Whelk, whelks

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

England (except EIFCA and KEIFA districts)


Picture of Whelk, whelks

Sustainability rating five info

Sustainability overview

The stock status of the whelk in English waters is unknown and localised stock assessments area needed.

There is a lack of management: current management includes a minimum landing size (MLS), and some effort restrictions. However, the MLS is too small to protect the whelks in this area. More management and monitoring is required, particularly since whelk landings have increased dramatically: in 2016, whelk landings represented the third largest landings of all species in England, worth over 10m pounds.

Pots generally cause a very low impact to the seabed.

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

Stock Area

UK

Stock information

Whelk populations are largely unknown. There have been anecdotal accounts of severely over exploited whelk stocks along the coast of England. Whelks are a particularly vulnerable species and once overfished they can potentially take a long time to recover.

Management

Criterion score: 0.75 info

There is a lack of management for whelk fisheries in English waters. Some Inshore Fisheries Conservation Authorities enforce a suite of management measures to protect the stock (see inshore ratings for more information).

The current management measure to regulate the whelk fishery is the 45mm shell length EU-wide Minimum Landing Size (MLS). However, the size at which half of the whelk population is mature varies largely throughout English waters e.g. between 57 mm to 75 mm total shell length (males) and 58 76 mm (females). Therefore, whelks are being caught before they get the chance to reproduce: in the Devon and Severn IFCA district, the MLS is too low to protect the spawning stock and ensure the sustainability of the fishery.

A landing size is not always suitable as the shape of whelks can vary considerably in different areas, from shorter squatter whelks to longer thinner whelks. Fishermen can catch multiple tonnes worth of whelk in one catch and therefore, it is extremely difficult to measure the size of all these small individuals effectively and the population crash in the Southern Irish fishery suggests that the EU-wide management measure for whelk is not sufficient to avoid such a crash.

There is some licensing and effort regulations throughout English waters but it is unknown if these are sufficient to protect the stock. Landings have been increasing in English waters, yet there have been anecdotal accounts of severely over exploited whelk stocks along the coast of England.

Vessels above 12m in legnth are required to use Vessel Monitoring Systems and record and report catch data electronically. Under 10m vessels must have a licence and collect data on effort and landings. A UK stock assessment has not been completed but populations vary spatially and therefore, stock assessments need to be made at a localised level.

A variety of data are required to determine the stock status: normally, CPUE data is collected, however, other biological parameters including recruitment and the stock (spawning stock biomass) should also be required.

Capture Information

Criterion score: 0.5 info

The majority of whelks are caught in pots. The risk to bycatch caused by these pots is generally low: bycatch typically consists of starfish (Asterias rubens) and various crab species (particularly Carcinus maenas). Bycatch are usually caught alive and undamaged and can be returned to the sea immediately. Endangered, threatened or protected species are rarely caught, though leatherback turtles have very occasionally become entangled in pot ropes. Recently a Humpback Whale was found entangled in whelk pot gear. There are a lack of data on interactions with protected species.

Whelk potting is a passive method of fishing: whelks enter the pot when they are attracted by bait. Pots are generally hauled every 1 to 3 days. The pots are laid on the seafloor (on muddy sand, gravel and/ or rocky substrates) in depths of around 10-30 m. 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.

Whelks are important prey for species such as cod, thornback rays, dogfish, bass and crustaceans; their populations have to be maintained to ensure a healthy ecosystem.

Since whelk pots are associated with negligible bycatch but there is a potential for distruption to sensitive habitats and known interactions with ETP species, which are not recorded, capture method is scored 0.5.

References

"KEIFCA. 2012. Impact Assessment for KEIFCA whelk byelaw. Available at: https://www.kentandessex-ifca.gov.uk/wp-content/uploads/2014/03/whelk-ia.pdf

Pearson, E. 2017. A collaborative study to develop and facilitate a fisher-directed stock assessment of Cancer pagurus in the inshore potting area, south Devon. University of Leicester.

Seafish. 2016. Project UK: Southwest Crab & lobster pot FIP: brown crab pre-assessment. Available at: http://www.seafish.org/industry-support/fishing/project-uk/project-uk-fisheries-improvements/southwest-crab-lobster-pot-fip

Southern IFCA. 2018. District Fisheries: Whelk. Available at: http://www.southern-ifca.gov.uk/district-fisheries#whelk-potting. [Accessed 17.11.17].

Association of IFCAs. 2014. New Whelk Byelaw embodies the IFCA vision. Available at: http://www.association-ifca.org.uk/Upload/K%20and%20E%20IFCA%20Whelk%20story%20.pdf

Devon and Severn IFCA. 2016. Determination of the Size of Maturity of the Whelk Buccinum undatum within the Devon & Severn IFCA District Supplementary Report: Start Bay. Research Report KS012016. Available at: https://secure.toolkitfiles.co.uk/clients/15340/sitedata/4F/Focussed_research_reports/Whelk-Report-2016.pdf

Eastern IFCA. 2016. Whelk permit whelk permit byelaw 2016. Available at: http://www.eastern-ifca.gov.uk/emergency-whelk-byelaw. [Accessed 16.11.17]. Eastern IFCA. 2016. Whelk permit byelaw. Available at: http://www.eastern-ifca.gov.uk/wp-content/uploads/2016/05/2016_11_03_Whelk_Permit_Byelaw_2016_Final.pdf.

Lawler, A. 2013. Determination of the Size of Maturity of the Whelk Buccinum undatum in English Waters Defra project MF0231. Report for CEFAS. Available at: file:///C:/Users/bev.o'kane/Downloads/11208_C5383-whelkmaturitystudyfinalreport%20(1).pdf.

Swarbrick, J. and Arkley, K., 2002. The evaluation of ghost fishing preventers for shellfish traps. Seafish Report No SR549. 46 pp.

Pierpoint, C. 2000. Bycatch of marine turtles in UK and Irish waters. JNCC Report No 310. 32 pp.

Vause, B. 2009. Species sheets available at: http://www.sussex-ifca.gov.uk/index.php?option=com_content&view=article&id=77&Itemid=173

ABPmer, 2015. Summary of Evidence Sources on Impacts of Potting on Designated Features. Workshop 25th February 2015. ABPmer. P1-9. "