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
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 varies from grayish to gray-brown, often with dark spiral bands. The base of the columella is white.[3] The shell lacks an umbilicus. The white outer lip is sometimes checkered with brown patches. The inside of the shell is chocolate brown.
The width of the shell ranges from 10 to 12 millimetres (3⁄8 to 1⁄2in) at maturity,[4] with an average length of 16 to 38mm (5⁄8 to 1+1⁄2in). Shell height can reach up to 30 to 52mm (1+1⁄8 to 2in),[4][5][3] The length is measured from the end of the aperture to the apex. The height is measured by placing the shell with the aperture flat on a surface and measuring vertically.[6]
L. littorea can be highly variable in phenotype, with several different morphs known. Its phenotypic variations may be indicative of speciation, as opposed to phenotypic plasticity. This is of particular importance to evolutionary biology, as it may represent an opportunity to observe a transitional phase in the evolution of an organism.[7]
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.[8] Females lay 10,000 to 100,000 eggs contained in a corneous capsule from which pelagic larvae escape and eventually settle to the bottom. This species can breed year round depending on the local climate. Benson suggests that it reaches maturity at 10mm and normally lives five to ten years.[9] while Moore suggests that maturity is reached in 18 months.[10] Some specimens have lived 20 years.
Female specimens have been observed to be ripe from February until end of May, when most are spawning. Male specimens are mainly ripe from January until the end of May and lose weight after copulation. The young seem to settle primarily from the end of May to the end of June,[citation needed] although other sources indicate earlier settlement.[10]
Growth rate
A study in Plymouth Sound suggests an initial growth reaching up to 14mm (1⁄2in) in height December the first year, and 17.4mm (5⁄8in) by the end of the second year. Females seem to grow more rapidly than males, and in specimens above 25mm (1in) in height, females seem to dominate.[10] Another study undertaken in Blackwater Estuary, Essex showed growth reaching up to 8mm (3⁄8in) the first winter.[11]
Distribution
Common periwinkles are native to the northeastern coasts of the Atlantic Ocean, including northern Spain, France, Great Britain, Ireland, Scandinavia, and Russia.[9]
There have been more than 14,000 observations made available as a dataset at the Global Biodiversity Information Facility - Littorina littorea,[12] which can be explored. More distribution information can also be found at Ocean Biographic Information System - Littorina littorea.[13] The NBN Gateway - Littorina littorea has a distribution map over the UK and Ireland.[14] These datasets may overlap.
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 native species.[9][8]
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 muddyhabitats such as estuaries and can reach depths of 55 metres (180 feet).[9] When exposed to either extreme cold or heat while climbing, a periwinkle will withdraw into its shell and start rolling, which may allow it to fall to the water.[16]
Zone
Movement both horizontally and vertically in response to light and dark as well as temperatures have been observed, but over a short timespan the movement seems to be random.
Experiments seem to indicate that the snail responds to light and current, and moves accordingly.[17]
The radula is taenioglossate, consisting of seven teeth per row: one middle tooth, flanked on each side by one lateral and two marginal teeth. The radula is used to scrape algae and detritus.
The common periwinkle can act as a host for various parasites, including Renicola roscovita, Cryptocotyle lingua, Microphallus pygmaeus and Himasthla sp. More studies are needed before any conclusions regarding the effect of parasites on growth can be reached. It seems that growth rate is primarily affected on available food and time available for feeding, rather than parasites.[20]
Polydora ciliata has also been found to excavate burrows in the shell of the common periwinkle when the snail is mature (above 10mm long). The reason why this happens only to mature snails is not yet known, but one hypothesis is that a mature snail will excrete a signal substance which attracts the P. ciliata larvae. Another hypothesis is that a mature snail has a change in the shell surface that makes it suitable for P. ciliata larvae to settle. The infection by this parasite does not seem to alter the growth and proportions of the snail shell.[21]
Mortality
A mortality rate of up to 94% per annum has been observed for the first two months, followed by up to 60% per annum for the rest of the first year:
...out of every 950 shells of all ages [collected] at that time, 850 are first year, and 100 are in their second or subsequent year.[22]
Older individuals above 15 months old seem to have a mortality of only 23% per annum. Cercaria emasculans is known to be fatal to the snail, but this does not account for the observed mortality.[10]
Human use
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 B.C.E. in Scotland.[23][full citation needed] It is still collected in quantity in Scotland, mostly for export to the Continent and also for local consumption. 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.[24][full citation needed]
Periwinkles 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 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 also used as bait for catching small fish. The shell is usually crushed and the soft parts extracted and put on a hook.
In accordance with their history as an ancient food source in Atlantic Europe, they are harvested and consumed in the Azores Islands by the Portuguese people, where they are usually called búzios, the generic name for sea snails.
The record for the farthest a human has spat a winkle was 10.4 metres by Alain Jourden (France) in 2006.[25]
Supply chain
As for seafood supply chains in general, the supply chain consists of a collector, processor, distributor and finally the retailer. The true nature of the supply chain is usually more complex and opaque, with the potential for records of harvesting areas and date of catch to be falsified.
Collection
Commonly harvested in buckets by workers walking in the intertidal zone on low tide; other methods have been tried.
In Maine, the snails are commonly collected by a dredge towed from a vessel.
The processor buys in bulk from the collector, involving a possibly long transport route by land in a refrigerator truck or airplane, taking care to avoid temperatures below 0°C.
If fresh seawater is readily available, the periwinkles are first graded if possible, using a machine custom built for the purpose. The method used for grading differs, but two proven methods include a Trommel screen with horizontal bars instead of a mesh, and a circle-throw vibrating machine also using bars. The price to purchase a complete sorting machine can be €10,000 or more.
Periwinkles are graded by number of snails per kilogram. The following table displays some common grades in France. The actual value depends upon supply and demand, with seasonal variations. The actual ranges may also differ from each establishment.
Grade name
Number per kilogram
Small
Unknown
Medium
Unknown
Large
180–240
Jumbo
140–180
Super Jumbo
90–140
After grading, the periwinkles are "climbed" close to the consumer, which involves checking whether they are still alive. This can take anywhere from a few hours to several days, depending on how healthy the periwinkles are and the temperature of the water they climb in. Any periwinkles left immobile at the bottom are considered dead and are discarded. It is not uncommon to have up to 8% waste in a shipment.
Hereafter, the winkles are commonly packed in smaller quantities before being distributed to customers. Mesh bags from 3 to 10kg are common.
Distributor
To sell large quantities, distributors are commonly used to move the periwinkles to the retailer. These have networks of transport available both internationally, regionally and locally inside a city. Several distributors are usually involved in the complete journey, each focusing on its own part of the transport network.
Retail
The common periwinkle is sold by fishmongers at seafood markets in large cities around the world, and is also commonly found in seafood restaurants as an appetizer or as a part of a seafood platter. In some countries, pubs may serve periwinkles as a snack.
Most of the volume fished is consumed by France, Belgium, Spain and the Netherlands.
Methods to increase commercial value
Ongrowing has been investigated as a potential way of increasing commercial value, but no documented pilot facilities have been established. By harvesting the periwinkle during the summer and storing them with feed until December, not only should the grade have been increased, but the market value should be higher since supply is lower in the cold winter months.[26]
Aquaculture
Raising the common periwinkle has not been a focus due to its abundance in nature and relatively low price; however, there are potential benefits from aquaculture of this species, including a more controlled environment, easier harvesting, less damages from predators, as well as saving the natural population from commercial harvesting.
Packaging
Commonly packed in 3kg boxes by the processor, the box is usually polystyrene foam or thin wood, depending on the market demands. Holes in the box ensures that any water lost by the snails drains out, so that they remain in better condition for longer. A label indicates the fishing zone, packaging date, and any other information required by law.
Storing
In a fridge, the common periwinkle can usually be stored for up to a week, but this may vary depending on how long they have been stored prior to sale, and how they have been kept since the moment they are fished. As long as they are kept moist and cold, they can survive well for a longer period of time. It is not recommended to store at temperatures below 0 degrees Celsius, even if research has shown a Median Lower Lethal Temperature of -13.0 degree Celsius.[27] Even if the common periwinkle survives when put back into seawater, they seem to be unable to move and climb.
Fucus vesiculosus, known by the common names bladderwrack, black tang, rockweed, sea grapes, bladder fucus, sea oak, cut weed, dyers fucus, red fucus and rock wrack, is a seaweed found on the coasts of the North Sea, the western Baltic Sea and the Atlantic and Pacific Oceans. It was the original source of iodine, discovered in 1811, and was used extensively to treat goitre, a swelling of the thyroid gland related to iodine deficiency.
Ascophyllum nodosum is a large, common cold water seaweed or brown alga (Phaeophyceae) in the family Fucaceae. Its common names include knotted wrack, egg wrack, feamainn bhuí, rockweed, knotted kelp and Norwegian kelp. It grows only in the northern Atlantic Ocean, along the north-western coast of Europe including east Greenland and the north-eastern coast of North America. Its range further south of these latitudes is limited by warmer ocean waters. It dominates the intertidal zone. Ascophyllum nodosum has been used numerous times in scientific research and has even been found to benefit humans through consumption.
Littorina is a genus of small sea snails, marine gastropod molluscs in the family Littorinidae, the winkles or periwinkles.
Pagurus bernhardus is the common marine hermit crab of Europe's Atlantic coasts. It is sometimes referred to as the common hermit crab or soldier crab. Its carapace reaches 3.5 centimetres (1.4 in) long, and is found in both rocky and sandy areas, from the Arctic waters of Iceland, Svalbard and Russia as far south as southern Portugal, but its range does not extend as far as the Mediterranean Sea. It can be found in pools on the upper shore and at the mean tide level down to a depth of approximately 140 metres (460 ft), with smaller specimens generally found in rock pools around the middle shore and lower shore regions, with larger individuals at depth. P. bernhardus is an omnivorous detritivore that opportunistically scavenges for carrion, and which can also filter feed when necessary.
Sea snails are slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the absence of a visible shell.
Littorina saxatilis, common name the rough periwinkle, is a species of small sea snail, a marine gastropod mollusc in the family Littorinidae, the winkles or periwinkles. First identified in the 1700s, it has been misidentified as a new species 112 times.
Peringia ulvae, commonly known as the Laver spire shell or mudsnail, is a European species of very small aquatic snail with gills and an operculum, a gastropod mollusk in the family Hydrobiidae.
Littoraria irrorata, also known by the common name the marsh periwinkle, is a species of sea snail, a marine gastropod mollusk in the family Littorinidae. The specific epithet irrorata means 'moistened' or 'dewy.'
Lottia gigantea, common name the owl limpet, is a species of sea snail, a true limpet, a marine gastropod mollusc in the family Lottiidae. Its genome has been sequenced at the Joint Genome Institute.
Melarhaphe neritoides, common name : the small periwinkle, is a species of small sea snail, a marine gastropod mollusc in the family Littorinidae, the winkles or periwinkles.
The marine snail Norrisia norrisii is a medium-sized gastropod mollusk within the family Tegulidae. It has several common names, including Norris's top snail, Norris's topsnail, norrissnail, smooth brown turban snail, or kelp snail. It was first described by G.B. Sowerby I under the name Trochiscus norrisii. It is the only species in the genus Norrisia.
Austrolittorina unifasciata, common name the banded periwinkle, is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles. It is also known as the blue periwinkle.
Echinolittorina meleagris is a species of small sea snail, a marine gastropod mollusc in the family Littorinidae, the winkles or periwinkles.
Lacuna vincta, commonly known as northern lacuna, wide lacuna, northern chink shell, or banded chink shell, is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles. It is found intertidally and in shallow waters in both the northern Atlantic Ocean and the northern Pacific Ocean. It is a herbivore, feeding on seaweed and diatoms with its toothed radula.
Littoraria pintado is a species of sea snail, a marine gastropod in the family Littorinidae, the winkles or periwinkles.
Littoraria scabra, common name : the mangrove periwinkle, is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles.
Littorina obtusata, common name the flat periwinkle, is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles.
Littorina scutulata is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles.
Parorchis acanthus is a parasitic flatworm of the class Trematoda. It is a parasitic castrator of the common periwinkle Littorina littorea. Unlike many trematode species it encysts on hard surfaces and not inside a second intermediate host.
Lirabuccinum dirum, commonly known as the dire whelk, the spindle shell or the spindle whelk, is a species of sea snail, a marine gastropod mollusk in the family Tudiclidae, the true whelks.
↑ Linnaeus C. (1758). Systema naturae per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. pp. [1–4], 1–824. Holmiae. (Salvius).
↑ Eschweiler, N., Molis, M. & Buschbaum, C. Helgol Mar Res (2009) "Habitat-specific size structure variations in periwinkle populations (Littorina littorea) caused by biotic factors" doi:10.1007/s10152-008-0131-x
↑ Grahame J. (1975). "Spawning in Littorina littorea (L.) (Gastropoda: Prosobranchiata)". Journal of experimental marine Biology and Ecology18: 185–196.
1 2 3 4 5 Chang A. L., Blakeslee A. M. H., Miller A. W. & Ruiz G. M. (2011). "Establishment Failure in Biological Invasions: A Case History of Littorina littorea in California, USA". PLoS ONE6(1): e16035. doi:10.1371/journal.pone.0016035.
1 2 3 4 The biology of Littorina littorea. Part 1. Growth of the shell and tissues, spawning, length of life and mortality. Hillary B. Moore,Journal of the Marine Biological Association of the UK, Volume 21, Issue 2, 1937, pages 721-742
↑ Report on the Maldon (Essex) Periwinkle Fishery. F.S. Wright, Great Britain. Ministry of Agriculture and Fisheries. Fishery Investigations. Ser. II, Vol. 14, no. 5 & 6., 1936
1 2 Chapman J. W., Carlton J. T., Bellinger M. R. & Blakeslee A. M. H. (2007). "Premature refutation of a human-mediated marine species introduction: the case history of the marine snail Littorina littorea in the northwestern Atlantic". Biological Invasions9:737-750.
↑ The Biology of Rocky Shores, page 94 By Colin Little, J. A. Kitching
↑ The Biology of Rocky Shores, page 83, Colin Little, J. A. Kitching
↑ Polyphenols in brown algae Fucus vesiculosus and Ascophyllum nodosum: Chemical defenses against the marine herbivorous snail, Littorina littorea. J. A. Geiselman and O. J. McConnell, Journal of Chemical Ecology,1981, Volume 7, Number 6, pages 1115-1133, doi:10.1007/BF00987632
↑ Influence of trematode infections on in situ growth rates of Littorina littorea. Kim N. Mouritsen, A. Gorbushin O and K. Thomas Jensen, Journal of the Marine Biological Association of the UK, Volume 79, Issue 3, 1999, pages 425-430
↑ On the shell growth of Littorina Littorea and the occurrence of Polydora Ciliata. Lars Orrhage, Zoologiska bidrag från Uppsala, Volume 38, 1969, pages 137-152
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