Plaice

Pleuronectes platessa

Method of production — Caught at sea
Capture method — Beam trawl
Capture area — North East Atlantic (FAO 27)
Stock area — Celtic Sea, Bristol Channel
Stock detail — 7f, 7g
Picture of Plaice

Sustainability rating three info

Sustainability overview

Updated: July 2019.

This stock appears to be in a good state, and fishing pressure is within sustainable limits. However, more than half the catch of plaice is discarded, as too many undersize individuals are caught as part of the fishery for sole. Better gear selectivity is needed. Beam trawling, which mostly operates on muddy seabeds, can have a high impact on benthic habitats. Demersal trawling is also an impactful method, but less so, concentrating on slightly less sensitive habitats.

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

Stock Area

Celtic Sea, Bristol Channel

Stock information

This stock appears to be in a good state, and fishing pressure is within sustainable limits.

This is a data limited stock, and proxies are used for biomass and fishing mortality. Fishing mortality (F) has been declining since the late 1990s and has been below FMSY proxy (which is calculated as 1, and is the ratio of F to FMSY) since 2010; in 2018 it was 0.33. The biomass (SSB) has an increasing trend since 2007 and has been above MSY Btrigger proxy (which is calculated as 1, and is the ratio of B to BMSY) since 2010; in 2018 it was 1.64.

ICES advises that when the precautionary approach is applied, catches in 2020 should be no more than 2,295 tonnes. This is an increase of 6% compared to the previous year, owing to the recent increasing trend in biomass index.

Unknown levels of discard mortality are a source of uncertainty in the assessment.

Management

Criterion score: 0.75 info

Bristol Channel and Celtic Seas plaice is not covered by the EU’s Western Waters Multi Annual management Plan (MAP), which only covers plaice in the English Channel, so there is no management plan in place for this stock.

Discards are very high - in 2018 the estimated landings were 422 tonnes, and estimated discards were 508 tonnes. They have exceeded landings since 2006. However, since 2014 Total Allowable Catches (TACs) and the actual catches (including discards) have been in line with advice. In 2019, TACs were increased to apply to both landings and discards.


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

Catch in 2018 was 930 tonnes. Of this, 422t was wanted catch, with otter trawl accounting for 42% and beam trawl accounting for 53%. Of the 508t of discarded plaice, 19% was caught by otter trawl, and 76% by beam trawl. Most of the catch is by Belgium and France, and a smaller amount by the UK and Ireland.

Plaice is primarily a bycatch of the sole fishery, with discards of plaice owing to a mismatch in the selectivity properties of the gear (80mm) and the plaice minimum landing size (27cm, although the approximate size at which 50% of females mature or first spawn is 30-34cm). In addition, the relatively low market value of plaice may contribute to the high and variable discard rates. It is estimated that the survival rate of discarded plaice is around 40%. Changes in effort in the sole fishery will impact fishing mortality on plaice.

ICES has recommended the introduction of technical measures to reduce the high overall levels of discards in the mixed-species beam trawl fishery in the Celtic Sea, including lemon sole, cuttlefish, benthic, and non-commercial species, but especially plaice. Specifically, this could include use of larger meshes, and seasonal closures. Cefas and the fishing industry have developed a number of measures to reduce bycatch and discards through improved design of nets and through benthic release panels, potentially reducing unwanted catches by around 50%. However, uptake of these measurers is not known.

A number of areas are closed to fishing at certain times of the year, e.g. the Trevose box, an area of sea around 11,400 square miles extending from Trevose head in Cornwall to the Gower peninsular in South Wales from January - March. This is the spawning period for a number of demersal stocks, so while it is primarily intended to reduce catches of spawning cod, other stocks are likely to benefit.

Beam trawling can have significant habitat impacts, although it is mainly used on common fishing grounds and therefore stays away from more sensitive areas. It can affect benthic species such as sponges and corals. There are a number of MPAs in UK and EU waters, some of which are designated to protect benthic features. If those MPAs were found to be subjected to bottom trawling, MCS would consider it a default red rating unless there is evidence (e.g. environmental impact assessment) indicating the activity does not damage the integrity of the site.

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)
Halibut, Pacific
Megrim
Plaice
Sole, Dover sole, Common sole
Sole, Lemon
Turbot (Caught at sea)
Turbot (Farmed)

References

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 https://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1554387217276&uri=CELEX:32019R0472 [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/ices.pub.4982. Available at http://www.ices.dk/sites/pub/Publication%20Reports/Expert%20Group%20Report/Fisheries%20Resources%20Steering%20Group/2019/WGCSE/01_WGCSE_2019.pdf [Accessed on 16.07.2019].

ICES. 2019. Plaice (Pleuronectes platessa) in divisions 7.f and 7.g (Bristol Channel, Celtic Sea). In Report of the ICES Advisory Committee, 2019. ICES Advice 2019, ple.27.7fg, doi: 10.17895/ices.advice.4800. Available at http://ices.dk/sites/pub/Publication%20Reports/Advice/2019/2019/ple.27.7fg.pdf [Accessed on 15.07.2019].

Seafish, 2018. RASS Profile: Plaice in the Celtic Sea, Beam trawl. Available at https://www.seafish.org/risk-assessment-for-sourcing-seafood/profile/plaice-in-the-celtic-sea-beam-trawl [Accessed on 16.07.2019]