Polycarpa

A Vulnerable genera from the “Other: Chordata” group, mostly found in Cobbles

Cobbles

Vulnerable

Other: Chordata

Genera Characteristics Recorded Traits Possible Values
Size in cm
  • 1-10 cm
  • <1 cm
  • 1-10 cm
  • 11-20 cm
  • >20 cm
Genera Characteristics Recorded Traits Possible Values
Motility (Adult)
  • Sedentary
  • Adult
  • Short Range Mobility
  • Sedentary

“Sedentary”

Motility (Larval)
  • Short Term Planktonic
  • Long Term Planktonic
  • Short Term Planktonic
  • Brooded or Laid Eggs

“Short Term Planktonic”

Lifespan
  • 3-10 years
  • >10 years
  • 3-10 years
  • 1-2 years
  • <1 year
Maturity
  • 1-2 years
  • >4 years
  • 3-4 years
  • 1-2 years
  • <1 year
Fecundity
  • 10000 - 1 million
  • 1 - 10
  • 10 - 100
  • 100 - 1000
  • 1000 - 10000
  • 10000 - 1 million
  • > 1 million

Image: Polycarpa © MES

Vulnerability

Polycarpa is a genus of small-medium sized solitary ascidians (Sea squirts) belonging to the Family Styelidae. The ascidian reaches a height of about 3-8cm & is attached to boulders, rocks & epigrowths on the seabed where it feeds by filtering particulate matter from the water column. It is vulnerable to dredging, to deposition of material mobilised by the dredging process & to clogging of the filtration mechanism by excessive particulate loads in the water column. It is also likely to be vulnerable to modification of the habitat of rock & epigrowths on which it depends for recolonisation & attachment.
 

Recoverability

Polycarpa probably has a life-span of 3-5yrs. The genus is hermaphrodite & reproductive maturity is reached in 1yr. As many as 20,000 yolk-filled eggs of 0.15-240mm diameter are fertilised externally in an annual episodic breeding season between April-November. The lecithotrophic tadpole larvae spend less than 1 day in the water column before settlement. This genus has a high fecundity but a larval dispersal potential of only 10-100m. The seabed is likely to be recolonised only very slowly from sources outside a site of disturbance. Recoverability low.
 

References

  • Biology

    • Millar, 1970
  • Taxonomy

    • Millar, 1970
  • Distribution

    • Hayward & Ryland, 1990
  • Reproduction

    • Chen & Dai, 2000
    • Millar, 1970