Sole, Dover sole, Common sole

Solea solea

Method of production — Caught at sea
Capture method — Demersal otter trawl
Capture area — North East Atlantic (FAO 27)
Stock area — Celtic Sea South, southwest of Ireland
Stock detail — 7h-k
Picture of Sole, Dover sole, Common sole

Sustainability rating three info

Sustainability overview

Updated: July 2019.

This is a data limited stock, and trends are used to indicate its state and provide proxies for MSY reference points. It is estimated that biomass is below the proxy for MSY BTrigger, but above its lower limit (Blim, at which the ability of the stock to reproduce may be compromised). Fishing pressure is within sustainable limits (below FMSY). The main management measure for this stock is an annual Total Allowable Catch, but scientific advice is that effort limitations in key areas would be more effective. Sole is a small (but valuable) component (up to 5%) of the landings in this mixed fishery, which also has a bycatch of the highly vulnerable plaice stock.

Biology

Sole is a right-eyed flatfish (eyes on the right hand side of the body) and belongs to the family of flatfishes known as Soleidae. It spawns in spring and early summer in shallow coastal water, from April to June in the southern North Sea, from May-June off the coast of Ireland and southern England, and as early as February in the Mediterranean. Common sole become sexually mature at 3-5 years, when 25-35cm long, the males being somewhat smaller than the females. It can attain lengths of 60-70cm and weigh 3kg.The maximum reported age is 26 years. Sole is a nocturnal predator and therefore more susceptible to capture by fisheries at night than in daylight.

Stock information

Criterion score: 0.5 info

Stock Area

Celtic Sea South, southwest of Ireland

Stock information

This stock is data limited, and the assessment is indicative of trends only. The spawning-stock biomass (SSB) shows an increasing trend since the mid-2000s until 2015, but has now declined and in 2018 was 1.01 - below MSY Btrigger proxy (1.11) but above Blim (0.8). Fishing mortality has been around FMSY over the last decade and in 2018 was estimated to be 0.47 - below FMSY proxy (0.66). Recruitment has fluctuated without trend, but the 2018 recruitment was the lowest on record.

ICES advises that when the precautionary approach is applied, catches in 2020 should be no more than 213 tonnes. This year’s advice has decreased by 32% when compared to last year’s advice, because of the decrease in the biomass index, and the application of the precautionary buffer (which is applied when the stock size is below BTrigger).

The TAC is set for divisions 7.h,j and k, but some data are unavailable for 7.h, so the assessment is performed for 7.jk only. It is likely that the sole from Division 7h are part of the divisions 7e or 7fg stocks. This stock is scheduled to be benchmarked in 2020.

Management

Criterion score: 0.5 info

This stock is covered by the EU’s Western Waters Multi Annual management Plan (MAP), which stipulates that when the FMSY ranges are not available, as in the case of this data-limited stock, the precautionary approach should be applied. While there is concern for the stock size, fishing pressure below Maximum Sustainable Yield.

From 2016 the landings obligation was phased in for this stock, and discards are considered to be negligible. Between 2013 and 2018, TACs averaged 170% of the scientifically advised catches (around 230 tonnes), while landings averaged 120% of the advice. However, constraining the landings by TAC will not constrain the catches. Because sole are caught in spatially distinct areas, restricting effort in these areas will be more effective than limiting landings.


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: 0.5 info

In 2018, 296 tonnes of sole were landed. Of this, otter trawl accounted for 54%, and beam trawl for 43%. The assessed part of the fishery focusses mainly on division 7j, where Irish vessels operate close to shore on sandy grounds off the southwest of Ireland. Sole is a small (but valuable) component (up to 5%) of the landings in this mixed fishery.

The minimum conservation reference size is 24cm for sole, and the minimum mesh size is 80 mm for trawl gears. This leads to bycatch of plaice, which has an MCRS of 27cm.

Beam trawling, especially using chain-mat gear, is known to have significant impact on seabed and benthic communities. Whilst discards of sole are considered negligible in the fishery, there is discarding of non-commercial species and commercial species of unmarketable size. Some beam trawlers are experimenting with benthic drop-out panels that release about 75% of benthic invertebrates from the catches. Full square mesh codends are being tested in order to reduce the capture of benthos further and improve selectivity of gadoids (cod and whiting etc.).

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. Sole (Solea solea) in divisions 7.h-k (Celtic Sea South, southwest of Ireland). In Report of the ICES Advisory Committee, 2019. ICES Advice 2019, sol.27.7h-k, https://doi.org/10.17895/ices.advice.4806. Available at http://ices.dk/sites/pub/Publication%20Reports/Advice/2019/2019/sol.27.7h-k.pdf [Accessed on 16.07.2019].

Seafish, 2019. RASS Profile: Sole in the Southwest of Ireland (Divisions 7h-k), Demersal otter trawl. Available at https://www.seafish.org/risk-assessment-for-sourcing-seafood/profile/sole-in-the-southwest-of-ireland-divisions-7h-k-demersal-otter-trawl [Accessed on 16.07.2019]