Ceramium virgatum

Researched By	Dr Keith Hiscock and Paolo Pizzolla	Data Supplied By	MarLIN
Refereed by	Dr Fabio Rindi
Taxonomy
Scientific name	Ceramium virgatum	Common name	A red seaweed
MCS Code	ZM519	Recent Synonyms	Ceramium nodulosum, Ceramium rubrum
Phylum	Rhodophycota	Subphylum
Superclass		Class	Rhodophyceae
Subclass	Florideophyceae	Order	Ceramiales
Suborder		Family	Ceramiaceae
Genus	Ceramium	Species	virgatum
Subspecies
Additional Information	Discrimination of separate species of Ceramium is often difficult. This species can be identified with certainty only by careful microscopic observation and in the field can be easily confused with other species of Ceramium with similar morphology namely Ceramium botryocarpum, Ceramium pallidum and Ceramium secundatum (F. Rindi, pers. comm.). The above taxonomy uses the recent nomenclature from Hardy & Guiry (2003). The confusion concerning Ceramium nodulosum and Ceramium rubrum was discussed by Maggs et al. (2002).
Taxonomy References	Dickinson, 1963, Fish & Fish, 1996, Maggs & Hommersand, 1993, Hiscock, 1986b, Maggs et al., 2002
General Biology
Growth form	Filiform	Feeding method	Photoautotroph
Mobility/Movement	Permanent attachment	Environmental position	Epifloral, Epilithic, Epiphytic, Epibenthic
Typical food types	Not relevant	Habit	Attached
Bioturbator	Not relevant	Flexibility	High (>45 degrees)
Fragility	Intermediate	Size	Medium-large(21-50cm)
Height		Growth Rate	Insufficient information
Adult dispersal potential	None	Dependency	Independent
Sociability	Solitary
Toxic/Poisonous?	No
Additional Information	Ceramium virgatum colonizes rock and algal habitats from the midshore in rockpools to the open shore near to low water level and in the shallow subtidal (see Maggs & Hommersand, 1993). It also grows attached to the leaves of Zostera marina (see, for instance, Whelan & Cullinane, 1985). It occurs on bedrock through to pebbles. Dickinson (1963) notes that the species is either perennial or pseudoperennial. Settlement onto new surfaces can be rapid. For instance, panels were colonized within a month of being placed in Langstone Harbour (Brown et al., 2001)
Biology References	Dickinson, 1963, Brown et al., 2001, Maggs & Hommersand, 1993, Edwards, 1973, Whelan & Cullinane, 1985
Distribution and Habitat
Distribution in Britain & Ireland	Found on most suitable shores around Britain and Ireland.
Global distribution	Maggs & Hommersand (1993) note that the 'Ceramium rubrum complex' is widely distributed in the North Atlantic but the distribution of component species requires reassessment.
Biogeographic range	Not researched	Depth range
Migratory	Non-migratory / Resident
Distribution Additional Information	Ceramium virgatum may be particularly abundant in the summer. It thrives in rockpools and occurs in still water situations where dilution with freshwater is likely to occur.
Substratum preferences	Cobbles, Pebbles, Gravel / shingle, Algae, Artificial (e.g. metal/wood/concrete), Rockpools	Physiographic preferences	Open coast, Strait / sound, Sealoch, Ria / Voe, Estuary, Enclosed coast / Embayment, Strait / sound
Biological zone	Mid Eulittoral, Lower Eulittoral, Sublittoral Fringe, Upper Infralittoral	Wave exposure	Extremely Exposed, Very Exposed, Exposed, Moderately Exposed, Sheltered, Very Sheltered, Extremely Sheltered
Tidal stream strength/Water flow	Weak (<1 kn), Very Weak (negligible)	Salinity	Variable (18-40 psu), Full (30-40 psu)
Habitat Additional Information
Distribution References	Dickinson, 1963, Fish & Fish, 1996, Maggs & Hommersand, 1993, Whelan & Cullinane, 1985, NBN, 2002, Hardy & Guiry, 2003, Hardy & Guiry, 2003
Reproduction/Life History
Reproductive type	Alternation of generations	Developmental mechanism	Spores (sexual / asexual)
Reproductive Season	See additional information	Reproductive Location	As adult
Reproductive frequency	Annual protracted	Regeneration potential	No
Life span	3-5 years	Age at reproductive maturity	Insufficient information
Generation time	See additional information	Fecundity	Insufficient information
Egg/propagule size		Fertilization type
Larvae/Juveniles Larval/Juvenile dispersal potential 10-100m Larval settlement period Duration of larval stage See additional information
Additional Information	Edwards (1973) reports that Ceramium virgatum (as rubrum) has a triphasic life history consisting of a sequence of gametophytic, carposporophytic and tetrasporophytic phases in which the first and the third are morphologically similar. Maggs & Hommersand (1993) report that spermatangia are recorded in January, March-April, June and August-September; cystocarps in January-February and April-September; tetrasporangia in February-September. Although no information on dispersal has been found directly for Ceramium virgatum, Norton (1992) concluded that dispersal potential is highly variable in seaweeds. Spores of Ulva sp. (as Enteromorpha) have been reported to travel 35 km, Phycodrys rubens 5 km and Sargassum muticum up to 1 km. However, the point is made that reach of the furthest propagule and useful dispersal range are not the same thing and recruitment usually occurs on a much more local scale, typically within 10 m of the parent plant.
Reproduction References	Maggs & Hommersand, 1993, Norton, 1992, Edwards, 1973