Dover sole

Stock Status Score: 0.25

Sole in the Celtic Sea and Bristol Channel is abundant, but continues to be fished above the MSY threshold.

Stock assessments are carried out by the International Council for Exploration of the Sea (ICES). This rating is based on the assessment published in 2026.

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.

Spawning stock biomass (SSB) of sole declined from a peak of 6,601 tonnes in 1971 and fell below MSY Btrigger (3,057 tonnes) in 1990 and again in 1994. However, it remained above Blim (2,184 tonnes) throughout the entire time series. Following a strong recruitment year in 1999, SSB increased and exceeded MSY Btrigger once more in 2001. It then fluctuated around this reference point until 2017, when another strong recruitment event, combined with a continued decline in fishing pressure, supported further recovery. In 2026, SSB is estimated at 4,580 tonnes, exceeding both MSY Btrigger and the BMSY proxy (4,280 tonnes). The stock is therefore considered to be currently under fished.

Fishing mortality (F) exceeded FMSY (0.251) for most of the period between 1971 and 2025, reaching a peak of 0.51 in 1997, which was also above Fpa (0.402). Since then, fishing pressure has declined, however, F in 2025 was still estimated at 0.29, remaining above FMSY but below Fpa. Therefore, the stock is currently being fished above FMSY.

ICES advises that when the MSY approach is applied, catches in 2027 should be no more than 972 tonnes. This is an increase of 98% from the previous year, which reflects an upward revision of stock abundance, particularly recent year classes, as well as revision of fishing mortality reference points.

Management of the Target Stock Score: 0.5

Alignment with Scientific Advice Score: 0.75

Monitoring, Control and Surveillance Score: 0.25

Despite being managed through a combination of the Landing Obligation, minimum conservation reference sizes (MCRS), and technical measures, fishing pressure on sole in the Celtic Sea and Bristol Channel remains above sustainable levels. Catches have exceeded scientific advice in each of the past four years, even though TACs were set in line with the advice. Nevertheless, the fishery benefits from a well-developed Monitoring, Control and Surveillance (MCS) system, with effective enforcement and low levels of illegal, unreported and unregulated (IUU) fishing.

The sole fishery in the Celtic Sea and Bristol Channel is managed through Total Allowable Catches (TACs) and a range of technical measures. While the stock is covered by the EU Multiannual Plan (MAP), there is currently no joint management plan agreed between the EU and the UK.

Sole is caught in a mixed fishery with plaice in this area. Fishing mortality for both species is affected by technical management measures, including gear selectivity requirements and mesh size regulations. The current UK technical gear measures are as follows:

• Beam Trawls: 80 mm mesh cod-end, with a headline panel of at least 180 mm mesh - additional prohibitions apply within the Biologically Sensitive Area (BSA).
• Otter Trawls: 110 mm mesh cod-end, with a 120 mm square mesh panel required within the Inner Celtic Sea Protection Zone (CSPZ) - derogations apply.

Sole in this area is subject to the Landing Obligation (LO). The LO was introduced to improve catch reporting, reduce unwanted catches, and encourage more selective fishing practices. However, some exemptions apply to this fishery, including de minimis exemptions for beam trawls fitted with Flemish panels, allowing certain catches to be returned to sea. A minimum conservation reference size (MCRS) of 24 cm applies throughout the fishery. Discard rates ranged from 4.2% to 13.5% between 2020 and 2025, with beam trawlers accounting for the majority of discards.

The stock is managed through a Total Allowable Catch (TAC) system. Between 2020 and 2026, TACs were set in line with, or below, ICES catch advice each year. However, since 2021, estimated catches have consistently exceeded both the TAC and the advised catch limit, reaching 101–123% of the advised level. In 2025, the TAC was set at 1,149 tonnes in line with ICES advice, but estimated catches totalled 1,215 tonnes, equivalent to 105.7% of both the TAC and the advised catch limit.

The Celtic Sea and Bristol Channel sole fishery operates within the Celtic Seas ecoregion, where sole is caught as part of mixed demersal fisheries. ICES notes that, under current fishing patterns, it is not possible to achieve all single-stock catch advice simultaneously because some choke species, including cod, haddock and whiting, are subject to zero-catch advice. Therefore choke species are largely overlooked. However, interactions between the sole fishery and these species are considered limited. In addition, measures to protect cod include seasonal closures in ICES rectangles 30E4, 31E4, and 32E3 from February to March each year.

Sole is more commonly caught alongside plaice, which is not included in the mixed-fishery advice. Given that the plaice stock in this area has declined substantially over the past decade and has remained below the MSY Btrigger proxy (Itrigger) since 2021, any changes in sole fishery management or fishing effort could influence plaice catches and potentially affect the stock's recovery.

Monitoring, control and surveillance of UK fisheries are delivered through licensing, vessel tracking, statutory reporting, observer coverage, inspections and other monitoring systems. All commercial fishing vessels must hold a valid UK fishing licence to operate in UK waters, although exemptions may apply to some unpowered vessels under 10 metres. Depending on the area, target species and activity, additional permits or authorisations may also be required.

Vessel tracking requirements vary by vessel size, area and administration through Vessel Monitoring Systems (VMS) and, where applicable, inshore VMS (iVMS).

• Vessels 12 m and over must report their position every two hours via VMS.
• Vessels under 12 m report their position continuously where iVMS applies, or may operate full VMS where required by licence conditions or when fishing offshore.

Reporting of fishing activity, catches, landings, discards and port movements is mandatory, with logbooks supporting traceability:

• Vessels 12 m and over submit electronic logbooks under Council Regulation 1224/2009.
• Vessels 10–12 m (and under 10 m Producer Organisation vessels) use paper logbooks, updated daily and submitted within 48 hours of landing.
• Non-PO vessels under 10 m are generally exempt unless required by licence conditions.

UK vessels must also carry fishery observers when directed, providing independent verification of activity and catch. Remote Electronic Monitoring (REM), using cameras, sensors and positional data, is being increasingly deployed to improve data quality and support enforcement. Its rollout is supported by the Fisheries Act 2020 and the Joint Fisheries Statement.

Together, these measures help prevent illegal, unreported and unregulated (IUU) fishing through vessel licensing, catch documentation, positional monitoring, statutory reporting and compliance checks. Enforcement action may include financial penalties, prosecution, licence suspension or other sanctions. The UK has committed to reducing IUU fishing and maintains a blacklist of vessels involved in such activities. This rating reflects full compliance with UK monitoring, control and surveillance requirements.

The Marine Conservation Society views Remote Electronic Monitoring (REM) with cameras as 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. 

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 impacts 

• Targets for fishing pressure and biomass, and additional management when those targets are not being met, based on the best scientific evidence 

• Timeframes for stock recovery 

• Improved 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 bycatch 

• Stakeholder engagement 

A Celtic Sea and Western Channel demersal FMP has been proposed, coordinated by Defra and the Welsh Government that incorporates this stock. At the time of writing, it is too soon to know whether 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]. 

Capture Method Score: 0.5

Habitat Impacts: 0.5

Bycatch Impacts: 0.5

Vulnerable and ETP Species: 0.5

Ecosystems and Trophic Webs: 0.25

Otter trawls are likely to cause some damage to the seabed, including damage to benthic communities and vulnerable marine habitats. Although interactions with zero-catch gadoid stocks are limited in this mixed demersal fishery, bycatch of plaice may be affecting the stock's recovery. This gear type can also interact with ETP species. While sole landings have remained stable, otter trawling may continue to exert pressure on an ecosystem already affected by historic fishing and climate change.

The majority of Celtic Sea and Bristol Channel sole landings come from beam trawls (90%), followed by otter trawls (9.5%), and other gears (<1%). In 2025, total catches were 1,164 tonnes.

Otter trawls make direct contact with the seabed, causing penetration and abrasion of habitat features. The extent of seabed impact depends on gear type, sediment composition, and the area's natural resilience. For instance, regions that are used to tidal and wave disturbances are less sensitive, whereas areas untrawled areas may be more vulnerable.

In the Celtic Seas ecoregion, impacts from bottom trawling are variable. Most fishing grounds consist of sand, which is less susceptible to damage than habitats like reefs and seagrass beds. In 2022, it was estimated that 61% of the Celtic Seas seabed shallower than 800m was trawled, consisting of 66% of 0-200m zone, and 59% of the 200-800m zone.

There are several Marine Protected Areas (MPAs) within the Celtic Sea and Bristol Channel, which are designated to protect sensitive benthic habitats and species that may be vulnerable to bottom-towed fishing gears. Restrictions on bottom-towed gears are already in place in some areas, including parts of Haig Fras SAC, East of Haig Fras MCZ, and South of Celtic Deep MCZ. However, protection across the MPA network remains incomplete, with several sites only recently being considered through the MMO's Stage 3 byelaw process. As such, some designated features may remain exposed to disturbance from bottom trawling, potentially limiting habitat recovery and the achievement of conservation objectives. Given the critical role MPAs play in recovering marine health and supporting ecosystem function, the Marine Conservation Society urges supply chain actors to verify whether their sources originate from within MPAs. If so, businesses should confirm that fishing operations are legally conducted and request evidence from the fishery or managing authority to ensure activities do not harm protected features or compromise conservation objectives.

Demersal otter trawls have the potential to take relatively high quantities of bycatch, including those of conservation concern. Bycatch data is limited in many UK and EU fisheries as they are generally not well monitored. In the Celtic Sea, trawl fisheries are known to interact with several elasmobranch species of conservation concern, including the prohibited common skate complex, an endangered, threatened, or protected (ETP) species. Otter trawls are also associated with some of the highest bycatch rates of common dolphins in the region. Although the sole fishery is likely responsible for only a small proportion of these interactions, they demonstrate that otter trawl gear can affect vulnerable and protected species, and therefore its impacts cannot be considered negligible.

Sole is caught as part of a mixed fishery within the Celtic Sea ecoregion, where cod, haddock, and whiting are choke species due to their zero-catch advice. However, these species may still be bycaught within the sole fishery. That said, catches of these species have declined steadily over the past decade, but otter trawls remain responsible for the majority of landings (54–78%). Despite this, interactions between the Celtic Sea and Bristol Channel sole fishery and cod, haddock, and whiting are considered low, and the fishery's contribution to bycatch and any associated impacts on stock recovery is likely to be limited. Additional protection for cod is provided through a seasonal closure covering ICES rectangles 30E4, 31E4, and 32E3 from February to March each year. Although introduced primarily to protect cod, this restriction applies to all gear types and is also likely to benefit other species occurring within the closed area, including benthic species that may otherwise be affected by trawling activity.

More common bycatch species in this fishery include anglerfish, plaice, lemon sole, and cuttlefish. Plaice discard rates in the Celtic Sea and Bristol Channel are high, often exceeding 50%, due to gear selectivity, the minimum conservation reference size (MCRS), and the species' relatively low market value. Plaice biomass has declined markedly over the past decade and has remained below the MSY Btrigger proxy (Itrigger) since 2021. Although around 40% of discarded plaice are estimated to survive, this is not accounted for in the stock assessment. Consequently, any changes in fishing effort or management measures within the sole fishery could influence plaice catches and potentially affect the stock's recovery.

More common bycatch species in this fishery include anglerfish, plaice, lemon sole, and cuttlefish. Plaice discard rates in the Celtic Sea and Bristol Channel are high, often exceeding 50%, due to gear selectivity, the minimum conservation reference size (MCRS), and the species' relatively low market value. Plaice biomass has declined markedly over the past decade and has remained below the MSY Btrigger proxy (Itrigger) since 2021. Although around 40% of discarded plaice are estimated to survive, this is not accounted for in the stock assessment. Otter trawls account for some plaice landings (26%) and discards (18%) in the area, indicating that the sole otter trawl fishery has some influence on plaice stock stability. Consequently, any increase in fishing effort or changes in management measures within the sole fishery could affect plaice mortality and potentially hinder stock recovery.

Sole occupy a mid-trophic-level position in the food web, feeding mainly on benthic invertebrates and serving as prey for larger fish and marine mammals. The Celtic Seas ecosystem has changed considerably over the past century, driven primarily by fishing and, more recently, climate change. From the mid- to late 20^th century, high fishing pressure depleted many commercial stocks, including cod, whiting, sole, plaice, and herring, as well as large elasmobranchs such as the previously abundant common skate complex. These declines altered trophic interactions and coincided with reductions in several seabird populations linked to changes in prey availability. Although some stocks have since recovered, others remain depleted. More recently, climate-driven changes in oceanographic conditions have altered plankton communities, shifted species distributions, and increased the prevalence of warm-water species. Together, changes in temperature, predation pressure, and food availability are thought to have reduced the productivity of commercial finfish stocks and slowed their recovery.

Despite these ecosystem-wide changes, sole catches from the Celtic Sea and Bristol Channel have remained relatively stable at around 1,000–1,500 tonnes since the 1970s. However, sole is primarily caught using bottom trawls, which can disturb seabed habitats and generate multi-species bycatch. As a result, habitat disturbance and incidental catches may continue to exert pressure on an ecosystem that has already been substantially altered by fishing and environmental change.