There is a general absence of stock data, insufficient to evaluate stock trends. Available information suggests the North Sea stock biomass, where 90% of the catches in the Northeast Atlantic are taken, is now increasing from a low level. Fishing mortality has decreased in recent years, probably as a consequence of decreased beam trawl effort directed toward the target species of plaice and sole. Overall managment of fisheries for turbot fisheries are inadequate.
Turbot belongs to a small family of left-eyed flatfish (both eyes on the left of the body), known collectively as the Scophthalmidae. This family of fish is confined to the North Atlantic basin and includes megrim and brill. Turbot becomes sexually mature at an age of 3-5 years, and in most parts of its range spawns in April to August, females each producing up to 10-15 million eggs. Turbot is one of the fastest growing flatfish with females growing faster than males, in the North Sea reaching a length of c. 30cm (males) and 35cm (females) in about 3 years. In the Baltic Sea growth is slower, and the males become sexually mature at a length of 15cm, the females at 20cm. By 10 years of age growth rates have reduced to 1-2cm per year for females and less than 1cm per year for males. Consequently, females are larger than males at any given age. Turbot can attain a length of 1m and a weight of 25kg. Maximum reported age 25 years. For some reason males are generally more abundant than females. Turbot is distributed from Iceland, down the coast of western Europe and into the Mediterranean. Turbot are typically found at a depth range of 10 to 70m, on sandy, rocky or mixed bottoms. It is one of the few marine fish species that inhabits brackish waters. Turbot appears to be a rather sedentary species, although some adult migration may occur.
ICES indicate that there are distinct turbot populations in the Baltic Sea and in the Irish Sea. Also, there are indications that turbot from the North Sea, the southern coast of Iceland, the western coast of Scotland and Ireland, and the Celtic Sea (including the Western Approaches) forms another (North Atlantic) stock, which differs from the Bay of Biscay and southern European Atlantic southern stock. Transition zones between stocks occur in the English Channel and around the Kattegat. The status of turbot stocks in the Mediterranean is unclear, but appears not to be homogenous. No assessments leading to fisheries advice for turbot have been carried out by ICES and available information is inadequate to evaluate stock trends. No explicit management objectives have been defined for stocks, no precautionary reference points have been proposed, and no management plans are in place. This species is not formally assessed by ICES, but instead is considered by the ICES Working Group on the Assessment of New MoU Species (WGNEW). 90% of the catches in the Northeast Atlantic are taken in the North Sea. A precautionary TAC has been defined historically for EU fisheries in ICES Division IIa (central/north Norway) and Subarea IV (North Sea) and applied to turbot and brill (Scophthalmus rhombus) combined. For 2011 it was set at 4,642 t. Available information suggests North Sea stock biomass is now increasing from a low level, and fishing mortality has decreased in recent years, probably as a consequence of decreased beam trawl effort directed toward the target species of plaice and sole. In 2014 ICES advises that catches in the North Sea should be no more than 2978t.
We are just updating our information please check back soon.
Turbot is a valuable bycatch species in trawl and gillnet fisheries for flatfish (plaice and sole) and demersal species. There is a targetted gillnet fishery in the North Sea that takes less than 10% of the total catch. Quota restrictions apply only to the North Sea, where they are included in the quota for brill. Since the 1970s, total landings have ranged from 3,504t to 9,361t per year, with the lowest in the mid 80s and highest in early 90s. In the last decade, the total landings of turbot reported to ICES/EC were between 5,000 and 6,500t, with the North Sea accounting for around 60% of the totals. The English Channel (VIId,e) and the Celtic Sea (VIIf + VIIg-k) are the second and third most important fishing grounds for turbot, at around 9% each. Less than 5% of landings are reported from areas IIIa, IIIb-d (Baltic and Approaches), VIIa (Irish Sea), VIII (Biscay) and IX (Portuguese Coast). There is no official EU minimum landing size, although Minimum Landing Sizes (MLS) have been introduced by different authorities. The most frequently applied MLS is 30cm (e.g. Belgium, Baltic, Cornwall). Beam trawl fisheries, where turbot are generally a valuable component of bycatch, are mostly conducted by Belgium, Demark, Netherlands and France, with the majority coming from the North Sea.
ICES Advice 2013, Book 6
Sign up to get all the latest marine related news from MCS
The UK charity for the protection of our seas, shores and wildlife.