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 — UK
Stock detail — UK EEZ (Except England 0-6nm and Welsh waters)
Picture of Whelk, common whelk

Sustainability rating five info

Sustainability overview

Updated: June 2020.

Across much of the common whelks range there is a lack of suitable data and therefore stock status is largely unknown in the UK and elsewhere, and regional stock assessments are needed. Although there is limited data available on whelk stocks, the data that does exist indicates that there is concern for biomass levels. UK whelk populations are likely to be subject to overfishing. 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 stock. 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 throughout UK waters. 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.

Biology

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 likely to be above sustainable levels.

Whelk (Buccinum undatum) populations around the UK are largely unknown and there have been anecdotal accounts of severely overexploited whelk stocks throughout the United Kingdom (UK) coastline. The lack of comprehensive stock assessments has resulted in a level of uncertainty of the current status of whelk populations around the UK. Whelks are a particularly vulnerable species and once overfished they can take a long time to recover. UK whelk landings increased from 8.4 to 22.7 thousand tonnes between 2003-2016, and were valued at £21.9 million in 2018.

UK whelk stocks are not formally assessed. 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 and 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.

Small artisanal whelk fisheries have existed in the UK since the early 1900s, with annual landings of 4.5 thousand tonnes reported for England and Wales in 1911. Increasing demand for whelks, particularly from overseas markets, and the depletion of some Pacific whelk stocks, have been significant drivers in increased landings in more recent years. Sea Fisheries Statistics identified a 667% rise in the total whelk landings between 2010 and 2013. The following year witnessed a plateau, despite an increase of 41% in the total number of vessels landing whelks per month. Between 2014 and 2016 the total landings rose from 19.8 to 22.7 thousand tonnes, plummeting to 20.7 and 17.9 thousand tonnes in 2017 and 2018, respectively, despite demand and value continuing to climb from approximately £500 per tonne in 2005 to £1,200 per tonne in 2018. Observations of a reduced Catch Per Unit Effort (CPUE) could be indicative of a fishery exceeding sustainable limits. Whelk fisheries are often considered as €˜boom and bust , i.e. catches increase while demand is high, until catch rates become less economically attractive.

There are several valuable whelk fisheries throughout the UK, some being of particular importance due to their localised nature and because they are often a seasonal alternative for fishers that predominantly target crab and lobster. They are reportedly becoming a popular displacement fishery as vessels move from other, more regulated species, into the less regulated whelk fisheries. For these reasons, they are amongst the most important shellfish fisheries for the UK, alongside Nephrops, scallop, crab and lobster. Whelks are now the 6th most economically important species in the UK.

Management

Criterion score: 1 info

There are no appropriate management measures in place for this fishery. The current management measure in place is not effective in managing the stock.

United Kingdom (UK) whelk fisheries are data-poor, and the absence of stock assessments has prevented the definition of Total Allowable Catch (TAC) limits and presents a number of challenges for management. There are no biologically referenced catch or effort restrictions. Fisheries management responses to whelk population declines have been precautionary in approach when compared to management decisions for other commercially important species. Some Inshore Fisheries Conservation Authorities (IFCA) enforce more comprehensive management to protect inshore whelk stocks.

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. This is the only management regulation transposed into UK fisheries legislation for the protection of whelk (B. undatum). 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 single increase to the current MCRS would impact fishers disproportionately. Smaller-scale management should be considered on a region-by-region basis throughout all UK waters, to assess the suitability of each measure per capture area.

Cefas research between 2012-2013 estimated whelk Size of Maturity (SOM - the size at which 50% of the population is sexually mature) in the main fishing grounds across England. It was determined, for all sampled sites except the Solent, that the current EU MCRS does virtually nothing to protect whelk spawning stocks. The study highlighted SOM, was on average >62.7mm in inshore areas. However, whelks caught in shallow waters mature at a smaller size than those in colder, deeper waters. Whelk SOM was identified at 116.8mm and lengths up to or >120mm in populations in cooler, and deeper waters further out to sea. Consequently, whelks are being caught before they have chance to reproduce. The current MCRS offers inadequate protection to the spawning stock and increases the probability of recruitment overfishing.

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.

Additional management measures must be employed to manage whelk stocks around the UK. Proposals have included a closed season during spawning periods to provide added protection to the spawning stocks, although due to limited data on the precise timings of whelk spawning further research is required to understand the most appropriate period for this closure. Secondly, in most commercially exploited fisheries, TACs are annually defined to provide a limit on the amount of biomass removed from a fishery. These values are set as numbers of individuals or tonnes based on accurate stock assessment evaluations. The absence of such assessments for whelk fisheries contributes to the dearth of data from which TACs can be set. Therefore, these data shortages need to be addressed in the future before this strategy can be adopted. Thirdly, limitations on the allowable number of pots and permit schemes are an effective, enforceable way of controlling fishing effort, and has been adopted by other shellfish fisheries (e.g. crab and lobster) and have already been implemented by some IFCA districts. A final overarching issue that is not clearly defined, which is paramount for any fisheries management decision, is having a defined target to which the fishery should be managed, this is often Maximum Sustainable Yield (MSY), but can also be based on spawning stock biomass.


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: 0.5 info

Whelks are caught by pots in the United Kingdom (UK) Exclusive Economic Zone (EEZ).

Almost all whelks are caught in baited pots, although some are taken as a bycatch of other fisheries. Whelk landed as bycatch is primarily from UK crab and lobster pot fisheries. Whelks are found between low-water and depths up to 1,000 metres but are commonly caught in subtidal depths between 40m and 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 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.

Whelk fishing may take place on a variety of substrates, most studies that have been carried out to date have not found any significant impacts of potting on benthic habitats and communities. However, there is potential for potting to disrupt specific, sensitive habitats (e.g. maerl, seagrass, mussel beds, Sabellaria, subtidal mixed sediments). Evidence from a sub-feature in one region may not be directly transferable to the same sub-feature in another region, because of site-specific differences (such as topography, species composition, wave energy and depth, as well as pot type and gear configuration).

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.

References

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]

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]

Elliot, M. and Holden, J. (eds) (2018). UK Sea Fisheries Statistics 2018. Marine Management Organisation, London. pp.1-155. Available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/863732/UK_sea_fisheries_statistics_2018.pdf [Accessed 11.06.2020]

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]

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]

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. Contract Reference: MMO1086. Final Report November 2015. DEFRA,UK. pp.1-49.