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

Jersey


Picture of Whelk, whelks

Sustainability rating five info

Sustainability overview

Whelk populations in Jersey appear to have declined since 2004 and there are signs of potential recruitment overfishing.

The current management in the fishery is not effective for managing the stock.

Pots generally cause a very low impact to the seabed and bycatch is limited in EIFCA because they mandate that pots have escape gaps.

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

A stock assessment in Jersey from 2015 found that whelk populations appear to have declined since 2004 and there are signs of potential recruitment overfishing. The report suggested that existing management measures may not be effective.

Management

Criterion score: 0.75 info

The current management in the fishery is not effective for managing the stock.

The current management measure to regulate the whelk fishery is the 45mm shell length EU-wide Minimum Landing Size (MLS). However, this is smaller than the size at which they mature throughout much of England’s waters (on average they mature between 57 mm to 75 mm total shell length (males) and 58 76 mm (females)). Minimal landing size are not an effective measure to manage whelks as an independent management measure and therefore, whelks are being caught before they get the chance to reproduce.

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 and 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 VMS 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 completed 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: 0.25 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. There are a lack of data on these interactions.

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 (includes juveniles, overfished and/or vulnerable or ETP species); but there is a potential for distruption to sensitive habitats, capture method is scored 0.25.

References

"Shrives, J.P., Pickup S.E., Morel, G.M. 2015. Whelk (Buccinum undatum L.) stocks around the Island of Jersey, Channel Islands:reassessment and implications for sustainable management. Fish Res 167: 236-242

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. "