MarLIN

information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles

Pollack (Pollachius pollachius)

Distribution data supplied by the Ocean Biogeographic Information System (OBIS). To interrogate UK data visit the NBN Atlas.

Summary

Description

Pollachius pollachius is a large fish up to 130 cm in length and weighing up to 14 kg. It has a relatively large mouth with a protruding lower jaw, no barbell and conspicuously large yellow eyes. Like other members of the cod family, this species has three dorsal fins; The first being triangular and the latter two longer. It has two anal fins. The tail is broad and slightly forked. The lateral line is dark green, strongly arched over the pectoral fin and straightens out just under the second dorsal fin. The pectoral fins are short, being as long as they are wide at the base. The colour of this species varies with habitat and age but it is usually dark brown or brownish-green on the back, abruptly paling to its yellow sides and paler undersides. All the fins are dark with the exception of the pelvic fins which may be slightly pink. The anus is just below the front half of the first dorsal fin.

Recorded distribution in Britain and Ireland

This species is found off all coasts of Britain and Ireland.

Global distribution

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Habitat

This species can be found to >100 meters depth, either solitary or in small shoals. It is both an offshore pelagic or coastal benthic species found on the sea bed around rocks, wrecks and kelp forests.

Depth range

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Identifying features

  • Large fish up to 130 cm in length and 14 kg in weight.
  • Eyes are yellow and conspicuously large.
  • Three dorsal fins with the first being triangular and 2 anal fins.
  • The lateral line is dark green and arches over the pectoral fin before straightening out.
  • Colour typically silvery with a brown or green back and yellow-silver sides.

Additional information

This is both a solitary and shoaling species, more likely to shoal during spawning events. Spawning in Pollachius pollachius occurs up to ca 100 meters depth between January and April, with the greatest intensity during March (Wheeler, 1969). The eggs and larvae drift in the water column towards the shallower coastal waters. Within the first year, juveniles can reach up to 17 cm in length. Juveniles live amongst rocks and algae mainly feeding on crustaceans in the shallows and then venture out to 40-100 m when about three years old with a body length of up to 40 cm (Wheeler, 1969). Young juveniles may also be found in estuaries.

Large, older individuals of Pollachius pollachius are usually darker in colour, where juveniles are green, brown or occasionally crimson and gold. Such colouration ensures the juveniles are inconspicuous, although they may be easily confused with juveniles of Pollachius virens (Saithe) and other cod species. Adults of Pollachius virens have a straight lateral line and equal length jaws. Other similar species that may be confused for Pollachius pollachius are: Merlangius merlangus (whiting) that has an upper jaw longer than the lower, and Melanogrammus aeglefinus, that has a black pectoral spot and a black lateral line (Gibson et al., 2001).

Pollachius pollachius feeds on deep sea prawns, Clupea harengus, Ammodytes tobianus, Sprattus sprattus, Mallotus villosus and other open water fish, and can be observed hanging above or within kelp forests and wrecks. This species hunts singly or in small groups by lying close to the sea bed watching sand eels shoaling above them. They suddenly dart up and grab their prey then resume their former position to let the shoal re-group. Such behaviour has been observed in juveniles hunting on groups of mysid shrimps or Gobius flavesecens (Naylor, 2003).

Pollachius pollachius has a small commercial fishery often caught with Gadus morhua in gill nets, traps or long lines. However, pollack is a popular species with anglers as they readily take bait (Wheeler, 1969).

Listed by

- none -

Further information sources

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Bibliography

  1. Bruce, J.R., Colman, J.S. & Jones, N.S., 1963. Marine fauna of the Isle of Man. Liverpool: Liverpool University Press.

  2. Costello, M.J., Bouchet, P., Boxshall, G., Emblow, C. & Vanden Berghe, E., 2004. European Register of Marine Species [On-line]. http://www.marbef.org/data/erms.php,

  3. Crothers, J.H. (ed.), 1966. Dale Fort Marine Fauna. London: Field Studies Council.

  4. Dipper, F., 2001. British sea fishes (2nd edn). Teddington: Underwater World Publications Ltd.

  5. Gibson, R., Hextall, B. & Rogers, A., 2001. Photographic guide to the sea and seashore life of Britain and north-west Europe. Oxford: Oxford University Press.

  6. Hayward, P., Nelson-Smith, T. & Shields, C. 1996. Collins pocket guide. Sea shore of Britain and northern Europe. London: HarperCollins.

  7. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  8. Moen, F.E. & Svensen, E., 2004. Marine Fish & Invertebrates of Northern Europe. Southend-on-Sea: Aqua Press.

  9. Muus, B.J. & Dahlstrom, P., 1974. Collins guide to the sea fishes of Britain and North-Western Europe. Wm Collins Sons & Co. Ltd: London.

  10. National Biodiversity Network (NBN) Atlas website. Available from: http://www.nbnatlas.org.  Accessed 01 April 2017

  11. Naylor, P., 2003. Great British Marine Animals. Plymouth: Sound Diving Publications.

  12. Wheeler, A., 1969. The fishes of the British Isles and north-west Europe. London: Macmillan.

Citation

This review can be cited as:

Rowley, S.J. 2008. Pollachius pollachius Pollack. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. Available from: http://www.marlin.ac.uk/species/detail/9

Last Updated: 03/07/2008