Capture method — Gill or fixed net
Capture area — North East Atlantic (FAO 27)
Stock area — Baltic Sea
Stock detail — 3d.24-32
Updated: July 2019.
This stock is data limited, but seems to be at a healthy level and fishing pressure is within sustainable limits. There is no direct management plan for plaice in the Baltic Sea, but 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.
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.
Criterion score: 0.25 info
The stock is at a healthy level and fishing pressure is within sustainable limits, and this species has a medium level of resilience to fishing pressure.
There are no reference points for this stock, so proxies are used instead, and the assessment is indicative of trend only. The relative spawning-stock biomass (SSB) and relative recruitment have been increasing significantly since 2013. The relative fishing mortality has been declining in recent years and relative F in 2018 is close to the lowest observed in the time-series. The relative fishing pressure is below FMSY proxy and the relative spawning stock size is above MSY Btrigger proxy.
ICES advises that when the precautionary approach is applied, catches in 2020 should be no more than 2826 tonnes. This is a decrease from last year’s advice, owing to the way that catch was calculated last year. In recent years, catches have been well below the advice.
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 2018 to maintain consistency with advice. Catches for this stock are smaller than the advice.
Landings of fish below the minimum conservation reference size (MCRS) are very low (8.6 tonnes in 2018), and discarding still takes place despite the fact that the landing obligation has been in place since 2017. The estimated discard amount of 720 tonnes in 2018 (approximately 30.5%) is based on observer data. The trawl fishery targeting cod in part of the stock area may even have a 100% discard rate of plaice throughout the year.
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).
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.
Gillnets cannot be specifically targeted to give clean catches and a wide range of other species can become enmeshed, particularly in demersal set gillnets. In the Baltic Sea there are concerns about the bycatch rates of flatfish and juvenile cod. 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.
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)
Sole, Dover sole, Common sole
Turbot (Caught at sea)
ReferencesEU, 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 11.07.2019].
Froese R. and Pauly D. (Editors), 2019. Pleuronectes platessa, European plaice. Available at: https://www.fishbase.se/summary/Pleuronectes-platessa.html [Accessed on 11.07.2019].
ICES. 2019. Baltic Fisheries Assessment Working Group (WGBFAS). ICES Scientific Reports. 1:20. 651 pp. doi: 10.17895/ices.pub.5256. Available at http://ices.dk/sites/pub/Publication%20Reports/Expert%20Group%20Report/Fisheries%20Resources%20Steering%20Group/2019/WGBFAS/1%20WGBFAS%202019.pdf [Accessed on 11.07.2019].
ICES. 2019. Plaice (Pleuronectes platessa) in subdivisions 24-32 (Baltic Sea, excluding the Soun and Belt Seas). In Report of the ICES Advisory Committee, 2019, ple.27.24-32. doi: 10.17895/ices.advice.4752. Available at http://ices.dk/sites/pub/Publication%20Reports/Advice/2019/2019/ple.27.24-32.pdf [Accessed on 11.07.2019].