Pleuronectes platessa

Method of production — Caught at sea
Capture method — Demersal otter trawl
Capture area — North East Atlantic (FAO 27)
Stock area — Irish Sea
Stock detail — 7a
Picture of Plaice

Sustainability rating three info

Sustainability overview

Updated: July 2019.

The Irish Sea plaice stock is in a very healthy state and fishing pressure is low, although the amount of fish discarded at sea is high. According to the EU Western Waters Multiannual Plan, bycatch species are managed using the precautionary approach “when no adequate scientific information is available”. In the case of this stock, despite information regarding stock size and fishing pressure being available, the European Commission requested advice according to the precautionary approach, resulting in catch advice for 2019 being above FMSY. Trawling can have impacts on the seabed, and there is concern over levels of bycatch of the vulnerable cod and whiting stocks in the Irish sea.


Plaice is a bottom-dwelling flatfish. It spawns in the early months of the year (January to March) and sometimes makes long spawning migrations. North Sea plaice reach between 35 and 45 cm in their 6th year. It is a long-lived species, becoming sexually mature at 3-7 years (females) 2-6 (males) and living 30 years or more. Maximum reported age 50 years.

Stock information

Criterion score: 0 info

Stock Area

Irish Sea

Stock information

The stock is in a very healthy state and fishing pressure is low.

The Spawning stock biomass (SSB) in 2018 was 17,522 tonnes. It has been increasing since 2012 and has been well above MSY Btrigger (8,757t) since 2013. Recruitment (R) has declined in recent years, which could lead to stock decline. Fishing mortality (F) was 0.064 in 2018. It has been generally decreasing since 1992 and has been below FMSY (0.196) since 2011.

In the context of the EU multiannual plan for Western Waters and adjacent waters, in which this stock is considered bycatch, the European Commission has requested that ICES provide advice based on the precautionary approach. ICES advises that catches of up to 5,640 tonnes are considered to be precautionary. Because the advice has moved from MSY to precautionary, this is an increase of 61% on the previous year. It is projected to lead to a 15% decline in SSB and equates to an F of 0.36 - above FMSY.


Criterion score: 0.5 info

This stock is covered by the EU’s Western Waters Multi Annual management Plan (MAP), in which it is considered bycatch. According to the MAP, bycatch species are managed using the precautionary approach, rather than an MSY-based approach, “when no adequate scientific information is available”. In the case of this stock, despite information regarding stock size and fishing pressure being available, the European Commission requested advice according to the precautionary approach, resulting in catch advice for 2020 being above FMSY. This could be cause for concern, but it remains to be seen whether the EC will act on this advice, or take an MSY-based approach.

TACs in recent years have been set in line with advice, and catches are usually below TACs, owing to limited market demand. A combination of this and a mismatch between the minimum landing size (27cm) and mesh size of the gear has resulted in the majority of the catch being discarded since 2004 (61% average discard by weight). Despite this excessive level of discarding, total fishing pressure on the stock is currently within sustainable levels. However, more should be done to reduce discarding. The landings obligation does not currently apply to this stock.

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: 0.75 info

Of the plaice that was landed in 2018, 33% was caught by beam trawl and 64% by otter trawl. Of the plaice that was discarded, which 40% survived, beam trawl accounted for 54% and otter trawl, 41%. 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 greater concern is the bycatch of the vulnerable cod and whiting stocks in this area. Technical measures to reduce bycatch levels in this fishery include minimum mesh sizes, and beam trawlers fishing with mesh sizes equal to or greater than 80 mm are obliged to have 180 mm mesh sizes in the entire upper half of the anterior part of their net to allow escapes.

Beam and otter trawling can have impacts on the seabed. Beam trawlers often use tickler chains to disturb fish from the seabed. Beam trawling is not a well targeted fishing activity, with poor selectivity and the potential to catch a wide variety of non-target species, including benthic invertebrates disturbed from the seabed. A seasonal closure of the spawning grounds for cod restricts the footprint of trawling on the seabed at certain times of the year.


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, 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 12.07.2019].

ICES, 2019. Plaice (Pleuronectes platessa) in Division 7.a (Irish Sea). In Report of the ICES Advisory Committee, 2019. ICES Advice 2019, ple.27.7a, Available at [Accessed on 12.07.2019].

Seafish, 2018. RASS Profile: Irish Sea plaice, beam trawl. Available at [Accessed on 12.07.2019]