Common cockle

Common cockle
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Cardiida
Family:	Cardiidae
Genus:	Cerastoderma
Species:	C. edule
Binomial name
Cerastoderma edule (Linnaeus,1758)
Synonyms
Cardium belgicumDe Malzine, 1867 Cardium crenulatumLamarck, 1819 Cardium eduleLinnaeus, 1758 (basionym) Cardium edule burchanaeGirscher, 1938 Cardium edulevar.batesoniBucquoy, Dautzenberg & Dollfus, 1892 Cardium edulevar.loppensiMars, 1951 Cardium edulevar.majorBucquoy, Dautzenberg & Dollfus, 1892 Cardium mercatoriumCoen, 1915 Cardium nunninkaeLucas, 1984 Cardium obtritumLocard, 1886 Cardium quadrariumReeve, 1845 Cardium vulgareDa Costa, 1778 Cerastoderma edulevar.sinicolaLacourt, 1974 Cerastoderma nunninkaeLucas, 1984

Thecommon cockle(Cerastoderma edule) is aspeciesof edible saltwaterclam,amarinebivalvemolluscin the familyCardiidae,the cockles. It is found in waters off Europe, from Iceland in the north, south into waters off western Africa as far south as Senegal. The ribbed oval shells can reach 6 centimetres (2.4 in) across and are white, yellowish or brown in colour. The common cockle is harvested commercially and eaten in much of its range.

Taxonomy and naming

Cerastoderma edulea) foot b) exhalant siphon c) branchial or inhalant siphon d) edge of mantle e) ligament f) umbones or beaks of the shell

The common cockle was one of the manyinvertebrate species originally describedbyCarl Linnaeusin the landmark 175810th editionofSystema Naturae,where it was given its old binomial nameCardium edule.The species name is derived from theLatinadjectiveĕdūlis,'edible'.Italian naturalistGiuseppe Saverio Polierected the genusCerastodermain 1795, making the common cockle the type species asCerastoderma edule.The genus name is derived from theAncient Greekwordsκέρας(keras,'horn') andδέρμα(derma,'skin').For many years it was referred to by both names.

Other common names in English are edible cockle and common edible cockle.On account of its heart-like shape, it is called the 'heart mussel' in German and Scandinavian languages (Hertzmuschelandhjertemusling,respectively).

Description

It typically reaches from 3.5 centimetres (1.4 in) to 5 centimetres (2.0 in) in length,but sometimes it reaches 6 centimetres (2.4 in).The shells are pale or whitish yellow, grubby white, or brown.The shell is oval, and covered by ribs, which are flattened in the middle part of the shell. The digestive glands are light brown to dark green.

In contrast, the similarlagoon cocklehas an elongated shell posteriorly, black digestive glands and is found in substrate of stagnant water.

Distribution and habitat

This species is found incoastalareas of the northern and easternAtlantic Ocean.It is widely distributed from Iceland and Norway in Europe, to Senegal along the coast of west Africa.The common cockle is one of the most abundant species of molluscs intidal flatslocated in the bays and estuaries of Europe. It plays a major role as a source of food forcrustaceans,fish,and wadingbirds.

Cerastoderma edule
Right and left valve of the same specimen:

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  Right valve
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  Left valve

Cerastoderma edulevar.belgicum
Right and left valve of the same specimen:

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  Right valve
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  Left valve

Cerastoderma edulevar.loppensi
Right and left valve of the same specimen:

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  Right valve
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  Left valve

Cerastoderma edulevar.maculatum
Right and left valve:

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  Right valve
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  Left valve

Ecology

This species is afilter feeder,meaning that it feeds by straining water to obtain suspended matter and food particles.Water is inhaled through aninhalant siphon,and exhaled through an exhalant siphon.

It tolerates a wide range of salinity (euryhaline), and wide range of temperatures (eurythermic), which helps to explain its very extensiverange.It has a first spawning period in early summer, and a second one in the fall. Lifespan is typically five to six years, though it may perish earlier due to predation by humans as well ascrabs,flounder,and various birds especially includingoystercatchers.A green shore crab (Carcinus maenas) can consume up to 40 common cockles a day, eating smaller cockles (under 1.5 cm diameter) much more quickly than larger ones. Hence they could have a greater impact in lean seasons where cockles did not grow so quickly.

Parasites and diseases

ThecercozoanspeciesMarteilia cochilliais a parasite of the common cockle, having caused a collapse in commercial harvests of cockle beds inGaliciain 2012. A survey of cockle beds in Galicia found that infestation by the gregarine parasiteNematopsiswas widespread, and that the most common pathological finding was disseminated neoplasia.

Uses

Cockle shell ridges imprinted in fragment of NeolithicCardial ware

These animals were probably a significant food source in hunter-gatherer societies ofprehistoric Europe,and the clay remains of shell-imprints have been found. The clay is imprinted with fine decorations, repetitions of the distinct curved ridges, undulating lines and/or edges characteristic to the cockle shell, a natural resource of coastal waters.

Cardial wareis the name of theNeolithicpottery from maritime cultures that colonized Mediterraneanshoresc. 6000 – 5,500 BC, this name being based upon the old binomial name of the species:Cardium edule.

In the 1800s, a song called "Molly Malone"was first published (also known as" Cockles and Mussels "), later becoming the unofficial song ofDublin,Ireland. The lyrics describe Molly Malone selling the common cockle in the streets of that city.

As food

Cockle bed with cockles (Cerastoderma edule) nearDe Cocksdorpon the island ofTexelin the Dutch province ofNorth Holland

This cockle is cooked and eaten in several countries (including the United Kingdom, France, Germany, Ireland, Japan, Portugal and Spain). It is also sometimes eaten pickled, or raw.

An important species for the fishing industry, it is commercially fished in the United Kingdom, Ireland and France by suction dredge and also raking by hand. Previously the greatest catch was from the Netherlands, but now fisheries restrictions have been put in place due to environmental concerns. Similar measures have been established elsewhere, for example in Scotland where dredging with vehicles is prohibited, and in parts of England and Wales where only old-fashioned hand-gathering is permitted (using a long plank that is rocked back and forth on the sand).

This species is also used inaquaculture.Farming of cockles is ongoing in the UK, the Netherlands and Portugal. However, production in those countries has not been very stable; for example, production fell from 107,800 tons in 1987 to 40,900 tons in 1997.In addition to being a food source, their shells have also been used industrially as a source oflime.

Gathering this species can be dangerous. In 2004, the incoming tide atMorecambe Bayin England caused23 cockle-gatherers to die.

External links

• Photos ofCommon cockleon Sealife Collection