This article was featured in Eurofish Magazine 6 2025.
Among the underestimated resources on the European seafood market are whelks, which are highly valued in other parts of the world, What kind of animals are these, how do they live, and what do they have to offer us?
The term “whelk” is used for numerous snail species, but strictly speaking it only applies to the roughly 50 species of the family Buccinidae, which differ slightly in size, shape, and colour, but all have a conical, spirally coiled shell. The majority of the “true” whelks live in temperate waters. Another common feature is the culinary value of the body of these molluscs, which are considered not only edible and nutritious, but in many regions of the world an outright delicacy. Whelks are unusually rich in protein (almost half of their dry matter consists of crude protein) and an excellent source of iron, zinc, copper, and potassium as well as vitamins B12 and E. They are typical marine inhabitants, preferring sandy or muddy habitats in coastal areas below the low-water line at ebb tide. Occasionally they have been found at depths of 1,400 m, but mainly the animals concentrate in the zone down to about 180 m.
Whelks are carnivores
A typical feature of whelks is their spiral conical shell of calcium carbonate, which depending on the species can be completely smooth or equipped with ribs or knobs in striking arrangements. It provides solid protection from surf in upper subtidal habitats and from predators. The soft body consists of the strong, very muscular foot and a relatively small head with a tubular “snout” containing a rasping tongue (radula) as its central feeding tool. Unlike land snails, the simple eyes (ocelli) are not at the tips of the sensory tentacles (“feelers”) but at their base. These sense organs react sensitively to light and tactile stimuli. When the snail retreats into its shell, it closes the oval opening with a perfectly fitting plate (operculum) made of robust material located on the foot. Oxygen is absorbed via a gill and transported to the tissues and organs by means of haemolymph, a blood-like fluid that circulates freely in the body (open circulatory system), driven by the two-chambered heart.
Unlike many other sea snails, whelks do not eat algae or other aquatic plants, but feed mainly as predators on various prey animals, though they occasionally rely on freshly dead carrion. Their prey spectrum includes polychaetes and other worms, small mussels, echinoderms, crustaceans, and fish eggs. They track down their prey by traces of its scent in the water. In the search they extend their tubular siphon and pump water into the gill, which is connected to highly sensitive chemoreceptors that perceive scent trails. As soon as the whelk has picked up a trace, it approaches the potential prey at “top speed” of up to 15 cm/min (this pace can be maintained over distances of several metres!). To get to the nutritious flesh hidden under the protective shell of mussels or crabs, the snail can use several techniques. For example, it can bore a hole in the armour of its prey with its rasping tongue, or it can press the sharp edge of its hard shell against a mussel shell so firmly and for so long that pieces eventually break off. Here the muscle strength of its foot pays off, as it can exert enormous pressure. Once an opening has been created, the meal can begin. With its rasping tongue, the whelk scrapes the victim’s flesh thoroughly from the shell in small pieces.
No pelagic larval stage
Incidentally, the living colouration of the snail shells can differ depending on species and location. Shells of dead snails, which one occasionally finds on beaches, usually appear white or cream-coloured. In living whelks, however, they are covered with a thin brownish layer, the so-called periostracum, whose exact shade is also influenced by the preferred diet. Yet, since healthy marine ecosystems usually maintain “balance and fairness,” whelks themselves are targeted by numerous predators. Young life stages in particular often appear on the menu of cod, spiny dogfish, rays, flatfish, large crabs, and sea turtles, as well as -starfish and sea urchins. Presumably only a few whelks reach their maximum age, which is reported to be a remarkable 40 years.
Globally, officially recorded landing volume of whelks rose temporarily to over 40,000 t
at the beginning of the 2020s.
The onset of sexual maturity varies in whelks depending on species, age, and size. Usually the female is fertilised by several males. It then develops thousands of eggs, which—enclosed in lens-shaped capsules that can contain several hundred eggs—are typically attached from October to May in long sticky strings to hard structures such as rocks, mussels, or stones. The capsule chains with the whitish eggs, from which after four to five months tiny and fully developed whelks hatch (there is no planktonic larval stage!), are often called “fishermen’s soap” because when rubbed with water they produce a foamy secretion. Because there is no swarming larval stage in whelk reproduction, their dispersal potential is low. In addition come the low mobility and limited activity radius of adult snails. Even directly neighbouring populations scarcely mix. Therefore, particular caution is required in whelk fisheries, as replenishment of overfished stocks and recolonisation of affected areas would be difficult and take a very long time.
Commercial interest in whelks is growing
The best protection for “population-dynamic low performers” such as whelks would naturally be a complete ban on their capture. However, this seems difficult, as interest in their commercial use is growing. Specimens are repeatedly found as bycatch in lobster pots, bottom trawls, and mussel dredges, which are now no longer discarded but landed. In some regions of the world they are considered annoying pests because they supposedly destroy local shellfish and crustacean stocks, among the reasons for which they were fished in the past.
When the snail retreats into its shell, it closes the oval opening
with a perfectly fitting plate (operculum) made of robust material located on the foot.
The most economically important whelk species in European waters is Buccinum undatum, usually called northern, edible, or simply European whelk. It is widespread in the North Atlantic and occurs along the coasts of North America from western Greenland to New Jersey and in Europe from Iceland and Norway to the Bay of Biscay. The shell of this snail species has 7 to 8 whorls with spiral ribs, whose wavy folding pattern is yellowish-brown with irregularly distributed light and dark spiral areas. At 10 cm high and 6 cm wide, it is the largest sea snail on Europe’s coasts.
Strong demand drives fishing
Driven by growing demand from domestic and foreign markets in the globalised seafood trade, targeted fishing of whelks experienced a visible upswing towards the end of the 20th century. According to FAO statistics, worldwide landings quintupled in just three decades from around 7,000 t in 1990 to nearly 41,000 t in 2021 (subsequently falling to 34,000 tonnes in 2023). Actual volumes are likely to be even higher, since data collection shows gaps especially with these “minor species.” This rapid increase in catch and landing volumes is not only the result of increased fishing effort, but also due to improved fishing technologies. Within a very short time, fishing methods for whelks were made more professional and perfected. The devices are baited traps that work on the principle of lobster pots. They are usually simple plastic tubes, weighted at one end with a concrete block for fixed positioning on the seabed, and fitted at the other end with a net that allows snails to enter, but keeps out fish, crabs, and other unwanted species attracted by the bait. To make retrieval of the traps more efficient, several are usually connected in a chain by ropes. Every two to three days they are hauled up from the seabed to remove the catch and, if necessary, renew the bait.
Stock control is relatively difficult
Although undersized snails identified during inspections were immediately thrown back, these devices fished so effectively that in many areas, with intensive fishing, clear signs of stock declines and overfishing soon appeared. This pointed emphatically to the necessity of effective fisheries management to protect whelks. Implementation of these demands was, however, more complicated than originally thought. Even the control of the prescribed minimum sizes was very difficult, because it was initially unclear how and at which points the asymmetrically built shells should be measured. Several methods proved impractical, as they were too cumbersome and inaccurate. In North America, therefore, a special procedure was developed that combines two measurement methods. The first—chute gauge—is a rigid three-sided measuring device whose internal wall distance corresponds to the minimum shell width. Subsequently, however, the snail is measured again with a second method. The animal must be pulled through the device lying flat with the shell opening facing downward, so that the axis between siphonal canal and shell top runs parallel to the walls of the device. Snails that pass through the device without difficulty are considered undersized and must be released. This procedure provides fairly reliable results, but is cumbersome and time-consuming and has therefore not yet been adopted everywhere.
Whelks should be cooked in salted water for not longer than 10-15 minutes depending
on the size otherwise they can get tough and rubbery.
To effectively protect whelk stocks, fisheries management therefore uses a whole bundle of measures. These range from licences for commercial fishers and precise specifications for the number and size of fishing gear used, as well as their individual marking to enable personal assignment to fishers, through the establishment of closed seasons, to catch limits, so-called bag limits. In addition, CPUE (catch per unit of effort), an important figure measuring the amount of snails caught in relation to the fishing effort applied, serves as a useful proxy for the biomass of stocks. A higher CPUE generally indicates a healthier or more numerous stock. However, only a small part of whelk fisheries is actually managed, since most animals are still collected or fished unregulated and uncontrolled. Nevertheless, there has been an MSC-certified whelk fishery in Normandy since 2021. The 72 boats of this fishery in Granville Bay between Granville and Cap de la Hague land about 6,000 to 9,000 t of whelks annually, mostly exported to the Far East. Attempts to produce these animals in aquaculture are also known, especially from China, South Korea, and Vietnam.
