BIOTIC

BIOTIC Species Information for Phymatolithon calcareum

Researched by

Angus Jackson

Data supplied by

MarLIN

Refereed by

Dr Christine Maggs

Reproduction/Life History

Reproductive type

Vegetative

Developmental mechanism

Insufficient information

Reproductive Season

Insufficient information

Reproductive Location

Insufficient information

Reproductive frequency

Insufficient information

Regeneration potential

Life span

51-100 years

Age at reproductive maturity

Not relevant

Generation time

Insufficient information

Fecundity

Insufficient information

Egg/propagule size

Insufficient information

Fertilization type

Insufficient information

Larvae/Juveniles
Larval/Juvenile dispersal potential	<10m	Larval settlement period	Insufficient information
Duration of larval stage	Insufficient information

Reproduction Preferences Additional Information

Recruitment in France is believed to be primarily through fragmentation from crustose forms. No crustose forms are known from the British Isles so propagation must be virtually entirely vegetative. Maerl beds in the Sound of Iona are recorded as containing dead nodules up to 4,000 years old (Farrow, 1983, cited in Maggs et al., 1998). Insufficient information is available on reproductive frequency, fecundity and developmental mechanism. In the British Isles there are a few records of fertile plants but no records of the crustose forms that this reproduction would produce. Plants may be fertile and develop conceptacles throughout the year. Plants from Brittany are mostly fertile in winter. Cabioch (1969) suggested that Phymatolithon calcareum may have phasic reproduction with peaks every six years. This may account for observed changes in the relative proportions of live Lithothamnion corallioides and Phymatolithon calcareum nodules in maerl beds. Dominance cycles with periods of about thirty years have been recorded on some of the maerl beds of northern Brittany. Adey & McKibbon (1970) undertook growth studies of Phymatolithon calcareum in the field and under laboratory conditions. Their results for field studies in the Ria de Vigo, expressed as µ/day, show that growth occurs predominantly in the summer and suggests an annual growth of about 0.55 mm/year for branch tips of Phymatolithon calcareum according to Maggs et al. (1998).

Reproduction References

Irvine & Chamberlain, 1994, Birkett et al., 1998(a), Cabioch, 1969, Franz et al. 2000, Halfar et al., 2000, Farrow (1983),