Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help
Researched by | Nicola White | Refereed by | Dr Richard S.K. Barnes |
Authority | (Bruguière, 1789) | ||
Other common names | - | Synonyms | Cardium lamarckii (Bruguière, 1789) |
The cockle, Cerastoderma glaucum is a filter feeding bivalve which burrows shallowly in soft sediments. The species exists in two forms, a typical thin-shelled variety found in brackish lagoon habitats and a thicker shelled variety occurring in estuaries. It is widely distributed in north-west Europe.
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Phylum | Mollusca | Snails, slugs, mussels, cockles, clams & squid |
Class | Bivalvia | Clams, cockles, mussels, oysters, and scallops |
Order | Cardiida | |
Family | Cardiidae | |
Genus | Cerastoderma | |
Authority | (Bruguière, 1789) | |
Recent Synonyms | Cardium lamarckii (Bruguière, 1789) |
Typical abundance | Low density | ||
Male size range | Up to 5cm | ||
Male size at maturity | |||
Female size range | Small-medium(3-10cm) | ||
Female size at maturity | |||
Growth form | Bivalved | ||
Growth rate | 9.6mm/year | ||
Body flexibility | |||
Mobility | |||
Characteristic feeding method | Active suspension feeder, No information | ||
Diet/food source | |||
Typically feeds on | |||
Sociability | |||
Environmental position | Infaunal | ||
Dependency | No information found. | ||
Supports | No information | ||
Is the species harmful? | No |
The species exists in two forms, a typical thin-shelled variety found in brackish lagoon habitats and a thicker shelled variety occurring in estuaries. Growth rate during the first year takes place at a mean of 9.6 mm per year in Essex. Thereafter growth rate decreases to 4.9 mm in the second year and 2.5 mm in the third year (Boyden, 1972).
Physiographic preferences | Estuary, Isolated saline water (Lagoon) |
Biological zone preferences | Lower eulittoral, Sublittoral fringe |
Substratum / habitat preferences | Coarse clean sand, Fine clean sand, Mud, Muddy sand, Sandy mud |
Tidal strength preferences | Weak < 1 knot (<0.5 m/sec.) |
Wave exposure preferences | Sheltered, Very sheltered |
Salinity preferences | Low (<18 psu), Variable (18-40 psu) |
Depth range | Shallow |
Other preferences | No text entered |
Migration Pattern | Non-migratory / resident |
Reproductive type | Gonochoristic (dioecious) | |
Reproductive frequency | Annual episodic | |
Fecundity (number of eggs) | No information | |
Generation time | Insufficient information | |
Age at maturity | Insufficient information | |
Season | May - July | |
Life span | 2-5 years |
Larval/propagule type | - |
Larval/juvenile development | Planktotrophic |
Duration of larval stage | 11-30 days |
Larval dispersal potential | No information |
Larval settlement period | Insufficient information |
The MarLIN sensitivity assessment approach used below has been superseded by the MarESA (Marine Evidence-based Sensitivity Assessment) approach (see menu). The MarLIN approach was used for assessments from 1999-2010. The MarESA approach reflects the recent conservation imperatives and terminology and is used for sensitivity assessments from 2014 onwards.
Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
High | Low | High | Low | |
Cerastoderma glaucum lives embedded within the substratum and would be removed upon substratum loss. The species has slow recovery due to its restricted distribution. | ||||
High | Low | High | Low | |
Bivalves have rather limited ability to burrow upwards so the species would be buried upon smothering. Cerastoderma glaucum has slow recovery due to it's restricted distribution. | ||||
Tolerant | Not relevant | Not sensitive | Low | |
The species is probably tolerant of siltation because it lives in estuaries and lagoons where siltation frequently occurs. | ||||
No information | ||||
High | Low | High | Moderate | |
The low shore position of Cerastoderma glaucum suggests that it has a low tolerance of desiccation. Boyden (1972) observed that the species can tolerate 33 percent water loss and that death occurs between 33 and 38 percent water loss. Recovery would be low due to the restricted distribution of this species. | ||||
High | Low | High | Low | |
The low shore position of Cerastoderma glaucum suggests that its has an inability to tolerate exposure to air and it's consequent conditions. Unlike Cerastoderma edule the shells of Cerastoderma glaucum remain closed upon exposure to air. The species may suffer desiccation, increased metabolic cost and exposure to predation by birds. Recovery would be low due to the restricted distribution of this species. | ||||
No information | ||||
Intermediate | Low | High | Very low | |
The species and its preferred habitat could be washed away by increased water flow rate. Recovery would be slow due to the restricted distribution of the species. | ||||
No information | ||||
Low | High | Low | Moderate | |
Cerastoderma glaucum can tolerate a wide range of temperatures. Populations have been observed to survive in lagoons in conditions from almost freezing to more than 30 degree C. However, a high mortality of cockles was observed in South East England after the exceptionally cold winter of 1962/3. Boyden (1972) observed that Cerastoderma glaucum has a LD50 of 62.3 hours at 20 degrees C in air. | ||||
No information | ||||
Low | High | Low | Low | |
The species is a suspension feeder so may benefit from increased turbidity by a greater food supply. However, if turbidity is caused by silt particles additional feeding costs would be imposed. | ||||
No information | ||||
High | Low | High | Low | |
It has been suggested that the juveniles of Cerastoderma glaucum are very intolerant of wave exposure which controls the species' distribution. The species is restricted to sheltered sites which suggests it is intolerant of increased wave exposure. Increased wave exposure may also remove the species preferred habitat. Recovery would be low due to the species' limited distribution. | ||||
No information | ||||
No information | Not relevant | No information | Not relevant | |
Insufficient information | ||||
No information | Not relevant | No information | Not relevant | |
Insufficient information | ||||
Intermediate | Moderate | Moderate | Very low | |
The shells of Cerastoderma glaucum are rather thin and brittle, so it is probably quite intolerant of abrasion. | ||||
Tolerant | Very high | Not sensitive | Moderate | |
The species is not sensitive to displacement. A population of Cerastoderma glaucum established itself in Emsworth Harbour by displacement of animals from adjacent lagoon habitats (Barnes, 1973). |
Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
No information | No information | No information | Not relevant | |
Insufficient information | ||||
No information | No information | No information | Not relevant | |
Insufficient information | ||||
No information | No information | No information | Not relevant | |
Insufficient information | ||||
No information | Not relevant | No information | Not relevant | |
Insufficient information | ||||
Intermediate | Low | High | Low | |
An increase in nutrients may lead to eutrophication and reduced oxygen levels. Juveniles of the species are very intolerant of reduced oxygen concentration. Recovery would be low due to the restricted distribution of this species. | ||||
Low | High | Low | Moderate | |
The species can survive in lagoons where salinity varies from 7 psu to 84 psu, so it has a high tolerance of different salinities. | ||||
No information | ||||
High | Low | High | Moderate | |
Juveniles of Cerastoderma glaucum are very intolerant of low oxygen concentrations. However adults can survive for 84 hours in oxygen free water (Boyden, 1972). |
Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
No information | Not relevant | No information | Not relevant | |
Insufficient information | ||||
No information | Not relevant | No information | Not relevant | |
Insufficient information | ||||
No information | Not relevant | No information | Not relevant | |
Insufficient information | ||||
No information | Not relevant | No information | Not relevant | |
Insufficient information |
Northern Ireland Priority Species |
National (GB) importance | Not rare/scarce | Global red list (IUCN) category | - |
Native | - | ||
Origin | - | Date Arrived | - |
Anonymous, 1999s. Saline lagoons. Habitat Action Plan. In UK Biodiversity Group. Tranche 2 Action Plans. English Nature for the UK Biodiversity Group, Peterborough., English Nature for the UK Biodiversity Group, Peterborough.
Ansell, A.D., Barnett, P.R.O., Bodoy, A. & Masse, H., 1981. Upper temperature tolerances of some European Mollusca III. Cardium glaucum, C. tuberculata and C. edule. Marine Biology, 65, 177-183.
Barnes, R.S.K., 1973. The intertidal lamellibranchs of Southampton Water, with particular reference to Cerastoderma edule and C. glaucum. Proceedings of the Malacological Society of London, 40, 413-433.
Barnes, R.S.K., 1980b. Coastal lagoons. The natural history of a neglected habitat. Cambridge: Cambridge University Press.
Barnes, R.S.K., 1994. The brackish-water fauna of northwestern Europe. Cambridge: Cambridge University Press.
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Brock, V., 1979. Habitat selection of two congeneric bivalves, Cardium edule and C. glaucum in sympatric and allopatric populations. Marine Biology, 54, 149-156.
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Seaward, D.R., 1990. Distribution of marine molluscs of north west Europe. Peterborough: Nature Conservancy Council.
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Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. Occurrence dataset https://www.nmni.com/CEDaR/CEDaR-Centre-for-Environmental-Data-and-Recording.aspx accessed via NBNAtlas.org on 2018-09-25.
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Norfolk Biodiversity Information Service, 2017. NBIS Records to December 2016. Occurrence dataset: https://doi.org/10.15468/jca5lo accessed via GBIF.org on 2018-10-01.
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OBIS (Ocean Biodiversity Information System), 2023. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2023-03-26
Outer Hebrides Biological Recording, 2018. Invertebrates (except insects), Outer Hebrides. Occurrence dataset: https://doi.org/10.15468/hpavud accessed via GBIF.org on 2018-10-01.
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This review can be cited as:
Last Updated: 15/07/2002