Dover sole
Solea solea
What to check for
Location
Baltic Sea (West), Skagerrak and Kattegat (Subdivisions 20-24)
Technical location
Atlantic, Northeast, Baltic Sea, Skagerrak and Kattegat, Transition Area - Belt Sea, Transition Area - Sound
Caught by
Net (gill or fixed)
Rating summary
Updated: July 2020.
Spawning-stock biomass has increased slowly over the last five years and the stock is now in a healthy state and fishing pressure is within sustainable limits. Total Allowable Catches (TACs) have been reduced over the years, successfully reducing fishing pressure. In 2020, the TAC is not expected to be fully utilised. Discards of sole are low, at 4%, but bycatch and discarding of other species could be a concern. In the trawl fisheries, the Kattegat cod stock may be bycaught, which has a recommendation for zero catch owing to its very overfished state. Gill netting in the Baltic Sea is likely to be adversely affecting the critically endangered central Baltic Sea harbour porpoise population.
How we worked out this Rating
This stock is in a healthy state and fishing pressure is within sustainable limits. Spawning-stock (SSB) in the past five years has increased slowly and in 2019 is estimated to be at 2561 tonnes and above MSY Btrigger (2,600 tonnes). Fishing mortality (F) is below FMSY (0.23) and in 2020 is estimated to be 0.197. Recruitment was low from 2010-2015 but has increased since with good years in 2018 and 2019.
ICES advises that when the EU multiannual plan (MAP) for the North Sea and adjacent waters is applied, catches in 2021 that correspond to the F ranges in the plan are between 502 tonnes and 665 tonnes. According to the MAP, catches higher than those corresponding to FMSY (596 tonnes) can only be taken under conditions specified in the MAP, whilst the entire range is considered precautionary when applying the ICES advice rule.
Although this stock straddles the Baltic and the North Sea, it is managed under the EU multiannual management plan (MAP) for stocks in the North Sea and adjacent waters. A Total Allowable Catch (TAC) is in place but these have not been fully utilised, including in 2019 and preliminary information on Danish catches in the first quarter of 2020 are the lowest in the time series. The TAC of 533 tonnes for 2020 is assumed unlikely to be caught. The average discard ratio from 2014-2018 was 4%. Danish discard sampling at sea is carried out within EU programmes that began in 1995 in both Kattegat and Skagerrak.
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).
There is a directed gillnet fishery, mainly in Skagerrak, in spring and summer. Gillnets can be very size selective for the target fish but can be unselective at the species level for both non-target fish and for mammals, birds and turtles. Gillnets cannot be specifically targeted to give clean catches of cod 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.
References
EU. 2018. Regulation (EU) 2018/973 of the European Parliament and of the Council of 4 July 2018 establishing a multiannual plan for demersal stocks in the North Sea and the fisheries exploiting those stocks, specifying details of the implementation of the landing obligation in the North Sea and repealing Council Regulations (EC) No 676/2007 and (EC) No 1342/2008. Official Journal of the European Union, L. 179. 13 pp. Available at http://data.europa.eu/eli/reg/2018/973/oj. [Accessed on 22.07.2020].
ICES. 2020. Baltic Fisheries Assessment Working Group (WGBFAS). ICES Scientific Reports, 2:45. 632 pp. Available at http://doi.org/10.17895/ices.pub.6024. [Accessed on 22.07.2020].
ICES. 2020. Sole (Solea solea) in subdivisions 20- “24 (Skagerrak and Kattegat, western Baltic Sea). In Report of the ICES Advisory Committee, 2020. ICES Advice 2020, sol.27.20-24. Available at https://doi.org/10.17895/ices.advice.5854. [Accessed on 22.07.2020].
Seafish, 2019. RASS Profile: Sole in Skagerrak, Kattegat and the Belts, Demersal trawls. Available at https://www.seafish.org/risk-assessment-for-sourcing-seafood/profile/sole-in-skagerrak-kattegat-and-the-belts-demersal-trawls [Accessed on 22.07.2019].
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