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 — FIP Stage 2
Picture of Scallop, King, scallops

Sustainability rating three info

Sustainability overview

The Lyme Bay Designated Area is a protected area 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.

The inshore scallop stocks are currently undergoing assessment. Therefore, route 2 deems the stock to have a medium vulnerability. The Inshore Fisheries Conservation Authority operates a closed season from 1 July to 30 September, a vessel size limit of 15.24m, a ban on night fishing, gear restrictions (dredge limit of 12 spring-loaded dredges) and a large closed area to protect a vulnerable area of mudstone reef (Lyme Bay Reef Marine Protected 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

Criterion score: 0.5 info

Stock Area


Stock information

The Lyme Bay scallop fishery lies within the West English Channel which is one of the biggest scallop fishing areas in the UK.

No formal stock assessment has been carried out through studies are currently being conducted to determine more about the local stock. Data-limited indicators show that landings, effort and productivity decreased in the English Channel between 2012 and 2015. However, the CEFAS Red Bag scheme concluded that The Lyme Bay stock appears to be fished at a much lower rate than other stocks such as the Inshore Cornwall stock. Additionally, the fishing mortality reference point (FMSY) estimate for the Lyme Bay stock was deemed higher than for other stocks such as the Cornwall stock, because of the higher growth rate of the Lyme Bay scallop populations. Data indicate that the level of fishing is unlikely to be below a rate associated with Maximum Sustainable Yield. However, these studies were not able to conclude a state of the stock.


Criterion score: 0.5 info

There is strong management in the Lyme Bay fishery to protect the stock. The Inshore Fisheries Conservation Authority operates a closed season from 1 July to 30 September, a vessel size limit of 15.24m, a ban on night fishing, gear restrictions (dredge limit of 12 spring-loaded dredges) and a large closed area to protect a vulnerable area of mudstone reef (Lyme Bay Reef Marine Protected Area). 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 management 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 mobile gears is prohibited under the Wildlife and Countryside Act to protect the pink sea fan. Lyme Bay is also a candidate Special Area of Conservation (cSAC) and consequently restrictions on the use of mobile gear will apply.

Capture Information

Criterion score: 0.25 info

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 ban on night fishing protects invertebrates (as they tend to be active at night).

The Inshore Fisheries Conservation Authority (IFCA) operates a closed season from 1 July to 30 September. 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 IFCA.

Between 6 and 12 miles the 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.


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Southern IFCA. 2017. Byelaws. Available at:

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Howarth, L. M. & Stewart, B. D. 2014. The dredge fishery for scallops in the United Kingdom (UK): effects on marine ecosystems and proposals for future management. Report to the Sustainable Inshore Fisheries Trust. Marine Ecosystem Management Report no. 5, University of York, 54 pp

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MMO. 2017. Evidence requirement R046: Impact of external pressures on fisheries in Western Waters (area 7). Available at:

Sciberras, M., Hinz, H., Bennell, J., Jenkins, S., Hawkins, S., Kaiser, M., 2013. Benthic community response to a scallop dredging closure within a dynamic seabed habitat. Mar. Ecol. Prog. Ser. 480, 83-98. doi:10.3354/meps10198

Seafish. 2017. Seafish Economic Analysis: UK king scallop dredging sector 2008-2016. Edinburgh, UK. Available at: