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Theragra chalcogramma  (Pallas, 1814)

Alaska pollock
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Image of Theragra chalcogramma (Alaska pollock)
Theragra chalcogramma
Picture by Archipelago Marine Research Ltd.

Classification / Names Common names | Synonyms | Catalog of Fishes (gen., sp.) | ITIS | CoL | WoRMS | Cloffa

Actinopterygii (ray-finned fishes) > Gadiformes (Cods) > Gadidae (Cods and haddocks)
Etymology: Theragra: Greek, theragros, -os, -on = good for hunting (Ref. 45335);  chalcogramma: From the Greek 'chalcos' meaning brass and 'gramma' meaning mark (Ref. 6885).

Issue
This species is placed in the genus Gadus in Eschmeyer (CofF ver. Jan. 2012: Ref. 89336). More studies are needed for a complete revision of all genera of Gadidae.

Environment / Climate / Range Ecology

Marine; brackish; benthopelagic; non-migratory; depth range 0 - 1280 m (Ref. 50550).   Polar; 68°N - 34°N, 129°E - 120°W (Ref. 54255)

Length at first maturity / Size / Weight / Age

Maturity: Lm 36.9  range ? - ? cm
Max length : 91.0 cm TL male/unsexed; (Ref. 2850); max. published weight: 3.9 kg (Ref. 56335); max. reported age: 28 years (Ref. 55701)

Short description Morphology | Morphometrics

Dorsal spines (total): 0; Dorsal soft rays (total): 38-48; Anal spines: 0; Anal soft rays: 33 - 42. The dorsal fins are widely separated. The pelvic fins have a slightly elongated filament. The lateral line is continuous to about the back end of the first dorsal-fin base; it is interrupted at the read of the body. On the head are lateral line pores. Body color is olive green to brown on the back and becomes silvery on the sides and pale ventrally, often with mottled patterns or blotches.

Distribution Countries | FAO areas | Ecosystems | Occurrences | Point map | Introductions | Faunafri

North Pacific: from Kivalina, Alaska, to the southern Sea of Japan and to Carmel, California, USA. The occurrence off the northern part of Baja California (Mexico), as reported from Quast and Hall, (1972) (Ref. 6876) is apparently erroneous.

Biology     Glossary (e.g. epibenthic)

The adults usually live near to the sea floor, but sometimes they also appear near the surface (Ref. 1371). They perform diurnal vertical migrations (Ref. 1371). They mainly feed on krill (Ref. 39882) but they also eat fishes and crustaceans (Ref. 6885). The adults which are spawning are often solely captured for their roe. The meat is used to produce Surimi (this is an imitation of shellfish meat) (Ref. 28499). They are traded as fresh fish, boneless flesh, in frozen blocks or as Surimi. The fish is cooked in the microwave, steamed or fried in butter (Ref. 9988). The Bering Sea/Aleutian Islands (BS/AI), http://www.msc.org/html/content_1176.htm, and Gulf of Alaska (GOA), http://www.msc.org/html/content_492.htm, pollock fisheries of this species have been certified by the Marine Stewardship Council (http://www.msc.org/) as well-managed and sustainable.

Life cycle and mating behavior Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae

Congregate in dense schools to spawn, usually at 50 to 250 m depth.

Main reference Upload your references | References | Coordinator | Collaborators

Cohen, D.M., T. Inada, T. Iwamoto and N. Scialabba, 1990. FAO species catalogue. Vol. 10. Gadiform fishes of the world (Order Gadiformes). An annotated and illustrated catalogue of cods, hakes, grenadiers and other gadiform fishes known to date. FAO Fish. Synop. 125(10). Rome: FAO. 442 p. (Ref. 1371)

IUCN Red List Status (Ref. 96402)

CITES (Ref. 94142)

Not Evaluated

Threat to humans

  Harmless




Human uses

Fisheries: highly commercial
FAO(fisheries: production, species profile; publication : search) | FisheriesWiki | Sea Around Us

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Estimates of some properties based on models

Phylogenetic diversity index (Ref. 82805):  PD50 = 0.7500   [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00708 (0.00601 - 0.00834), b=3.00 (2.95 - 3.05), based on LWR estimates for this species (Ref. 93245).
Trophic Level (Ref. 69278):  3.6   ±0.1 se; Based on diet studies.
Resilience (Ref. 69278):  Low, minimum population doubling time 4.5 - 14 years (Musick et al. 2000 (Ref. 36717); tmax = 28).
Vulnerability (Ref. 59153):  Moderate to high vulnerability (47 of 100) .
Price category (Ref. 80766):   Low.