BIOTIC

BIOTIC Species Information for Owenia fusiformis

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

May to June

Reproductive Location

Water column

Reproductive frequency

Annual episodic

Regeneration potential

Life span

3-5 years

Age at reproductive maturity

1-2 years

Generation time

1-2 years

Fecundity

70000

Egg/propagule size

100 µm diameter

Fertilization type

External

Larvae/Juveniles
Larval/Juvenile dispersal potential	>10km	Larval settlement period	Insufficient information
Duration of larval stage	11-30 days

Reproduction Preferences Additional Information

This polychaete has a life span of up to four years in British waters (Rouse & Pleijel, 2001) and has a polymodal population structure of three to five year classes (Menard et al., 1990). The mortality rate increases gradually with age but suddenly increases in the fourth year of life (Menard et al., 1990). Growth is rapid in summer, slows in the autumn and is negligible in winter, resuming in April each year. Owenia fusiformis is an annual breeder, gonochoric, with external fertilization (Rouse & Pleijel, 2001). Up to 70,000 oocytes mature from September to April (Gentil et al., 1990) and are spawned during May and June (Rouse & Pleijel, 2001). Oocytes are up to 100 µm in diameter (Rouse & Pleijel, 2001). The sex ratio is female biased and is around 0.86:1. Maturity is size-dependent and all worms 6 cm long or more are mature but some individuals reach maturity at 2.4 cm. Some individuals may breed in their first year if they can grow fast enough (Gentil et al., 1990). In late May, larval densities can be up to 100,000 per m³ (Thiebaut et al., 1992) and settled densities vary from 4,000 to 15,000 juveniles per m² (Menard et al., 1990).

Reproduction References

Rouse & Pleijel, 2001, Menard et al., 1990, Gentil et al., 1990, Thiebaut et al., 1992, Barnay et al., 2003, Eckert, 2003, Heidi Tillin, unpub data,