The common cockle (''Cerastoderma edule'') is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of edible saltwater

clam Clam is a common name for several kinds of bivalve mollusc. The word is often applied only to those that are deemed edible and live as infauna, spending most of their lives halfway buried in the sand of the sea floor or riverbeds. Clams h ...

, a marine

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

in the family Cardiidae, 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 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

The common cockle was one of the many invertebrate species originally described by

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

in the landmark 1758 10th edition of , where it was given its old binomial name ''Cardium edule''. The species name is derived from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

adjective , 'edible'. Italian naturalist Giuseppe Saverio Poli erected the genus '' Cerastoderma'' in 1795, making the common cockle the type species as ''Cerastoderma edule''. The genus name is derived from the

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

words (, 'horn') and (, '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 ( and , respectively).

Description

It typically reaches from to in length,Considine, Douglas and Considine, Glenn.
Van Nostrand's Scientific Encyclopedia
'', p. 2086 (Springer Science & Business Media, 2013). but sometimes it reaches . 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 similar lagoon cockle has an elongated shell posteriorly, black digestive glands and is found in substrate of stagnant water.

Distribution and habitat

This species is found in

coast A coast (coastline, shoreline, seashore) is the land next to the sea or the line that forms the boundary between the land and the ocean or a lake. Coasts are influenced by the topography of the surrounding landscape and by aquatic erosion, su ...

al areas of the northern and eastern

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

. 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 in

tidal flats Mudflats or mud flats, also known as tidal flats or, in Ireland, slob or slobs, are coastal wetlands that form in intertidal areas where sediments have been deposited by tides or rivers. A global analysis published in 2019 suggested that tidal ...

located in the bays and estuaries of Europe. It plays a major role as a source of food for

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

, and wading

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

''Cerastoderma edule''
Right and left valve of the same specimen: File:Cerastoderma edule 01.jpg, Right valve File:Cerastoderma edule 02.jpg, Left valve ''Cerastoderma edule'' var. ''belgicum''
Right and left valve of the same specimen: File:Cerastoderma edule belgicum 01.jpg, Right valve File:Cerastoderma edule belgicum 02.jpg, Left valve

''Cerastoderma edule'' var. ''loppensi''
Right and left valve of the same specimen: File:Cerastoderma edule loppensi 01.jpg, Right valve File:Cerastoderma edule loppensi 02.jpg, Left valve

''Cerastoderma edule'' var. ''maculatum''
Right and left valve: File:Cerastoderma edule maculatum 01.jpg, Right valve File:Cerastoderma edule maculatum 02.jpg, Left valve

Ecology

This species is a

filter feeder Filter feeders are aquatic animals that acquire nutrients by feeding on organic matters, food particles or smaller organisms (bacteria, microalgae and zooplanktons) suspended in water, typically by having the water pass over or through a s ...

, meaning that it feeds by straining water to obtain suspended matter and food particles.Dauvin, Jean-Claude.
Biological heritage and food chains
'', p. 25 (Quae, Centre de coopération internationale en recherche agronomique pour le développement, 2006). Water is inhaled through an inhalant siphon, and exhaled through an exhalant siphon. It tolerates a wide range of salinity (

euryhaline Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the short-finned molly, '' Poecilia sphenops'', which can live in fresh water, brackish water, or salt water. The green crab ('' Carcinus m ...

), and wide range of temperatures ( eurythermic), which helps to explain its very extensive

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

. It has a first spawning period in early summer, and a second one in the fall.

Lifespan and predation

Lifespan is typically five to six years, though it may perish earlier due to predation by humans as well as

crab Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropo ...

flounder Flounders are a group of flatfish species. They are demersal fish, found at the bottom of oceans around the world; some species will also enter estuary, estuaries. Taxonomy The name "flounder" is used for several only distantly related speci ...

, and various birds especially including

oystercatcher The oystercatchers are a group of waders forming the family (biology), family Haematopodidae, which has a single genus, ''Haematopus''. They are found on coasts worldwide apart from the polar regions and some tropical regions of Africa and Sout ...

s. A green shore crab (''

Carcinus maenas ''Carcinus maenas'' is a common littoral crab. It is known by different names around the world. In the British Isles, it is generally referred to as the shore crab or green shore crab. In North America and South Africa, it bears the name Europe ...

'') can consume up to 40 common cockles a day, eating smaller cockles (under 1.5 cm diameter) much more quickly than larger ones. As cockles size increases it takes exponentially more time for the green crabs to break into the shell. This leads to the crabs preferring smaller cockles as prey. In lean seasons where cockles did not grow so quickly the crabs may have a greater influence on the population due to their preference for smaller individuals.

Parasites and diseases

The

cercozoa Cercozoa (now synonymised with Filosa) is a phylum of diverse single-celled eukaryotes. They lack shared morphological characteristics at the microscopic level, and are instead united by phylogeny, molecular phylogenies of rRNA and actin or Ubiqu ...

n species '' Marteilia cochillia'' is a parasite of the common cockle, having caused a collapse in commercial harvests of cockle beds in Galicia in 2012. A survey of cockle beds in Galicia found that infestation by the gregarine parasite '' Nematopsis'' was widespread, and that the most common pathological finding was disseminated neoplasia.

Uses

These animals were probably a significant food source in hunter-gatherer societies of prehistoric 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.

As food

This cockle is eaten in the United Kingdom, France, Germany, Ireland, Japan, Portugal and Spain and elsewhere. It is generally cooked but is also sometimes eaten pickled or raw. In addition to the meat being a food source, their shells have been used industrially as a source of lime. 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 restrictions have been put in place due to environmental concerns. Similar measures have been established elsewhere, for example in Scotland where dredging using 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). In 2004, the incoming tide at

Morecambe Bay Morecambe Bay is an estuary in north-west England, just to the south of the Lake District National Park. It is the largest expanse of intertidal mudflats and sand in the United Kingdom, covering a total area of . In 1974, the second largest ga ...

in England caused 23 cockle-gatherers to die.Chambers, Paul.
British Seashells: A Guide for Collectors and Beachcombers
', p. 158 ( Casemate Publishers, 2009). This species is also used in

aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. Nelu ...

in the UK, the Netherlands and Portugal. However, production has not been stable; for example, production fell from 107,800 tons in 1987 to 40,900 tons in 1997.Spencer, Brian.
Molluscan Shellfish Farming
', p. 103 (John Wiley & Sons, 2008). Cardial_Impression_2

In culture

Cardial ware is the name of the

Neolithic The Neolithic or New Stone Age (from Ancient Greek, Greek 'new' and 'stone') is an archaeological period, the final division of the Stone Age in Mesopotamia, Asia, Europe and Africa (c. 10,000 BCE to c. 2,000 BCE). It saw the Neolithic Revo ...

pottery from maritime cultures that colonized Mediterranean shores c. 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 of

Dublin Dublin is the capital and largest city of Republic of Ireland, Ireland. Situated on Dublin Bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, and is bordered on the south by the Dublin Mountains, pa ...

, Ireland. The lyrics describe Molly Malone selling the common cockle in the streets of that city.

References

External links

* {{Authority control Cardiidae Commercial molluscs Molluscs described in 1758 Taxa named by Carl Linnaeus Molluscs of the Atlantic Ocean Molluscs of the Mediterranean Sea Marine molluscs of Europe Bivalves of Europe Marine molluscs of Africa