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Scallop, King, scallops

Pecten maximus

Method of production - Caught at sea
Capture method - Dredge
Capture area - North East Atlantic (FAO 27)
Stock area - UK
Stock detail - All Areas
Certification -
Fish type - Shellfish

Sustainability rating Click for explaination of rating

This fish, caught by the methods and in the area listed above, is not a good choice of sustainable fish to eat and should be only eaten very occasionally. Click on the rating icon above to read more and on the alternatives tab below to find more sustainable fish to eat.

Sustainability overview

When buying dredged scallops the best choices are from fisheries where: there are comprehensive closures to protect sensitive habitat e.g. Lyme and Cardigan Bay; restrictions on the numbers of dredges per side e.g. In Lyme Bay and inshore waters of Cornwall and Devon the restriction is to 6 dredges per side, each of 85mm; Vessel Monitoring Systems (VMS) is in use to monitor access; and from areas where there are seasonal closures to protect stocks (e.g. Wales and S Devon). Some fishermen are also signed up to the Scallop Good Practice Guide. See for more information. Dredged scallops from Shetland are certified as an environmentally responsible fishery by the MSC and are another more sustainable choice for eating dredged scallops. In some areas of the UK, e.g. Isle of Man, Devon, Isles of Scilly, Dorset, Hampshire, Isle of White Cornwall and Cardigan Bay, Wales, byelaws restrict dredging in large areas, or impact on the permitted design and limit the number of dredges per side of the boat for example. There are also comprehensive spatial restrictions on scallop dredging to protect Special Areas of Conservation, particularly in the Isles of Scilly, Cornwall, Devon, Dorset, inshore Welsh waters, Hampshire, Isle of White, and inshore Sussex. Some vessels are using Inshore Vessel Monitoring Systems (VMS) known as Succorfish to allow limited access fishing in small, less sensitive sections of protected areas such as in Wales and Lyme Bay. Avoid eating scallops below their legal minimum landing size and during their breeding season (April to September).


King scallops are bivalve molluscs found in a range of depths from shallow waters in sea lochs to over 100m. They inhabit sandy-gravel and gravel seabeds. They have 2 shells or valves, the upper being flat, and the under or right valve, cup shaped. They are hermaphrodites (i.e. both male and female) and become fully mature at about 3 years old (80 to 90mm in length). Spawning occurs in the warmer months, from April to September. The species can grow to more than 20cm in length and live for more than 20 years, although average sizes are in the range of 10-16cm.

Stock information

Stock area

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Stock information
There are 4 main scallop fishing areas in UK waters: the English Channel, Irish Sea (Isle of Man), west of Scotland and the Moray Firth. In comparison to other commercial species, relatively little is currently known about the state of scallop stocks and no formal assessment of stocks is carried out in England and Wales. Although the Centre for Environment Fisheries and Aquaculture Science (Cefas) and the University of Bangor are developing surveys to improve understanding of the status of scallop stocks and better inform stock assessment through increased understanding of sub-stocks. There are signs of decline in some parts of the UK, but scientific interpretations of landings data suggest the majority of stocks in English waters is currently relatively healthy. This is especially true in the English Channel, an important scalloping area, where landings per unit effort has increased significantly in recent years. Marine Scotland defines 8 scallop management areas for Scottish waters, and undertakes both fishery and fishery-independent research as the basis for stock assessments. Similarly, the Irish Government introduced improved data collection for fisheries management purposes in the southern Irish Sea scallop fishery, including fishery independent surveys and habitat mapping. Formal stock assessment or quota management have not yet been implemented. Lack of coordination between various governments involved in the management of scallops in UK waters appears to be a major limitation to the improvement of this fishery.


Approximately 95% of scallops are caught by vessels using dredges, with a much smaller amount harvested by divers. Approximately 60% of these scallops are exported to European Countries, and France in particular, where British scallops are held in high regard. Commercial scallop dredging has taken place in the waters surrounding England for over 30 years and has developed into one of the country's most valuable fisheries. A stakeholder-based National Scallop Group, coordinated by Seafish, was established in 2008 to address industry issues, including environmental impacts. There are no quotas set for this species. Effort in these fisheries i.e. UK fleet capacity is capped through restrictive licensing. There are no seasonal closures in UK waters generally to protect stocks. For king scallops, current European Union (EU) legislation specifies a minimum landing size of 100 Mm shell length, except in the English Channel and Irish Sea where the limit is 110 mm. Generally, the maximum number of dredges is restricted to 6-8 per side within 6 nautical miles of the shore around the UK. Between 6 and 12 miles the fishery is less restricted, with a maximum of 8 dredges per side allowed in English waters, And 10 per side in Scottish waters. Outside the 12 mile limit, up to 14 dredges are permitted in Scotland, but in England there are no limits. As a result, some boats fish more than 20 per side, with dredge number only being limited by the size and horsepower of the fishing vessels. Scallop fisheries in Wales are more strictly regulated than Anywhere else in the UK. No scallop fishing is allowed within 1 mile of the shore and dredging between 1 and 3 miles is only permitted by boats less than 10 m in length and towing no more than 6 dredges in total. Within 3-6 miles and 6-12 miles respectively, totals of 8 and 14 dredges are allowed. Furthermore, all scallop dredgers in Wales must carry and use working satellite Vessel Monitoring Systems (VMS). Throughout Northern Irish waters out to 12 miles there is a maximum limit of 6 dredges per side. Finally, within Manx (Isle of Man) waters, dredges are limited to 25 feet total width out to 3 miles, and 40 feet between 3 and 12 miles. VMS is also compulsory around the Isle of Man. Apart from these general regulations, various local authorities impose stricter rules in specific areas throughout the UK. For example, some Inshore Fisheries and Conservation Authorities (IFCAs) in England limit vessel sizes within their jurisdictions to 12-15 m in length. In addition, scallop dredging is banned within 3 miles of the shore in the Sussex IFCA district, and in an increasing number of European Marine Sites - Special Areas of Conservation (SACs) - in both England and Wales. For example, recent byelaws introduced by the Southern IFCA in England, who manage a total area of 670km2, ban the use of towed fishing gear (including scallop dredges) within 25% of their coastal waters ( Likewise, dredging is banned within the Cardigan Bay SAC in Wales ( and in 6 fishery exclusion zones around the Isle of Man a network of Marine Conservation Zones (MCZs) is currently being introduced in England and Wales through the UK Marine and Coastal Access Act and a network of Scottish Marine Protected Areas (MPAs) is currently being consulted on in Scotland through the Marine (Scotland) Act. However, it is still unclear how these designations will regulate fisheries.

Capture information

Scallop dredging is a significantly more damaging method of fishing compared to manual harvesting by divers. Dredging can cause considerable disturbance of the seabed leading to damage to important habitats and reduced biodiversity. The impact of dredging and of other towed gears on the seabed however is largely determined by how exposed the seabed is to natural disturbance i.e. wave action. Consequently less exposed areas such as those found in inshore waters are more vulnerable to the effects of dredging. These effects can however be mitigated by a combination of technical conservation and spatial protection measures such as permanent and rotational closures. A typical or standard scallop dredge, known as a Newhaven dredge, comprises a heavy steel frame, with a mesh net top and belly rings of interlocked steel forming the cod end. At the front of the dredge a toothed bar is present which penetrates the seabed, removing the recessed scallop and flipping it into the body of the dredge. Dredges are used in series, connected to a rigid wheeled bar and may have up to 20 dredges per bar. Typically two dredge-bar units will be deployed, one on either side of the vessel. Non-target species, such as echinoderms (starfish, urchins etc.), crabs and undersized scallops are often taken as bycatch or damaged in situ. When undamaged, undersize scallops can be returned live to the sea. A project to assess new dredge types - the ecodredge - with less invasive teeth and rollers instead of belly rings will commence shortly in the Moray Firth. Management measures drafted for Special Areas of Conservation (SACs) and Marine Coastal Zones (MCZs) are likely however to recommend no demersal towed gears in areas where the seabed habitat type is a protected or sensitive feature e.g. reef. There are also access restrictions in some areas for towed gear to protect nursery and spawning areas e.g. Start Bay. Closures have also been introduced in some areas e.g. Devon to reduce conflict between mobile gear including dredges and static gears such as pots and gill nets. The number of dredges is also limited by fisheries management legislation. Within 6 miles of the coast the number of dredges per bar is dictated by the local Inshore Fisheries Conservation Authority (IFCA). Between 6 and 12 miles the new harmonised English and Scallop Orders limit the number of dredges to 8 per side of the vessel. The gear mesh or ring size should be as selective as possible to allow juveniles to escape. The minimum landing size for scallop in EU waters is 100mm, except in the northern Irish Sea (Isle of Man), Eastern English Channel and Welsh waters where it is 110 mm.

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