Common whelk (Buccinum undatum)
|Size||Shell height: 110 mm (2)|
Shell width: 60 mm (3)
Common and widespread; not listed under any conservation designations (2).
This large, common whelk has a stout, yellowish-brown shell with lighter and darker spiral areas (3). It has 7-8 whorls, and a large oval aperture (opening), which tapers to a point (3).
Common around all coasts of Britain (3), it also has a wide distribution in northwest Europe (2).
Found from the extreme low water mark of the intertidal zone down to depths of 1200m (3). It lives on soft sediments including muddy sand and gravel as well as on rocks (3).
This whelk is carnivorous, and feeds on polychaete worms and other molluscs, such as bivalves. It uses the edge of its shell to prize open bivalve shells (2), and may drill holes into the shell of its prey in order to access the soft tissues inside. It also scavenges for carrion, which it detects by smell from some distance (2). When searching for food, whelks extend a tube known as the 'siphon', which is used to funnel water to the gills, and leads to a sensory organ used for smelling prey (4).
The sexes are separate; breeding takes place from October to May, and the eggs are attached to rocks, shells and stones in protective capsules. Each capsule contains as many as 1000 eggs, and the capsules of several females are grouped together in large masses of over 2000 (2). Only a few of these eggs will develop; most eggs are used as a source of food by the growing embryos (3). There is no free-swimming larval stage (4), instead, crawling young emerge from the capsules after several months (3). Empty egg masses frequently wash up on beaches, and are often mistaken for sponges (2). They are known as 'sea wash balls' because they were once used to wash with (3).
Common whelks are thought to live for 10 years. They are fished commercially using traps; most whelks are exported to the Far East (2).
This species is currently widespread and not threatened.
Conservation action has not been targeted at this species.
For more information on this species see the Marine Link Information Network (MarLIN) species account, available at:
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- Larval: of the stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
- Whorls: in animals, the spiral or convolutions in the shell of a snail. In plants, a set of leaves, flowers, or branches that spring from a stem at the same point and encircle it.
National Biodiversity Network Species Dictionary (August, 2002)
- Fish, J.D. and Fish, S. (1989) A student's guide to the seashore. 2nd Edition. Cambridge University press, Cambridge.
Ager, O.E.D., 2001. Buccinium undatum. Common Whelk. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme. [on-line]. Plymouth: Marine Biological Association of the United Kingdom. (December, 2002)
The Living World of Molluscs (December, 2002)