John Dory

Zeus faber

Method of production — Caught at sea
Capture method — Gill or fixed net
Capture area — North East Atlantic (FAO 27)
Stock area — North East Atlantic
Stock detail — 1 to 9
Picture of John Dory

Sustainability rating four info

Sustainability overview

Updated: July 2019.

Very little is known about John Dory, and there has been no formal stock assessment for over 10 years. While there is no information about the status of the stock, in the UK there is no targeted fishery for this species, and it is only caught as unavoidable bycatch. It has previously been identified as an underutilised species by CEFAS. As long as this remains the case, MCS considers that fishing pressure is not of concern. There are no management measures in place (e.g. minimum size or catch limit), and therefore the stock is not protected from overfishing. John Dory are normally caught as part of a mixed fishery targeting hake, anglerfish and megrim. Due to the John Dory’s unusual shape, few gear adaptations can feasibly be implemented to increase selectivity. Both demersal trawls and gill nets can catch endangered, threatened and protected species and interactions with these species must be recorded. Bycatch rates of harbour porpoise in the Celtic Seas ecoregion are highly variable and data is limited, but a recent ICES report (Sept 2018) indicates that modelled total catch rates are above conservation (ASCOBANS) reference points.

Avoid eating small John Dory smaller than 35cm, which won’t haven’t had the opportunity to reproduce yet.


John Dory has a distinctive appearance with its laterally compressed body and large dark “eyespot”. John Dory also known as dory or St Peter’s fish is an ambush predator. When it approaches its prey, it opens its huge mouth and sucks it in.

John Dory are found in the Eastern Atlantic from Norway to southern Africa, as well as in the Mediterranean and the Black seas, and the western Pacific and Indian oceans. They are found at depths from 20 m to over 400 m.

John Dory usually lives a solitary life or is found in small schools in inshore waters. They become sexually mature at an age of around 4 years and at a length of 29-35cm. Spawns in June-August off the coasts of southern England, earlier in the Mediterranean. It can reach lengths of 70cm and has a maximum age of about 12 years. John Dory are a relatively vulnerable species.

Stock information

Criterion score: 0.5 info

This is a severely data-limited stock, with no formal stock assessment for over 10 years. While there is no information about the status of the stock, in the UK there is no targeted fishery for this species, and it is only caught as unavoidable bycatch. As long as this remains the case, MCS considers that fishing pressure is not of concern. This species has medium resilience to fishing pressure.

Little is known about John dory. It is a widely distributed species throughout the world, but there are no formal stock assessments or management measures in place. In at least one part of its range, off Mauritania, the species experienced a rate of decrease in biomass of 7% annually over a period of 24 years. It continues to be heavily exploited off Mauritania. In the UK, however, a 2011 report assessed it as an ‘underutilised’ species.

John dory is generally found shallower than 200m, and shows preference for warmer temperatures. Consequently, it is considered a climate change ‘winner’, with increasing sea temperatures resulting in more suitable habitat being available. Their distributions are shifting northwards and fishers have recently seen more of more of them in the North Sea.

This is not a targeted species, occurring instead as bycatch in demersal fisheries. FAO data indicates that catches of this species in the North East Atlantic (NEA) peaked in 2010 at 5,100 tonnes and then declined to 3,131t in 2016 - the lowest catch since 2002. According to the Marine Management Organisation, 225.5 tonnes of John Dory were landed by UK vessels in 2017, about half of which was caught in the western English Channel. Most of the rest was caught to the west of that, in the Bristol Channel, Celtic Sea and south and west of Ireland. It is possible that the fish in these areas constitute one stock, with another off the Iberian coast, but stock structure is unknown. 80-90% of the catch over the past five years has been by demersal trawl or seine, and most of the rest (around 10%) by beam trawl. As with the wider NEA fishery, recent UK catches have declined (from 308 tonnes in 2014). This could be caused by a number of factors.


Criterion score: 0.75 info

There are no management measures in place, and therefore the stock is not protected from overfishing. There is too little scientific evidence to inform effective management, even if measures were to be developed.

In the English Channel, the mean length of first maturity has been estimated at 26cm in males and 34.5cm in females - around age 5. This species is usually solitary and spawns in the spring in the northeast Atlantic. It is a demersal species, and feeds on a variety of fish, cephalopods and crustaceans.

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

John Dory are normally bycaught as in mixed demersal fisheries targeting hake, anglerfish and megrim. Almost all (99%) of catches are made between 20m and 160m. Bottom trawling can have habitat impacts and catch vulnerable species. John Dory live on soft and muddy substrates, close to rocks. To mitigate the impact of capture on the species, rockhoppers are advised on bottom trawling gear. Due to the John Dory’s unusual shape, few gear adaptations can feasibly be implemented to increase selectivity. There are general adaptations used in the fishery on beam trawl, demersal trawl and gill nets, though these are not specific to the species.

Gillnets and fixed nets can be very size selective, but can bycatch species such as sharks, cetaceans and other marine mammals. Reports indicate that there is concern regarding the bycatch of cetaceans, particularly harbour porpoise, by gillnets. One of the areas of most concern is off the South West of England, where areas of higher gillnet fishing effort coincide with areas of larger harbour porpoise populations. However, these reports are based on highly uncertain data which cannot indicate the likelihood of bycatch either causing populations to decline or preventing populations from recovering. Progress on this issue is being made in some areas, with Defra leading work to improve monitoring and mitigation of cetacean bycatch (“Hauling Up Solutions”). A pilot project trialling self-reporting of bycatch is taking place in Cornwall, potentially backed up by electronic monitoring and VMS in time, and trialling the use of pingers and other mitigation technologies, which are known to deter harbour porpoise from entanglement in nets. MCS is pleased to see this progress, but notes that if catch rates of harbour porpoise do not show a decrease then scoring of this capture method may be affected. Because of gillnets’ durability (they are made of nylon), if lost, they can continue to fish for several weeks before becoming tangled and bundled up, a phenomenon known as ‘ghost fishing’. However, static nets, as with all gear, represent an investment by fishermen, and therefore there are incentives to avoid losing or damaging gear.


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.

Basa, Tra, Catfish or Vietnamese River Cobbler
Cod, Atlantic Cod
Cod, Pacific Cod
Coley, Saithe
Hake, European
Monkfish, Anglerfish, White
Pollock, Alaska, Walleye
Spurdog, Spiny Dogfish, Dogfish, Rock Salmon or Flake
Sturgeon (Farmed)


FAO, 2018. Fishery and Aquaculture Statistics. Global capture production 1950-2016 (FishstatJ). In: FAO Fisheries and Aquaculture Department [online]. Rome. Updated 2018. Available at [Accessed on 18.07.2019].

Froese R. and Pauly D. (Editors), 2019. Zeus faber Linnaeus, John dory. Available at [Accessed on 18.07.2019].

Iwamoto, T. 2015. Zeus faber. The IUCN Red List of Threatened Species 2015: e.T198769A42390771. Available at [Accessed on 18.07.2019].

Maravelias, C.D., Tsitsika, E.V., Papaconstantinou, C., 2007. Seasonal dynamics, environmental preferences and habitat selection of John Dory (Zeus faber). Estuarine, Coastal and Shelf Science, 72:4, pp.703-710.

Marine Management Organisation, 2018. UK Sea Fisheries Statistics 2017: 2013 to 2017 UK fleet landings by ICES rectangle. Available at [Accessed on 18.07.2019].

Pinnegar, J. 2017. Fisheries and aquaculture climate science: Potential impacts, adaptation and mitigation - overview of current scientific knowledge and cutting-edge developments. Presented to the Seafish Common Language Group, June 2017, London, UK. Available at: [Accessed on 18.07.2019].

Project Inshore. 2013. John dory: Western Approaches (VIIe-j VIII a,b): gill net. Available at:

Fox C.J., Valcic L. and Veszelovszki A. 2015. Evidence Gathering in Support of Sustainable Scottish Inshore Fisheries: A Pilot Study to Define the Footprint and Activities of Scottish Inshore Fisheries by Identifying Target Fisheries, Habitats and Associated Fish Stocks. Published by MASTS. 190pp. ISBN 978-0-9934256-4-6

Jin, D. et al. 2014. An empirical analysis of portfolio management as a tool for implementing ecosystem-based fishery management. Available at:

ICES. 2012. ICES Implementation of Advice for Data-limited Stocks in 2012 in its 2012 Advice. ICES CM 2012/ACOM 68. 42 pp.

ICES. 2013. Report of the Working Group on Elasmobranch Fishes (WGEF), 17-21 June 2013, Lisbon, Portugal. ICES CM 2013/ACOM:19. 649 pp.