BIOTIC Species Information for Cordylophora caspia
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Researched byDr Harvey Tyler-Walters & Paolo Pizzolla Data supplied byMarLIN
Refereed byThis information is not refereed.
Scientific nameCordylophora caspia Common nameA hydroid
MCS CodeD285 Recent SynonymsCordylophora lacustris (Allman, 1844)

PhylumCnidaria Subphylum
SuperclassHydrozoa ClassLeptolida
SubclassAnthoathecatae OrderFilifera
Suborder FamilyClavidae
GenusCordylophora Speciescaspia

Additional InformationNo text entered
Taxonomy References Hayward & Ryland, 1995b, Barnes, 1994, Hincks, 1868, Allman, 1871-1872, Foster-Smith, 2000, Gili & Hughes, 1995,
General Biology
Growth formTurf
Feeding methodPassive suspension feeder
Mobility/MovementPermanent attachment
Environmental positionEpibenthic
Typical food typesSmall zooplankton, small crustacea, oligochaetes, insect larvae and probably detritus. HabitAttached
BioturbatorNot relevant FlexibilityHigh (>45 degrees)
FragilityFragile SizeSmall-medium(3-10cm)
HeightUp to 10 cm Growth Rateca 0.05-0.1 mm/hr
Adult dispersal potentialSee additional information DependencyIndependent
General Biology Additional InformationGrowth form
Growth form is highly variable in Cordylophora caspia. The colony of consists of a mass of stolons (hydrorhizae) growing across the surface of the substratum. Growth is apical, with side stolons arising at right angles. Upright hydrocauli bear apical polyps (hydranths), and side branches at 45° (Fulton, 1961).The degree of branching, length and spacing of hydrocauli, cell size, size and shape of polyps and the number and length of tentacles vary with environmental conditions (Fulton, 1962; Kinne, 1970, 1971; Arndt, 1989). For example, colonies have short, polyps that grow directly from the hydrorhiza at 0.5psu; more elongate polyps with longer tentacles and multiply branched uprights at 15psu, but smaller polyps and less branched uprights at 30psu than at 15psu (see Kinne 1970, 1971 for review; Arndt, 1989, Gili & Hughes, 1995). Gaulin et al. (1986) noted that predation by the nudibranch Tenellia fuscata resulted in denser colonies.

Growth rates
Growth rates are variable depending on environmental or laboratory conditions. Growth in number of polyps is exponential, the colonies doubling in polyp number every 2-4 days, although growth rate can very as much as two-fold even under standard conditions (Fulton, 1961, 1962). In addition, although old colonies could reach as much as 2000 polyps in size growth rates decreased with age (Fulton, 1962). Fulton (1961) reported that uprights grew at 0.05mm/hr while stolons extension rates vary from 0.1mm/hr (Fulton, 1961) to 2-3mm3/day (Chester et al., 2000). Fulton (1962) reported that growth rates varied with temperature, salinity, ionic composition, oxygen tension and feeding rate (see sensitivity).

Seasonal changes
Cordylophora caspia dies back in late autumn and over-winters as dormant stolons and resting stages (menonts) inside the remnants of the uprights (see Roos, 1979 for figure, Arndt, 1989, Jormalainen et al. 1994). Arndt (1989) reported that colonies died back in autumn when the temperature fell to about 10 °C only to germinate in spring when the temperature exceeded 5 °C. Roos (1979) reported that colonies died back in October and new polyps budded again in early spring in the Netherlands. In the Baltic Sea growth was maximal in spring, uprights reaching maximal height at the peak of sexual reproduction in July, with a decline after sexual reproduction, and subsequent growth in August (Jormalainen et al., 1994). However, in one year, Jormalainen et al (1994) noted that the colonies regressed to the dormant condition after sexual reproduction then started growing again by mid August.

Hydroids are passive carnivores that capture prey that swim into, or are brought into contact with their tentacles by currents. Prey are then killed or stunned by the nematocysts born on the tentacles and swallowed. Diet varies but is likely to include small zooplankton (e.g. nauplii, copepods), small crustacea, chironomid larvae, detritus and oligochaetes, but may include a wide variety of other organisms such as the larvae or small adults of numerous groups (see Gili & Hughes, 1995).

Biology References Barnes, 1994, Hincks, 1868, Allman, 1871-1872, Gili & Hughes, 1995, Arndt, 1989, Arndt, 1984, Kinne, 1970, Kinne, 1971, Fulton, 1961, Fulton, 1962, Chester et al., 2000, Roos, 1979, Jormalainen et al. 1994), Gaulin et al., 1986,
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,
Reproduction/Life History
Reproductive typeBudding
Developmental mechanismLecithotrophic
Direct Development
Reproductive SeasonJune-August Reproductive LocationAs adult
Reproductive frequencyAnnual episodic Regeneration potential No
Life spanSee additional information Age at reproductive maturity<1 year
Generation time<1 year FecunditySee additional information
Egg/propagule sizeInsufficient information Fertilization typeInternal
Larval/Juvenile dispersal potential<10m Larval settlement periodSee additional information
Duration of larval stage<1 day   
Reproduction Preferences Additional InformationMost hydroids (including Cordylophora caspia) are dioecious. The reproductive organs are carried in gonophores. Sperm are released into the sea and eggs are fertilized within the female gonophores where the embryos develop into planulae. Sperm swim towards female gonophores, however, sperm probably have a limited life span and hence a limited range for fertilization of only a few metres. Hence the growth of hydroids in clumps may enhance fertilization rates, albeit at the cost of intraspecific competition. Temperature is critical for stimulating or preventing reproduction in hydroids (see distribution; Gili & Hughes, 1995).
Sexual reproduction
Early seasonal growth from winter dormancy in early spring is rapidly followed by formation of gonophores and sexual reproduction in midsummer followed by active growth in late summer. However, sexual reproductive effort may retard growth (see general biology). Jormalainen et al. (1994) reported that reproduction began in early June, peaked in July (80% uprights with gonophores) and rapidly reduced by August (30% uprights with gonophores). Similar reproductive periods have been reported by other authors (Allman, 1871-1872; MBA, 1957; Roos, 1979; Foster-Smith, 2000). Roos (1979) and Jormalainen et al. (1994) reported that the sex ratio was biased in favour of females.

Each upright branch may bear between 1-3 gonophores each with between 10 - 6 eggs, the number decreasing in autumn (Hincks, 1868; Jormalainen et al., 1994). Therefore, fecundity is dependant on the number of branches and hence the number of gonophores, and in large colonies of 70-2000 polyps (Fulton, 1962), may be high. The larvae are released as planulae and no medusoid stage occurs. However, in some cases the larvae may develop directly into juvenile polyps in the gonophore before release (Bouillon, 1963).

Asexual reproduction
Hydroids may reproduce asexually by budding to from another colony. A common form of asexual reproduction in hydroids is the formation of vertical stolons, which then adhere to adjacent substratum, detach and form another colony (Gili & Hughes, 1995). Hydroids exhibit remarkable powers of regeneration and Cordylophora caspia can be cloned in culture from detached uprights or excised tissue (Moore, 1952;Fulton, 1961, 1962). Asexual reproduction by fission or mechanical fragmentation of the colony may be an important factor in dispersal (Gili & Hughes, 1995).

While uprights have a short, finite life span from about early spring to autumn, no information concerning the life span of the dormant stages (menonts) was found. Unless destroyed by predators or physical damage, the colony may have a long life span (perhaps very long (Gili & Hughes, 1995). The ability to reproduce asexually and regenerate from damaged sections means that although any individual colony may have a finite life span the genetic individual (genet) may be considerably longer lived (Gili & Hughes, 1995).

Rapid growth, budding and the formation of stolons allows hydroids to colonize space rapidly. Hydroids are often the first organisms to colonize available space in settlement experiments (Gili & Hughes, 1995). Planula larvae swim or crawl for short periods (e.g. <24hrs) so that dispersal away from the parent colony is probably very limited (Gili & Hughes, 1995). Fragmentation may also provide another route for short distance dispersal. However, it has been suggested that rafting on floating debris (or hitch hiking on ships hulls or in ship ballast water) as dormant stages or reproductive adults, together with their potentially long life span, may have allowed hydroids to disperse over a wide area in the long term and explain the near cosmopolitan distributions of many hydroid species, including Cordylophora caspia (Gili & Hughes, 1995; Folino, 1999).
Reproduction References Hincks, 1868, Gili & Hughes, 1995, MBA, 1957, Arndt, 1989, Fulton, 1961, Fulton, 1962, Roos, 1979, Jormalainen et al. 1994), Bouillon, 1963, Folino, 1999,
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