BIOTIC Species Information for Cordylophora caspia
Researched byDr Harvey Tyler-Walters & Paolo Pizzolla Data supplied byMarLIN
Refereed byThis information is not refereed.
Distribution and Habitat
Distribution in Britain & IrelandThe species has a sporadic distribution associated with areas of low salinity within estuaries and brackish lagoons.
Global distributionFound in estuarine, lagoonal and coastal lake habitats in boreal to subtropical waters.
Biogeographic rangeNot researched Depth rangeLow shore to ca 2m.
MigratoryNon-migratory / Resident   
Distribution Additional InformationSubstrata
Most hydroids do not show a high specificity of substrata. Cordylophora caspia has been recorded from a wide variety of hard substrata including rocks, shells and artificial substrata (pilings, harbour installations, bridge supports), floating debris and occasionally from the leaves of reeds (Phragmites) or stalks of water lilies (MBA, 1957; Roos, 1979; Morri & Boero, 1986; Arndt, 1986, 1989; JNCC, 1999; Foster-Smith, 2000).

Non-native status
Cordylophora caspia was thought to have been introduced to British waters on foreign timber (Allman, 1871-1872). Cordylophora caspia was introduced into the Baltic Sea in ca 1803 and was reported as an alien species in the Baltic Sea and the Chesapeake Bay region, USA (Folino, 1999 (summary only); Olenin et al., 2000). Folino (1999, summary only) suggested that the distribution of Cordylophora spp. was expanding globally due to increased boat travel and ballast discharge.

Substratum preferencesArtificial (e.g. metal/wood/concrete)
Large to very large boulders
Small boulders
Under boulders
Physiographic preferencesSealoch
Ria / Voe
Isolated saline water (Lagoon)
Enclosed coast / Embayment
Biological zoneLower Eulittoral
Sublittoral Fringe
Upper Infralittoral
Lower Infralittoral
Wave exposureVery Sheltered
Extremely Sheltered
Tidal stream strength/Water flowStrong (3-6 kn)
Moderately Strong (1-3 kn)
Weak (<1 kn)
Very Weak (negligible)
SalinityReduced (18-30 psu)
Low (<18 psu)
Habitat Preferences Additional InformationThe distribution of Cordylophora caspia is determined by availability of suitable hard substratum, food availability, range and variability of temperature and salinity. Cordylophora caspia can survive between -10 °C (as resistant dormant stages, menonts) and 35 °C. Colonies tolerate 5 to 35 °C, and reproduce between 10 to 28 °C. It can also survive 0 to 35psu as resistant stages, grow between 0.2 to 30 psu, reproduce between 0.2 to 20psu and possesses the ability to ionic regulate (Kinne, 1971; reviewed by Arndt, 1986, 1989). In nature, well developed colonies are usually found in water of 2 -12psu where tidal influence is considerable or between 2 -6psu where conditions are constant (Arndt, 1989). It may also occur at full salinities, and fast flowing, well oxygenated freshwater containing Ca, Mg, Na Cl and K ions (Fulton, 1962; Arndt, 1989). Arndt (1986, 1989) suggested that respiration, growth and reproduction were optimal between 4-7psu and that food intake was high in comparison to other hydroids so that growth and reproduction rates required for the survival of the species could only occur in eutrophic or hypertrophic waters where food is plentiful. Its marine distribution is probably limited by food availability, competition from Clava spp. or Laomedea spp. and predation e.g. from the nudibranch Tenellia adspersa (as Embletonia pallida) (Arndt, 1989). Cordylophora caspia prefers conditions of low light (Allman, 1871-1872, Arndt, 1989), although light intensity did not affect growth (Fulton, 1963), which probably reflects the settlement preferences of the planula larvae.
Distribution References Hayward & Ryland, 1995b, Barnes, 1994, Hincks, 1868, Allman, 1871-1872, Foster-Smith, 2000, JNCC, 1999, Gili & Hughes, 1995, MBA, 1957, Arndt, 1989, Arndt, 1984, Kinne, 1970, Kinne, 1971, Morri & Boero, 1986, Olenin et al., 2000, Folino, 1999,
About MarLIN | Contact, Enquiries & Feedback | Terms & Conditions | Funding | Glossary | Accessibility | Privacy | Sponsorship

Creative Commons License BIOTIC (Biological Traits Information Catalogue) by MarLIN (Marine Life Information Network) is licensed under a Creative Commons Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales License. Permissions beyond the scope of this license are available at Note that images and other media featured on this page are each governed by their own terms and conditions and they may or may not be available for reuse. Based on a work at