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The common periwinkle, or the winkle, Littorina littorea, is a small edible species of gilled sea snail with an operculum, a marine gastropod mollusc in the family Littorinidae, the winkles.
Shell descriptionThe male and female range between 10 to 12 mm at maturity, with 30 mm being the upper size limit.1 Shell height can reach up to 55 mm. DistributionNative distribution of this species is on the northeastern of the Atlantic Ocean: coast of northern Spain, Ireland, to Scandinavia and Russia. Nonindigenous distributionIt is nonindigenous in and northwestern shores of Atlantic Ocean in Canada and in the United States. It may have been introduced with rock ballast in the mid-1800s.2 First found in North America in 1840 in the southern Gulf of St. Lawrence in Canada.2 It is a predominant mollusk from New Jersey northward. In the U.S., it is found in coastal areas on the eastern coast from Maine to Virginia and on the western coast from California to Washington. It has had large negative impacts on invaded ecosystems because it competes with native gastropods. EcologyLike almost all snails, the periwinkle crawls using a muscular, fleshy foot which is lubricated by a film of mucus. When not active, it often nestles in a crack or gully. During low tide when it is exposed to the air, it can seal the gap between its shell and the rock with mucus to prevent desiccation. When loosened from the substrate it can effectively seal its shell against desiccation or predation using its operculum. HabitatWorld-wide there are numerous species of periwinkles or littorinids, all of which live in the intertidal zone. Some species are adapted to living very high up in the splash zone, in a habitat that may be dry much of the time. Nevertheless, all true periwinkles are gilled snails more closely related to other marine gastropods than they are to the pulmonate land snails. The common periwinkle is mainly found on rocky coasts in the higher and middle intertidal zone. It sometimes lives in small tide pools ranging from 1 to 2 m or about 3 to 6 ft in characteristic size. It is also found in muddy habitats such as estuaries. They are situated on the splash zone, the extreme high tide mark. It can reach depth to 60 m. Life cycleFemales lay 10,000-100,000 eggs contained in a horny capsule from which larvae escape and settle to the bottom. It can breed all year depending on the climate. It reaches mature at 10 mm. It lives 5-10 years Feeding habitsIt is primarily an algae grazer, but will feed on small invertebrates such as barnacle larvae. Periwinkles feed by grazing along the surface on which they live. They use their radula to scrape algae from rocks, and, in the salt marsh community, pick up algae from the cord grass or from the film that covers the surface of mud in estuaries or bays. Human use
Edible or common periwinkles have long been gathered from the shore for food. The are eaten in Britain and Ireland where they are commonly referred to as "winkles" (or in some areas "willicks" or "wilks"). It is not uncommon to find cooked periwinkles on sale in paper bags at beaches in Ireland, usually salted, with a pin attached to the bag to assist extracting the winkle from the shell. In Belgium, where they are also eaten, they are referred to as "crickles". Periwinkles are a delicacy in African and Asian cuisine. The meat is high in protein but low in fat content; 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 can also be used as bait for catching small fish. The shell is usually crushed and the soft periwinkle extracted and put on a hook. References
This article incorporates public domain text (a public domain work of the United States Government) from:
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