# Scallop fishing
Scallop fishing is the commercial harvesting of wild scallops, mostly by dredges towed along the seabed: wild-capture scallop fisheries contributed 811,000 tonnes to global landings in 2019, of which 26,000 tonnes worth £60 million were landed in the UK alone.[1](https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0302225) Because most scallop species live on or recessed into the seabed, the vast majority are taken with towed gears such as dredges and trawls, which distinguishes the wild fishery from [scallop aquaculture](https://www.edgepedia.org/scallop-aquaculture).[2](https://www.sciencedirect.com/science/article/abs/pii/B9780444627100000183) The United States operates the largest wild scallop fishery in the world.[3](https://www.fisheries.noaa.gov/species/atlantic-sea-scallop/management)
| Key fact | Figure |
|---|---|
| Global wild scallop landings (2019) | 811,000 tonnes[1](https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0302225) |
| US Atlantic sea scallop landings (2023) | 27.4 million lb of meats, valued at $360 million[3](https://www.fisheries.noaa.gov/species/atlantic-sea-scallop/management) |
| UK king scallop landings | 14,000 t (1994) to 53,300 t (2012), a 281% rise[4](https://eprints.whiterose.ac.uk/id/eprint/79233/1/Howarth_and_Stewart_2014_Ecosystem_effects_management_of_UK_scallop_fisheries.pdf) |
| Bycatch share of a dredge tow | Non-target organisms 15–53% of total catch biomass; one review puts finfish bycatch of standard dredges at 2–11%[1](https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0302225) • [5](https://fisheryprogress.org/sites/default/files/documents_actions/Review_of_Alt_measures_scallopsv4_09032023.pdf) |
| Newhaven dredge teeth | 8–9 spring-loaded teeth, up to 11 cm long, spaced 8 cm apart, penetrating 3–10 cm into the seabed[4](https://eprints.whiterose.ac.uk/id/eprint/79233/1/Howarth_and_Stewart_2014_Ecosystem_effects_management_of_UK_scallop_fisheries.pdf) |
| Recovery of sensitive biogenic reefs after dredging | 10 or more years[6](https://archimer.ifremer.fr/doc/00586/69859/67754.pdf) |
| Canada Georges Bank 'a' biomass | Fell 56%, from 31,095 t (2023) to 13,570 t (2024)[7](https://open-science.canada.ca/handle/123456789/4026) |
## Major scallop stocks and fisheries
The US Atlantic sea scallop stock spans Georges Bank, southern New England, and the Mid-Atlantic, with a small [Gulf of Maine](https://www.edgepedia.org/gulf-of-maine) component assessed separately.[8](https://www.fishsource.org/fishery_page/1384) Per the 2020 stock assessment it was not overfished and not subject to overfishing.[3](https://www.fisheries.noaa.gov/species/atlantic-sea-scallop/management) The Canadian Georges Bank 'a' stock (SFA 27A) deteriorated sharply: median fully-recruited biomass fell 56% from 31,095 t in 2023 to 13,570 t in 2024, and 2024 recruit biomass of 1,391 t was 72% below 2023 and under the 1986–2023 long-term median of 3,428 t.[7](https://open-science.canada.ca/handle/123456789/4026)
[English Channel](https://www.edgepedia.org/english-channel) king scallops support a large international fishery: in 2021, landings were 13,745 t from the eastern English Channel (27.7.d) and 8,929 t from the western English Channel (27.7.e).[9](https://assets.publishing.service.gov.uk/media/682da6a8e9440506ee9538d1/SCE_assessment_report_2024_annexe.pdf) The eastern Channel 2022 assessment gave a provisional harvest rate of 19.5, just below the MSY proxy of 21.5, while Lyme Bay (7e) averaged a harvest rate of 53.2% over 2017–2020, twice the 21% MSY value, prompting closure measures.[10](https://assets.publishing.service.gov.uk/media/645364b5faf4aa000ce1327c/Decision_Document_Response_to_the_call_for_evidence_on_ICES_area_7d_king_scallop_closure.pdf) New Zealand scallop landings fell from 1,952 t to 526 t across the FAO reported series.[11](https://www.fao.org/fishery/static/Yearbook/YB2015_CD_Master/root/capture/b55.pdf)
## Gear: how scallops are caught
**Newhaven dredges** dominate the king scallop fishery: over 95% of UK king scallop landings are caught by these dredges, towed in sets on both sides of the vessel at 3–4 knots. Each dredge's opening carries a spring-loaded bar of 8–9 teeth, up to 11 cm long and spaced 8 cm apart, which penetrate 3–10 cm into the seabed depending on substrate.[4](https://eprints.whiterose.ac.uk/id/eprint/79233/1/Howarth_and_Stewart_2014_Ecosystem_effects_management_of_UK_scallop_fisheries.pdf) Regulations require 4-inch (10.2 cm) minimum rings in dredge gear on US Scallop Access Area trips, allowing smaller scallops and small marine life to escape.[3](https://www.fisheries.noaa.gov/species/atlantic-sea-scallop/management) • [12](https://federal.elaws.us/cfr/title50.part648.section648.59)
Capture efficiency is highly variable. UK assessments report 5–41% of legal-sized scallops caught depending on seabed and conditions,[4](https://eprints.whiterose.ac.uk/id/eprint/79233/1/Howarth_and_Stewart_2014_Ecosystem_effects_management_of_UK_scallop_fisheries.pdf) while an experimental study found dredges caught 51–56% of commercial-sized scallops on soft, flat, muddy sediments and were least efficient on firm ground.[13](https://doi.org/10.1139/f98-194) This disagreement between field experiments and fishery-wide estimates remains unresolved.
Queen scallops swim, so some gear exploits that behavior: a rubber lip on the gear stimulates [queen scallops](https://www.edgepedia.org/queen-scallop) to swim into the water column, where they are caught in a mesh belly bag; otter trawls and Newhaven-type dredges are both used.[14](http://sustainable-fisheries-iom.bangor.ac.uk/documents/government-reports/scallop/2009/BangorFisheriesReport_No8.pdf)
**Hand-diving** accounts for only around 2–4% of UK king scallop landings, limited to depths under 30 m, and targets the largest individuals, which contribute disproportionately to recruitment.[4](https://eprints.whiterose.ac.uk/id/eprint/79233/1/Howarth_and_Stewart_2014_Ecosystem_effects_management_of_UK_scallop_fisheries.pdf) Diving avoids seabed contact entirely but yields far smaller volumes than dredging.
## Habitat impacts and the dredging controversy
Newhaven-style spring-toothed dredges are likely the most damaging type of scallop dredge because their long teeth penetrate 3–10 cm into the seabed.[2](https://www.sciencedirect.com/science/article/abs/pii/B9780444627100000183) Experimental dredging on maerl habitat cut a 2.54 m wide disturbed track with three parallel furrows, eliminated natural seabed features, dragged boulders up to 1 m³, buried live maerl up to 8 cm deep, and crushed biogenic carbonate structures.[15](https://doi.org/10.1006/jmsc.2000.0918) Slow-growing biogenic reefs such as maerl and horse mussel beds are the most vulnerable habitats and are likely to take 10 or more years to recover.[4](https://eprints.whiterose.ac.uk/id/eprint/79233/1/Howarth_and_Stewart_2014_Ecosystem_effects_management_of_UK_scallop_fisheries.pdf) • [6](https://archimer.ifremer.fr/doc/00586/69859/67754.pdf) A global meta-analysis found slow-growing, large-biomass biota such as sponges and soft corals took up to 8 years to recover from benthic fishing, while short-lived polychaetes recovered in under a year.[16](https://www.int-res.com/journals/meps/articles/meps311001)
Bycatch numbers vary by measure: non-target organisms can make up 15–53% of total catch biomass,[1](https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0302225) but one review puts finfish bycatch of standard spring-toothed dredges lower, at 2–11%, related to shell strength varying between grounds.[5](https://fisheryprogress.org/sites/default/files/documents_actions/Review_of_Alt_measures_scallopsv4_09032023.pdf) Non-target catch suffers mortality through injury, stress, and predation after return to sea.[4](https://eprints.whiterose.ac.uk/id/eprint/79233/1/Howarth_and_Stewart_2014_Ecosystem_effects_management_of_UK_scallop_fisheries.pdf)
Gear modification shows mixed results. Adding skids to the dredge bag increased marketable catch per unit area by about 5%, but also increased bycatch by 11% and undersize scallop catch by 16%.[1](https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0302225) N-Viro dredge modifications cut fuel use by 30%, equating to CO₂ reductions of 164,571 kg CO₂-e/year for vessels over 15 m and 37,235 kg for vessels under 15 m, with annual fuel savings of £46,250 and £10,465 respectively.[17](https://doi.org/10.1002/aff2.70225) In the US Mid-Atlantic, vessels must use turtle deflector dredges and chain mats when and where sea turtles occur on scallop grounds.[3](https://www.fisheries.noaa.gov/species/atlantic-sea-scallop/management)
Conflict between gears and with conservation goals is documented: along the east [Yorkshire](https://www.edgepedia.org/yorkshire) coast, static potters claimed £100,000 of damage to their gear from scallop dredgers over several weeks in 2012.[4](https://eprints.whiterose.ac.uk/id/eprint/79233/1/Howarth_and_Stewart_2014_Ecosystem_effects_management_of_UK_scallop_fisheries.pdf) In October 2022, ROV footage from [Greenpeace](https://www.edgepedia.org/greenpeace) and Open Seas showed scallop dredger tracks damaging pink maerl inside a Scottish MPA, and dredgers remain legally entitled to fish inside that MPA.[18](https://www.theguardian.com/environment/2022/oct/06/video-reveals-severe-dredging-damage-to-mpa-protected-area-of-scottish-seabed) Research continues into whether dredging can be sustainable within protected areas, including a Before-After Control-Impact experiment in the Cardigan Bay SAC, closed since 2009, to identify sustainable dredging levels.[19](http://sustainable-fisheries-wales.bangor.ac.uk/documents/61.pdf) The king scallop fishery's primary environmental impact is seabed disturbance, and scallop fishing within MPAs is managed in the 0–12 nautical mile zone in English and Welsh waters.[20](https://consult.defra.gov.uk/fisheries-management-plans-1/kingscallop-fmp-consultation/supporting_documents/Environmental%20Report%20King%20Scallop%20FMP%20Nontechnical%20SummaryJuly%202023.pdf)
## Fishery management
**US rotational management.** The formal access-area rotational program was established in 2003: areas with dense, fast-growing small scallops are closed before exposure to fishing and reopened once the scallops are larger, boosting meat yield and yield per recruit.[21](https://www.federalregister.gov/documents/2026/03/27/2026-05990/fisheries-of-the-northeastern-united-states-framework-adjustment-40-to-the-atlantic-sea-scallop) The limited-access fleet is managed with days-at-sea allocations combined with these rotational access areas.[3](https://www.fisheries.noaa.gov/species/atlantic-sea-scallop/management) US fishermen also receive annual allocations of windowpane and yellowtail flounder, with gear restrictions and seasonal closures if exceeded.[3](https://www.fisheries.noaa.gov/species/atlantic-sea-scallop/management) MSC assessment records accountability measures for yellowtail, windowpane, and winter flounder, adjusted based on final catch estimates.[22](https://cert.msc.org/FileLoader/FileLinkDownload.asmx/GetFile?encryptedKey=N492WlBMhB8tcVJpUmXAq3G%2FllZbQuRuzaQ+eUjU2FGh%2Fknc%2FieDc0iifPU3rG04)
**Real-time closures in Maine.** Maine prohibits scallop dragging in territorial waters from April 16 to November 30 and diving from April 30 to November 14.[23](https://www.maine.gov/dmr/sites/maine.gov.dmr/files/regulations-2026-01/Chapter%2011.08%20Emergency%20Rulemaking%20Targeted%20C.pdf) In January 2026 the state closed the Pickering Island rotational area after in-season surveys showed legal scallop density falling from 0.07 to 0.04 scallops/m², a 43% decline; the spring 2025 survey density of 0.04/m² was one third below the 2022–2023 season's 0.06/m².[23](https://www.maine.gov/dmr/sites/maine.gov.dmr/files/regulations-2026-01/Chapter%2011.08%20Emergency%20Rulemaking%20Targeted%20C.pdf)
**UK and EU approach.** King scallop fisheries lie outside the EU TAC and quota regime, with management largely controlled by individual states.[9](https://assets.publishing.service.gov.uk/media/682da6a8e9440506ee9538d1/SCE_assessment_report_2024_annexe.pdf) UK scallop fisheries have no TACs or quotas; control relies on minimum landing sizes, gear restrictions, seasonal closures, and effort limits on vessels over 15 m.[4](https://eprints.whiterose.ac.uk/id/eprint/79233/1/Howarth_and_Stewart_2014_Ecosystem_effects_management_of_UK_scallop_fisheries.pdf) Since the EU Landing Obligation phased in fully in 2019, scallop dredgers must land all quota species except skates and rays; before 2019 a 5% limit on retained fish bycatch applied and still applies to non-quota species.[9](https://assets.publishing.service.gov.uk/media/682da6a8e9440506ee9538d1/SCE_assessment_report_2024_annexe.pdf)
## Certification and comparison with UK/EU management
The US Atlantic sea scallop fishery holds MSC certification; its assessment cites recovery of sandy seabed habitats after dredging predicted to occur in about 10 years (Collie et al. 2005).[22](https://cert.msc.org/FileLoader/FileLinkDownload.asmx/GetFile?encryptedKey=N492WlBMhB8tcVJpUmXAq3G%2FllZbQuRuzaQ+eUjU2FGh%2Fknc%2FieDc0iifPU3rG04) The Isle of Man queen scallop fishery's MSC certification was suspended in May 2014 after stock assessments showed a dramatic biomass drop.[4](https://eprints.whiterose.ac.uk/id/eprint/79233/1/Howarth_and_Stewart_2014_Ecosystem_effects_management_of_UK_scallop_fisheries.pdf)
The two management models differ fundamentally. The US combines hard catch controls (days-at-sea, quota-like access allocations) with spatial rotation to let scallops grow before harvest.[3](https://www.fisheries.noaa.gov/species/atlantic-sea-scallop/management) • [21](https://www.federalregister.gov/documents/2026/03/27/2026-05990/fisheries-of-the-northeastern-united-states-framework-adjustment-40-to-the-atlantic-sea-scallop) The UK and EU rely on seasonal closures, minimum landing sizes, and effort limits without stock-wide TACs.[4](https://eprints.whiterose.ac.uk/id/eprint/79233/1/Howarth_and_Stewart_2014_Ecosystem_effects_management_of_UK_scallop_fisheries.pdf) • [9](https://assets.publishing.service.gov.uk/media/682da6a8e9440506ee9538d1/SCE_assessment_report_2024_annexe.pdf)
## References
1. Catch yield and selectivity of a modified scallop dredge to reduce seabed impact (PLOS One, 2024). https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0302225
2. Quantifying and Managing the Ecosystem Effects of Scallop Dredge Fisheries (ScienceDirect). https://www.sciencedirect.com/science/article/abs/pii/B9780444627100000183
3. Atlantic Sea Scallop: Management, NOAA Fisheries. https://www.fisheries.noaa.gov/species/atlantic-sea-scallop/management
4. Howarth & Stewart (2014). The dredge fishery for scallops in the UK: effects on marine ecosystems and proposals for future management. https://eprints.whiterose.ac.uk/id/eprint/79233/1/Howarth_and_Stewart_2014_Ecosystem_effects_management_of_UK_scallop_fisheries.pdf
5. Review of alternative measures that minimise mortality of unwanted catch and reduce habitat impact in UK king scallop fisheries (FisheryProgress, 2023). https://fisheryprogress.org/sites/default/files/documents_actions/Review_of_Alt_measures_scallopsv4_09032023.pdf
6. Report of the Scallop Assessment Working Group (WGScallop), ICES/Ifremer. https://archimer.ifremer.fr/doc/00586/69859/67754.pdf
7. 2025 Assessment of Sea Scallop in SFA 27A (Georges Bank 'a'), Government of Canada. https://open-science.canada.ca/handle/123456789/4026
8. FishSource – American sea scallop, US Atlantic. https://www.fishsource.org/fishery_page/1384
9. Cefas king scallop stock assessment report 2024 annexe. https://assets.publishing.service.gov.uk/media/682da6a8e9440506ee9538d1/SCE_assessment_report_2024_annexe.pdf
10. Defra, Response to the call for evidence on ICES area 7d and Lyme Bay area of 7e king scallop dredge fishery closure. https://assets.publishing.service.gov.uk/media/645364b5faf4aa000ce1327c/Decision_Document_Response_to_the_call_for_evidence_on_ICES_area_7d_king_scallop_closure.pdf
11. FAO Capture production yearbook – scallops, pectens. https://www.fao.org/fishery/static/Yearbook/YB2015_CD_Master/root/capture/b55.pdf
12. 50 CFR § 648.59. https://federal.elaws.us/cfr/title50.part648.section648.59
13. Impacts and efficiency of scallop dredging on different soft substrates. https://doi.org/10.1139/f98-194
14. Efficiency and environmental impacts of three different Queen scallop fishing gears, Bangor University. http://sustainable-fisheries-iom.bangor.ac.uk/documents/government-reports/scallop/2009/BangorFisheriesReport_No8.pdf
15. Scallop dredging has profound, long-term impacts on maerl habitats. https://doi.org/10.1006/jmsc.2000.0918
16. Global analysis of response and recovery of benthic biota to fishing (MEPS). https://www.int-res.com/journals/meps/articles/meps311001
17. Evaluation of Catch Performance and Environmental Impact of Technical Gear Modifications for a More Sustainable Scallop Dredging Fishery. https://doi.org/10.1002/aff2.70225
18. The Guardian (2022). Video reveals severe dredging damage to MPA-protected area of Scottish seabed. https://www.theguardian.com/environment/2022/oct/06/video-reveals-severe-dredging-damage-to-mpa-protected-area-of-scottish-seabed
19. Impact of scallop dredging on benthic communities and habitat features in the Cardigan Bay SAC, Bangor University. http://sustainable-fisheries-wales.bangor.ac.uk/documents/61.pdf
20. Defra King Scallop FMP Strategic Environmental Assessment (July 2023). https://consult.defra.gov.uk/fisheries-management-plans-1/kingscallop-fmp-consultation/supporting_documents/Environmental%20Report%20King%20Scallop%20FMP%20Nontechnical%20SummaryJuly%202023.pdf
21. Federal Register, Framework Adjustment 40 to the Atlantic Sea Scallop FMP (March 2026). https://www.federalregister.gov/documents/2026/03/27/2026-05990/fisheries-of-the-northeastern-united-states-framework-adjustment-40-to-the-atlantic-sea-scallop
22. MSC Fishery Assessment Report, US Atlantic sea scallop. https://cert.msc.org/FileLoader/FileLinkDownload.asmx/GetFile?encryptedKey=N492WlBMhB8tcVJpUmXAq3G%2FllZbQuRuzaQ+eUjU2FGh%2Fknc%2FieDc0iifPU3rG04
23. Maine DMR Emergency Rulemaking, Targeted Closures. https://www.maine.gov/dmr/sites/maine.gov.dmr/files/regulations-2026-01/Chapter%2011.08%20Emergency%20Rulemaking%20Targeted%20C.pdf
24. NOAA Fisheries, 2026 Fishing Year Limited Access Allocations for the Atlantic Sea Scallop Fishery. https://www.fisheries.noaa.gov/bulletin/2026-fishing-year-limited-access-allocations-atlantic-sea-scallop-fishery
25. Atlantic Fisherman, DFO Decreases Nova Scotia 2026 Scallop TAC. https://atlanticfisherman.com/dfo-decreases-nova-scotia-2026-scallop-tac/
26. GOV.UK, King scallop dredge fishery temporary closure decision. https://www.gov.uk/government/news/king-scallop-dredge-fishery-temporary-closure-decision
27. GOV.UK, Temporary queen scallops closure. https://www.gov.uk/government/news/temporary-queen-scallops-closure
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*Topic: Encyclopedia › Life and health › Animals › Invertebrates › Molluscs › Bivalves › Bivalves and human use › Fisheries, aquaculture, and reef restoration › Scallop fisheries and aquaculture*
*Initially written Sep 17, 2026 · Reviewed: Sep 19, 2026 · Edited: Sep 19, 2026; Oct 11, 2026 · Last review: Sep 19, 2026*
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License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license