Dover sole

Sole biomass in the North Sea is in a good state and fishing pressure is within sustainable limits.Stock assessments are carried out annually by the International Council for Exploration of the Sea (ICES). The most recent assessment was published in 2024.The stock assessment defines reference points for fishing pressure (F) and biomass (B). For fishing pressure, there is a target to keep F at or below Maximum Sustainable Yield (MSY). For biomass, there is no target. However, there is a trigger point (MSY BTrigger). Below this level, F should be reduced to allow the stock to increase. Because BMSY is not defined, the Good Fish Guide applies its own definition of 1.4 x MSY BTrigger.In 2023, spawning stock biomass (SSB) is 55,955 tonnes. This is a decline from a recent peak in 2021, but it remains above MSY Btrigger (52,532 tonnes). In 2025, it is predicted to increase further to 61,320 tonnes. However, recruitment in the last 5 years has been relatively low.Fishing pressure (F) has decreased in recent years from 0.33 in 2011 to 0.079 in 2023. This is below FMSY.ICES advises that when the MSY approach is applied, catches in 2025 should be no more than 10,196 tonnes. This is an increase of 177% from the previous years advice due to the upward revision of stock status after the recent benchmark. The SSB for the stock was previously estimated around Blim and SSB is now above MSY Btrigger.

There is no management plan in place for North Sea Dover sole, but some measures are in place which are largely effective. Discarding is high for this stock.The sole fishery in the North Sea is managed by Total Allowable Catch (TAC) and technical measures. TAC has been set in line with scientific advice in recent years and catches have been in line with the TAC. Since 2022, the TAC has followed the MSY approach, rather than having an upper and lower limit. In 2025, advice has increase substantially, however, TAC uptake has been less than 100% in recent years and it is thought that catch will remain below advice.Sole in the North Sea has been under the landing obligation since 2016, and Norway and UK national legislation regarding discards. Catch monitoring programs estimate that discarding in 2023 amounted to 8.22% of the total catch (includes below minimum size landings (BMS)).Technical measures in place for this fishery are:Minimum mesh sizes and minimum conservation reference size (MCRS) of 24cm.Mesh size regulations for towed trawl gears require that vessels fishing North of 55°N (or 56°N east of 5°E, since January 2000) should have a minimum mesh size of 100 mm, while to the south of this limit, where the majority of the sole fishery takes place, an 80 mm mesh is allowed. In the fishery with fixed gears a minimum mesh size of 100 mm is required.A closed area has been in operation since 1989 (the plaice box) - this applies to vessels using towed gears, but vessels smaller than 300 HP are exempt.In the plaice box, and in the 12 nautical mile zone, the maximum aggregated beam length is 9m.Between 2014 and 2018 the use of pulse trawls in the main fishery operating in the North Sea increased and fewer vessels were operating with traditional beam trawls. The pulse gear allows fishing of softer grounds and as a result the spatial distribution of the main fisheries has changed to the southern part of the Division 4.c. As a consequence, a larger proportion of the sole catch is now taken in this area. Following the EU decision in February 2019 to revise the technical measures regulations, the pulse gear was prohibited from 1st July 2021. It is expected that the fleets will revert to the traditional gears and fishing grounds.A number of Marine Stewardship Council certifications are available for North Sea sole.The EU and UK both have fishery management measures, which can include catch limits, population targets, and gear restrictions. However, compliance in the EU and UK has been inconsistent, with ongoing challenges in implementing some regulations. The goal of reaching Maximum Sustainable Yield (MSY) by 2020 was missed, with less than half of UK TACs in 2024 following ICES advice. In 2024, the EU and UK reaffirmed their commitment to sustainable fisheries by aligning management with scientific advice to gradually approach MSY. However, no new target date has been set for achieving MSY across all fisheries. The Landing Obligation (LO), an EU law retained by the UK post-Brexit, requires all quota fish to be landed, even if unwanted (over-quota or below minimum size). It aims to encourage more selective fishing methods, reduce bycatch, and improve catch reporting. However, compliance is poor, and accurate discard levels are hard to quantify with current monitoring programmes. The UK is in the process of replacing the LO with country-specific Catching Policies.The Marine Conservation Society views Remote Electronic Monitoring (REM) with cameras is one of the most cost-effective tools for providing reliable fisheries data and aiding informed management decisions. Fully monitored fisheries enhance collaboration, data accuracy, stock recovery, and reduce impacts on marine wildlife and habitats. However, the full potential of REM may only be achieved when it tracks fishing location and documents catch and bycatch, particularly where vulnerable species and habitats are at risk. As of January 2024, the EU is introducing a Remote Electronic Monitoring (REM) mandate for EU vessels, including CCTV cameras on vessels 18m or more that pose a potential risk of non-compliance, within the next 4 years. Across the UK, different approaches to REM are being taken and legislation is expected to be in place across all 4 countries within the next few years.The Fisheries Act (2020) requires the development of Fisheries Management Plans (FMPs) (replacing EU Multi-Annual Plans) in the UK. 43 FMPs have been proposed and are at various stages of development and implementation, these should all be published by the end of 2028. FMPs have the potential to be very important tools for managing UK fisheries, although data limitations may delay them for some stocks. It is also essential the UK governments define and adopt a standardised approach or model across the four nations to a universally defined FMP design, to ensure the consistence, quality and coherence of all the proposal FMPs.The Marine Conservation Society is keen to see publicly available Fishery Management Plans for all commercially exploited stocks, especially where stocks are depleted, that include:An overview of the fishery including current stock status, spatial coverage, current fishing methods and impactsTargets for fishing pressure and biomass, and additional management when those targets are not being met, based on the best scientific evidenceTimeframes for stock recoveryImproved data collection, transparency, and accountability, supported by technologies such as Remote Electronic Monitoring (REM)Consideration of wider environmental impacts of the fishery, including habitat impacts and minimising bycatchStakeholder engagementA Southern North Sea and Eastern Channel mixed flatfish FMP has been proposed, coordinated by Defra that covers the English waters within ICES divisions 4b, 4c and 7d. The FMP covers the following flatfish species (quota and non-quota): sole, dab, plaice, flounder, halibut, lemon sole, witch, turbot, brill. It is too soon to know whether the proposed management measures will be effective in managing the stock. For more information about this FMP and expected progress and timelines, see https://www.gov.uk/government/collections/fisheries-management-plans#published-fmps.

Beam trawls have significant impacts on the seabed, including damage to benthic communities and vulnerable marine habitats. They can also have high bycatch, potentially of vulnerable species.Dover sole in the North Sea are taken by beam trawlers (96%), gillnets and trammel nets (2%), bottom trawls (1%) and other gear types (1%).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 (sole is 24cm, plaice is 27cm). Mesh enlargement would reduce the catch of undersized plaice, but would also result in loss of marketable sole.Beam trawls have the potential to take relatively high quantities of bycatch (more than 50% of catch weight), including those of conservation concern. In the North East Atlantic there are reported catches of demersal elasmobranchs and endangered, threatened and protected (ETP) species, such as sharks, rays and marine mammals. Bycatch data is limited in many UK and EU fisheries as they are generally not well monitored. However, a proportion of the trawl fisheries in the North Sea are Marine Stewardship Council-certified and record bycatch. MCS assumes these records will be indicative of bycatch in the uncertified component. Bycatch includes the vulnerable North Sea cod, which is below safe reproductive levels. Endangered, threatened or protected species included the Critically Endangered common skate complex (blue skate and flapper skate), porbeagle, and other skates and rays.Some mitigation measures are in place in some areas. There is a UK North Sea cod avoidance plan, requiring a minimum 120mm mesh size in the Scottish North Sea, seasonal closures to protect spawning stocks, and a requirement to move away from areas where large numbers of cod are observed in catches.For blue and flapper skate, mitigation measures include a prohibition on landing either species, and some protection for nursery areas. It is not clear if this fishery is having an impact at population level for any of these species. Given that bycatch is ongoing, MCS considers it possible that the bycatch level is contributing to population decline and/or preventing recovery.Demersal trawls have contact with the seabed resulting in penetration and abrasion of habitat features. The impact of trawling on the seabed depends on the location and scale in which trawling occurs. For example, areas that are used to natural disturbance through tides and waves, are less sensitive to habitat impacts. Areas not used to mobile towed gears are typically more sensitive to trawling.Beam trawling, especially using chain-mat gear, is a high impact method of fishing and can have a significant impact on benthic communities. Heavy gear tends to have a higher seabed impact than otter trawling and seabed penetration can vary between 1cm and 8cm, depending on the sediment.In the North Sea area, impacts from bottom trawling are variable. Fishing grounds vary, but the habitat is generally mud and sand, which are less vulnerable to trawling than features such as reefs and seagrass. Data from 2018 indicates that trawling was happening on 73% of the seabed area. Fishing effort in the region has halved since 2002, mainly in the trawl fisheries, which is reducing pressure on the seabed and on bycatch species. However, fishing in the North Sea in general has reduced the number of large fish in the ecosystem (mostly cod, saithe, ling, sturgeon, and some elasmobranchs). There are concerns about the impact of North Sea trawling on sea pens.There are Marine Protected Areas (MPAs) in this area, some of which are designated to protect seabed features from damaging activities. This 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 or effort), 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 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).To improve monitoring and reporting of fishing activity, MCS would like to see remote electronic monitoring (REM) with cameras implemented, used and enforced. To reduce the impacts of fishing on the marine environment we would like to see a just transition to the complete removal of bottom towed gear from offshore Marine Protected Areas designated to protect the seabed. We also want to see reduction and mitigation of environmental impacts including emissions and blue carbon habitat damage.

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