Witch (righteye flounder)

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Witch
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Pleuronectiformes
Family: Pleuronectidae
Genus: Glyptocephalus
Species:
G. cynoglossus
Binomial name
Glyptocephalus cynoglossus
Synonyms[2]
  • Pleuronectes cynoglossus Linnaeus, 1758
  • Pleuronectes saxicola Faber, 1828
  • Pleuronectes nigromanus Nilsson, 1829
  • Platessa elongata Yarrell, 1839
  • Glyptocephalus acadianus Gill, 1873-74

The witch (Glyptocephalus cynoglossus), known in English by a variety of other common names including the witch flounder, pole flounder, craig fluke, Torbay sole, and grey sole, is a species of flatfish from the family Pleuronectidae. It occurs on both sides of the North Atlantic Ocean on muddy sea beds in quite deep water. In northern Europe it has some importance in fisheries as a food fish.

Description

The witch is a

pectoral fin on the eyed side is shorter than the head and the pectoral fins are blackish towards their tips.[6] Almost all of the head and body, apart from the tip of the snout and the lower jaw is covered in smooth scales which make the fish slippery when held.[3] They are brownish grey to greyish brown in colour on their eyed side,[4] with less variation in colour than other flatfish,[3] with the body and fins densely spotted with muted black spots; the median fins become duskier towards their margins.[6] The blind side is white, marked with tiny black dots, although occasionally fish are recorded with the blind side a similar colour to the eyed side.[3] They grow to a maximum size of 60 cm standard length but are normally no more than 40 cm.[4]

Distribution

The witch occurs on both sides of the North Atlantic Ocean. In the northeastern Atlantic Ocean it is found from the northernmost part of the

Gulf of St Lawrence and the Scotian Shelf.[8][5]

Habitat

Witch adults are found on the

nektonic when they grow to lengths of 5–6 cm (2.0–2.4 in) and adopt a benthic habit at shallower depths than the adults.[7]

Biology

The witch feeds on invertebrates and in European waters the main prey items are small crustaceans, starfish, small molluscs, and worms. Fish are rarely taken, if at all, and it does not take baits.[3] Spawning occurs between May and September.[4] and can take place in temperatures ranging from near freezing to 8.8-10 °C, experiments have demonstrated that the eggs continue to incubate normally in water which is as cold as 7.2 °C (45.0 °F). and as warm as 12.77 °C (54.99 °F).[3] The eggs take around a week to hatch, the newly hatched

larvae being about 4.9 mm (0.19 in) in length with a relatively large yolk sac. As the larvae grow they develop five transverse bands on their body, the reduced yolk and the fin folds. The entire yolk is absorbed when the larva is around 10 days old. At around 40 mm (1.6 in) the left eye has migrated to the dorsal surface of the head, the migration of the eye is completed at lengths of between 40 and 50 mm (1.6 and 2.0 in). and it is at this point that the young fish adopts a benthic habit.[3] It is a slow growing species, sexual maturity is reached at 3–4 years and they have a lifespan of up to 14 years,[4] although the maximum reported age is 25 years.[7] Off Norway a sex ratio of 1:1 was found for fish up to the age of 9 years but in older fish this was skewed towards females.[9] The fecundity of females varies with size with 48,800 eggs borne by a fish of 31 cm (12 in) in length to 508,300 eggs in one of 60 cm (24 in).[10]

Fisheries

landed Glyptocephalus cynoglossus

The witch is commercially important as a bycatch and there are fisheries directed at this species, except that it is occasionally targeted in the Skagerrak. It is an important bycatch species in some fisheries which target the langoustine (

Least Concern, but the damaging bottom trawling methods used to catch it may cause issues, and the large number discarded as bycatch by commercial vessels which are targeting other species is unknown.[11] The flesh is marketed fresh or frozen and is eaten steamed, fried, microwaved and baked.[4] The name Torbay sole appears to be a mainly culinary term,[12] following the habit of renaming certain fish to broaden their appeal.[11]

References

  1. doi:10.2305/IUCN.UK.2022-2.RLTS.T18214757A162704857.en
    . Retrieved 9 December 2022.
  2. ^ a b Froese, Rainer; Pauly, Daniel (eds.) (2018). "Glyptocephalus cynoglossus" in FishBase. February 2018 version.
  3. ^ a b c d e f g h i j Henry B. Bigelow & William C. Schroeder (1953). "Witch flounder Glyptocephalus cynoglossus (Linnaeus) 1758". Fishes of the Gulf of Maine. Vol. 53. United States Department of the Interior Fish and Wildlife Service. Retrieved 24 March 2018. {{cite book}}: |journal= ignored (help)
  4. ^ a b c d e f g h i j k "Glyptocephalus cynoglossus (Linnaeus, 1758)". Species Fact Sheets. Food and Agriculture Organization of the United Nations Fisheries and Aquaculture Department. Retrieved 24 March 2018.
  5. ^ a b c d "Witch Flounder". Fisheries and Oceans Canada. 2016-12-19. Retrieved 24 March 2018.
  6. ^ a b c J.C. Hureau. "Fishes of the NE Atlantic and the Mediterranean". Marine Species Identification Portal. ETI Bioinformatics. p. Witch (Glyptocephalus cynoglossus). Retrieved 24 March 2018.
  7. ^ a b c d e Monroe, T.; Costa, M.; Nielsen, J.; Herrera, J. & de Sola, L. (2015). "Glyptocephalus cynoglossus (Europe assessment)". IUCN Red List of Threatened Species. 2015: e.T18214757A45790104. Retrieved 23 March 2018.
  8. ^ "Glyptocephalus cynoglossus". NatureServe Explorer An online encyclopedia of life. 7.1. NatureServe. Retrieved 11 August 2023.
  9. doi:10.1016/0165-7836(91)90098-Z
    . Abstract
  10. doi:10.2960/J.v12.a2
    .
  11. ^ a b c "Witch". British Seafishing. 31 August 2012. Retrieved 24 March 2018.
  12. ^ Witch | InterSites
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