Plaice

Irish Sea plaice are harvested sustainably but there is concern for biomass stock.Stock assessments are carried out annually by the International Council for the Exploration of the Sea (ICES). The most recent assessment was published in 2025.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) has remained above the MSY Btrigger reference point of 8,757 tonnes since 2009, peaking at 1,863 tonnes in 2016. However, due to reduced recruitment from 2015 onward, SSB has steadily declined. In 2022, it fell below the MSY Btrigger, and since 2023 it has remained below Bpa (5,294 tonnes). As of 2025, SSB stands at 4,506 tonnes, which is between Blim (3,958 tonnes) and Bpa.Historically, fishing pressure (F) exceeded the precautionary reference point (Fpa = 0.403) until 1999. It then declined, falling below FMSY (0.196) in 2003, and has remained beneath this threshold from 2007 to the present. In recent years, F reached its lowest point in 2020 at 0.055, but has since shown an upward trend. In 2024, F was 0.190, just below FMSY.ICES advises that when the MSY approach is applied, catches in 2026 should be no more than 614 tonnes. This represents a 59% reduction compared to the 2025 catch advice, reflecting a downward revision of the SSB and a recommendation to reduce fishing pressure, given that the 2026 SSB is expected to remain below MSY Btrigger.

There is no management plan in place for this stock. There are some measures but more must be done to reduce discards.Irish Sea plaice is managed through a Total Allowable Catch (TAC), which in recent years has been set in line with ICES scientific advice. However, quota uptake (landings) has remained low, primarily due to poor market demand and the low commercial value of smaller plaice, rather than the inability to catch fish above the Minimum Conservation reference Size (MCRS) of 270mm.Technical measures in place for this fishery include:Minimum Conservation reference Size (MCRS): 270 mmOtter Trawls: Minimum 80mm codend with an 80mm square mesh panel – varies with target species and vessel length.Beam Trawls: Minimum 80mm codend and a headline panel with at least 180mm mesh.Landing Obligation (LO):Beam Trawls: survivability exemption with strict spatial and technical conditions.Otter Trawls: no exemptions, all plaice must be landed.A combination of limited market demand and a mismatch between the MCRS and the selectivity of common gears has contributed to persistently high discard levels. Since 2004, an average of 62% of plaice catch has been discarded, primarily consisting of undersized or low-value individuals. While discards from beam trawls may be legal under a survivability exemption, all plaice caught by otter trawls must be retained and landed. However, otter trawls were responsible for an estimated 63% of plaice discards in 2024. As otter trawl discards are illegal and therefore not self-reported, ICES relies on observer sampling, statistical modelling, and historical reconstructions for discard estimates.As part of a mixed demersal fishery, plaice are frequently taken as bycatch in fisheries targeting higher-value species such as sole, whiting, and cod. In such cases, fishers may discard plaice to prioritise storage space for more profitable catches or to prevent exceeding quota limits, which could result in the closure of the wider fishery.Despite persistent high discard rates, total fishing mortality remains within sustainable limits. However, reducing discards is a key management priority, especially with a post-release survival rate of only 40%. Recommendations include improved fishing gear selectivity, stricter enforcement, and spatial avoidance of known juvenile areas to help minimise unwanted catch. However, the long-term benefits of increased yield and improved quota uptake may be limited unless market incentives improve for landing smaller (but above MCRS) plaice.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 engagementPlaice is included in the Irish Sea demersal FMP, coordinated by DAERA. 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/publications/joint-fisheries-statement-jfs/list-of-fisheries-management-plans].

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. In the Irish Sea, there is concern over levels of bycatch of the vulnerable cod and whiting stocks.In 2024, 70% of the landings were taken by beam trawls, 23% by otter trawls, and 7% by other gear types. Of a total catch of 678 tonnes, 567 tonnes were also discarded (83.6%). Of the plaice that was discarded, which 40% survived, beam trawls accounted for 34% and otter trawls, 63%. The beam trawl fleet is generally targeting sole. Plaice is primarily caught by Irish, UK and Belgian fleets. High levels of discarding are known to occur in all fisheries that catch plaice in the Irish Sea, which indicates a mismatch between the minimum conservation reference size (27cm) and the mesh size of the gear being used. The approximate size at which 50% of females mature or first spawn is around 30-34cm. Spatial management of fleets in the Irish Sea may reduce the discarding of plaice.Of greatest concern is the bycatch of the vulnerable cod and whiting stocks in this area. Both species are under zero catch advice, but 11 out of the 12 defined fleets in the area still catch them both. For vessel targeting other species within the mixed fishery, there are specific gear requirements depending on the combined catch percentage of species such as haddock, cod, skates, rays, and nephrops.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.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. Trawl gears are known to have some of the greatest impacts on Vulnerable Marine Ecosystems (VMEs).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 Celtic Seas region, an estimated 66% of the 0-200m zone, and 59% of the 200-800m zone, has been at least partially trawled. Fishing effort in the area has been decreasing since the early 2000s. This has reduced the spatial fishing footprint and the average number of times the seabed is trawled per year. Most habitats are mud and sand, which are less vulnerable to trawling. However, in the Celtic Seas, 95% of areas where VMEs such as cold-water corals and sponges occur or are likely were found to have been fished between 2009 and 2011.Mitigation measures include a ban on bottom trawling below 800m, and restrictions from 400-600m – the areas where most VMEs are found. There remains some uncertainty about the location of some sensitive seabed habitats, so these remain at risk.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.

Catchpole, T., Randall, P., Forster, R., Smith, S., Ribeiro Santos, A., Armstrong, F., Hetherington, S., Bendall, V., Maxwell, D. (2015). Estimating the discard survival rates of selected commercial fish species (plaice - Pleuronectes platessa) in four English fisheries (MF1234), Cefas report, pp108.Eigaard, O.R., Bastardie, F., Breen, M., Dinesen, G.E., Hintzen, N.T., Laffargue, P., Mortensen, L.O., Nielsen, J.R., Nilsson, H.C., O'Neill, F.G., Polet, H., Reid, D.G., Sala, A., SkOld, M., Smith, C., Sorensen, T.K., Tully, O., Zengin, M., Rijnsdorp, A.D., 2016. Estimating seabed pressure from demersal trawls, seines, and dredges based on gear design and dimensions. ICES Journal of Marine Science, Volume 73, Issue suppl 1. Pages i27-i43. Available at https://academic.oup.com/icesjms/article/73/suppl_1/i27/2573989 [Accessed on 03.07.2025].Ellis, J. R., Bendall, V. A., Hetherington, S. J., Silva, J. F. and McCully Phillips, S. R. 2016. National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE). Project Report (Cefas) V1.4. Available at http://randd.defra.gov.uk/Document.aspx?Document=13513_MB5201NEPTUNEFinalReportv1.4.pdf [Accessed on 12.07.2024].EU. 2019. Regulation (EU) 2019/1241 of the European Parliament and of the Council of 20 June 2019 on the conservation of fisheries resources and the protection of marine ecosystems through technical measures, amending Council Regulations (EC) No 1967/2006, (EC) No 1224/2009 and Regulations (EU) No 1380/2013, (EU) 2016/1139, (EU) 2018/973, (EU) 2019/472 and (EU) 2019/1022 of the European Parliament and of the Council, and repealing Council Regulations (EC) No 894/97, (EC) No 850/98, (EC) No 2549/2000, (EC) No 254/2002, (EC) No 812/2004 and (EC) No 2187/2005. Official Journal of the European Union, L 198, 25.7.2019, p. 105. http://data.europa.eu/eli/reg/2019/1241/2024-04-09 GOV.UK. 2025. Technical Conservation and Landing Obligation rules and regulations 2025. Available at: https://www.gov.uk/guidance/technical-conservation-and-landing-obligation-rules-and-regulations-2025 [Accessed on 03.07.2025]Hiddink, J., Jennings, S., Sciberras, M., Szostek, C.L., Hughes, K.M., Ellis, N., Rijnsdorp, A.D., McConnaughey, R.A., Mazor, T., Hilborn, R., Collie, J.S., Pitcher, C.R., Amoroso, R.O., Parma, A.M., Suuronen, P. and Kaiser, M.J. 2017. Global analysis of depletion and recovery of seabed biota after bottom trawling disturbance. PNAS. 114:31, pp. 8301-8306. https://doi.org/10.1073/pnas.1618858114.ICES. 2025. Plaice (Pleuronectes platessa) in Division 7.a (Irish Sea). In Report of the ICES Advisory Committee, 2025. ICES Advice 2025, ple.27.7a. https://doi.org/10.17895/ices.advice.27202785ICES. 2025. Working Group on Mixed Fisheries Advice (WGMIXFISH-ADVICE; outputs from 2024 meeting). ICES Scientific Reports. Report. https://doi.org/10.17895/ices.pub.28182638.v1 Irish Sea mixed fisheries considerations. In Report of the ICES Advisory Committee, 2024. ICES Advice 2024. https://doi.org/10.17895/ices.advice.26763907 ICES. 2023. Advice on fishing opportunities. In Report of the ICES Advisory Committee, 2023. ICES Advice 2023, section 1.1.1. https://doi.org/10.17895/ices.advice.22240624 ICES. 2017. Report of the Benchmark Workshop on the Irish Sea Ecosystem (WKIrish3), 30 January–3 February 2017, Galway, Ireland. ICES CM 2017/BSG:01. ICES Expert Group Reports. 220 pp. https://doi.org/10.17895/ices.pub.8713Kennelly, S. J. & Broadhurst, M. K., 2021. A review of bycatch reduction in demersal fish trawls. Rev Fish Biol Fisheries 31, 289–318. https://doi.org/10.1007/s11160-021-09644-0.Kynoch, R., Fryer, R. & Neat, F., 2015. A simple technical measure to reduce bycatch and discard of skates and sharks in mixed-species bottom-trawl fisheries. ICES J Mar Sci,72(6):1861.Silva, F., Ellis, J. & Catchpole, T., 2012. Species composition of skates (Rajidae) in commercial fisheries around the British Isles and their discarding patterns. J Fish Biol., 80:1678–1703.van Denderen, P. Bolam, S., Hiddink, J.G., Jennings, S., Kenny, A., Rijnsdorp, A., and van Kooten, T., 2015. Similar effects of bottom trawling and natural disturbance on composition and function of benthic communities across habitats. Mar Ecol Prog Ser. 2015;541:31–43.