BIOTIC

BIOTIC Species Information for Amphiura chiajei
All Taxonomy Biology Distribution Reproduction

Researched by	Lizzie Tyler	Data supplied by	University of Sheffield
Refereed by	This information is not refereed.
General Biology
Growth form	Stellate Radial	Feeding method	Surface deposit feeder Sub-surface deposit feeder
Mobility/Movement	Crawler Burrower	Environmental position	Infaunal
Typical food types	Organic detritus.	Habit	Free living
Bioturbator		Flexibility	High (>45 degrees)
Fragility	Fragile	Size	Small-medium(3-10cm)
Height	Insufficient information	Growth Rate	0.5 mm/year
Adult dispersal potential	1km-10km	Dependency	Independent
Sociability	Gregarious
Toxic/Poisonous?	No
General Biology Additional Information	Feeding method Amphiura chiajei buries in the sediment with its disc at 4-6 cm depth. One or two arms are stretched up above the sediment to collect food at the surface. Food particles are then transported along the arms to its mouth and ingested (Buchanan, 1964). Population densities The species is mostly found in low numbers throughout its range, although a number of high density populations are reported. Survey work by Keegan & Mercer (1986) revealed Amphiura chiajei to be a dominant member of the bottom community in Killary Harbour (a fjord-like inlet on the west coast of Ireland). The highly dense population of about 700 individuals per m², occurred in sediments with a silt/clay content of 80-90% and organic carbon levels of 5-7%. In contrast, Buchanan (1964) reported the mean population density of Amphiura chiajei to be 13 individuals per m² off the Northumbrian coast. Interactions with other species The heart urchin, Brissopsis lyrifera, which typically co-occurs with Amphiura chiajei, can negatively affect the growth of body and gonads of Amphiura chiajei, whilst Amphiura chiajei seemingly has no effect on the growth of Brissopsis lyrifera. Hollertz et al. (1998) suggested that this was attributable to the extensive bioturbation of the sediment caused by Brissopsis lyrifera.
Biology References	Buchanan, 1964, Keegan & Mercer,1986, Hollertz et al., 1998, Aizenberg et al., 2001, Hayward & Ryland, 1990,