Scophthalmus rhombus

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

Sustainability rating three info

Sustainability overview

Updated: July 2019.

Brill in these regions 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 is based on a commercial biomass index used as an indicator of stock size. 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 MSY Btrigger proxy, but as no absolute values are known, the data limited scoring approach has been applied by MCS. Management of turbot and brill is under a combined species Total Allowable Catch (TAC) which prevents effective control of the single-species exploitation rates and could lead to high-grading (where lower value fish are discarded to make room for higher value fish) of the lower value species (brill). Despite this, catches of brill in recent years have been below the recommended level. Beam trawls can encounter relatively high levels of bycatch including demersal elasmobranchs and occasionally protected, endangered and threatened (PET) species (e.g. sharks and rays). Beam trawlers interact with the seabed and can modify bottom topography and cause damage to seafloor habitats.


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 other 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

The stock was last assessed in 2019 and indicated that the stock was likely in a healthy state. The Surplus Production in Continuous Time (SPiCT) analysis suggests the fishing mortality is below, and the stock size it above, proxies of the MSY reference points. The biomass index has been gradually increasing over the time-series with moderate interannual variability but has been decreasing since 2015. ICES advises that when the precautionary approach is applied, catches should be no more than 2559 tonnes in each of the years 2020 and 2021 which represents a 19% reduction in advised catch from the previous two years, although only a minor reduction in terms of actual catch.

The stock is classed 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.


Criterion score: 0.5 info

Management of brill in the North Sea is only partially effective. Brill here is a bycatch species 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 restores 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 and the precautionary approach when no adequate scientific information is available. However, MCS has concerns that the NSMAP is not being adhered to for all bycatch stocks, especially where adequate scientific advice is available.

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 the scientifically recommended levels.

The stock classed 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.

There is no official EU minimum conservation reference size (MCRS) for brill, although some regional authorities have applied their own. The most frequently applied is 30cm (e.g. in Belgium, Baltic, Cornwall), although even this size could be considered too small as brill do not mature until 33 -40cm for males and females respectively.

Brill has been under the landing obligation since the start of 2019 without exemptions.

Surveillance activities on fisheries for demersal stocks in the North Sea, Skagerrak and Kattegat and English Channel include the use of vessel monitoring systems (VMS) on vessels over 12m; direct observation by patrol vessels and aerial patrols; inspections of vessels, gear, catches at sea and on shore and requirements to record data in electronic logbooks (although vessels under 10m do not have to keep logbooks).

Capture Information

Criterion score: 0.75 info

Brill is mainly taken as a bycatch species in Dutch and Belgian beam trawl fisheries for plaice and sole in the North Sea. In 2018, about 63% of the catch was taken in beam trawl fisheries, 22% taken in otter trawl fisheries and 12% in trammel and gill net fisheries. The North Sea accounts for almost half of landings of brill from the northeast Atlantic. The English Channel is the second most productive area for brill.

Beam trawls have the potential to take relatively high quantities of bycatch (> 50% of catch weight) including sharks, skates and rays and occasionally protected, endangered and threatened (PET) species.

Beam trawls disturb seabed habitats and in the North Sea, beam trawlers have reduced the biomass and production of bottom-dwelling organisms. Sustained fishing within the core areas for this fishery are in relatively shallow areas of fine sand and sandy mud which are heavily fished. This has resulted in a shift from communities dominated by relatively sessile, emergent and high biomass species to communities dominated by infaunal, smaller bodied and faster growing organisms. The penetration depth of a beam trawl depends on sediment characteristics and varies between 1 cm and 8 cm. Trawls leave detectable marks on the seabed and the pressure exerted on the sea floor is strongly related to the towing speed, which is very high in flatfish fisheries as the gear itself is very heavy. The habitat risks are related to the types of seabed communities and other sources of seabed disturbance such as wave and tidal action. Within the North Sea, one of the more sensitive habitats that may be impacted by beam trawl is slow growing Sabellaria reef, frequently found in shallower areas of the southern North Sea. Further north, the large and very long-lived bivalve Arctica islandica (Ocean quahog), can also suffer damage in trawls. Some spatial management is in place but there remains a need to implement management measures in many designated marine protected areas to allow for the protection and recovery of these areas and sensitive designated features.

There are MPAs designated to protect seabed features from damaging activities in this region. The fishery overlaps with parts of these MPAs, but the proportion of the catch coming from these areas is expected to be relatively low in relation to the unit of assessment (i.e. less than 20% of the catch) and so these impacts have not been assessed within the scale of this rating. Given the important role that MPAs have in recovering the health and function of our seas, MCS encourages the supply chain to identify if their specific sources are being caught from within MPAs. If sources are suspected of coming from within designated and managed MPAs, MCS advises businesses to: establish if the fishing activity is operating legally inside a designated and managed MPA; and to request evidence from the fishery or managing authority to demonstrate that the activity is not damaging to protected features or a threat to the conservation objectives of the site[s].

The overall capacity and effort of the North Sea beam trawl fleet has been substantially reduced since 1995, likely due to a number of reasons, including effort limitations between 2008 and 2016 for the recovery of the cod stock. Fishing effort of the beam trawl fleet has shifted towards the southern North Sea to target sole over the past decade. Juvenile plaice tend to be relatively abundant there, leading to relatively high discarding rates of small plaice. In addition, the minimum mesh size of 80 mm selects sole at the minimum conservation size, but generates high discards of plaice, which have a larger minimum size (27cm, although approximate size at which 50% of females mature or first spawn is around 30-34cm). Mesh enlargement would reduce the catch of undersized plaice, but would also result in loss of marketable fish.


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)
Halibut, Pacific
Sole, Dover sole, Common sole
Sole, Lemon
Turbot (Caught at sea)
Turbot (Farmed)


Engelhard GH, Lynam CP, Garcia-Carreras B, Dolder PJ, Mackinson S (2015) Effort reduction and the large fish indicator: spatial trends reveal positive impacts of recent European fleet reduction schemes. Environmental Conservation, 42, 227-236.

EU, 2019. Technical measures regulation. EU 2019/1241. Available at [Last accessed 13.09.2019].

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 02.07.2019].

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 [Last accessed 13.09.19].

FAO, 2001. Fishing gear types; beam trawls. Available at [Last accessed 23.09.19].

Hiddink, J., Jennings, S., Kaiser, M., Queiros, A., Duplisea, D. and Piet, Gerjan. 2006. Cumulative Impacts of Seabed Trawl Disturbance on Benthic Biomass, Production, and Species Richness in Different Habitats. Canadian Journal of Fisheries and Aquatic Sciences 63 (2006) 4. 63. 10.1139/f05-266.

ICES, 2019. Brill (Scophthalmus rhombus) in Subarea 4 and divisions 3.a and 7.d-e (North Sea, Skagerrak and Kattegat, English Channel). Available at [Last accessed 15.09.2019].

ICES, 2019. Turbot (Scophthalmus maximus) in Subarea 4 (North Sea). Available at [Last accessed 15.09.2019].

Lakkeborg, S. 2005. Impacts of trawling and scallop dredging on benthic habitats and communities. FAO Fisheries Technical Paper. No. 472. Rome, FAO. 2005. 58p.

Tillin, H.M., Hiddink, J.G., Jennings, S. and Kaiser, M. J., 2006. Chronic bottom trawling alters the functional composition of benthic invertebrate communities on a sea-basin scale. Marine Ecology Progress Series. Vol. 318. 31-45.