BIOTIC

BIOTIC Species Information for Amphiura chiajei

Researched by

Lizzie Tyler

Data supplied by

University of Sheffield

Refereed by

This information is not refereed.

Reproduction/Life History

Reproductive type

Gonochoristic

Developmental mechanism

Planktotrophic

Reproductive Season

End of summer until middle of autumn

Reproductive Location

As adult

Reproductive frequency

Annual episodic

Regeneration potential

Life span

6-10 years

Age at reproductive maturity

3-5 years

Generation time

See additional information

Fecundity

Egg/propagule size

Fertilization type

External

Larvae/Juveniles
Larval/Juvenile dispersal potential	See additional information	Larval settlement period	Insufficient information
Duration of larval stage

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).
Reproduction
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).
Cohort dominance
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,