Japanese Seaweed or Wakeme

Japanese seaweed or Wakeme (Undaria pinnatifida) has been found in Tasmanian and Victorian waters. It has not yet been identified in South Australian waters but could have significant adverse affects on the marine environment if introduced.

Habitat

  • Temperate waters
  • Sheltered reef areas subject to oceanic influence
  • Intertidal to subtidal zone (to 15 metres)

Japanese Seaweed Wakeme

Description

  • Up to 3 metres high
  • Usually golden brown in colour
  • Distinctive sporophyll at the base of the plant
  • Strap-like midrib, full length of plant body, up to 3 cm wide
  • Leaf blade terminates well short of base of plant
  • Young fronds are simply a blade and have no distinct pinnae
  • Holdfast (roots) attaches plant to reef substrate
  • An annual species, difficult to detect in late summer and early autumn, can cover large areas of shallow reef in spring

You can help

Early detection and monitoring by the community are vital tools in controlling the spread and minimising the impact of marine pests.

If you know what species are normally present in all marine habitats you can learn to recognise any unusual species or species showing an abnormal change in abundance. 

You might not be able to identify a particular organism as a new invading species based on its shape or colour, but you might notice that this new organism has rapidly overgrown rocks and shoreline that historically had been a diverse community of other types of marine life.


What to do if you find an introduced species

  • Record the location accurately (use Global Positioning System (GPS) coordinates if possible)
  • Record the depth and type of bottom (eg sandy, rocky and so on)
  • Record how it was found, for example tangled in fishing tackle or anchor, drifting or sighted attached to a substrate
  • Collect a sample (except in an aquatic reserve) and store it in a plastic bag
  • Don’t throw any suspicious animal or weed back in the water
  • Report all sightings of suspected marine pests to the 24 hour FISHWATCH hotline on 1800 065 522