Additional Info

• Where does this species come from?

  Australia.

  What is its invasive status in South Africa?

  NEMBA Category 1b

  Where in South Africa is it a problem?

  Cape Peninsula in Western Cape.

  How does it spread?

  It is often introduced to new regions by fouling on ship and boat hulls, although some of its transport may have occurred as larvae in ballast water or in some cases as fouling on transported oyster shells.

  Why is it a problem?

  It invades and alters habitats, reduces water quality, depletes resources and causes biofouling. It has become a major nuisance in the lower Diep River Estuary in Cape Town, particularly in the area around the wooden bridge and the Woodbridge Island Road bridge.

  What does it look like?

  Description: The tubes are somewhat flared at their open ends and have conspicuous, collar-like rings or flanges spaced irregularly along their lengths. Older tubes are typically stained a gold-brown or dark brown along much of their length, with the areas around the flanges and the flared ends usually remaining white. Habitat: It grows in the low intertidal to shallow sub tidal range on rocks, concrete, wood, shells and other hard surfaces, including pilings and the sides of floating docks, buoys and boat hulls. Breeding: It can survive in ocean salinity, but grows and reproduces only in lower salinity at temperatures above 18°C. During spawning, eggs and sperm are released into the water where fertilisation occurs. The larvae develop in the plankton and after 20-25 days settle on and attach to an appropriate hard surface.