Common periwinkle

For the shrub with the same vernacular name, see Vinca minor.

Common periwinkle
File:Sea snail, underneath, full view.jpg
Periwinkle emerging from its shell, Sweden
File:Littorina littorea 001.jpg
L. littorea on the edge of a small sandy beach in Woods Hole, Massachusetts
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
(unranked):	clade Caenogastropoda clade Hypsogastropoda clade Littorinimorpha
Superfamily:	Littorinoidea
Family:	Littorinidae
Genus:	Littorina
Species:	Littorina littorea
Binomial name
Littorina littorea (Linnaeus, 1758)
Synonyms
Littorina armoricana Locard, 1886 Littorina bartonensis Brown, 1843 Littorina communis Brown, 1843 Littorina litorea (Turton, 1819) Littorina litorea var. brevicula Jeffreys, 1865 Littorina litorea var. paupercula Jeffreys, 1865 Littorina litorea var. sinistrorsa Jeffreys, 1865 Littorina litorea var. turrita Jeffreys, 1865 Littorina littorea f. intermedia Brøgger, 1901 Littorina littorea var. angulata Harmer, 1920 Littorina littorea var. antiqua Wood, 1848 Littorina littorea var. balteata Dautzenberg & Durouchoux, 1912 Littorina littorea var. complanata Harmer, 1920 Littorina littorea var. conica Harmer, 1920 Littorina littorea var. deformis Wood, 1848 Littorina littorea var. delphinula Wood, 1848 Littorina littorea var. distorta Harmer, 1920 Littorina littorea var. elegans Wood, 1848 Littorina littorea var. fuscofasciatus Middendorff, 1849 Littorina littorea var. major Dautzenberg & Durouchoux, 1913 Littorina littorea var. miniata Dautzenberg & Durouchoux, 1900 Littorina littorea var. pallida Dautzenberg & Durouchoux, 1900 Littorina littorea var. pallidefasciatus Middendorff, 1849 Littorina littorea var. parva Harmer, 1920 Littorina littorea var. picta Wood, 1848 Littorina littorea var. pyramidata Wood, 1848 Littorina littorea var. sanguinea Dautzenberg & Durouchoux, 1906 Littorina littorea var. truncata Harmer, 1920 Littorina littorea var. unicarinata Raeymaekers, 1889 Littorina parva Teilman-Friis, 1898 Littorina rudis var. aurantia Dautzenberg & P. Fischer, 1925 Littorina rudis var. reevei Harmer, 1921 Littorina sphaeroidalis Locard, 1886 Littorina vulgaris J. Sowerby, 1832 Turbo bicarinatus Woodward, 1833 Turbo carinatus Woodward, 1833 Turbo elongatus Woodward, 1833 Turbo litoreus Turton, 1819 Turbo littoreus Linnaeus, 1758 (basionym) Turbo sulcatus Woodward, 1833 Turbo ustulatus Lamarck, 1822 Turbo ventricosus Woodward, 1833

The common periwinkle or winkle (Littorina littorea) is a species of small edible sea snail, a marine gastropod mollusc that has gills and an operculum, and is classified within the family Littorinidae, the periwinkles.

This is a robust intertidal species with a dark and sometimes banded shell. It is native to the rocky shores of the northeastern, and introduced to the northwestern, Atlantic Ocean.

Description

File:Littorina littorea 02.JPG

Shell of the common periwinkle

The shell is broadly ovate, thick, and sharply pointed except when eroded. The shell contains six to seven whorls with some fine threads and wrinkles. The color is variable from grayish to gray-brown, often with dark spiral bands. The base of the columella is white. The shell lacks an umbilicus. The white outer lip is sometimes checkered with brown patches. The inside of the shell has a chocolate-brown color.

The width of the shell ranges from 10 to 12 mm at maturity, with an average length of 16–38 mm.

Shell height can reach up to 30 mm, 43 mm or 52 mm.

As a result of its robust nature, Littorina littorea can be highly variable in phenotype with several different morphs present. Its phenotypic variations may be indicative of a speciation event, as opposed to phenotypic plasticity. This is of particular importance to evolutionary biology, as it presents the possible opportunity to view a transitional phase in the evolutionary life of an organism.

Distribution

Common periwinkles are native to the North-eastern coasts of the Atlantic Ocean, including northern Spain, France, England, Scotland, Ireland, Scandinavia, and Russia.

Introductions to North America

Common periwinkles have been introduced to the Atlantic coast of North America, possibly by rock ballast in the mid-19th century. The first recorded case was in 1840 in the Gulf of St. Lawrence. It is now a predominant mollusc from New Jersey northward to Newfoundland. It was accidentally introduced to the North American East Coast within the last few centuries and it is now extraordinarily abundant on New England rocky shores. In Canada, their range includes New Brunswick, Nova Scotia, Quebec, Newfoundland and Labrador.

This species is also found on the West Coast of the United States, from Washington to California. L. littorea is now the most common marine snail along the North Atlantic coast. It has changed North Atlantic intertidal ecosystems via grazing activities, altering the distribution and abundance of algae on rocky shores and converting soft-sediment habitats to hard substrates, as well as competitively displacing some native species. The presence of this species has caused extensive damage due to interspecific competition with native intertidal gastropods.

Ecology

Habitat

The common periwinkle is mainly found on rocky shores in the higher and middle intertidal zone. It sometimes lives in small tide pools. It may also be found in muddy habitats such as estuaries, and can reach depths of 180 feet.

Feeding

L. littorea is an omnivorous, grazing intertidal gastropod. It is primarily an algae grazer, but it will feed on small invertebrates such as barnacle larvae. They use their radulae to scrape algae from rocks, and, in the salt marsh community, pick up algae from the cord grass, or from the biofilm that covers the surface of mud in estuaries or bays.

Phlorotannins in the brown algae Fucus vesiculosus and Ascophyllum nodosum act as chemical defenses against L. littorea.

Life cycle

L. littorea is oviparous, reproducing annually with internal fertilization of egg capsules that are then shed directly into the sea, leading to a planktotrophic larval development time of four to seven weeks. Females lay 10,000 to 100,000 eggs contained in a corneous capsule from which larvae escape and settle to the bottom. This species can breed year round depending on the local climate. It reaches maturity at 10 mm, and lives five to ten years.

Human use

File:Altamira Littorina littorea Édouard Harlé MHNT.PRE.2012.0.609.jpg

Remains of an ancient meal. Winkle shells from Cantabrian Lower Magdalenian layer (15 000 before present) in the Altamira cave

This species appears in prehistoric shellfish middens throughout Europe, and is believed to have been an important source of food since at least 7500 BC in Scotland. It is still collected in huge quantities in Scotland, mostly for export to the Continent, and also consumed locally. The official landings figures for Scotland indicate over 2,000 tonnes of winkles are exported annually. This makes winkles the sixth most important shellfish harvested in Scotland in terms of tonnage, and seventh most important in terms of value. However, since actual harvests are probably twice reported levels, the species may actually be the fourth and sixth most important, respectively.

They are usually picked off the rocks by hand or caught in a drag from a boat. They are mostly eaten in the coastal areas of Scotland, England, Wales and Ireland, where they are commonly referred to as winkles or in some areas buckies, willicks, or wilks. In Belgium, they are commonly called kreukels or caracoles. They are commonly sold in paper bags near beaches in Ireland and Scotland, boiled in their local seawater, with a pin attached to the bag to enable the extraction of the soft parts from the shell.

Periwinkles are considered a delicacy in African and Asian cuisines. The meat is high in protein, omega-3 fatty acids and low in fat; according to the USDA National Nutrient Database for Standard Reference, raw snails in general are about 80% water, 15% protein, and 1.4% fat.

Periwinkles are also used as bait for catching small fish. The shell is usually crushed and the soft parts extracted and put on a hook.

Following their history as an ancient food source in Atlantic Europe, they are harvested and consumed in the Azores Islands by the Portuguese people, usually called búzios, the generic name for sea snails.

Similar foods are consumed by other maritime cultures throughout the world, such as the Chinese people. Periwinkles, or a similar species, are sold at the live seafood counter in the Chinese-Canadian grocery chain, T&T Supermarket.

References

This article incorporates a public domain text (a public domain work of the United States Government) from references and CC-BY-2.5 text from the reference

Further reading

• Abbott R. T. (1974). American Seashells. Second edition. Van Nostrand Rheinhold, New York
• Abbott R. T. (1986). Seashells of North America, St. Martin's Press, New York

External links

• Littorina littorea (mollusc) from the Invasive Species Specialist Group website of the World Conservation Union
• Common periwinkle from the Marine Life Information Network for Britain and Ireland
• Anatomy of the Periwinkle from a Lander University website