Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help
Researched by | Dr Harvey Tyler-Walters | Refereed by | Dr David McGrath |
Authority | Linnaeus, 1758 | ||
Other common names | - | Synonyms | Patina laevis , Patina pellucida Linnaeus, 1758, Helcion laevis , Helcion pellucidum |
Weber et al. (1997) suggested that Patella pellucida (as Helcion pellucidum) was genetically distinct from its South African con-geners and may have arisen independently. Studies of morphological features (Ridgeway et al., 1998) and molecular characteristics (Koufopanou et al., 1999) suggested that Helcion pelludicum belonged to the genus Patella and the species name was restored to Patella pellucida (Linnaeus, 1758).
Specimens found in cavities in holdfasts develop into the laevis form (Patella pellucida var. laevis). The laevis form has a taller, more robust opaque shell, ledged in profile, with blue rays that alternate with reddish brown rays. The most noticeable ledge of the shell indicates the size at which the individual enters the holdfast.
- none -
Phylum | Mollusca | Snails, slugs, mussels, cockles, clams & squid |
Class | Gastropoda | Snails, slugs & sea butterflies |
Family | Patellidae | |
Genus | Patella | |
Authority | Linnaeus, 1758 | |
Recent Synonyms | Patina laevis Patina pellucida Linnaeus, 1758Helcion laevis Helcion pellucidum |
Typical abundance | Moderate density | ||
Male size range | 3 - 12mm | ||
Male size at maturity | 5mm | ||
Female size range | 5mm | ||
Female size at maturity | |||
Growth form | |||
Growth rate | 1-2mm/month | ||
Body flexibility | Low (10-45 degrees) | ||
Mobility | Crawler / Walker, Creeper | ||
Characteristic feeding method | Grazer | ||
Diet/food source | Herbivore | ||
Typically feeds on | %Laminaria hyperborea%, %Laminaria digitata%, %Alaria esculenta%, %Saccorhiza polyschides%, %Fucus serratus%, and when young %Himanthalia elongata% and %Mastocarpus stellatus%. | ||
Sociability | No information | ||
Environmental position | Epifaunal | ||
Dependency | Not relevant. | ||
Supports | Not relevant | ||
Is the species harmful? | No No text entered |
Adults can recolonize vacant fronds (McGrath, 1997), perhaps via the surface of the substratum or by mucus rafting, and if dislodged adults can right themselves and be carried to neighbouring plants by currents by secreting a mucus 'sail' (Vahl 1983).
Kain & Svendsen (1969) provide pictures of Patella pellucida on blades of Laminaria hyperborea together with the cavities grazed in the fronds and in holdfasts. Kain & Svendsen (1969) noted that in Norwegian populations severe grazing by Patella pellucida may result in perforation of blades by autumn (before new blades develop) and in some cases grazing where the blade and stipe meet may 'cut off' the blade.Physiographic preferences | Open coast, Strait / sound, Sea loch / Sea lough, Open coast, Sea loch / Sea lough, Strait / sound |
Biological zone preferences | Lower eulittoral, Sublittoral fringe, Upper infralittoral, Lower eulittoral, Sublittoral fringe, Upper infralittoral |
Substratum / habitat preferences | Macroalgae, Macroalgae |
Tidal strength preferences | Moderately Strong 1 to 3 knots (0.5-1.5 m/sec.), Moderately Strong 1 to 3 knots (0.5-1.5 m/sec.) |
Wave exposure preferences | Exposed, Moderately exposed, Exposed, Moderately exposed |
Salinity preferences | Full (30-40 psu), Full (30-40 psu) |
Depth range | ca +1 m - ca 25 m |
Other preferences | Occurs at 15 psu in Norway. |
Migration Pattern |
Adults show a seasonal migration on Laminaria hyperborea, migrating down to the stipe before the old blade tissue is discarded in spring to early summer. Larger individuals prefer the lower wave exposure of deeper water (Warburton 1976).
Approximately one third of the population examined by Graham & Fretter (1947) were the laevis form. However, Kain & Svendsen (1969) did not find any specimens in Laminarian holdfasts in Norwegian populations and the laevis form may be absent in Norway.Reproductive type | Gonochoristic (dioecious) | |
Reproductive frequency | Annual protracted | |
Fecundity (number of eggs) | No information | |
Generation time | <1 year | |
Age at maturity | circa 6 months (5mm in size) | |
Season | Insufficient information | |
Life span | 1-2 years |
Larval/propagule type | Veliger |
Larval/juvenile development | Planktotrophic |
Duration of larval stage | 11-30 days |
Larval dispersal potential | 10 -100 m |
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 | Very high | Low | Moderate | |
Loss of the substratum, this species food plants, will involve removal of the adults themselves. Adults may be lost with plants during storms or swept off the fronds. However, McGrath (1997) demonstrated that Patella pellucida can rapidly recolonize available plants with as little as three days from adjacent plants. It is likely that recolonization from adjacent populations would be fairly rapid. | ||||
Intermediate | Very high | Low | Low | |
Smothering by 5 cm of material is unlikely to affect adults on the fronds of kelps. The laevis form in holdfasts may be more intolerant. Similarly, the typical food species have a low intolerance to smothering. Smothering is likely to interfere with the settlement of larvae which, if lost, may significantly reduce the population of this near annual species. | ||||
Intermediate | Very high | Low | Low | |
Patella pellucida is not found in areas of low water flow and siltation. Increased levels of suspended sediment are likely to interfere with feeding. However, its typical food species has a low intolerance to siltation. Larvae may be more intolerant at settlement which, if lost, may significantly reduce the population of this near annual species. | ||||
No information | ||||
Intermediate | Very high | Low | Low | |
Subtidal adults are unlikely to be affected except at extreme low tides. Increased desiccation is likely to affect the juvenile stages found in the lower eulittoral and adults on Fucus serratus. These are likely to be intolerant of an increased desiccation equivalent to moving from the lower to mid eulittoral for a year. Although the limpet can close tightly to macroalgae and creates pits and scars like its littoral co-familial Patella spp. the typical food plants (its substratum) are likely to be intolerant of increased desiccation and increased competition from other algal species more tolerant of desiccation. However, it is likely that recolonization from neighbouring populations would be rapid once the original conditions returned. | ||||
Low | Immediate | Not sensitive | Low | |
Decreased emergence is likely to increase the distribution of kelps up the shore and therefore Patella pellucida. Increasing emergence may reduce the upper extent of the kelp species, however, Patella pellucida could move to alternative food species such as Fucus serratus. | ||||
No information | ||||
Intermediate | Very high | Low | Moderate | |
The distribution of Patella pellucida is dependent on water flow rate. Studies in Lough Ine rapids (Ebling et al. 1948) found that Patella pellucida was very scarce on Saccorhiza polyschides in weak currents, plentiful in moderately strong currents (0.6-1.5 m/s) and scarce in strong currents (>1.5 m/s). Warburton (1976) demonstrated that large individuals could resist currents up to 0.9-1.3 m/s and smaller individuals resisted stronger currents before being swept off the fronds of kelp. Adults aligned themselves with the current flow above 0.5m/s and currents above 1.0- 1.4 m/s interfered with feeding and normal behaviour. Larger individuals are found in higher abundance in deeper water although Fretter & Graham (1994) suggested that larger individuals migrate to holdfasts. Therefore, it is likely that this species would be intolerant of either a decrease or increase in the water flow rate, equivalent to the benchmark, outside its habitat preferences. | ||||
No information | ||||
Intermediate | Very high | Low | ||
The wide distribution of this species suggests that it is tolerant of a wide range of temperatures. However, no information on the temperature tolerance of this species was found. It is likely that its food species are intolerant of increases in temperature consistent with the benchmark, so an intermediate intolerance has been recorded. | ||||
No information | ||||
Intermediate | Very high | Low | ||
Turbidity resulting from suspended sediment may interfere with feeding as above. Reduced light penetration will reduce the extent of the food species (kelps). | ||||
No information | ||||
Low | Immediate | Not sensitive | ||
This species prefers exposed to moderately exposed shores and it is likely to be intolerant of a change in wave exposure. The available food kelp species will change with exposure and increasing exposure may result in loss of older plants , especially those whose holdfasts had been weakened by Patella pellucida feeding, and adults of this species. | ||||
No information | ||||
Tolerant | Not relevant | Not sensitive | Moderate | |
There is no known effect of noise on this species or its prey species. | ||||
Tolerant | Not relevant | Not sensitive | Moderate | |
Although this species probably displays phototaxis there is no evidence of disturbance due to visual stimuli. | ||||
Intermediate | Very high | Low | Low | |
The shell in this species is relatively thin when compared with other limpets. Abrasion at the benchmark level is likely to knock some individuals off its food plant and crush or fracture the shell of others. A passing scallop dredge is likely to remove its substratum, i.e. kelps resulting in substratum loss as above. Therefore, a single scallop dredge will remove or damage a proportion of the kelp canopy and hence a proportion of Patella pellucida. Therefore, intolerance has been assessed as intermediate. | ||||
Tolerant | Not relevant | Not sensitive | Moderate | |
It is presumed that individuals of this species are periodically swept off their food plant. Although some individuals may be lost to deep water, Patella pellucida can re-orientate itself (as it will land upside down, foot upper most) and move to other plants using a mucus 'sail', secreted by the glands of the foot (Vahl 1983). McGrath (1997) demonstrated that plants cleared of Patella pellucida are rapidly recolonized by adults. |
Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
Intermediate | Very high | Low | Low | |
Gastropod molluscs are known to be sensitive to endocrine disruption from synthetic chemicals such as tri-butyl tin. However no information on the specific effects of tri-butyl tin on Patella pellucida was found. Hoare & Hiscock (1974) reported that Patella pellucida was excluded form Amlwch Bay, Anglesey by the presence of acidified, halogenated effluent; only eight specimens being found in Amlwch harbour where the silt levels probably reduced the toxicity of chlorine. Patella pellucida probably has an intermediate intolerance to, at least, this form of pollution. | ||||
No information | No information | No information | Not relevant | |
Bryan (1984) suggested that gastropods are rather tolerant of heavy metals. Crompton (1997) states that the following concentrations of heavy metals have caused mortalities in gastropods after 4-14days (short term); Cu (0.01-0.1 mg/l), Pb (0.1-1mg/l) , Zn (1-10mg/l), Cr and Ni (10-100mg/l). However, no data for this species was found. | ||||
No information | No information | No information | Not relevant | |
Insufficient information | ||||
No information | No information | No information | Not relevant | |
Insufficient information | ||||
Intermediate | Very high | Low | ||
Increased nutrients are likely to increase epiphyte and food plant growth, potentially increasing the availability of food for Patella pellucida. However, significant increases in nutrient levels (eutrophication), resulting in excessive growth of epiphytes and phytoplankton may have a detrimental effect on this species food plants and, therefore the population of Patella pellucida. | ||||
Intermediate | Very high | Low | Low | |
Patella pellucida is found in full salinity but not in areas of freshwater influence. Juveniles settle on the lower eulittoral and are likely to be subject to freshwater runoff and rainfall at low tide. However, adults are primarily subtidal and likely to be intolerant of long term reduction in salinity outlined in the benchmark. | ||||
No information | ||||
Intermediate | Very high | Low | ||
Oxygen concentrations at the level of the benchmark thought to likely to cause effects on marine organisms. In areas of exposure and moderately strong current flow it is unlikely to experience low oxygen levels. Therefore, it is likely to be intolerant of any spillage or activity that reduced the dissolved oxygen concentration to the level of the benchmark |
Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
No information | No information | No information | Not relevant | |
No microbial pathogens were reported in the literature. | ||||
Not relevant | Not relevant | Not relevant | Not relevant | |
No known alien or non-native species compete with Patella pellucida. | ||||
Not relevant | Not relevant | Not relevant | Not relevant | |
This species is not subject to extraction. | ||||
High | Very high | Low | Moderate | |
Kelp species are harvested in Scotland, Isle of Man and Ireland. Extraction of kelp is equivalent to removal of substratum (see above) in Patella pellucida. |
- no data -
National (GB) importance | - | Global red list (IUCN) category | - |
Native | - | ||
Origin | - | Date Arrived | Not relevant |
Bryan, G.W., 1984. Pollution due to heavy metals and their compounds. In Marine Ecology: A Comprehensive, Integrated Treatise on Life in the Oceans and Coastal Waters, vol. 5. Ocean Management, part 3, (ed. O. Kinne), pp.1289-1431. New York: John Wiley & Sons.
Crompton, T.R., 1997. Toxicants in the aqueous ecosystem. New York: John Wiley & Sons.
Ebling, F.J., Kitching, J.A., Purchon, R.D. & Bassingdale, R., 1948. The ecology of Lough Ine rapids with special reference to water currents. 2. The fauna of the Saccorhiza canopy. Journal of Animal Ecology, 17, 223-244.
Fish, J.D. & Fish, S., 1996. A student's guide to the seashore. Cambridge: Cambridge University Press.
Fretter, V. & Graham, A., 1994. British prosobranch molluscs: their functional anatomy and ecology, revised and updated edition. London: The Ray Society.
Fretter, V., & Graham, A., 1976. The Prosobranch Molluscs of Britain and Denmark. Part 1. - Pleurotomariacea, Fissurellacea and Patellacea. Journal of Molluscan Studies, Supplement 1.
Graham, A. & Fretter, V., 1947. The life history of Patina pellucida. Journal of the Marine Biological Association of the United Kingdom, 26, 590-601.
Hayward, P.J. & Ryland, J.S. (ed.) 1995b. Handbook of the marine fauna of North-West Europe. Oxford: Oxford University Press.
Hoare, R. & Hiscock, K., 1974. An ecological survey of the rocky coast adjacent to the effluent of a bromine extraction plant. Estuarine and Coastal Marine Science, 2 (4), 329-348.
Kain, J.M. & Svendsen, P., 1969. A note on the behaviour of Patina pellucida in Britain and Norway. Sarsia, 38, 25-30.
Koufopanou, V., Reid, D.G., Ridgeway, S.A., & Thomas, R.H., 1999. A Molecular Phylogeny of the Patellid Limpets (Gastropoda: Patellidae) and Its Implications for the Origins of Their Antitropical Distribution. Molecular Phylogenetics and Evolution, 11, 138-156.
Lebour, M.V., 1937. The eggs and larvae of the British Prosobranchs with special reference to those living in the plankton. Journal of the Marine Biological Association of the United Kingdom, 22, 105-166.
MBA (Marine Biological Association), 1957. Plymouth Marine Fauna. Plymouth: Marine Biological Association of the United Kingdom.
McGrath, D., 1992. Recruitment and growth of the Blue-rayed limpet, Helcion pellucidum in south east Ireland. Journal of Molluscan Studies, 58, 425-431.
McGrath, D., 1997. Colonization of artificially cleared Laminaria digitata (Huds.) Lamour, by the blue-rayed limpet Helcion pellucidum (L.) (Mollusca: Gastropoda). Biology and Environment: Proceedings of the Royal Irish Academy, 97B, 245-248.
Ridgeway, S.A., Reid, D.G., Taylor, J.D., Branch, G.M. & Hodgson, A.N., 1998. A cladistic phylogeny of the family Patellidae (Mollusca: Gastropoda). Philosophical Transactions of the Royal Society of London, Series B, 353(1375), 1645-1671.
Seaward, D.R., 1982. Sea area atlas of the marine molluscs of Britain and Ireland. Peterborough: Nature Conservancy Council.
Seaward, D.R., 1990. Distribution of marine molluscs of north west Europe. Peterborough: Nature Conservancy Council.
Vahl, O., 1971. Growth and density of Patina pellucida (L.) (Gastropoda: Prosobranchia) on Laminaria hyperborea (Gunnerus) from Western Norway. Ophelia, 9, 31-50.
Vahl, O., 1983. Mucus drifting in the limpet Helcion (=Patina) pellucidus (Prosobranchia, Patellidae). Sarsia, 68, 209-211.
Warburton, K., 1976. Shell form, behaviour and tolerance to water movement in the limpet Patina pellucida (L.) (Gastropoda: Prosobranchia). Journal of Experimental Marine Biology and Ecology, 23, 307-325
Weber, L.I., Gray, D.R., Hodgson, A.N., & Hawkins, S.J., 1997. Genetic divergence between South African Helcion species and North Atlantic Helcion pellucidum (Mollusca: Patellogastropoda). Journal of the Marine Biological Association of the United Kingdom, 77, 1139-1150.
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.
Cofnod – North Wales Environmental Information Service, 2018. Miscellaneous records held on the Cofnod database. Occurrence dataset: https://doi.org/10.15468/hcgqsi accessed via GBIF.org on 2018-09-25.
Conchological Society of Great Britain & Ireland, 2018. Mollusc (marine) data for Great Britain and Ireland - restricted access. Occurrence dataset: https://doi.org/10.15468/4bsawx accessed via GBIF.org on 2018-09-25.
Conchological Society of Great Britain & Ireland, 2018. Mollusc (marine) records for Great Britain and Ireland. Occurrence dataset: https://doi.org/10.15468/aurwcz accessed via GBIF.org on 2018-09-25.
Environmental Records Information Centre North East, 2018. ERIC NE Combined dataset to 2017. Occurrence dataset: http://www.ericnortheast.org.ukl accessed via NBNAtlas.org on 2018-09-38
Fenwick, 2018. Aphotomarine. Occurrence dataset http://www.aphotomarine.com/index.html Accessed via NBNAtlas.org on 2018-10-01
Fife Nature Records Centre, 2018. St Andrews BioBlitz 2014. Occurrence dataset: https://doi.org/10.15468/erweal accessed via GBIF.org on 2018-09-27.
Fife Nature Records Centre, 2018. St Andrews BioBlitz 2015. Occurrence dataset: https://doi.org/10.15468/xtrbvy accessed via GBIF.org on 2018-09-27.
Kent Wildlife Trust, 2018. Biological survey of the intertidal chalk reefs between Folkestone Warren and Kingsdown, Kent 2009-2011. Occurrence dataset: https://www.kentwildlifetrust.org.uk/ accessed via NBNAtlas.org on 2018-10-01.
Kent Wildlife Trust, 2018. Kent Wildlife Trust Shoresearch Intertidal Survey 2004 onwards. Occurrence dataset: https://www.kentwildlifetrust.org.uk/ accessed via NBNAtlas.org on 2018-10-01.
Manx Biological Recording Partnership, 2017. Isle of Man wildlife records from 01/01/2000 to 13/02/2017. Occurrence dataset: https://doi.org/10.15468/mopwow accessed via GBIF.org on 2018-10-01.
National Trust, 2017. National Trust Species Records. Occurrence dataset: https://doi.org/10.15468/opc6g1 accessed via GBIF.org on 2018-10-01.
NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.
OBIS (Ocean Biodiversity Information System), 2023. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2023-03-25
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.
South East Wales Biodiversity Records Centre, 2018. SEWBReC Molluscs (South East Wales). Occurrence dataset: https://doi.org/10.15468/jos5ga accessed via GBIF.org on 2018-10-02.
The Wildlife Information Centre, 2018. TWIC Biodiversity Field Trip Data (1995-present). Occurrence dataset: https://doi.org/10.15468/ljc0ke accessed via GBIF.org on 2018-10-02.
Yorkshire Wildlife Trust, 2018. Yorkshire Wildlife Trust Shoresearch. Occurrence dataset: https://doi.org/10.15468/1nw3ch accessed via GBIF.org on 2018-10-02.
This review can be cited as:
Last Updated: 08/05/2008