BIOTIC Species Information for Clavelina lepadiformis
Researched byKaren Riley Data supplied byMarLIN
Refereed byDr Xavier Turon
Distribution and Habitat
Distribution in Britain & IrelandClavelina lepadiformis occurs around most coasts of Britain and Ireland.
Global distributionIts distribution extends from southern Norway to the Mediterranean.
Biogeographic rangeNot researched Depth rangeSublittoral to 50 m
MigratoryNon-migratory / Resident   
Distribution Additional Information
  • The species is absent in the Bristol Channel, between Morecambe Bay and Colwyn Bay on the west coast of England, between the Firth of Forth and Newcastle upon Tyne, and the Humber Estuary and Dover on the east coast of Britain. It also has a variable abundance in Ireland.
  • Clavelina lepadiformis is a very common shallow water sea squirt that is usually found on vertical rock faces and on the sides of boulders, to about 50 m depth down (Picton, 1997; Berrill, 1950). It is also found on shells, stones and seaweeds (Picton, 1997), is a typical species of harbour areas, commonly found growing on artificial surfaces.
  • Naranjo et al. (1996) found that the light bulb sea squirt preferred light, shallow environments and was tolerant of salinities as low as 14 psu (Fish & Fish, 1996). It occurs in a wide range of exposure, but is most abundant in moderately exposed sites in the infralittoral zone (Picton, 1997).
  • Naranjo et al. (1996) found that the species was dominant in a low rate of water renewal, excess silting and high suspended solid concentrations, although the species also occurred in other more wave exposed sites.
  • In a study comparing Mediterranean and Atlantic populations of Clavelina lepadiformis in interior (harbours, marinas and fjords) and exterior (open rocky littoral) areas, Turon et al. (2003) found strong evidence that the interior Mediterranean clade (group of organisms sharing the same common ancestry) originated from the Atlantic clade. The Atlantic forms were not found to be divided between interior and exterior clades (Turon et al., 2003).

Substratum preferencesArtificial (e.g. metal/wood/concrete)
Large to very large boulders
Small boulders
Physiographic preferencesOpen coast
Offshore seabed
Strait / sound
Enclosed coast / Embayment
Biological zoneSublittoral Fringe
Upper Infralittoral
Lower Infralittoral
Wave exposureVery Exposed
Moderately Exposed
Very Sheltered
Extremely Sheltered
Tidal stream strength/Water flowSee additional information
Insufficient information
SalinityFull (30-40 psu)
Variable (18-40 psu)
Habitat Preferences Additional Information
Distribution References Fish & Fish, 1996, Berril, 1950, Naranjo et al., 1996, Picton & Costello, 1998, De Caralt et al., 2002, Turon et al., 2003,
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