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 — North Sea, South-East coast of England
Stock detail — 4c: Kent and Essex IFCA District (0-6nm)
Picture of Whelk, common whelk

Sustainability rating four info

Sustainability overview

Updated: June 2020.

Whelk populations in English waters are largely unknown and localised 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 biomass levels. Whelk populations within Kent and Essex IFCA district, in the South-East coast of England 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. Some management measures are in place, including a Minimum Landing Size (MLS), fishing effort limitations and gear restrictions within the district. However, the current MLS is too small to protect the whelk stock in the Kent and Essex IFCA district and 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 along the coast of England. The lack of comprehensive stock assessments has resulted in a level of uncertainty of the current status of English whelk populations. Whelks are a particularly vulnerable species and once overfished they can take a long time to recover. Whelk fishing has been increasing throughout England over the past few years. UK whelk landings have steadily increased from 8.4 to 22.7 thousand tonnes between 2003 and 2016 and were valued at over £22.9 million in 2016. Within England, whelk catches are regularly recorded along its entire coastline.

Whelk stocks within Kent and Essex IFCA district are not formally assessed. The recent increase in exploitation of whelk fisheries within England 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.

Sea Fisheries Statistics over the last decade revealed the total whelk (B. undatum) landings in Kent and Essex IFCA have shown a substantial increase of ca. 4,600%, rising from 36 tonnes to 1,700 tonnes between 2008 and 2016. Although, MMO landings data from 2014-2016 did not place Kent and Essex IFCA district s ports within the top 10 ranking ports out of the ten IFCA districts, based on whelk landings (tonnage). Moreover, annual whelk landings in 2017 dropped to ~1,100 tonnes (live weight) compared to ~1,700 tonnes recorded in 2016. Annual landings fluctuations can be indicative of boom and bust fisheries.

Management

Criterion score: 0.5 info

There are management measures in place for this fishery, which are partly effective in managing the stock.

Availability of UK whelk fishery data is generally quite 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.

The current management measure in place for this fishery is a Minimum Landing Size (MLS) of 53mm, which was introduced on 1st February 2020 under the Whelk Minimum Size Emergency Byelaw 2020. This emergency byelaw replaces the previous whelk MLS of 45mm, shell height. 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. Cefas estimates of SOM for all sampled sites except the Solent indicate that the current EU Minimum Conservation Reference Size (MCRS) of 45mm does virtually nothing to protect whelk spawning stocks across England. The study found that SOM in the Kent and Essex IFCA district was greater than the EU MCRS of 45mm, generally above that of the current MLS and up to 64mm in some areas. Therefore, the current emergency MLS of 53mm still offers insufficient protection to the spawning stock, reflective of the entire district.

Permits are now required to catch whelk within the Kent and Essex IFCA district. Further management measures which have been introduced in the Kent and Essex IFCA district, which, as part of the Whelk Fishery Permit Byelaw conditions includes pot limitations, escape holes and a minimum riddle size. The whelk permit stipulates a limitation of 300 pots per vessel which must be tagged. From the 3rd April 2017 permit conditions altered the original specified riddle size of 22mm to 25mm, which affords greater protection to immature (smaller) whelks, and a minimum of two escape holes to increase to 10 per whelk pot, equal to or >25mm. The whelk byelaw requires fishers to fish in accordance with flexible permit conditions, which are updated annually. Fishers are required to provide monthly submissions of catches, fishing effort and areas fished.

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.

Kent and Essex IFCA have conducted some initial studies on the effectiveness of the type of riddle used (cylindrical or mechanical), to implement appropriate changes to landing size restrictions and riddle conditions. Kent and Essex IFCA have also conducted a suite of research projects, largely in collaboration with Bangor University. Studies have been commencing for almost 5 years focusing on sampling whelks from different areas within the district to determine spatial distributions of length, width, sex-ratio, maturity and age. Subsequently, this research has supported Kent and Essex IFCA in introducing conditions as part of the Whelk Fishery Permit Byelaw. The district is continuing to explore other management measures to improve sustainability goals, such as the introduction of new riddle designs. Continued research could lead to the future development of improved management practices within the whelk fishery.

Indeed, several viable management strategies have been suggested by various IFCA districts 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 important reproductive periods. An increase to the current MLS has been suggested as another feasible management measure in numerous studies. Such measures, could support better management of the stock within the districts alongside localised stock assessments.

The Whelk Working Group (WWG) was formed in 2019 to facilitate the exchange of information relating to the common whelk, Buccinum undatum, between Fisheries and Conservation Authorities (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 WWG offers encouraging opportunities for future growth of effective whelk management by working together to improve communication, collaboration and consistency.


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

Whelks are caught by pots in Kent and Essex IFCA district, within the North Sea off the South-East coast of England.

Whelks in the UK are almost exclusively caught using baited traps, set for approximately 48 hours, as attraction to bait reduces significantly beyond that period of time. Kent and Essex IFCA whelk fishery uses baited whelk pots in subtidal depths between 10-30m. Whelk pots are baited with edible crab or dogfish and set using a number of pots attached to one string. Once hauled the catch from each pot is passed through a riddle with a minimum bar spacing of 25mm or greater. A riddle or any like instrument 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 the larger whelks.

The risk of bycatch from whelk potting is generally low and typically consists of starfish and various crab species, particularly spider crab. 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.

References

Brown, J., Macfadyen, T., Huntington, J., Magnus and J. Tumilty (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.

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

Hollyman, P. and Richardson, C. (2018). Age and growth rate of whelks, Buccinum undatum, in Kent and Essex waters. KEIFCA and Bangor University: Anglesey, 22pp.

Kent and Essex IFCA (2013). New Whelk Byelaw embodies the IFCA vision. Kent and Essex Inshore Fisheries and Conservation Authority, 3pp.

Kent and Essex IFCA (2014). Whelk Fishery Permit Byelaw. Kent and Essex Inshore Fisheries and Conservation Authority, 8pp.

Kent and Essex IFCA (2020). Potting whelks. Available at https://www.kentandessex-ifca.gov.uk/im-interested-in/fishing-commercially/potting-2/whelks/ [Accessed 02.06.2020]

Kent and Essex IFCA (2020). Whelk Minimum Size Emergency Bylaw (2020). Kent and Essex Inshore Fisheries and Conservation Authority, 2pp.

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]

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]