Plaice

Pleuronectes platessa

Method of production — Caught at sea
Capture method — Gill or fixed net
Capture area — North East Atlantic (FAO 27)
Stock area — Baltic Sea (East)
Stock detail — 3d (subdivisions 24-32)
Picture of Plaice

Sustainability rating three info

Sustainability overview

Updated: July 2020.

This stock is at a healthy level and fishing pressure is within sustainable limits. There are no reference points for this stock and proxies are used instead, therefore the assessment is indicative of trends only. There is no direct management plan for plaice in the Baltic Sea, but it is recognised in the Baltic multiannual plan as a bycatch species. The MAP which empowers member states & the European Commission to adopt measures to maintain bycatch stocks at healthy levels according to the best available science. The main concern is the level of discarding, which can be as much as 100% in some cases (when plaice is bycaught in the cod fishery). This is despite the Landing Obligation, and indicates poor levels of compliance and enforcement. Gillnetting in the Baltic Sea is likely to be adversely affecting the critically endangered central Baltic Sea harbour porpoise population.

Biology

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

This stock is at a healthy level and fishing pressure is within sustainable limits. There are no reference points for this stock and proxies are used instead, therefore the assessment is indicative of trends only. The relative spawning stock biomass (SSB) and relative recruitment have increased significantly since 2012, however, they have declined in the last two years. SSB is still thought to above the proxy for MSY Btrigger. Relative fishing mortality (F) is well below the proxy for FMSY which is estimated to be 1.53.

ICES advises that when the precautionary approach is applied, catches in 2021 should be no more than 3297 tonnes. This is an increase on last years advice by 471 tonnes. In recent years, catches have been well below the advice.

Management

Criterion score: 0.75 info

The EU Baltic Sea Multiannual Plan (MAP) covers plaice as a bycatch species. According to the MAP, specific conservation measures should be adopted when scientific advice indicates that remedial measures are needed, such as limits on characteristics or use of gear (e.g. mesh size, depth); time/area closures; and minimum conservation reference sizes. There is no specific management plan for plaice in this area, and management areas do not match areas covered by the two stocks (western and eastern Baltic). However, Total Allowable Catches are split between the two stocks, and calculated based on the catch ratios in 2019 to maintain consistency with advice. Only Denmark, Sweden, Poland, Germany and Finland (traded quota from Sweden) have a TAC for landing plaice. Catches for this stock are smaller than the advice.

Landings (wanted catch) in 2019 was at the same level as in 2018 and about three times higher than in 2017 with about 1741 tonnes. Since 2017, the landings obligation is in place, resulting in an additional 17.4 tonnes of “BMS landings” (i.e. landings of plaice below the minimum conservation reference size of 25 cm) in 2019, which accounted for 0.74% of the total catch. The trawl fishery targeting cod in part of the stock area may also have a 100% discard rate of plaice throughout the year.


The UK is due to leave the EU on 31st December 2020, and new UK Fisheries legislation is being developed during 2020. MCS will update ratings with new management information when new legislation comes into force.

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

Plaice are mainly caught by demersal trawlers and gillnetters in the Baltic Sea. Bottom trawling can cause damage to the seabed in sensitive areas. Trawl fisheries can also have a high level of bycatch. The minimum landing size for plaice in the Baltic Sea it is 25cm. The approximate size at which 50% of females mature or first spawn is around 30-34cm. Plaice and eastern Baltic cod overlap in subdivisions 24-25. Therefore, there are no areas or months where flatfish fisheries with non-selective gears could be conducted in subdivisions 24-26 without a risk of bycatch of cod. Eastern Baltic cod is considered to be extremely overfished.

Gillnets cannot be specifically targeted to give clean catches and a wide range of other species can become enmeshed, particularly in demersal set gillnets. Harbour porpoise are highly prone to bycatch in bottom-set gillnets, due largely to their feeding habits on or near the seabed. Dead harbour porpoises exhibiting evidence of gillnet entanglements are found and reported regularly, so it is likely that bycatch in gillnets is adversely affecting the critically endangered central Baltic Sea population. Studies conducted between 1980 and 2005 indicated that at least 76 000 birds, mostly sea ducks, were killed annually in Baltic Sea gillnets. This number may have declined in more recent years, probably due to the consequential decline in sea duck populations. Because of their durability (gillnets are made of nylon), if lost the net can continue to fish, a phenomenon known as ‘ghost fishing’.

Drifting gillnets have been banned in the Baltic Sea since 2008.

Alternatives

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.

Dab
Halibut, Atlantic (Farmed)
Megrim
Plaice
Sole, Dover sole, Common sole
Turbot (Farmed)

References

EU, 2016. Regulation (EU) 2016/1139 of the European Parliament and of the Council of 6 July 2016 establishing a multiannual plan for the stocks of cod, herring and sprat in the Baltic Sea and the fisheries exploiting those stocks. Available at https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32016R1139 [Accessed on 23.07.2020].

Froese R. and Pauly D. (Editors), 2019. Pleuronectes platessa, European plaice. Available at: https://www.fishbase.se/summary/Pleuronectes-platessa.html [Accessed on 23.07.2020].

ICES. 2019. Report on eastern Baltic cod bycatch in non-targeted fisheries, mixing with western Baltic cod in SD24, and stock situation in SDs 27-32 (Ad hoc). ICES Scientific Reports. 1:76. 69 pp. Available at http://doi.org/10.17895/ices.pub.5635 [Accessed on 23.07.2020].

ICES. 2020. Baltic Fisheries Assessment Working Group (WGBFAS). ICES Scientific Reports. 2:45. 643 pp. Available at http://doi.org/10.17895/ices.pub.6024 [Accessed on 23.07.2020].

ICES. 2020a. Plaice (Pleuronectes platessa) in subdivisions 24–32 (Baltic Sea, excluding the Sound and Belt Seas). In Report of the ICES Advisory Committee, 2020. ICES Advice 2020, ple.27.24-32. Available at https://doi.org/10.17895/ices.advice.5871. [Accessed on 23.07.2020].