BIOTIC

BIOTIC Species Information for Crepidula fornicata

Researched by

Will Rayment

Data supplied by

MarLIN

Refereed by

Dr Frédérique Viard

Reproduction/Life History

Reproductive type

Protandrous hermaphrodite

Developmental mechanism

Planktotrophic

Reproductive Season

February to October

Reproductive Location

Insufficient information

Reproductive frequency

Annual protracted

Regeneration potential

Life span

6-10 years

Age at reproductive maturity

<1 year

Generation time

1-2 years

Fecundity

Ca 4000 larvae

Egg/propagule size

Fertilization type

Insufficient information

Larvae/Juveniles
Larval/Juvenile dispersal potential	>10km	Larval settlement period	Insufficient information
Duration of larval stage	1-2 months

Reproduction Preferences Additional Information

General
Crepidula fornicata is a protandrous hermaphrodite. This means that the animals start their lives as males and then subsequently may change sex and develop into females. Although breeding can occur between February and October, peak activity occurs in May and June when 80-90% of females spawn. Most females spawn twice in a year, apparently after neap tides. The spat settle in isolation or on top of an established chain. If the individual settles alone, it becomes male briefly, passing rapidly on to a female, especially if another animal settles on it to initiate chain formation. Sex change can only occur to the bottom-most male in a stack and takes approximately 60 days, during which the penis regresses and the pouches and glands of the female duct develop. If a juvenile settles on an established stack it develops and may remain as a male for an extended period (up to 6 years), apparently maintained by pheromones released by females lower in the stack (Fretter & Graham, 1981).

Age at maturity
Due to the protandrous hermaphroditic lifecycle of Crepidula fornicata, age at maturity is difficult to ascertain. Warne(1956), cited in Fretter & Graham (1981), reported size at maturity to be 4mm but it is unclear whether this refers to both sexes or males only. A size of 4mm would be achieved approximately 2 months after settlement. Under laboratory conditions, Nelson et al.(1983) report that the mean time from being spawned to first larval release for females was 300 days, i.e.. maturity is reached approximately 10 months after settlement.

Generation time
Generation time is complicated by the hermaphroditic life-cycle of Crepidula fornicata. Incubation of the eggs takes 2-4 weeks and the duration of the larval phase is 4-5 weeks (Fretter & Graham, 1981; Thouzeau, 1991). Using the ages at maturity quoted above, it would appear that males are capable of breeding as little as 4 months after fertilization. Under laboratory conditions, Nelson et al. (1983) reported the female generation time to be 300 days. However, in situ females were not reported to spawn until their third year (Deslou-Paoli & Heral, 1986).

Fecundity
Females can lay around 11000 eggs at a time contained in up to 50 egg capsules (Deslou-Paoli & Heral, 1986). Laboratory experiments by Thain (1984) revealed that following incubation, approximately 4000 larvae were released per female.

Reproduction References

Fretter & Graham, 1981, Fish & Fish, 1996, Nelson et al., 1983, Thain, 1984, Deslou-Paoli & Heral, 1986, Montaudouin de et al., 2001,