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, Celtic Sea: St. Georges Channel, Bristol Channel
Stock detail — 7a, 7f, 7g: Wales (Welsh Zone)
Picture of Whelk, common whelk

Sustainability rating five info

Sustainability overview

Updated: June 2020.

Whelk populations throughout Wales are largely unknown and regional stock assessments are needed. Although there is limited data available on whelk stocks, the data that does exist indicates that there could be concern for whelk biomass levels within Welsh waters, and populations are being unsustainably exploited. 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. Some management measures are in place, including a Minimum Landing Size (MLS) and some fishing effort restrictions. However, the current MLS is too small to protect most of the whelk stocks within Welsh waters. The MLS is not specific to regions within Wales, unlike England. Further management measures and population monitoring is required, particularly as whelk landings have increased substantially in recent years. Pots generally cause a very low impact to the seabed and 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

There is concern for the stock and fishing pressure is above sustainable levels.

Whelk (Buccinum undatum) populations in Wales are largely unknown and being fished unsustainably. The lack of comprehensive stock assessments has resulted in a level of uncertainty of the current status of whelk populations. Whelks are a particularly vulnerable species and once overfished, they have a slow path to population recovery.

Welsh whelk stocks have never been formally assessed, however, the Welsh Government are currently commissioning a stock assessment to inform future management. The first stock assessment was planned for Spring 2020, to inform the setting of an annual catch limit, due to be enacted in March 2022. Concerns regarding the status of whelk stocks have risen following recent increases in fishing effort. 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.

Whelks are an important commercial non-quota shellfish and the value of whelks landed into Wales by UK vessels was greater than all other species combined in 2017. ‘Landings into Wales by UK vessels: 2013 to 2017’ from the UK Sea Fisheries Statistics 2017 Report indicates that UK vessels landed whelks worth a value £7.9 million into Wales in 2017. Landings were valued around £4 million in 2019. What was once a small-scale inshore fishery is now characterised by a fleet increasing in average length and fishing capacity. Regionally, the Irish Sea has an estimated 447% increase in the total landed weight of whelk between 2000 and 2016 by British registered vessels, with the most significant increases being recorded in the Isle of Man territorial sea and Welsh waters. 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 Welsh whelk fishery saw a steep rise in landings during the period 2015-2017. This was largely driven by an increasing value per tonne (from £500 per tonne in 2005 to £1,200 per tonne in 2018), increasing demand from overseas markets and a need to fill a gap due to declining Pacific whelk populations. In 2016, Welsh whelk landings amounted to 6.5 thousand tonnes. Landings fell steeply in 2018 and 2019. At present, the reduced landings in 2018 and 2019 cannot be attributed to a specific cause. The reduction may have been influenced by a combination of factors including, a reduction in the number of vessels fishing for whelks, an increased Minimum Landing Size (July 2019), adverse weather conditions, or may be indicative of unhealthy populations. Whelk fisheries are often considered as ‘boom and bust’, i.e. catches increase while demand is high, until catch rates become less economically attractive.


Criterion score: 0.75 info

There are management measures in place for this fishery, but they are not effectively managing the stock.

The Welsh whelk fishery is data-poor, and the absence of stock assessments has prevented the definition of Total Allowable Catch (TAC) limits.

The current management measure in place for this fishery, under The Whelk Fishing (Wales) Order 2019 is a Minimum Landing Size (MLS) of 65mm, which came into force 4th July 2020. Following a consultation on ‘Sustainable Management Measures for the Welsh Whelk Fishery’ in 2017, the Welsh Government increased the MLS from the EU-wide MLS of 45mm, to 55mm in July 2019, and a further increase to 65mm was set for July 2020. The MLS applies to all UK vessels taking whelks in the Welsh zone (which includes but is not limited to the territorial sea out to 12nm). However, Size of Maturity (SOM - the size at which 50% of the population is sexually mature) of whelks ranged between 67mm and 70.2mm in inshore areas of Fishguard and Saundersfoot. A further study has highlighted that whelks caught in warmer, shallower inshore waters mature at a smaller size than those in cooler, deeper waters. Whelk SOM was identified in Swansea Bay at 59.9mm, in the cooler waters of North Wales SOM ranged between 80.6-90.9mm, and in the Northern Irish Sea 116.8mm. Populations in deeper, cooler waters may reach lengths up to or >120mm. Whelks reach sexual maturity at different sizes around areas of Wales, depending on environmental conditions. Scientific evidence indicates many Welsh whelks, especially from cooler regions, do not reach sexual maturity until after they exceed the current MLS. Therefore, they do not have a chance to reproduce before they are fished.

Significant differences for most measured parameters (e.g. size, growth, age, maturity), suggest that large-scale management measures, such as the countrywide MLS currently adopted, is not a practical solution for management with regards to biological sustainability. Increases to the MLS would affect different regions of Wales, disproportionately. Small-scale management should be considered on a region-by-region basis, to assess the suitability of management measures. This approach has already been adopted by England, in the development of Inshore Fisheries Conservation Authorities (IFCA).

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.

The Welsh Government have proposed additional management measures outlined in the ‘Whelk Management Measures 2020’ consultation, which include an authorisation scheme (permits or licences) for all UK vessels taking whelk with pots in the Welsh zone, an annual limit on the total amount of whelk that can be taken from the Welsh zone to control fishing pressure, and a flexible monthly landing cap for authorised vessels. The consultation suggested whelk landings are lower during the biologically sensitive period (October-December) as sexually mature whelks do not tend to feed and consequently whelks are not attracted to baited pots at a time when adverse weather condition usually limits fishing activity. No known research has corroborated this submission and dismissal of spawning season protection is contrary to spawning season closures being proposed by other UK whelk fisheries. Given the lack of formal comparative stock assessments, proposed measures should do as much as possible to protect spawning individuals and maximise recruitment. The sharp decrease in whelk landings seen after 2017 may be indicative of unhealthy populations and dismissal of restrictions on fishing during spawning season could have detrimental effects on whelk populations. 78% of respondents to the 2017 whelk management consultation agreed that ‘closed seasons’ during spawning seasons were an effective management tool. Suggestions were also made that a biologically sensitive period may be required as an additional precaution in the 2020 consultation responses. Welsh Government policy officials are now considering all responses and seek to prepare new legislation and a new management process to sustainably manage the Welsh whelk fishery. Initially, these measures if enforced, will apply only to UK vessels. Once the post-Brexit regulatory and legislative framework has been determined, the Welsh Government may consider applying these measures to non-UK vessels.

The Whelk Working Group (WWG) was formed in 2019 to facilitate the exchange of information relating to the common whelk, Buccinum undatum, between IFCAs, other government agencies, fisheries authorities, academics, researchers and others interested in whelk fisheries. WWG aims to help improve and develop the understanding of whelk and look at the advantages of joint working to develop appropriate management. WWG is comprised of representatives from organisations engaged in the provision of evidence, advice and management of the whelk fishery on a national level. The Welsh governments involvement in WWG offers encouraging opportunities for future developments of effective whelk management by working together to improve communication, collaboration and consistency.

The UK is due to leave the EU on 31st December 2020, and new UK Fisheries legislation is being developed during 2020. MCS will update ratings with new management information when new legislation comes into force.

In the European Union (EU), EU fishing vessels can fish up to 12 nautical miles of any Member State coast, and closer by agreement. There is overarching fisheries legislation for all Member States, but implementation varies between fisheries, Member States and sea basins.

The EU Common Fisheries Policy (CFP) is the primary overarching policy. Its key environmental objectives are to restore and maintain harvested species at healthy levels (above BMSY), and apply the precautionary and ecosystem-based approaches to fisheries management. To achieve the MSY objective, the MSY exploitation rate is supposed to be achieved by 2020, but this seems unlikely to happen.

The CFP also introduced a Landing Obligation (LO) which bans the discarding at sea of species which are subject to catch limits. Some exemptions apply to species with high post-capture survival, and where avoiding unwanted catches is very difficult. These exemptions are outlined in regional discard plans. Despite quota ‘uplift’ being granted to fleets under the LO, available evidence suggests there has been widespread non-compliance with the policy, and illegal and unreported discarding is likely occurring.

Multi-Annual Plans (MAPs) are a tool for implementing the CFP regionally, with one in place or being developed for each sea basin. They specify fishing mortality targets and ranges for the main targeted species, as well as lower biomass reference points. If populations drop below these points it should trigger a management response. The MAPs also empower Member States to jointly apply measures such as closures, gear or capacity limits, and bycatch limits. There is concern however that the MAPs do not provide adequate safeguards to maintain all stocks at healthy levels.

The EU Technical Measures regulation addresses how, where and when fishing can take place in order to limit unwanted catches and ecosystem impacts. There are common measures that apply to all EU sea basins, and regional measures that vary between sea basins. Measures include Minimum Conservation Reference Sizes (MCRS, previously Minimum Landing Sizes, MLS), gear specifications, mesh sizes, closed areas, and bycatch limits.

The Control Regulation, which is being revised in 2019, addresses application of and compliance with the above, e.g. keeping catches within limits, recording and sharing data, and satellite tracking of vessels over 12 metres (VMS).

Capture Information

Criterion score: 0.25 info

Whelks are caught by pots in Welsh waters of the Irish Sea, St. Georges Channel, Celtic Sea, and Bristol Channel.

Almost all whelks are caught in baited pots, although some are taken as a bycatch of other fisheries. Whelks are found between low-water and depths up to 1,000 metres, but are most commonly caught in subtidal depths ranging between 40 to 60m. It is common for whelk pots to be left at sea permanently and hauled on a 1 to 3-day basis, re-baited and set again. Once hauled, most fishers in North and South Wales 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 potting is generally low and typically consists of starfish and various 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.

There is potential for potting to disrupt sensitive habitats.

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.


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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]

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