Dab

Limanda limanda

Method of production — Caught at sea
Capture method — Seine net
Capture area — North East Atlantic (FAO 27)
Stock area — North Sea, Skagerrak and Kattegat
Stock detail — IV, IIIa
Picture of Dab

Sustainability rating two info

Sustainability overview

Dab is mainly a bycatch species in bottom trawl fisheries for North Sea plaice and sole. Dab are mostly discarded due to their low commercial value and poor market demand, with discard rates in the order of 90%. As a relatively abundant species, dab is potentially a more sustainable alternative to longer-lived and more vulnerable and overfished flatfish species, such as plaice. Avoid eating immature fish below the size at which they breed (20-26cm) and fresh (not previously frozen) fish caught during or prior to the breeding season (April - June).

Biology

Dab is a widespread demersal species on the Northeast Atlantic shelf and distributed from the Bay of Biscay to Iceland and Norway, including the Barents Sea and the Baltic. It is one of the most abundant demersal species in the North Sea, with its centre of distribution in the Southern North Sea. Dab is a right-eyed flatfish (both eyes are on the right side of the body) related to the plaice, flounder and sole. It can reach a length of about 40 cms and an age of 10-12 years. Spawns in January to August, earliest off Britanny and southern England, later in the North Sea (April to June) and in the Barents Sea (June-July). In the Baltic Sea they spawn in April-August. In the North Sea the males become sexually mature at 2-3 years when 10-20 cms long, the females at 3-5 years when 20-25 cms. Because of its sedentary nature, dab has proved to be a valuable indicator in eco-toxicological studies.

Stock information

Stock Area

North Sea, Skagerrak and Kattegat

Stock information

Distributed throughout the northeast Atlantic, dab is an abundant fish on shallow, sandy grounds off coasts of northern Europe. Dab is considered an under-utilised species. Under-utilised species are ones that fishermen don't catch their full quota of, or they catch them but then discard the fish because no one wants to buy them. CEFAS have compiled a list of these species using quota and discard information, expert advice and local knowledge and chose around 50 under-utilised species to study. To determine their sensitivity to over-fishing CEFAS has developed a system, the Relative Life History Sensitivity Analysis, to study the risk. It uses biological information like growth and breeding strategies to see how increased fishing pressure might damage each species. They then ranked the species by how tolerant they are to being over-fished. For a full list of the species that are most under-utilised AND most tolerant of over-fishing and therefore the best ones for consumers to consider choosing see www.cefas.defra.gov.uk/our-science/fisheries-information/marine-fisheries/under-utilised-species.aspx. The state of the stock and fishery relative to MSY proxy reference points is known however the assessment is indicative of trends only. The biomass (SSB) has been increasing since 2006. Total mortality (Z) has declined since 2003. Recruitment (R) showed an increasing trend until 2014, but has declined in the latest two years of the time-series. ICES advises that when the precautionary approach is applied, catches should be no more than 64 452 tonnes in each of the years 2018 and 2019. If discard rates (90%) do not change from the average of the last three years (2014-2016), this implies annual landings of no more than 6116 tonnes.

Management

There are no specific management objectives for this species. There was a joint total allowable catch (TAC) for dab and flounder in the North and Norwegian Seas. However, scientists were concerned that management of dab and flounder under a combined species TAC prevented effective control of single species exploitation rates and could potentially lead to over fishing of either species. ICES was further concerned that TACs might not be an appropriate management tool for bycatch species such as dab. ICES was therefore requested to assess the risk to the stocks of dab and flounder of having no catch limits for these stocks. ICES have advised that the risk of having no catch limits for the stocks of dab and flounder is currently considered to be low and not inconsistent with the objectives of the Common Fisheries Policy as long as dab and flounder remain largely bycatch species, with the main fleets catching dab and flounder continuing to fish the target species (plaice and sole) sustainably within the FMSY ranges provided by ICES. Consequently, the combined TAC for dab and flounder for Subarea 4 and Division 2.a was removed by the European Commission Council Regulation (EU) 2017/595 in March. Minimum Landing Sizes are stipulated by local byelaws. Cornwall, North Wales and Northwestern Inshore Fisheries Conservation Authorities (IFCAs) currently offer the best local management.

Capture Information

Seine netting causes less damage to the seabed than trawling. It is also less fuel intensive and the catch of a better quality, as it is not bumped along the seabed as with trawling. Dab catches are generally discarded based on the availability of target species and market price; dab has a low commercial value. However, the limited survival data available suggests that dab have a high survival rate when returned to the sea (77-88% depending on trawl duration and processing time). There is no minimum landing size specified for dab in EU waters, therefore there is potential for landing of immature fish. In the Cornwall and North Western & North Wales Sea Fisheries Districts, landing dab below 15 cm is prohibited. Dab mature at a range of sizes between 13-29 cm, but the average size of a mature Dab is is 26 cm.

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
Turbot (Farmed)

References

EU. 2017. COUNCIL REGULATION (EU) 2017/595 of 27 March 2017 amending Regulation (EU) 2017/127 as regards certain fishing opportunities. Official Journal of the European Union, L 81/6. http://eur-lex.europa.eu/legalcontent/EN/TXT/PDF/?uri=CELEX:32017R0595&from=EN
ICES. 2017. Advice http://ices.dk/sites/pub/Publication%20Reports/Advice/2017/2017/dab.27.3a4.pdf
ICES. 2017a. EU request on a combined dab and flounder TAC and potential management measures besides catch limits. In Report of the ICES Advisory Committee, 2017. ICES Advice 2017, sr.2017.04.