BIOTIC

BIOTIC Species Information for Cordylophora caspia
All Taxonomy Biology Distribution Reproduction

Researched by	Dr Harvey Tyler-Walters & Paolo Pizzolla	Data supplied by	MarLIN
Refereed by	This information is not refereed.
Distribution and Habitat
Distribution in Britain & Ireland	The species has a sporadic distribution associated with areas of low salinity within estuaries and brackish lagoons.
Global distribution	Found in estuarine, lagoonal and coastal lake habitats in boreal to subtropical waters.
Biogeographic range	Not researched	Depth range	Low shore to ca 2m.
Migratory	Non-migratory / Resident
Distribution Additional Information	Substrata 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 preferences	Artificial (e.g. metal/wood/concrete) Bedrock Caves Cobbles Large to very large boulders Overhangs Small boulders Pebbles Under boulders	Physiographic preferences	Sealoch Ria / Voe Estuary Isolated saline water (Lagoon) Enclosed coast / Embayment
Biological zone	Lower Eulittoral Sublittoral Fringe Upper Infralittoral Lower Infralittoral	Wave exposure	Very Sheltered Extremely Sheltered
Tidal stream strength/Water flow	Strong (3-6 kn) Moderately Strong (1-3 kn) Weak (<1 kn) Very Weak (negligible)	Salinity	Reduced (18-30 psu) Low (<18 psu)
Habitat Preferences Additional Information	The 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,