Balanus spp.

Researched By	Dan Bayley	Data Supplied By
Refereed by	This information is not refereed.
Taxonomy
Scientific name	Balanus spp.	Common name	A barnacle
MCS Code	R74	Recent Synonyms
Phylum	Arthropoda	Subphylum	Crustacea
Superclass		Class	Maxillopoda
Subclass	Cirripedia	Order	Sessilia
Suborder	Balanomorpha	Family	Balanidae
Genus	Balanus	Species
Subspecies
Additional Information
Taxonomy References	Hayward & Ryland, 1995b, Rainbow, 1984, Bassindale, 1964, Campbell, 1982, Howson & Picton, 1997
General Biology
Growth form		Feeding method	Active suspension feeder, Detritivore
Mobility/Movement	Permanent attachment	Environmental position	Epilithic
Typical food types	Zooplankton, detritus	Habit	Attached
Bioturbator		Flexibility	None (< 10 degrees)
Fragility	Robust	Size	Small(1-2cm)
Height		Growth Rate
Adult dispersal potential	None	Dependency	Independent
Sociability	Gregarious
Toxic/Poisonous?	No
Additional Information	Feeding Barnacles feed by extending thoracic appendages called cirri out from the shell to filter zooplankton from the water. In the absence of any current, the barnacle rhythmically beats the cirri. When a current is present the barnacle holds the cirri fully extended in the current flow. Barnacles feed most during spring and autumn when plankton levels are highest. Little if any feeding takes place during winter, when barnacles rely on stored food reserves. Feeding rate is important in determining the rate of growth. Moulting Barnacles need to moult in order to grow. Frequency of moulting is determined by feeding rate and temperature. Moulting does not take place during winter when phytoplankton levels and temperatures are low.
Biology References	Rainbow, 1984, Barnes et al., 1963, Bassindale, 1964
Distribution and Habitat
Distribution in Britain & Ireland	All Great Britain
Global distribution
Biogeographic range		Depth range
Migratory
Distribution Additional Information	Balanus balanus restricted from Cornwall.
Substratum preferences	Bedrock, Large to very large boulders, Small boulders	Physiographic preferences	Open coast
Biological zone		Wave exposure
Tidal stream strength/Water flow		Salinity
Habitat Additional Information
Distribution References	Hayward & Ryland, 1995b, Rainbow, 1984, Barnes, 1953, Barnes et al., 1963, Bassindale, 1964, Southward, 1998, Fish & Fish, 1996, Hiscock et al, 2001, Herbert et al., 2003
Reproduction/Life History
Reproductive type	Permanent hermaphrodite	Developmental mechanism	Planktotrophic
Reproductive Season		Reproductive Location
Reproductive frequency	Annual episodic	Regeneration potential	No
Life span	3-5 years	Age at reproductive maturity	<1 year
Generation time	<1 year	Fecundity	up to 8000 eggs
Egg/propagule size		Fertilization type	Internal
Larvae/Juveniles Larval/Juvenile dispersal potential >10km Larval settlement period Duration of larval stage
Additional Information
Reproduction References	Høpner Petersen, 1966, Rainbow, 1984, Barnes & Powell, 1953, Barnes & Bagenal, 1951, Herbert et al., 2003, Crisp, 1954