Introduced seaweed

Aquarium caulerpa (Caulerpa taxifolia) is an introduced aquatic pest in South Australia and listed as a noxious species.

It is bright green seaweed with stems that grow up to 200 fronds, as long as 3 metres, which look like feathers or ferns.

This seaweed is a serious threat to:

  • native sea-grass meadows
  • bottom-dwelling communities
  • fish breeding grounds.

Fish do not eat the weed because it contains a toxin.

How it spreads

The weed can start a new colony of only 1 square centimetre. Pieces of the weed can survive up to 2 weeks out of water.

This means the weed can easily spread between bays and waterways on boats, or fishing equipment.

Under the Fisheries Management Act 2007, penalties apply for people caught intentionally translocating or possessing the weed in any SA waters.

Port River and Barker Inlet infestations

The weed was found in West Lakes, and the Port River near the Jervois Bridge, in March 2002. It was eradicated from West Lakes.

The infestation continues in the Port River despite many attempts to eradicate it. More infestations were found in the Port River Estuary in 2004.

Containment area

In 2011, a containment area was enforced in the Port River Estuary.

See the map for exact description and coordinates for the Port River Estuary containment area.

Avoid spread

Take these steps to avoid spreading the weed:

  • Avoid boating nearby, or disturbing beds of the weed.
  • Inspect any equipment used in the Port River before using it in any other area.
  • Wash ropes and other equipment after use in plastic bins using freshwater and bleach.
  • Inspect diving and boating equipment for the weed before and after use.
  • Collect any fragments of the weed that may have accidentally attached to your equipment and place it in a biodegradable plastic bag. Place it in a garbage bin. Do not return any fragments to the sea.
  • Do not use the weed in an aquarium.
  • Do not release any water, plants, or animals from a saltwater aquarium into a drain, creek, or the sea.

How to report the weed

Take these steps to report the weed if you find any:

  1. Accurately record the location. Include Global Positioning System coordinates if possible.
  2. Record the depth.
  3. Record the type of bottom the weed was found in – this may be rocky, or sandy.
  4. Record how it was found.
  5. Collect sample and store it in a plastic bag. Do not throw any suspicious weeds back into the water.
  6. Report your sighting to the Fishwatch Hotline as below.
  7. Dispose of the weed in a biodegradable bag and place it in a garbage bin.

Report suspected exotic species and diseases

Early detection is important to stop the establishment and spread of aquatic pests and diseases – report unusual sightings immediately.

24 hours a day, 7 days a week

Fishwatch hotline: 1800 065 522 SA Fishing app
Page last reviewed: 24 Oct 2022

 


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