevents greasiness during cooking. the fish imparts a firm texture and a distinctive pink color reminiscent of , enhancing its appeal in preserved forms. The is widely processed into convenient products such as fish fingers, patties, burgers, and croquettes, where its firm texture holds up well during breading and . These items are popular in everyday meals, often masking the 's slightly grayish raw appearance with coatings. is less prized than due to its darker flesh and stronger flavor but serves as a cost-effective, versatile substitute in recipes calling for whitefish. Significant portions of the catch are exported to markets in and , where fresh and frozen fillets are incorporated into local dishes like stews and grilled preparations. Quality is optimal when consumed fresh, as the lean meat develops off-flavors and texture softening from oxidation during prolonged frozen storage. Its low fat content contributes to a clean, non-oily but requires prompt handling to maintain freshness. In Nordic , saithe features traditionally in creamy fish soups, such as , where young specimens provide a lean base alongside and cream, and in fermented or dried preparations like Faroese ræstur fiskur for long-term storage.

Other commercial uses

Beyond its role in human consumption, Pollachius virens (saithe) serves several industrial and commercial purposes. By-products from saithe processing, including heads, viscera, and frames, are converted into fishmeal and on-board Norwegian trawlers, yielding products with approximately 62% protein and 9% fat content that are primarily used in , aquaculture diets, and pet foods such as . The skin, while a minor resource, is processed into or for applications in and food industries, with extraction yields supporting sustainable utilization. Due to its abundance and availability, saithe is widely employed as bait in commercial pot and trap fisheries, particularly for lobster and crustaceans like whelk and crab, where chopped saithe outperforms some formulated alternatives in catch rates; it is also used in squid fisheries leveraging its pelagic distribution. Nutritionally, raw saithe offers a lean profile with 85 kcal, 18.3 g , and 1.3 g fat per 100 g serving, making it suitable for health-focused products. It is particularly rich in at 3.8 µg (providing nearly 160% of the daily value), at 27 µg, and at 235 mg per 100 g, contributing to its value in fortified feeds and supplements. Saithe exhibits low mercury concentrations, typically around 0.05 mg/kg, well below the regulatory limit of 0.3 mg/kg wet weight. The flesh contains approximately 0.3 g of omega-3 fatty acids per 100 g, enhancing its utility in nutritional oils. Viscera by-products from saithe are a source of endogenous enzymes, such as proteases, which are harnessed in biotechnological processes like to produce bioactive peptides and hydrolysates for and pharmaceutical uses.

References

  1. https://en.wikisource.org/wiki/An_Etymological_Dictionary_of_the_Gaelic_Language/P
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