Scophthalmus rhombus

Method of production — Caught at sea
Capture method — Gill or fixed net
Capture area — North East Atlantic (FAO 27)
Stock area — North Sea, Skagerrak and Kattegat, English Channel
Stock detail — 4, 3a, 7d, 7e
Picture of Brill

Sustainability rating three info

Sustainability overview

Updated: July 2020.

Brill in this area is mainly landed as bycatch in beam trawl and pulse beam trawl fisheries for plaice and sole, particularly in the North Sea. Scientific advice for this stock indicates that it’s likely that the stock is not at risk as ICES assesses that fishing pressure on the stock is below the FMSY proxy and spawning stock size is above the MSY Btrigger proxy. Management of turbot and brill is under a combined species Total Allowable Catch (TAC) which prevents effective control of the single-species exploitation rates. Despite this, catches of brill in recent years have been below the recommended level. Whilst gill net fisheries can be very selective with regards to targeted fish species, they can encounter bycatch of vulnerable species including porpoise, sharks and seabirds. Bycatch of harbour porpoise in the North Sea is not considered to be a threat to the population, but localised depletion may be an issue in some areas.


Brill, like turbot, belongs to the family Scophthalmidae, a group of left-eyed flatfish (they lie on their right side and both eyes are on the left). Similarly, brill are distributed from southern Iceland, down the coast of western Europe, including the Baltic, and into the Mediterranean and Black Seas. Brill is a shallow-water fish (between 5 - 70m) mainly found in areas close inshore and even in estuaries. Mature fish tend to inhabit offshore areas and are rarely observed inshore. Brill prefer sandy bottoms, but are also found on gravel and muddy grounds. They can attain a length of 75cm, but usually no more than 55cm, and a weight of around 2.5kg for females (which are larger). Length at first maturity is 33-40cm, with females fully mature at about 4 years and 40cm. Maximum reported age is 6 years. They spawn in spring and summer. Larger brill (> 40cm) are primarily piscivorous. Small brill feed on small benthic fishes, sandeels, gobies, anchovy, and crabs; with increasing length the diet moves to small gadoids. Brill grows relatively fast and generally reaches a certain length faster (at younger ages) than flatfish, such as sole and plaice, in the same areas.

Stock information

Criterion score: 0.25 info

Stock Area

North Sea, Skagerrak and Kattegat, English Channel

Stock information

This stock is data limited and no reference points are defined for this stock in terms of absolute values. There is no concern for the biomass and no concern for fishing pressure. The stock was last assessed in 2020 and stock size is considered to be above the MSY Btrigger proxy. The biomass index has been gradually decreasing since 2015, however there was an increase again in 2019. The same trend can be seen in the total annual landings. From 2010-2019, total annual landings fluctuated around an average of 2232 tonnes (range: 1947-2538 tonnes) and after a decrease in 2018, 2019 landings were again higher (2172 tonnes). The Surplus Production in Continuous Time (SPiCT) analysis suggests that fishing mortality is below the FMSY proxy. ICES advises that when the precautionary approach is applied, catches should be no more than 2559 tonnes in 2020 and 2047 tonnes in 2021, a 20% reduction from 2020 to 2021. Brill has a medium resilience to fishing pressure.

ICES class this stock as data limited (category three) and the assessment is based on a commercial biomass index which may not accurately detect changes due to changing fishing patterns, including the use of pulse trawls. ICES note that the current surveys in this area are not designed for catching brill, especially large brill, and that a fisheries-independent survey that covered the entire distribution area of the stock, would improve the assessment. To address this issue in future assessments, a Dutch science-industry partnership initiated a new fisheries independent beam trawl survey for turbot and brill in 2019. Once a period of 5 years is covered, the index of this new survey is a potential candidate to include in the brill assessment.


Criterion score: 0.5 info

Management of brill in the North Sea is only partially effective. Brill in this area is managed under a combined total allowable catch (TAC) together with turbot. ICES have indicated that management of brill and turbot under a combined species TAC prevents effective control of the single-species exploitation rates which can result in high-grading and discarding of the lesser value species, in this case, brill. Despite this, the total catches of brill have been within scientifically recommended levels. Since 1 January 2019, brill is entirely under the landing obligation. Dutch producer organisations still cap weekly landings for brill and turbot (e.g. at 3000kg), but the maximum conservation reference size (MCRS) of e.g. 27cm is no longer valid for brill.

Brill in the North Sea is caught in fisheries for plaice and sole and is classed as a bycatch species under the EU North Sea Multiannual Management Plan (NSMAP) for demersal stocks which came into effect in 2018. The NSMAP aims to ensure that exploitation of living marine biological resources and maintains populations of harvested species above levels which can produce the Maximum Sustainable Yield (MSY) and that the precautionary approach to fisheries management is applied. Bycatch stocks do not have specific targets under the NSMAP but are supposed to be managed in accordance with the best available scientific advice. However, MCS has concerns that the NSMAP is not being adhered to for all bycatch stocks, especially where adequate scientific advice is available.

The UK is due to leave the EU on 31st December 2020, and new UK Fisheries legislation is being developed during 2020. MCS will update ratings with new management information when new legislation comes into force.

In the European Union (EU), EU fishing vessels can fish up to 12 nautical miles of any Member State coast, and closer by agreement. There is overarching fisheries legislation for all Member States, but implementation varies between fisheries, Member States and sea basins.
The EU Common Fisheries Policy (CFP) is the primary overarching policy. Its key environmental objectives are to restore and maintain harvested species at healthy levels (above BMSY), and apply the precautionary and ecosystem-based approaches to fisheries management. To achieve the MSY objective, the MSY exploitation rate is supposed to be achieved by 2020, but this seems unlikely to happen.
The CFP also introduced a Landing Obligation (LO) which bans the discarding at sea of species which are subject to catch limits. Some exemptions apply to species with high post-capture survival, and where avoiding unwanted catches is very difficult. These exemptions are outlined in regional discard plans. Despite quota ‘uplift’ being granted to fleets under the LO, available evidence suggests there has been widespread non-compliance with the policy, and illegal and unreported discarding is likely occurring.
Multi-Annual Plans (MAPs) are a tool for implementing the CFP regionally, with one in place or being developed for each sea basin. They specify fishing mortality targets and ranges for the main targeted species, as well as lower biomass reference points. If populations drop below these points it should trigger a management response. The MAPs also empower Member States to jointly apply measures such as closures, gear or capacity limits, and bycatch limits. There is concern however that the MAPs do not provide adequate safeguards to maintain all stocks at healthy levels.
The EU Technical Measures regulation addresses how, where and when fishing can take place in order to limit unwanted catches and ecosystem impacts. There are common measures that apply to all EU sea basins, and regional measures that vary between sea basins. Measures include Minimum Conservation Reference Sizes (MCRS, previously Minimum Landing Sizes, MLS), gear specifications, mesh sizes, closed areas, and bycatch limits.
The Control Regulation, which is being revised in 2019, addresses application of and compliance with the above, e.g. keeping catches within limits, recording and sharing data, and satellite tracking of vessels over 12 metres (VMS).

Capture Information

Criterion score: 0.5 info

Brill is mainly taken as a bycatch species in Dutch and Belgium beam trawl fisheries for plaice and sole in the North Sea. In 2019, 60% of the catch was taken in bean trawl fisheries, 28% was taken in otter trawl fisheries and 8% was taken in trammel and gill net fisheries. The North Sea accounts for around 68% of total brill landings from the northeast Atlantic. The English Channel and the Skagerrak-Kattegat area are responsible for 20% and 12% respectively.

Gillnets and fixed nets can be very size selective, but can bycatch species such as sharks, cetaceans and other marine mammals. Reports indicate that there is concern regarding the bycatch of cetaceans, particularly harbour porpoise, by gillnets. One of the areas of most concern is off the South West of England, where areas of higher gillnet fishing effort coincide with areas of larger harbour porpoise populations. However, these reports are based on highly uncertain data which cannot indicate the likelihood of bycatch either causing populations to decline or preventing populations from recovering. Progress on this issue is being made in some areas, with Defra leading work to improve monitoring and mitigation of cetacean bycatch (“Hauling Up Solutions”). A pilot project trialling self-reporting of bycatch is taking place in Cornwall, potentially backed up by electronic monitoring and VMS in time, and trialling the use of pingers and other mitigation technologies, which are known to deter harbour porpoise from entanglement in nets. Because of gillnets’ durability (they are made of nylon), if lost, they can continue to fish for several weeks before becoming tangled and bundled up, a phenomenon known as ‘ghost fishing’. However, static nets, as with all gear, represent an investment by fishermen, and therefore there are incentives to avoid losing or damaging gear.


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.

Halibut, Atlantic (Farmed)
Sole, Dover sole, Common sole
Turbot (Farmed)


ASCOBANS, 2009. Conservation Plan for Harbour Porpoises in the North Sea as adopted at the 6th Meeting of the Parties to ASCOBANS, Bonn, Germany. 16 - 18 September 2009. Available at [Accessed on 03.07.2020].

Calderan, S. and Leaper, R., 2019. Review of harbour porpoise bycatch in UK waters and recommendations for management. January 2019, WWF. Available at [Accessed on 03.07.2020].

EU, 2019. Technical measures regulation. EU 2019/1241. Available at [Accessed on 03.07.2020].

EU, 2018. Regulation 2018/973 establishing a multiannual plan for demersal stocks in the North Sea and the fisheries exploiting those stocks. Available at [Accessed on 03.07.2020].

EU, 2018. Commission Delegated Regulation (EU) 2018/2035 of 18 October 2018 specifying details of implementation of the landing obligation for certain demersal fisheries in the North Sea for the period 2019-2021. Available at [Accessed on 03.07.2020].

ICES. 2020. Brill (Scophthalmus rhombus) in Subarea 4 and divisions 3.a and 7.d-e (North Sea, Skagerrak and Kattegat, English Channel). In Report of the ICES Advisory Committee, 2020. ICES Advice 2020, bll.27.3a47de Advice provided in 2020,

ICES. 2020. Turbot (Scophthalmus maximus) in Subarea 4 (North Sea). In Report of the ICES Advisory Committee, 2020. ICES Advice 2020, tur.27.4.

ICES. 2020. Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak (WGNSSK). ICES Scientific Reports. 2:61. 1140 pp.

ICES, 2018. ICES Advice: Bycatch of small cetaceans and other marine animals - review of national reports under Council Regulation (EC) No. 812/2004 and other information. Published 11 September 2018. Available at [Accessed on 03.07.2020].

OSPAR, 2017. Intermediate Assessment 2017: Harbour Porpoise Bycatch. Available at [Accessed on 03.07.2020].