Whelk

Whelk
	Whelk ( Buccinum undatum )
Systematics
Order :	Sorbeoconcha
Partial order :	New snails (Neogastropoda)
Superfamily :	Buccinoidea
Family :	Horn snails (Buccinidae)
Genre :	Buccinum
Type :	Whelk
Scientific name
	Buccinum undatum
	Linnaeus , 1758

Egg capsules

Housing of Buccinum undatum

The Whelk ( Buccinum undatum ) is a snail species from the family of horn worm (Buccinidae, genus Buccinum ) that throughout the North Atlantic Ocean is located. It feeds mainly on poly bristles , mussels and carrion . In the North Sea , their stocks have declined sharply due to water pollution.

features

The right-hand wound, pointed egg-shaped snail shell of Buccinum undatum is about 6 to 11 cm high in adult snails. It is therefore the largest snail species in the North Sea. The eight arched, rarely rather flat whorls are separated by a depressed, wavy seam and increase regularly. The body circumference is very large and takes up about three fifths of the length of the housing. The case is more or less corrugated across the turns by oblique indentations, hence the name. The grooving can also be missing on the lowest turns. There are also finer ribs that run spirally, i.e. parallel to the windings. The oval housing mouth is large and wide, but lower than the thread and has an outer lip that is thickened in the adult stage and more or less bulged at the top and drawn out into a short siphon canal at the bottom. The irregularly wound spindle is provided with a callus.

The surface of the housing, which has a thin, smooth, brown periostracum , is whitish to yellowish brown. The mouth is usually whitish, the spindle usually orange, but the inside of the housing can also have a stronger orange color.

The horny operculum is oval and has a nucleus close to the edge.

The snail has a flat head, truncated in front. The very long antennae are located at the corners, with the small black eyes at the base of a broadening. The foot is rounded at the back and at the front corners. The animal's coat and foot are cream colored with black spots.

Occurrence

The whelk can be found in the coastal areas of the entire North Atlantic . It is found on the west coast of Europe from the Arctic Ocean to the Bay of Biscay , on the east coast of North America it occurs from the Arctic to the height of New Jersey . It rarely occurs at greater depths in the Mediterranean .

It prefers cold waters with a salt content of two to three percent and lives at depths between 5 and 1200 meters. The snails occur mainly on soft soils, on which they can move quickly, but also on hard soils.

Life cycle

The whelks live up to 15 years old and, like most front gill snails, are of separate sexes. The sexual maturity is reached at about 6 cm length of casing. The male mates with the female with the help of his penis , which in mature males is more than half as long as the snail shell. In autumn the female lays fist-sized clumps of up to 2000 egg capsules, each containing an average of around 1000 (up to 3000) eggs. Of these, around ten to fourteen eggs develop per capsule, while the rest serve as food eggs. Sometimes the clutches attached to stones, rocks or mollusc shells, which can come from several dams, grow up to 50 cm.

The spherical, on average 340 μm large fertile eggs do not differ externally from the diet eggs. The entire development up to the finished young snail takes place in the egg capsule. After about ten weeks (at 8-11 ° C), young animals hatch whose brown snail shell measures about 2 millimeters and has one and a half to two whorls. According to other studies, the development takes 133 to 140 days at 6 ° C.

nutrition

Whelks are carnivorous mollusks and prey on worms , crabs and mussels . In addition, they eat carrion .

Clams are attacked when the snail puts its foot on the edge of the clamshell. As soon as the mussel opens, the snail pushes the edge of its shell between the shells. An opening of 1.3 mm is sufficient to insert the proboscis . A 5 cm whelk will eat a 2.5 cm cockle in 10 to 20 minutes. While the cockle Cardium edule is quickly captured in this way, other types of mussels flee, for example scallops swim away. Other types of mussels, including mussels , remain closed long enough for the snail to crawl away.

Remains of polychaetes , mussels and sea urchins have been found in the stomachs of whelks . It is unclear how high the proportion of animals captured alive or found dead was in each case. Whelks can spot carrion with their sense of smell over long distances. Adult whelks appear to benefit from the hunting activity of starfish , which they seek proximity to consume leftover meat.

According to intestinal examinations, polychaetes make up about 60% of Buccinum undatum's prey in the Northwest Atlantic .

Enemies

Important enemies of the whelk are various birds, including waders such as the oystercatcher . Some fish and crabs can also crack the shells of the snail.

The enemies of the whelk also include various types of starfish . The snails can perceive them by their smell ( saponins ) and also distinguish them from harmless starfish. Small whelks can avoid approaching the starfish by evading. Larger whelks are more tolerant of starfish than small ones; they only show violent escape reactions such as rollover when they come into direct contact . The snails apparently benefit from the starfish, which only partially eat the mussels, leaving the snails with the remains of their prey to eat.

Danger

Since the beginning of the 1970s, a decrease up to the point of collapse of the whelk population has been observed, so that the snail has become extinct in the Wadden Sea on the entire Dutch coast and in the German Bight . Studies have shown that tributyltin (C ₄ H ₉ ) ₃ SnH, a chemical used for protective coatings on ships, leads to the formation of male reproductive organs in females of whelks, but also in other snails (e.g. spiked snails ). These females, affected by the so-called imposex , can no longer lay eggs.

commercial use

Boiled whelks pulled out of the house

Whelks used to be an important food for the poor population in coastal regions . Today, however, they no longer play a major role as seafood in Europe . They are considered a delicacy in France , Belgium , the Netherlands and Korea .

Others

In the past, empty, detached egg clusters collected on the beach were used as cleaning sponges. When dried and crushed, the egg shells act as itch powder . The shells of dead whelks are preferably inhabited by hermit crabs . Therefore whelk shells are rarely found on the beach.

Individual evidence

↑ E. Kenchington and A. Glass: Local Adaptation and Sexual Dimorphism in the Waved Whelk (Buccinum undatum) in Atlantic Nova Scotia with Applications to Fisheries Management (PDF file; 2.16 MB). Canadian Technical Report of Fisheries and Aquatic Sciences No. 2237, Dartmouth, Nova Scotia 1998.

↑ Erwin Stresemann (Ed.): Excursions fauna. Invertebrates I. SH Jaeckel: Mollusca . People and Knowledge, Berlin 1986. P. 133 f. Whelk, Buccinum undatum L.

↑ Syafruddin Nasution (2003): Intra-Capsular Development in Marine Gastropod Buccinum undatum (Linnaeous 1758) ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (PDF; 49 kB) [sic!]. Jurnal Natur Indonesia 5 (2): 124-128 (2003)@1@ 2Template: Dead Link / www.unri.ac.id

↑ Kathryn E. Smith, Sven Thatje (2012): Nurse egg consumption and intracapsular development in the common whelk Buccinum undatum (Linnaeus 1758) . Helgoland Marine Research, 2012, doi : 10.1007 / s10152-012-0308-1 .

↑ Claus Nielsen (1975): Observations on Buccinum undatum L. attacking bivalves and on prey responses, with a short review on attack methods of other prosobranchs. Ophelia, 13: 87-108. doi : 10.1080 / 00785326.1974.10430593 , picture from the article with comment

↑ JH Himmelman and J. -R. Hamel (1993): Diet, behavior and reproduction of the whelk Buccinum undatum in the northern Gulf of St. Lawrence, eastern Canada . Marine Biology, vol. 116, Number 3 (1993), pp. 423-430.

↑ John D. Taylor (1978): The diet of Buccinum undatum and Neptunea antiqua (Gastropoda: Buccinidae) . Journal of Conchology, vol. 29, p. 309

Jump up ↑ Christian Harvey, Francois-Xavier Garneau, John H. Himmelman (1987): Chemodetection of the predatory seastar Leptasterias polaris by the whelk Buccinum undatum (PDF file; 631 kB). Marine Ecology Progress Series, vol. 40, pp. 79-86,1987.

↑ Ten Hallers-Tjabbes, CC, Everaarts, JM, Mensink, BP, & Boon, JP (1996) The Decline of the North Sea Whelk (Buccinum undatum L.) Between 1970 and 1990: A Natural or Human-Induced Event? 17: 1-3. pp. 333-43. Marine Ecology.

↑ Mensink, BP, Everaarts, JM, Kralt, H., ten Hallers-Tjabbes, CC, & Boon, JP (1996) Tributyltin exposure in early life stages induces the development of male sexual characteristics in the common whelk, Buccinum undatum. 42: 1-4. pp. 151-154. Marine Environmental Research .

↑ Beatrice Froese, Barbara Kohmanns (1997): Environmental chemicals with hormonal effects. (PDF file; 260 kB) Bavarian State Office for the Environment.

literature

Wilhelm Kobelt : The genus Buccinum L. P. 12-93: Genus Buccinum L. s. st. (Tritonium Müller). Pp. 15-21, No. 1: 1. Buccinum undatum Linné . W. Kobelt and HC Weinkauff (eds.): Systematisches Conchylien-Cabinet, Nuremberg 1883.
Peters S. Dance (Ed.): The great book of sea shells. Snails and mussels of the world's oceans. German edited by Rudo von Cosel, Verlag Eugen Ulmer, Stuttgart 1977, ISBN 3-8001-7000-0
John D. Fish, Susan Fish: A Student's Guide to the Seashore . Cambridge University Press, Cambridge 2011. 540 pages. Buccinum undatum Linnaeus , p. 233.