Queen scallop

The queen scallop stock around the Isle of Man appears to have recovered from low levels. There is uncertainty about whether fishing pressure is at sustainable levels.This rating covers the stock within Isle of Man waters (0-12 nautical miles). The most recent stock assessment was carried out by Bangor University in 2025 using data up to 2025. Route 2 scoring has been applied to this rating as there are no reference points to indicate a healthy biomass or fishing pressure. Queen scallops are considered to have medium resilience to fishing pressure.Landings of queen scallops from around the Isle of Man (ICES rectangles 36E5, 37E5, and 38E5) increased rapidly between 2009 and 2011, tripling from 5015 tonnes to 16,957 tonnes. Since then. Landings have declined significantly, reaching a low of 920 tonnes in 2020. However, there has been a partial recovery, with catches rising to 4154 tonnes in 2024.Biomass assessments are based on an abundance index derived from annual research surveys. Given the annual fluctuations, a 3 over 2 rule is applied in which the average of the last two year’s indices - Index A (2024 and 2025) - are compared to the average of the three preceding years - Index B (2021-2023). Based on this measure, Index A (351) shows a 134.5% increase from Index B (261), indicating a rise in abundance. Therefore, there is no immediate concern for biomass. However, there remains a need for caution as although the post-recruit abundance in 2025 (292) is the highest recorded since 2013, it is still below the long-term average (~377). There is no formal assessment of fishing pressure. Although catches remain at low levels, they are increasing and have historically been too high. Scallop densities within 12 nautical miles of the Isle of Man vary across survey stations, with increases at 11 stations and declines at 4 observed between 2024 and 2025. These spatial differences may reflect localised impacts of fishing activity. The assessment suggests that targeted spatial management could help to protect areas with high densities of recruits and post-recruits, especially in regions of overlap. However, due to the lack of information, and the potential of fishing activity hindering recovery in low density areas, there remains a concern for fishing pressure. The Isle of Man stocks are closely linked to those in the broader Irish Sea. Research indicates that managing scallops in the northern Irish Sea as a single stock may be more effective, given the influence of regional fishing pressure on Isle of Man reproductive capacity. As such, a long-term management plan for the wider Irish Sea is recommended. Nonetheless, stock assessments at the level of individual fishing grounds are also vital, particularly for spatial management, including closures of high-density areas to protect spawning scallops.

In recent years, a number of management measures have been brought in to control scallop fishing around the Isle of Man. The fishery is now closely monitored. However, it is not yet clear if measures have resulted in sustainable levels of fishing and stock stability.There are a number of queen scallop beds in the Irish Sea, which may be connected. It is possible that they therefore should be treated and managed as a single stock. However, no joint management approach currently exists. This rating applies to Isle of Man waters only (0-12 nautical miles).Fishing for queen scallop is carried out by Isle of Man and UK vessels. In 2024, 35 vessels were licenced to fish in Isle of Man territorial waters. Manx vessels fish exclusively with otter trawls, but one UK vessel are permitted to use toothless dredge. A long term management plan for queen scallops is being developed but is not currently in force.Management of this fishery differs by area, with the 2024 season measures including:Trawling Total Allowable Catch (TAC): 726 – 1144 tonnesDredging TAC: ~58 tonnesWeekly Catch Limits (WCL): 7098kg (General Territorial Sea, Weeks 1-4)9210kg (General Territorial Sea, Weeks 4-7)10,140kg (General Territorial Sea, Weeks 7-17)2730kg (Additional Exploratory, Point of Ayre, Weeks 1-6)Seasonal Closures: April – May (spawning) and April – June (ICES areas 6a and 7a).Fishing curfew: 1800 – 0600Minimum Landing Size (MLS): 55mm.Closed areas: both temporary and permanent closures to protect stocks.Gear restrictions and vessel controls (see Bloor et al. 2023).Monitoring and compliance: use of Vessel Monitoring Systems (VMS) and submission of logbooks for daily catch returns.For 2025, the TAC is set at 1350 tonnes – a 20% increase on 2024 landings. The Department of Environment, Food and Agriculture (DEFA) highlights that strong compliance with TAC limits is more likely due to management measures and market fluctuations than to declining stock abundance. That said, some areas may be experiencing disproportionate high levels of fishing pressure, potentially causing localised decline in queen scallop abundance at survey sites. However, there is no formal assessment of fishing pressure against biological reference points, so it remains unclear whether current measures are achieving sustainable harvest levels.This fishery is also covered by the Western Waters Effort regime, which limits the number of days vessels over 15m can dredge in ICES area 7. However, it has had no limiting effect on the Isle of Man fishery to date.Nonetheless, high fishing effort elsewhere in the Irish Sea may still affect the stability of Isle of Man stocks. This highlights the need for further research and the development of collaborative, pan-Irish Sea management measures to safeguard scallop sustainability across connected populations in the region.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 impacts Targets for fishing pressure and biomass, and additional management when those targets are not being met, based on the best scientific evidence Timeframes for stock recovery Improved 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 bycatch Stakeholder engagementQueen scallop is included in the Queen 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].

Most queen scallops from the Isle of Man are caught with otter trawls, which can have an impact on seabed habitats and bycatch vulnerable species. There are a number of protections in place to reduce habitat impacts.There are several scallop beds in the northern Irish Sea that may be ecologically or genetically connected. However, no joint management framework currently exists. This assessment applies only to Isle of Man territorial waters only (0-12 nautical miles).MMO landings data from the Economic Exclusion Zone (EEZ) of the Isle of Man waters show that queen scallop is predominantly caught by demersal trawls (98.4%), and some by dredging (1.6%), as this is restricted. When adjacent waters in the Irish Sea are included, dredging is the primary method for queen scallop catches, accounting for 82.2% of landings.Demersal trawls have contact with the seabed, resulting in penetration and abrasion of habitat features. 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.The Isle of Man supports sensitive habitats, including horse mussels and maerl reefs, which provide shelter for juvenile fish and other marine life. Trawling in these areas can have broader ecosystem consequences and may take decades to recover. To protect these areas, 10 Marine Nature Reserves (MNRs) have been designated in inshore waters (0-3nm), covering 51.8% of this zone, and 10.8% of the Isle of Man’s total territorial waters. Towed gear is banned in all MNRs, except Ramsey Bay, where limited dredging is allowed under strict conditions.In open areas of the 0-3nm zone, Fisheries Zones have tailored management plans regulating vessel access and gear use. Outside this zone, other management measures are in place and temporary closures may be used to protect areas with high scallop densities. An analysis carried out in 2014 showed that over 85% of Isle of Man territorial seas was not trawled for queen scallops. Impacts on habitats are therefore mitigated to a large extent.Bycatch has been monitored by the Isle of Man Department of Environment, Food and Agriculture (DEFA) in the past. Bycatch surveys were conducted in 2009, 2012 and 2014. In 2009, bycatch was estimated to be 3.4% of the total catch by weight. This increased to 6.8% in 2012, which was verified by independent observers. In 2014 it was estimated to be 7.1%, which appears to indicate a steady increase over time. However, these rates are lower than in other trawl fisheries. For example, bycatch in the Irish Sea Nephrops trawl fisheries is estimated to be 25%.Cod and whiting are the primary bycatch species of concern, particularly as their populations in the Irish Sea are critically low and subject to zero catch advice. However, their catch rates in Manx waters remain low. Other commercially caught bycatch species include flatfish, skates, rays, cat sharks, and monkfish. However, not all bycatch is documented, and some organisms remain on the seabed. These may suffer high mortality from trawling damage, raising concerns about unmeasured impacts on vulnerable species.To mitigate bycatch, gear restrictions are in place. Manx trawlers also observe nighttime curfews to protect species more active during those hours. Trials have also been conducted to assess the effectiveness of square mesh panels and LED lights in reducing bycatch.

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