King scallop

King scallops from the North Sea appear to be declining in abundance but are not subject to overfishing. Therefore, there is concern for biomass but not for fishing pressure.Since 2017, Cefas has conducted annual stock assessment for king scallops in ICES Divisions 27.7.e, 27.7.d, 27.7.f, and 27.4.b. Specific assessment areas were selected within these based on regional differences in scallop growth and fishery exploitation rates. This rating focuses on the southern part of the North Sea (4.b.S), along the Yorkshire and Durham coast. Between 2017 and 2023, international landings, primarily by UK vessels, average around 1,700 tonnes per year.Scoring for this stock is based on assessments published in 2025, using data up to 2023/2024. Due to the absence of a biomass reference pointed needed to estimate Maximum Sustainable Yield (MSY), there is some uncertainty in the assessment. As a result, Route 2 scoring has been applied, with king scallops considered to have a high resilience to fishing pressure.Harvestable biomass (the weight of scallops above the minimum landing size and within areas open to dredging) has fluctuated between 5,400 and 9,000 tonnes from 2018 to 2024. A gradual decline has been observed in recent years – from 8,911 tonnes in 2022 to 6,739 tonnes in 2024. Without reference points, it remains unclear whether this represents an unhealthy stock level. However, as this latest figure (6,739 tonnes) is below the average from 2021 to 2023 (7,418 tonnes), there is concern for biomass.Fishing pressure is assessed using the harvest rate (HR), defined as the proportion of harvestable biomass removed by fishing in the 12 months following each stock survey. Cefas estimates that a harvest rate of 23.0% corresponds to MSY, which would maintain the stock at 35% unfished levels. In 2023, the estimated HR was 11.48% – the lowest since 2018 – indicating no concern for fishing pressure as it remains well below the MSY threshold.Nonetheless, there remains some uncertainties with this assessment. Biomass surveys use both dredging and underwater video systems to account for areas where dredging is not possible (e.g., conservation zones or unsuitable habitats). Additional scallop stocks are known to exist outside of survey areas, but it remains unclear how these unfished areas interact with fish stock, and specifically, whether larval exchange occurs or if dredged areas are self-sustaining.

Appropriate management measures are in place to control scallop dredging in this area. These appear to be responsive to stock status, with the use of emergency byelaws playing a key role in protecting scallop stocks.Stock assessments for king scallops off the Yorkshire and Durham coast only began in 2018. While data quality has improved since then, some uncertainties still remain, which may limit the effectiveness of evidence-based management measures. It is also possible that inshore and offshore scallop stocks are connected, potentially through larval exchange, which suggests a more coordinated approach is needed across management areas.This rating focuses on the inshore dredge fishery for scallops in the North Sea (central south). Some of the scallop beds fall within 6 nautical miles of the coast and are managed by the North Eastern Inshore Fisheries and Conservation Authority (NEIFCA). However, some beds extend beyond the 6nm boundary into areas management under national legislation, again highlighting the need for coordination between local and national management frameworks.NEIFCA has introduced local management measures to reduce pressure on scallop stocks, with some measures responsive to stock status. These are primarily implemented though the Method and Area of Fishing (Scallop Dredges) Byelaw XXIII 2015 and, more recently, through emergency action addressing emerging fishing practices.Current Management Measures:Bottom towed gear is prohibited in majority of district, including designated Marine Protected Areas (MPAs).Permit required for scallop dredgingMaximum vessel length: 12mDredge limits: maximum of 10 dredgesFishing curfew: 1900 – 0700Closed season: 1 May to 31 OctoberMinimum Conservation Reference Size (MCRS): 100mmMonthly catch and effort returns required, including dredge use, tow data, landings, and bycatch.AIS tracking required for all vessels.At-sea observers are occasionally deployed for verification and data collection.Although these measures help to control fishing effort, there is no Total Allowable Catch (TAC) set for king scallops. Instead, the 2015 byelaw limits the number of permits available each year in relation to the assessed exploitable stock, which is reviewed annually. If demand exceeds availability, permits are awarded based on longest track record. According to an NEIFCA impact assessment, the 2015 byelaw led to an estimated 44% reduction in vessel numbers from 2014, 46% reduction in number of dredges, and capacity reduction from 273 days to 182 days per year. Since the 2018/19 season, only three dredge permits have been issued annually. However, while fishing pressure is currently below MSY proxy, biomass has fallen below the 3-year average, and the number of permits has not been adjusted in response.In June 2023, a new beam trawl fishery for scallops emerged, landing 57 tonnes – approximately a fifth of the previous year’s dredged landings. This raised concerns, as no scallops-specific management measures applied to beam trawling at the time, including no spatial restrictions. In response, NEIFCA introduced an emergency byelaw in July 2023, which prohibited beam trawling for scallops, but allowed scientific exemptions to investigate the fishery further. In 2024, this was formalised through the Beam Trawling Byelaw, which requires all scallops to be returned to sea as close as possible to the capture location. This emergent fishery may have contributed to the observed decline in biomass between 2022 and 2024. Ongoing monitoring and research will help determine the impact of the new beam trawling byelaw on king scallop stocks in the region.This fishery is also part of the UK King Scallop Fishery Improvement Project (FIP), a six-year initiative launched in March 2025. The project aims to elevate king scallop fisheries to a level which meets the certification standards set by the Marine Stewardship Council (MSC).Management compliance in the EU and UK has been inconsistent, with ongoing challenges in enforcing some regulations.The Marine Conservation Society views Remote Electronic Monitoring (REM) with cameras is one of the most cost-effective tools for providing reliable fisheries data and aiding informed management decisions. Fully monitored fisheries enhance collaboration, data accuracy, stock recovery, and reduce impacts on marine wildlife and habitats. However, the full potential of REM may only be achieved when it tracks fishing location and documents catch and bycatch, particularly where vulnerable species and habitats are at risk. As of January 2024, the EU is introducing a Remote Electronic Monitoring (REM) mandate for EU vessels, including CCTV cameras on vessels 18m or more that pose a potential risk of non-compliance, within the next 4 years. Across the UK, different approaches to REM are being taken and legislation is expected to be in place across all 4 countries within the next few years.The Fisheries Act (2020) requires the development of Fisheries Management Plans (FMPs) (replacing EU Multi-Annual Plans) in the UK. 43 FMPs have been proposed and are at various stages of development and implementation, these should all be published by the end of 2028. FMPs have the potential to be very important tools for managing UK fisheries, although data limitations may delay them for some stocks. It is also essential the UK governments define and adopt a standardised approach or model across the four nations to a universally defined FMP design, to ensure the consistence, quality and coherence of all the proposal FMPs.The Marine Conservation Society is keen to see publicly available Fishery Management Plans for all commercially exploited stocks, especially where stocks are depleted, that include:An overview of the fishery including current stock status, spatial coverage, current fishing methods and impactsTargets for fishing pressure and biomass, and additional management when those targets are not being met, based on the best scientific evidenceTimeframes for stock recoveryImproved data collection, transparency, and accountability, supported by technologies such as Remote Electronic Monitoring (REM)Consideration of wider environmental impacts of the fishery, including habitat impacts and minimising bycatchStakeholder engagementKing scallop is included in the King scallop FMP, coordinated by Defra. At the time of writing, it is too soon to know whether proposed management measures will be effective in managing the stock. For more information about this FMP and expected progress and timelines, see [https://www.gov.uk/government/publications/joint-fisheries-statement-jfs/list-of-fisheries-management-plans].

Scallop dredging can be very damaging to seabed habitats and species. However, an extensive area of this IFCA district is closed to scallop dredging, which helps to protect vulnerable ecosystems.According to MMO landings data in this region of the North Sea, dredging accounts for approximately 92.8% of king scallop landings. This method remains dominant due to its efficiency, but poses significant environmental risks, particularly to sensitive seabed habitats.A standard king scallop dredge (Newhaven dredge) consists of a heavy steel frame and chainmail net, with a toothed bar that flips scallops into the net. Dredges are attached to tow bars dragged along the seabed, with up to 2 dredges per bar. The number of dredges used is limited by vessel engine power and regional legislation.On average, scallop dredging penetrates the seabed by up to 6cm, and can reduce species abundance and richness by 8-12% per pass. Recovery times vary depending on the species and habitat, ranging from months to years. More dynamic environments, such as sandy or wave-exposed areas, support faster-growing species that recover more quickly. In contrast, sheltered habitats like gravel beds or inshore zones, often host slow-growing, long-lived species such as maerl, horse mussels, seagrass, and sea fans, which are more vulnerable to damage and slower to recover.Within 6 nautical miles of the coast, the seabed is primarily composed of sand, mixed sediments, and rock, but also supports highly diverse and vulnerable habitats such as mussel beds and rocky reefs. To protect these sensitive ecosystems, the North Eastern IFCA district has established areas with permanent or seasonal closures to scallop dredging, some of which overlap with designated Marine Protected Areas (MPAs).Scallop dredging in these sensitive habitats can cause long-lasting ecological damage, with recovery potentially taking decades. While dredging activity is generally lower in inshore areas compared to offshore waters, enforcement remains essential. The recent rollout of mandatory inshore Vessel Monitoring Systems (iVMS) in May 2025 now provides more detailed tracking of inshore fishing activity, helping to detect and respond to incursions. Additional management measures, including gear restrictions and curfews, also help to reduce dredging pressure.Bycatch is another key concern. Since 2019, scallop dredgers have been required to land all quota species under the EU Landing Obligation, with the exception of skates and rays. For non-quota species, bycatch must not exceed 5% of total retained catch. Common bycatch species include queen scallop, brown crab, and spider crab. While bycatch levels are not currently thought to threaten theses populations, it is not fully recorded, and some organisms remain on the seabed after the dredge passes, of which can experience high mortality from incurred damage. This raises concerns about unmeasured impacts on vulnerable species and habitats.Discarding, often due to minimum size restrictions, also occurs. While post-release survival is believed to be relatively high, no quantitative assessments of discard rates or survival have been conducted.

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