Scottish scallop stocks: results of 2023 stock assessments

15th October 2025

The commercial dredge fishery for the king scallop (Pecten maximus) in Scotland began in the 1930s as a seasonal (winter) fishery prosecuted by approximately 10 small inshore vessels in the Clyde.

The fishery developed rapidly during the 1960s and 1970s, expanding northwards around the rest of the west coast of Scotland, Shetland and the northeast Scottish coast. It is now a year-round activity with some fishing grounds up to 40 miles from the coast.

In 2023, total landings into Scotland were in excess of 7,000 tonnes, which with a first-sale value of over £19 million made the fishery one of the most important shellfish fisheries in Scotland (Scottish Sea Fisheries Statistics 2023). Around 90% of the landings came from dredge fisheries and most of the remainder was taken by commercial divers.

The scallop dredge fleet consists of vessels ranging in size from under 10 m to over 30 m in length. The smaller vessels tend to work locally in inshore waters while the larger vessels are more nomadic and may move between fishing grounds around the coast of Scotland and the rest of the UK.

Management framework and regulations

Scottish scallop fisheries are not subject to TAC regulations. There are measures to restrict effort in certain areas, in addition to a variety of national regulations. Under the Western Waters effort regime (retained EU legislation) which applies to all UK waters except the North Sea, effort limits are applicable to all vessels over 15 m in length, including those fishing for scallops. The limits for UK vessels are 1,974,425 kW days for ICES (International Council for the Exploration of the Sea) Sub-areas 5 and 6, and 3,315,619 kW days for Sub-area 7 (Council Regulation (EC) No. 1415/2004).

The minimum conservation reference size (MCRS) is specified through UK and Scottish legislation. Scottish legislation implemented in mid-2017 increased the MCRS to 105 mm for UK vessels in all areas around Scotland excluding the Irish Sea and Shetland (The Regulation of Scallop Fishing (Scotland) Order 2017). In the Irish Sea north of 52°30'N, the MCRS is 110 mm while around Shetland it is 100 mm.

All vessels fishing commercially for scallops in Scotland are required to have a licence and no new licences are granted. Vessels over 10 metres in length also require special permission (a scallop entitlement) to fish for king scallops using towed mechanical dredges. Under new legislation introduced in June 2024 (Sea Fisheries (Remote Electronic Monitoring and Regulation of Scallop Fishing) (Scotland) Regulations 2024), all scallop dredge vessels fishing within Scottish waters are required to have a functioning REM (Remote Electronic Monitoring) system. This legislation also consolidated the previous scallop dredge restrictions such that: a maximum of eight dredges per side is allowed in Scottish inshore waters (out to six nautical miles); a maximum of ten dredges per side is allowed in the six to 12 mile zone provided a vessel has a recent track record of operating nine or ten dredges per side (otherwise eight dredges is the maximum); and 14 per side in any other part of the Scottish zone (out to 200 nautical miles).

In addition, a number of areas around Scotland are subject to seasonal (e.g. Luce Bay) or other temporal closures (e.g. a weekend ban in the Clyde) and there are also a number of marine protected areas (MPA) in which dredge fishing is banned (e.g. South Arran MPA, Wester Ross MPA) (Scottish Government, 2016).

Shellfish fisheries (including the dredge fishery for scallops) around Shetland are managed under a Regulating Order (The Shetland Islands Regulated Fishery (Scotland) Order 1999) by the Shetland Shellfish Management Organisation (SSMO). Scallop vessels at Shetland are limited to a maximum of ten dredges in total (within six nautical miles) and to fishing within the hours of 0600 to 2100. As a condition of the licences issued by the SSMO, fishermen are required to provide detailed records of landings and fishing effort (Leslie et al., 2009). There are also a number of areas closed to dredge fishing.

The Scottish itinerant fleet of large dredge vessels regularly fish in the Irish Sea in the waters around the Isle of Man (ICES division 7.a), and also further afield in the English Channel (ICES division 7.d). Their activity is regulated in these areas by local restrictions which include gear restrictions, curfews and a series of permanent and temporary closed areas.

Read the full report at
https://www.gov.scot/publications/scottish-scallop-stocks-results-2023-stock-assessments/pages/2/