BIOTIC Species Information for Amphiura chiajei
|Researched by||Lizzie Tyler||Data supplied by||University of Sheffield|
|Refereed by||This information is not refereed.|
|Scientific name||Amphiura chiajei||Common name||A brittlestar|
|MCS Code||ZB152||Recent Synonyms||None|
|Additional Information||Other Amphiura species are similar. Mixed populations of Amphiura chiajei and Amphiura filiformis are common.|
|Taxonomy References||Mortensen, 1927, Hayward et al., 1996, Picton, 1993, Hayward & Ryland, 1995b,|
|Feeding method||Surface deposit feeder
Sub-surface deposit feeder
|Typical food types||Organic detritus.||Habit||Free living|
|Bioturbator||Flexibility||High (>45 degrees)|
|Height||Insufficient information||Growth Rate||0.5 mm/year|
|Adult dispersal potential||1km-10km||Dependency||Independent|
|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).
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,|
|Distribution and Habitat|
|Distribution in Britain & Ireland||Recorded off the west, north and east coasts of the British Isles, mostly below 10 m in depth. There is some doubt over records from the south coast.|
|Global distribution||Distributed from western Norway (Trondhjemfjord), southwards along European coasts to the Mediterranean, the west coast of North Africa, and the Azores.|
|Biogeographic range||Not researched||Depth range||9 - 1000 m|
|Migratory||Non-migratory / Resident|
|Distribution Additional Information|
|Physiographic preferences||Open coast
Enclosed coast / Embayment
|Biological zone||Upper Circalittoral
|Tidal stream strength/Water flow||Weak (<1 kn)
Very Weak (negligible)
|Salinity||Full (30-40 psu)
Variable (18-40 psu)
|Habitat Preferences Additional Information|
|Distribution References||Mortensen, 1927, Picton, 1993, Crothers, 1966, Bruce et al., 1963, Foster-Smith, 2000, Mortensen, 1927,|
|Reproductive Season||End of summer until middle of autumn||Reproductive Location||As adult|
|Reproductive frequency||Annual episodic||Regeneration potential||No|
|Life span||6-10 years||Age at reproductive maturity||3-5 years|
|Generation time||See additional information||Fecundity|
|Egg/propagule size||Fertilization type||External|
|Reproduction Preferences Additional Information||Life span
Munday (1992) suggested from his observations in Killary Harbour, Ireland that individuals of Amphiura chiajei attained an age of 10 years, an estimate that was consistent with that reported for populations of Amphiura chiajei living off the Northumbrian coast (Buchanan, 1964).
In most species of ophiuroids the sexes are separate and fertilization external, leading to the development of a pelagic larva, the ophiopluteus (Fish & Fish, 1996). Individuals reach reproductive maturity after four years and in Amphiura chiajei there is a seasonal cycle in gonad development. A period of rest occurs at the end of autumn followed by growth over winter. Gonads reach maturity towards the end of spring and summer. Spawning occurs over the period from the end of summer until the middle of autumn (Fenaux, 1970).
Larval settling time and recruitment
In the laboratory, Fenaux (1970) observed a complete larval metamorphosis through to the formation of a young ophiuroid within 8 days at temperature 18-20 °C. Fenaux (1970) suggested that for eggs laid at the end of summer and at the beginning of autumn in which the water temperature exceeds 20°C, the pelagic life is probably shorter. With such a short life in the plankton the dispersal potential is likely to be rather limited in comparison to other echinoderms.
Amphiura chiajei is a species with sporadic recruitment, which, in combination with its slow growth rate, later maturity and longevity make it a striking contrast to Amphiura filiformis (see Buchanan, 1964).
A heavy and successful settlement of Amphiura chiajei can dominate an area for over 10 years. Buchanan (1964), sampled Amphiura chiajei off the Northumbrian coast between 1958 and 1965, and found the entire population to consist of large individuals (disc diameter > 7.5 mm). Between 1958 and 1964, there was no evidence of any new recruitment to the population, but at the end of 1965 a heavy and successful recruitment occurred. Prior to this settlement it was apparent that the same single ageing population had been measured for over 8 years. Spawning had occurred but without successful recruitment. This pattern of longevity and of episodic recruitment is consistent with that if the population of Amphiura chiajei in Killary Harbour, west coast of Ireland (Munday & Keegan, 1992). The mortality rate was measured between 1961-1963 and shown to be small.
|Reproduction References||Buchanan, 1964, Munday, 1993, Fish & Fish, 1996, Munday & Keegan, 1992, Fenaux, 1970, Eckert, 2003,|