Whelk, common whelk

Buccinum undatum

Method of production — Caught at sea
Capture method — Pot or creel
Capture area — North East Atlantic (FAO 27)
Stock area — Irish Sea, North Channel, Atlantic Ocean
Stock detail — 6a, 7a: Northern Ireland Territorial Waters
Picture of Whelk, common whelk

Sustainability rating five info

Sustainability overview

Updated: December 2020.

The absence of stock assessments in Northern Ireland results in a level of uncertainty of the current status of whelk populations in this area. However, lack of data coupled with recent increases in fishing effort, declining trends in LPUE, and significant increase in whelk value in the last decade, issues concern for the stock biomass and fishing pressure. Whelks (Buccinum undatum) are a particularly vulnerable species and once overfished, they have a slow path to population recovery.

There is little known about the species resilience to fishing pressure and vulnerability, but, the recent and significant increase in exploitation of whelk fisheries alongside the life history characteristics of the species, high larval mortality from urchin predation, occurrence of stocklets in small spatial scales, together suggests whelks are particularly vulnerable to overfishing, and possibly more so for certain localised populations.

There is no appropriate management in place to protect the stocks in Northern Ireland. A single management measure currently exists, being the EU-wide Minimum Conservation Reference Size (MCRS). The MCRS is too small to protect the whelk stocks within Northern Ireland. Further management measures and population monitoring is required, particularly as whelk landings have increased substantially in recent years throughout the United Kingdom.

Pot fishing is seen as a relatively benign form of fishing having little impact on the environment. Nonetheless, there is potential for potting to disrupt sensitive habitats. Some seabed abrasion may occur from movement of whelk pots on the seabed. Bycatch is negligible.


Whelks are large marine gastropods, or snails, with strong, whitish shells. They are found from Iceland and northern Norway to the Bay of Biscay, and can be locally abundant around the UK except for the Isles of Scilly. They inhabit sandy and muddy areas, although they can be found on gravel and rocky surfaces, down to depths of 1,200 metres.

Whelks mate during autumn and winter and baby whelks emerge in the spring.

Whelks are carnivorous. They scavenge at depths between 3 - 600m. They have an exceptionally acute chemical sensory ability - which enables whelks to be commercially exploited in baited pots.

Whelks are a particularly vulnerable species because they are long-lived (up to about 15 years), mature late (5-7 years) and produce relatively low number of eggs. In addition, they aggregate together, lay their eggs on the seafloor and are easy to catch. Their exceptional acute sense makes it easy to attract them to whelk pots. These factors make them more susceptible to local overfishing, and once overfished, have a slow path to population recovery. This is further exacerbated when few whelks have had a chance to mature, which can lead to stock collapse e.g. in the Dutch Wadden Sea in the mid 1970as.

Stock information

Criterion score: 1 info

The absence of stock assessments in Northern Ireland results in a level of uncertainty of the current status of whelk populations in this area. However, lack of data coupled with recent increases in fishing effort, declining trends in LPUE, and significant increase in whelk value in the last decade, issues concern for the stock biomass and fishing pressure. Whelks (Buccinum undatum) are a particularly vulnerable species and once overfished, they have a slow path to population recovery.

Concerns regarding the status of whelk stocks have risen following recent increases in fishing effort throughout UK waters. The recent increase in exploitation alongside the sedentary life history characteristics of the species, a high larval mortality from urchin predation, occurrence of sub-populations in small spatial scales, together suggests whelks are particularly vulnerable to overfishing, and possibly more so for certain localised populations. Mostly, it has only been within the last few decades that these biological vulnerabilities have been exacerbated, due to the overall (global) increase in demand for whelks, and have highlighted species vulnerabilities to overexploitation.

The Irish Sea has seen an estimated 447% increase in the total landed weight of whelks between 2000 and 2016 by British registered vessels. In the Irish Sea, whelk is the third most valuable shellfish resource after Nephrops and scallops (Pecten maximus), worth £8.5 million in 2017 (16.5% of the total value of all species landed by UK vessels in ICES 7a). The Northern Ireland whelk fishery has significantly increased in value in the last decade from approximately £500 per tonne in 2010 to £1,600 per tonne in 2018. As noted for other UK whelk fisheries, this is likely to be driven by increasing demand from overseas markets and a need to fill a gap due to declining Pacific whelk populations.

AFBI carry out monitoring of the stocks targeted by the Northern Ireland pot fishery. Whilst this work concentrates primarily on crab and lobster, there is some work on whelks. There is currently no assessment for whelks. Whelk landings and effort data (provided through the Monthly Shellfish Returns to DAERA) has been analysed for NI ICES rectangles (37E3, 37E4, 38E4, 39E3, 39E4). The landings from these rectangles, which show quite wide fluctuations, equated to 78 tonnes in 2019. The number of NI registered vessels landing whelks (from all areas) has increased from 6 in 2007 to 38 in 2019. There has also been an increase in the number of pots deployed to catch whelks. This has led to a decreasing trend in Landings per Unit Effort (LPUE- kg of whelks caught per pot).

Large fluctuations in annual landings can be indicative of boom-and-bust fisheries. Whelk fisheries are often considered as boom-and-bust, where catches increase while demand is high until catch rates become less economically attractive.


Criterion score: 1 info

There are no appropriate management measures in place for this fishery.

The Northern Ireland whelk fishery is data-poor, and the absence of stock assessments has prevented the application of biologically referenced catch or effort restrictions.

The current management measure in place to regulate this fishery is the EU-wide Minimum Conservation Reference Size (MCRS) shell height of 45mm, as defined under EC regulation No 850/98. However, the size at which whelks mature varies throughout UK waters, and the shape of whelks can vary considerably in different areas, from shorter wider whelks to longer thinner individuals. Significant differences for most measured parameters (e.g. size, growth, age, maturity), suggest that large-scale management measures, such as the single MCRS currently employed, is not a practical solution for management with regards to biological sustainability. A recent study of whelks in the Irish Sea (ICES area 7a) confirmed that whelks caught in shallow waters mature at a smaller size than those in colder, deeper waters. Whelk Size of Maturity (SOM - the size at which 50% of the population is sexually mature) in Northern Ireland waters was no smaller than 90 mm and >120mm in some areas. Consequently, the current MCRS offers inadequate protection to the spawning stock and increases the probability of recruitment overfishing; whelks are being caught before they have chance to reproduce.

A countrywide increase to the current MCRS would affect different regions disproportionately. Small-scale management should be considered on a region-by-region basis, to assess the suitability of management measures.

Vessels >12m in length are required to use Vessel Monitoring Systems (VMS) and record and report catch data electronically. Vessels <10m must have a licence and collect data on fishing effort and landings.

Indeed, several viable management strategies have been suggested by various fisheries management authorities in the United Kingdom to protect and rebuild overexploited stocks, including compulsory sorting based on defined length-width relationships, gear and effort constraints (e.g. limits on pot size and quantity), and closed seasons during reproductive periods. An increase to the current MCRS has been suggested as another feasible management measure in numerous studies. Such measures could support better management of the stock within Northern Ireland alongside localised stock assessments.

Both the EU and UK have fishery management measures in place, which can include catch limits, targets for population sizes and fishing mortality, and controls on what fishing gear can be used and where. In the EU, compliance with regulations has been variable, and there are ongoing challenges with implementing some of them. There was a target for fishing to be at Maximum Sustainable Yield by 2020, but this was not achieved. The Landing Obligation (LO), an EU law that the UK has kept after Brexit, requires all fish and shellfish to be landed, even if they are unwanted (over-quota or below minimum size). It aims to promote more selective fishing methods, reduce bycatch, and improve recording of everything that is caught, not just what is wanted. Compliance with the LO is generally poor and actual levels of discards are difficult to quantify using the current fisheries observer programme.

In the UK, it is too early to tell how effective management is, as the Fisheries Act only came into force in January 2021. The Act requires the development of Fisheries Management Plans (FMPs) (replacing EU Multi-Annual Plans) but there are no details yet on how and when these will be developed. FMPs have the potential to be very important tools for managing UK fisheries, although data limitations may delay them for some stocks. MCS is keen to see FMPs for all commercially exploited stocks, especially where stocks are depleted, that include:
Targets for fishing pressure and biomass, and additional management when those targets are not being met
Timeframes for stock recovery
Technologies such as Remote Electronic Monitoring (REM) to support data collection and improve transparency and accountability
Consideration of wider environmental impacts of the fishery

Capture Information

Criterion score: 0.25 info

In Northern Ireland whelks, also known as Buckies, are fished using pots.

In Northern Ireland, whelk pots are made from a plastic container, usually a drum. One end is partially removed and covered with netting and the rest of the pot perforated with 2-3 cm holes. The pot usually has sand at the bottom to weigh it down. A large number of pots may be attached to a single string which is marked by a buoy at each end. The pots are baited and placed on the seabed to soak for a number of days before being hauled. Once hauled, most fishers grade whelks with a riddle that allows the retention of whelks >45mm. A riddle is a piece of equipment made of parallel metal bars. The spacing between the bars allows for undersized whelks and bycatch to fall through the bars, collected and returned to the sea. This minimises bycatch of non-target species by filtering catch, whilst retaining larger whelks.

The risk of bycatch from whelk potting is generally low and typically consists of lobster and crab species. Bycatch is normally caught alive and undamaged and can be returned to the sea immediately. Endangered, threatened or protected species (ETP) are rarely caught. Leatherback turtles have been known to become entangled in pot ropes in UK waters, yet this is extremely rare and there is a lack of data on these interactions.

Whilst mobile gear such as dredges and trawls can damage the sea bed, pot fishing is seen as a relatively benign form of fishing having little impact on the environment. Nonetheless, there is potential for potting to disrupt sensitive habitats and a possibility of some seabed abrasion. Abrasion may occur from movement of the pots on the seabed, but this would be restricted to areas of strong tides or seabed turbulence in bad weather.

Whelk potting is a passive method of fishing. Whelks enter the pot when they are attracted by the bait. Pots are generally hauled every 1 to 3 days after being laid on the seafloor (on muddy sand, gravel and/or rocky substrates) in depths of around 10-30m. The effect to the seafloor is likely to be insignificant compared with mobile fishing gears. Studies show that the impact on the habitat is insignificant to substantial cumulative damage from mechanical abrasion due to the deployment and retrieval of pots, especially on sessile, slow-growing or friable flora and fauna such as ross coral or sabellaria. Ghost fishing is generally rare.


AFBI Fisheries and Aquatic Ecosystems Branch (2010). Pot Fishing in Northern Ireland. Fisheries and Aquatic Ecosystems Branch, Belfast. Available at https://www.afbini.gov.uk/sites/afbini.gov.uk/files/publications/%5Bcurrent-domain%3Amachine-name%5D/pot%20fishing%20in%20northern%20ireland.pdf [Accessed 24.11.2020]

AFBI (personal communication, 17th December 2020).

Brown, J., Macfadyen, T., Huntington, J., Magnus and Tumilty, J. (2005). Ghost Fishing by Lost Fishing Gear. Final Report to DG Fisheries and Maritime Affairs of the European Commission. Fish/2004/20. Institute for European Environmental Policy / Poseidon Aquatic Resource Management Ltd joint report. Available at https://ieep.eu/uploads/articles/attachments/4a24b509-013d-44ca-b26e-47c8f52e29c4/ghostfishing.pdf?v=63664509699 [Accessed 08.6.2020]

DAERA (personal communications, November-December 2020).

DEFRA (2015). Summary of Evidence on Impacts of Potting on Designated Features pp.16-44, ‘In’ DEFRA (2015) Evidence for Management on Potting Impacts on Designated Features, MMO1086, Final Report November 2015, pp.1-111.

EC (2015). COUNCIL REGULATION (EC) No 850/98 of 30 March 1998 for the conservation of fishery resources through technical measures for the protection of juveniles of marine organisms. Available at http://www.legislation.gov.uk/eur/1998/850/pdfs/eur_19980850_2015-06-01_en.pdf [Accessed 09.06.2020]

Emmerson, J., Hollyman, P., Bloor, I. and Jenkins, S. (2020). Effect of temperature on the growth of the commercially fished common whelk (Buccinum undatum, L.): A regional analysis within the Irish Sea. Fisheries Research, 223 (105437), 10pp. doi: https://doi.org/10.1016/j.fishres.2019.105437 [Accessed 09.06.2020]

FAO (2020). Species Fact Sheets: Buccinum undatum. Available at http://www.fao.org/fishery/species/2659/en [Accessed 22.05.2020]

Gafeira, J., Green S., Dove, D., Morando, A., Cooper, R., Long, D. and Gatliff R. W. (2010). Developing the necessary data layers for Marine Conservation Zone selection - Distribution of rock/hard substrate on the UK Continental Shelf, MB0103 Final Report. British Geological Survey, UK.

Lawler, A. (2013). Determination of the Size of Maturity of the Whelk Buccinum undatumin English Waters - Defra project MF0231, DEFRA, pp1-39.

MRAG (2018). Management recommendations for English non-quota fisheries: Common whelk, Final Report 16th July 2018. Available at https://www.bluemarinefoundation.com/wp-content/uploads/2019/05/MRAG_Final_Whelk_Report.pdf [Accessed 27.05.2020]

Piperpoint, C. (2000). Bycatch of marine turtles in UK and Irish waters. JNCC Report No 310. 32 pp. Available at https://www.researchgate.net/publication/245592683_Bycatch_of_marine_turtles_in_UK_and_Irish_waters [Accessed 26.05.2020]

UK Government (2020). Guidance: Fishing data collection, coverage, processing and revision. Available at https://www.gov.uk/guidance/fishing-activity-and-landings-data-collection-and-processing [Accessed 09.06.2020]

Science Direct (2020). Buccinum undatum, Shellfish: Commercially Important Molluscs, in Duncan, P. (2003) Encyclopedia of Food Sciences and Nutrition (2nd Ed.). Available at https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/buccinum-undatum [Accessed 22.05.2020]

Seafish (2020). Pots and Traps – Whelks. Available at https://www.seafish.org/responsible-sourcing/fishing-gear-database/gear/pots-and-traps-whelks/ [Accessed 01.12.2020]

SeaLifeBase (2020). Waved whelk, Buccinum undatum. Available at https://www.sealifebase.se/summary/Buccinum-undatum.html [Accessed 21.05.2020]

Walmsley, S.F., Bowles, A., Eno, N.C. and West, N. (2015). Evidence for Management of Potting Impacts on Designated Features. DEFRA. Contract Reference: MMO1086. Final Report November 2015, pp.1-49.