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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 - England
Stock detail - Lyme Bay
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 the most sustainable choice of fish to eat. Click on the rating icon above to read more and on the alternatives tab below to find more sustainable fish to eat.

Sustainability overview

The Lyme Bay Designated Area (Fishing Restrictions) Order 2008 (SI 2008/1584) affords protections to an area in Lyme Bay which includes a substantial part of the Lyme Bay and Torbay candidate Special Area of Conservation (cSAC). The order prohibits dredging for shellfish and demersal trawling in the designated area. 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
Since 2009 Scallops (Pecten maximus) have been the most valuable fishery to England. In comparison to other commercial species, relatively little is currently known about the state of scallop stocks as no formal stock assessment is carried out. 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. The Centre for Environmental, Fisheries and Aquaculture Science (Cefas) is working to improve understanding of the status of scallop stocks and research being carried out by Bangor University at the moment will better inform stock assessment through increased understanding of sub-stocks. Launched in 2011 the Cefas red bag scheme is a means of obtaining sufficient biological information regarding scallop stocks with which to run stock assessments. 7 sampling areas were defined on the basis of knowledge regarding fisheries and biology. To establish whether a stock is being exploited sustainably, scientists looked at the population age structure to see what proportion of individuals are surviving to maturity and the overall rate at which individuals are dying. To obtain this information, individual scallops from the fishery needed to be sampled to determine their age and relative abundance. Although estimates of mortality can be made with only one year's worth of data, these will be very approximate. The accuracy of such estimates is greatest when data are collected over a long timescale. The Red Bag scheme is therefore a long-term programme that aims to provide the data required for regular stock assessments. These can then be used by fisheries managers to help plan for a sustainable scallop fishery into the future. However, a wider participation is needed from the industry to make this scheme a success. The data collected to date has permitted a preliminary investigation into the potential exploitation rates experienced by two of the stock areas (Inshore Cornwall and Lyme Bay). There were insufficient samples to attempt any form of assessment in the other areas. Analysis of the age structure from the landings indicates that fishing activity is unlikely to be below a rate associated with Maximum Sustainable Yield.


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 is capped through restrictive licensing. All vessels are required to carry Vessel Monitoring Systems (VMS). VMS provides a fisheries managment agency with accurate information about the location and activity of regulated fishing vessels and is a cost effective tool for the successful monitoring, control and surveillance (MCS) of fisheries activities. A large part of Lyme Bay is protected from mobile gear. For example the use of mobiles gear is prohibited under the Wildlife &Countryside Act to protect the pink sea fan. Lyme Bay is also a candidate Special Area of Conservation (cSAC) and consequently restricitons on the use of mobile gear will apply. A MMO report (2012) on a study to evaluate the operational effectiveness of succorfish or inshore VMS as a managment tool to allow controlled fishing access to a marine protected area (MPA) whilst protecting its sensitive features concluded that provided a collaborative approach to the management of the MPA network between the regulators and the regulated can be achieved there is the potential to allow access to commercially important fishing areas where opportunities occur, rather than blanket closures, while also protecting sensitive marine habitats. This in turn can help to reduce the effects of displacement of fishing activity from one area to another.

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.

Read more about capture methods

References; Lyme Bay and Torbay cSAC, VMS trial final report, 24 July 2012;

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