Sole, Dover sole, Common sole

Solea solea

Method of production — Caught at sea
Capture method — Demersal otter trawl
Capture area — North East Atlantic (FAO 27)
Stock area — Celtic Sea, Bristol Channel
Stock detail — 7f, 7g
Picture of Sole, Dover sole, Common sole

Sustainability rating two info

Sustainability overview

Updated: July 2019.

This stock was reassessed in 2019 and is now considered to be in a healthy state with sustainable levels of fishing mortality. It is managed through the EU Western Waters Multi Annual management Plan (MAP), which sets Total Allowable Catches. There are few technical measures relating to management of this fishery, and while sole discards are generally low, plaice is also caught here, and discards of that stock are significant. Better selectivity is needed (e.g. increase minimum mesh size from 80mm to 100mm) to reduce bycatch. All demersal trawling can have seabed impacts, but otter trawling tends to be slightly less impactful as it is in less sensitive areas (e.g. not on muddy substrates).


Sole is a right-eyed flatfish (eyes on the right hand side of the body) and belongs to the family of flatfishes known as Soleidae. It spawns in spring and early summer in shallow coastal water, from April to June in the southern North Sea, from May-June off the coast of Ireland and southern England, and as early as February in the Mediterranean. Common sole become sexually mature at 3-5 years, when 25-35cm long, the males being somewhat smaller than the females. It can attain lengths of 60-70cm and weigh 3kg.The maximum reported age is 26 years. Sole is a nocturnal predator and therefore more susceptible to capture by fisheries at night than in daylight.

Stock information

Criterion score: 0 info

Stock Area

Celtic Sea, Bristol Channel

Stock information

The stock has recently (2019) been reassessed, and is now in a very good state, with fishing pressure within sustainable limits.

Spawning-stock biomass (SSB) has been above MSY Btrigger (2,228 tonnes) since 2001 and shows an increasing trend over the last few years. In 2018 it was 3,557t. Fishing mortality (F) has decreased in recent years to below FMSY (0.297) since 2017, and in 2018 it was 0.23. Recruitment has been variable without an overall trend, but the 2015 and 2017 recruitments are estimated to be among the highest in the time series.

ICES advises that when the EU multiannual plan (MAP) for Western waters and adjacent waters is applied, catches in 2020 that correspond to the F ranges in the MAP are between 1020 and 2665 tonnes. According to the MAP, catches higher than those corresponding to FMSY (1731 tonnes) can only be taken under conditions specified in the MAP, whilst the entire range is considered precautionary when applying the ICES advice rule. This is double the advice from 2019, because of a substantial upwards revision in the stock size and the resulting increase in SSB. It will equate to a 106% increase in Total Allowable Catch (TAC) if the advice is followed. The stock assessment underwent an inter-benchmark in 2019, causing this substantial change in perception.


Criterion score: 0.25 info

This stock is covered by the EU’s Western Waters Multi Annual management Plan (MAP). In the last few years TACs have been at or slightly above scientific advice (TAC was 131% of advice in 2015, 103% in 2016, 105% in 2017 and 99% in 2018). Catches have generally been in line with TACs, although they exceeded TACs by 4% in 2014 and 7% in 2016. Spawning Stock Biomass has increased during recent years as a result of decreasing fishing mortality and continuous good recruitment.

Discarding of sole increased in 2017 and 2018: the average discard rate from 2013-2017 was 3%, increasing to 5% in 2017 and 14.8% in 2018. The Belgian beam trawl fleet mainly discarded fish of 22 and 23 cm (Minimum Conservation Reference Size is 24cm), aged 2, likely owing to the high recruitment of fish from the 2016 year class. While the Landings Obligation is in force for this stock, there is a North-Western Waters Discard Plan detailing some exemptions for unavoidable bycatch by some gears.

The Celtic Sea is an area without days-at-sea limitations for demersal fisheries. In this context and given that many demersal vessels are very mobile, effort limitations in other areas can result in displacement of effort into the Celtic Sea (as happened in 2004). This should be taken into account as part of management considerations.

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

Total catch in 2018 was 997 tonnes, of which 850 tonnes was landed (i.e. wanted catch). Of this, 90% was accounted for by beam trawlers, and 9.3% by otter trawlers. Of the 147 tonnes discarded, 99.7% was caught by beam trawlers. The stock is mostly caught by Belgium (70%), with some from the UK (20%) and a smaller amount from France and Ireland.

The sole fishery catches significant amounts of plaice, most of which is undersized and discarded. This is because the minimum mesh size of this fishery is 80mm: selective for sole (MCRS of 24cm) but not plaice (27cm). Therefore, better selectivity is needed.

A number of areas are closed to fishing at certain times of the year, e.g. the Trevose box, an area of sea around 11,400 square miles extending from Trevose head in Cornwall to the Gower peninsular in South Wales from January - March. This is the spawning period for a number of demersal stocks, so while it is primarily intended to reduce catches of spawning cod, other stocks are likely to benefit. However, beam trawlers have been allowed to fish there since 2005.< br>
Demersal otter trawling is not a well-targeted fishing activity, and this fishery catches a wide variety of mixed demersal finfish, such as sole, lemon sole, plaice, monkfish, John dory and skates and rays. Smaller, demersal sharks are occasionally taken as bycatch in otter trawl fisheries such as Starry smooth-hound and spurdog. In addition, common skate can be taken as bycatch in offshore otter trawl fisheries. These elasmobranchs must be returned to the sea where they have a chance of survival. In this fishery, using 100 mm instead of 80 mm cod ends, both as conventional diamond and as a square configuration, can substantially reduce discards (around 70%) and improve survival of discarded fish without loss of commercial catch.

There are a number of MPAs in UK and EU waters, some of which are designated to protect benthic features. If those MPAs were found to be subjected to bottom trawling, MCS would consider it a default red rating unless there is evidence (e.g. environmental impact assessment) indicating the activity does not damage the integrity of the site.


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 (Caught at sea)
Turbot (Farmed)


EU, 2018. Commission Delegated Regulation (EU) 2018/2034 of 18 October 2018 establishing a discard plan for certain demersal fisheries in North-Western waters for the period 2019-2021. Available at [Accessed on 23.07.2019].

EU, 2019. Regulation (EU) 2019/472 of the European Parliament and of the Council of 19 March 2019 establishing a multiannual plan for stocks fished in the Western Waters and adjacent waters, and for fisheries exploiting those stocks. Available at [Accessed on 12.07.2019].

ICES. 2019. Working Group for the Celtic Seas Ecoregion (WGCSE). ICES Scientific Reports. 1:29. 1078 pp. doi: 10.17895/ Available at [Accessed on 16.07.2019].

ICES, 2019. Sole (Solea solea) in divisions 7.f and 7.g (Bristol Channel, Celtic Sea). In Report of the ICES Advisory Committee, 2019. ICES Advice 2019, sol.27.7fg, Available at [Accessed on 16.07.2019].

Seafish, 2018. RASS Profile: Sole in the Celtic Sea, Demersal otter trawl. Available at [Accessed on 16.07.2019]