Witch, Witch flounder, Torbay sole

Glyptocephalus cynoglossus

Method of production — Caught at sea
Capture method — Demersal otter trawl
Capture area — North East Atlantic (FAO 27)
Stock area — North Sea, Skagerrak and Kattegat, Eastern English Channel
Stock detail — IV, IIIa and VIId
Picture of Witch, Witch flounder, Torbay sole

Sustainability rating four info

Sustainability overview

Fisheries for witch in EU waters outside 6 miles are unregulated, i.e. there is no Minimum Landing Size or other measures specified and they are generally taken as bycatch in trawls targeting whitefish. In some coastal areas of England and Wales MLSs are enforced, e.g. in Cornwall landing of witch below 28cm is prohibited. Avoid sourcing immature fish (less than 28cm) and fresh fish caught during the breeding season (March -September). Choose fish landed in Cornwall or North West Wales where available.

Biology

Witch is common in the northern North Sea, west of the British Isles, in Icelandic waters and along the North American east coast. It is a right-eyed flat fish (both eyes on the right-hand side of the body) belonging to a group of fish known as the family Pleuronectidae. Witch spawn in summer, have a slow growth rate, and reach sexual maturity in 3-4 years. Witch on average live for about 14 years, but the maximum reported age is 25 years. The species is mainly found on soft sea bottoms, mostly clay or clean sand, around 100-400 m depth. Their main diet consists of crustaceans, worms, brittle stars and fish.

Stock information

Stock Area

North Sea, Skagerrak and Kattegat, Eastern English Channel

Stock information

No reference points are defined for this stock and there is no analytical assessment of it. Information on stock structure, biological data and catch at age information is needed to be able to perform this type of assessment. Available survey information indicates a declining trend of abundance since the peak observed in 2000 with an increase in more recent years (2014-2015). Fishing pressure is unknown. ICES advises that catches should be no more than 2212 tonnes in each of the years 2016 and 2017. If discard rates (between 23% and 10% of the total catches) do not change this implies landings of no more than 1889t ( 1574 t in 2014 and 2015).

Management

Witch is mainly a bycatch species and as such the fishery is currently largely unmanaged. The only management of the fishery is under a combined total allowable catch (TAC) with lemon sole. Scientists are concerned this prevents effective control of single species exploitation rates and could potentially leading to overfishing of either species.

Capture Information

Witch is typically a bycatch species, mostly captured in bottom otter trawls (88%) targeting whitefish (such as cod and haddock), or other flat fish species such as plaice etc. It is also an important bycatch species in some Nephrop fisheries. No Minimum Landing Size specified in EU waters outside 6 miles. In some coastal areas of England and Wales MLSs are enforced, e.g. In Cornwall the Inshore Fisheries Conservation Authority prohibits the landing of witch below 28cm. Witch mature at around 30-34 cms. Females mature at a later age and larger size than males.

Alternatives

Based on method of production, fish type, and consumer rating: only fish rated 2 and below are included as an alternative in the list below. Click on a name to show the sustainable options available.

Dab
Halibut, Atlantic (Farmed)
Halibut, Pacific
Megrim
Plaice
Sole, Dover sole, Common sole
Turbot (Farmed)

References

ICES Advice 2015, Book 6 http://www.ices.dk/sites/pub/Publication%20Reports/Advice/2015/2015/wit-nsea.pdf;
http://www.fishbase.org/Summary/SpeciesSummary.php?ID=26&AT=witch